Abstract:
An animal feeder comprising a hopper for storing pieces of food is provided. The hopper includes an opening and a gate movable with respect to the hopper between an open position rendering the opening at least partially accessible to an animal and a closed position at least partially preventing access to the opening by an animal. A switch is coupled for activation by movement of the gate.

Description:
[0001]    This Application is a U.S. National Phase Application of PCT International Application PCT/US2006/007606 which claims priority based on U.S. Provisional Application 60/658,818, filed Mar. 4, 2005. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    Most biological values measured in laboratory animals respond to qualitative and quantitative variations in food intake. Therefore, methods to assess and vary food quality and quantity are important to all biological researchers, especially to nutrition biologists. For example, measuring and evaluating the ingestive behavior of laboratory animals is important in the study of animal behavior, metabolism, and perturbations thereof due to disease or therapeutic intervention. 
         [0003]    It has been recognized, however, that the presence of human interaction during the assessment of ingestive behavior may introduce error to the assessment through disturbance to the animal&#39;s native behavior. Accordingly, systems have been proposed for feeding and monitoring laboratory animals in such a way as to reduce the disturbance of the animal&#39;s native behavior. 
         [0004]    For example, U.S. Pat. No. 6,748,898 to Ulman et al., the disclosure of which is incorporated herein by reference in its entirety, discloses an animal feeder, a feeder mount, a feeder monitor, and a feeder monitoring network. Specifically, the system disclosed in U.S. Pat. No. 6,748,898 may include (1) a spill-proof food hopper, which does not limit or interfere with the natural food intake of ad libitum fed animals; (2) a hardware and software system to continuously monitor the weight of this hopper, detecting and recording the time, duration and amount of each meal; (3) a gate system to restrict food intake by time, amount, or both; and (4) a means to do this for one, tens or hundreds of animals coincidentally. 
         [0005]    Although the system disclosed in U.S. Pat. No. 6,748,898 represents a significant improvement over prior systems, there remains a need for improved systems for monitoring the intake of food by animals. 
       SUMMARY OF THE INVENTION 
       [0006]    According to one aspect of the invention, an animal feeder comprising a hopper for storing pieces of food is provided. The hopper includes an opening and a gate movable with respect to the hopper between an open position rendering the opening at least partially accessible to an animal and a closed position at least partially preventing access to the opening by an animal. A switch is coupled for activation such as by movement of the gate. The animal feeder optionally includes one or more of the following features: activation of the switch by an animal signals a motivation of the animal to eat food stored in the hopper; the switch is activated by pushing or pulling of the gate by the animal; the feeder is configured to open the gate after an animal activates the switch by contacting the gate; the feeder is configured to open the gate after an animal contacts the gate a pre-determined number of times; a cam is coupled to the gate and an arm is coupled to the switch, wherein the cam moves with respect to the arm; and/or the switch may be a vibration sensor, an accelerometer, a displacement switch, a light beam switch or other detector. 
         [0007]    According to another aspect of the invention, an animal feeder comprises a screen coupled to the hopper to retain food within the hopper and to provide access by an animal to the food. The animal feeder optionally includes one or more of the following features: the screen is positioned at least partially within the hopper in such a way as to contain food within the hopper while permitting access to the food by an animal; a mesh is engaged by a surface of the screen; the mesh is releasably engaged with respect to the screen so that it can be removed and replaced; the mesh is formed from at least one wire; elongated runs of the wire run in a substantially horizontal direction; elongated runs of the wire run in a substantially vertical direction; the wire is rounded or has a circular cross-sectional shape; the screen is metallic; the screen is a one-piece component; the screen includes at least one flange to facilitate interconnection of the screen and a surface of the hopper; the screen comprises a plurality of formed wires coupled to opposing headers; the opposing headers are configured to engage or snap onto the hopper; the screen is shaped to allow an animal access to contained food from at least one of the top, side or bottom of the hopper; and/or the screen defines openings that are larger than an animal muzzle but smaller than pellets of the food. 
         [0008]    According to yet another aspect of the invention, an animal feeder comprises a reservoir defined by the hopper for storing a liquid. A valve is configured to permit selective flow of liquid from the reservoir. The animal feeder optionally includes one or more of the following features: means are provided for transmitting the weight of liquid contained within the hopper; a top end of the reservoir is open to the atmosphere; the reservoir is defined by a body portion of the hopper; the valve is coupled to the body portion of the hopper; the valve comprises a valve housing and a nipple mounted for movement with respect to the valve housing to permit selective flow of liquid from the reservoir; the nipple is spring loaded; an seal is positioned to provide a selective seal between the nipple and the valve housing; the seal closes an interface between the nipple and the valve housing in a closed position of the valve; a recess is defined in the body portion of the hopper to provide at least partial clearance for the head of the laboratory animal; and/or the recess comprises a sloped wall disposed to capture unconsumed liquid released from the reservoir. 
         [0009]    According to still another aspect of the invention, an animal feeder comprises a gate movable with respect to the hopper between an open position rendering the opening at least partially accessible to an animal and a closed position at least partially preventing access to the opening by an animal, the gate being pivotable to rotate between the open and closed positions. The animal feeder optionally includes one or more of the following features: a cam is coupled to the gate; an arm is connected to a servo, wherein the cam moves with respect to the arm; the cam is mechanically grounded against the arm in the closed position of the gate; the servo is configured to be deactivated in one or more positions of the gate; the gate and servo are configured to maintain one or more positions when the servo is deactivated; the gate is configured to be captured in a pre-selected position; a surface is associated with the cam or the gate to capture the gate in a pre-selected position; the gate is biased toward a desired position under the force of gravity; and/or the gate is pivotable about a shaft to rotate between the open and closed positions. 
         [0010]    According to another aspect of the invention, a method of communicating feeding activity of an animal is provided. The method comprises the steps of storing data corresponding to individual feeding bouts and displaying the individual feeding bouts. The method optionally includes one or more of the following steps: a displaying step comprising displaying the individual feeding bouts in a graphical user interface (GUI); a step of storing data corresponding to a cumulative feeding bout; a step of storing cumulative feeding bout data of at least one group of animals, wherein at least one animal is a member of a group of animals; a step of calculating an average cumulative feeding bout of a group of animals; a step of displaying the average cumulative feeding bout of a group of animals; a step of resetting the cumulative feeding bout measurement to a pre-determined value in the event of a change in an environmental condition; a step of resetting the cumulative feeding bout measurement to a pre-determined value after a pre-determined time interval; a step of displaying the cumulative feeding bout; steps of displaying the individual feeding bouts and displaying an environmental condition with respect to time; a step of filtering individual feeding bout data in a specified data range; a step of displaying the individual feeding bout within the specified data range; and/or a step of displaying the individual feeding bout outside of the specified data range. 
         [0011]    According to still another aspect of the invention, a method of monitoring feeding activity of an animal is provided. The method comprises the steps of communicating data corresponding to individual feeding bouts to a remote location and displaying the individual feeding bouts at the remote location. The method optionally includes one or more of the following steps: a step of communicating data corresponding to individual feeding bouts of multiple animals to a remote location; and/or a step of communicating the data over a network. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]    The invention is best understood from the following detailed description when read in connection with the accompanying drawing. It is emphasized that, according to common practice, the various features of the drawing are not to scale. On the contrary, the dimensions of the various features are arbitrarily expanded or reduced for clarity. Included in the drawing are the following figures: 
           [0013]      FIG. 1A  is a partial end view of an exemplary embodiment of an animal cage according to an aspect of this invention. 
           [0014]      FIG. 1B  is a partial cross-sectional side view of the animal cage shown in  FIG. 1A . 
           [0015]      FIG. 2A  is a front view of an exemplary embodiment of a molding component configured for use in an animal cage according to an aspect of this invention. 
           [0016]      FIG. 2B  is a side view of the molding component shown in  FIG. 2A . 
           [0017]      FIG. 2C  is a top view of the molding component shown in  FIG. 2A . 
           [0018]      FIG. 3A  is a partial cross-sectional side view of an embodiment of an adapter assembly according to an aspect of this invention. 
           [0019]      FIG. 3B  is a cross-sectional opposite side view of the adapter assembly shown in  FIG. 3A . 
           [0020]      FIG. 3C  is a partial cross-sectional rear view of the adapter assembly shown in  FIG. 3A , with a hopper assembly of the adapter assembly removed to reveal additional features. 
           [0021]      FIG. 3D  is a partial cross-sectional top view of the adapter assembly shown in  FIG. 3A , with the hopper assembly and other components of the adapter assembly removed to reveal additional features. 
           [0022]      FIG. 3E  is a partial cross-sectional bottom view of the adapter assembly shown in  FIG. 3A , with a plate component of the adapter assembly removed to reveal additional features. 
           [0023]      FIG. 3F  is an enlarged bottom view of a portion of the adapter assembly shown in  FIG. 3E . 
           [0024]      FIG. 3G  provides cross-sectional side and front views of an embodiment of a hopper component configured for use in the adapter assembly shown in  FIG. 3A . 
           [0025]      FIG. 3H  provides cross-sectional side and front views of another embodiment of a hopper component configured for use in the adapter assembly shown in  FIG. 3A . 
           [0026]      FIG. 3I  is a partial end view of an exemplary embodiment of an animal cage and an adapter assembly according to an aspect of this invention. 
           [0027]      FIG. 3J  is a partial cross-sectional side view of the animal cage and the adapter assembly shown in  FIG. 3I . 
           [0028]      FIG. 3K  is a partial cross-sectional side view of an embodiment of an adapter assembly according to another aspect of this invention. 
           [0029]      FIG. 4A  is a cross-sectional side view of an embodiment of a hopper assembly configured for use in the adapter assembly shown in  FIG. 3A . 
           [0030]      FIG. 4B  is a front view of the hopper assembly shown in  FIG. 4A . 
           [0031]      FIG. 4C  is a bottom view of the hopper assembly shown in  FIG. 4A . 
           [0032]      FIG. 5A  is a cross-sectional side view of an embodiment of a screen component configured for use in the hopper assembly shown in  FIG. 4A . 
           [0033]      FIG. 5B  is a front view of the screen component shown in  FIG. 5A . 
           [0034]      FIG. 5C  is a top view of the screen component shown in  FIG. 5A . 
           [0035]      FIG. 5D  is an enlarged cross-sectional side view of the screen component shown in  FIG. 5A . 
           [0036]      FIG. 6  is a front view of an embodiment of a mesh component configured for use with the screen component shown in  FIG. 5A . 
           [0037]      FIG. 7  is a front view of another embodiment of a mesh component configured for use with the screen component shown in  FIG. 5A . 
           [0038]      FIG. 8A  is a side view of a support component configured for use in the hopper assembly shown in  FIG. 4A . 
           [0039]      FIG. 8B  is a bottom view of the support component shown in  FIG. 8A . 
           [0040]      FIG. 9A  is a cross-sectional side view of another embodiment of a screen component configured for use in the hopper assembly shown in  FIG. 4A . 
           [0041]      FIG. 9B  is a front view of the screen component shown in  FIG. 9A . 
           [0042]      FIG. 9C  is a top view of the screen component shown in  FIG. 9A . 
           [0043]      FIG. 10A  is a partial cross-sectional front view of an adapter component configured for use in the adapter assembly shown in  FIG. 3A . 
           [0044]      FIG. 10B  is a side view of the adapter component shown in  FIG. 10A . 
           [0045]      FIG. 10C  is a cross-sectional opposite side view of the adapter component shown in  FIG. 10A . 
           [0046]      FIG. 10D  is a partial cross-sectional top view of the adapter component shown in  FIG. 10A . 
           [0047]      FIG. 10E  is a bottom view of the adapter component shown in  FIG. 10A . 
           [0048]      FIG. 11A  is a side view of an embodiment of a hook component configured for use in the adapter assembly shown in  FIG. 3A . 
           [0049]      FIG. 11B  is a top view of the hook component shown in  FIG. 11A . 
           [0050]      FIG. 11C  is a front view of the hook component shown in  FIG. 11A . 
           [0051]      FIG. 12  is a side view of an embodiment of a clip component configured for use in the adapter assembly shown in  FIG. 3A . 
           [0052]      FIG. 13A  is a front view of an embodiment of a gate component configured for use in the adapter assembly shown in  FIG. 3A . 
           [0053]      FIG. 13B  is a side view of the gate component shown in  FIG. 13A . 
           [0054]      FIG. 13C  is an end view of the gate component shown in  FIG. 13A . 
           [0055]      FIG. 14A  is a front view of an embodiment of a bracket component configured for use in the adapter assembly shown in  FIG. 3A . 
           [0056]      FIG. 14B  is a cross-sectional side view of the bracket component shown in  FIG. 14A . 
           [0057]      FIG. 14C  is a top view of the bracket component shown in  FIG. 14A . 
           [0058]      FIG. 15A  is a partial cross-sectional side view of an embodiment of a coupling component configured for use in the adapter assembly shown in  FIG. 3A . 
           [0059]      FIG. 15B  is an end view of another embodiment of a coupling component configured for use in the adapter assembly shown in  FIG. 3A . 
           [0060]      FIG. 15C  is a cross-sectional side view of the coupling component shown in  FIG. 15B . 
           [0061]      FIG. 16  is a cross-sectional side view of an embodiment of a cam component configured for use in the adapter assembly shown in  FIG. 3A . 
           [0062]      FIG. 17A  is a front view of an embodiment of a blocker assembly configured for use with the animal cage shown in  FIG. 19A . 
           [0063]      FIG. 17B  is a cross-sectional side view of the blocker assembly shown in  FIG. 17A . 
           [0064]      FIG. 18  is a cross-sectional opposite side view of another embodiment of an adapter assembly. 
           [0065]      FIG. 19A  is a side view of the bracket configured for use in the hopper assembly shown in  FIG. 18 . 
           [0066]      FIG. 19B  is a top view of the bracket shown in  FIG. 19A . 
           [0067]      FIG. 20A  is a side view of the screen component configured for use in the hopper assembly shown in  FIG. 18 . 
           [0068]      FIG. 20B  is a front view of the screen component shown in  FIG. 20A . 
           [0069]      FIG. 21  is a cross-sectional opposite side view of another embodiment of an adapter assembly including a water hopper assembly. 
           [0070]      FIG. 22A  is a cross-sectional side view of the water hopper configured for use in the adapter assembly shown in  FIG. 21 . 
           [0071]      FIG. 22B  is a top view of the water hopper shown in  FIG. 22A . 
           [0072]      FIG. 22C  is a perspective view of the water hopper shown in  FIG. 22A . 
           [0073]      FIG. 23  is a single screen view of an exemplary ‘Startup’ graphical user interface (GUI) of the BioDAQ software tool. 
           [0074]      FIG. 24  is a single screen view of an exemplary Network Population GUI of the BioDAQ software tool. 
           [0075]      FIG. 25  is a single screen view of an exemplary Measurement Parameter Setting GUI of the BioDAQ software tool. 
           [0076]      FIG. 26  is a single screen view of an exemplary Food Intake Recordation GUI of the BioDAQ software tool. 
           [0077]      FIG. 27  is a single screen view of an exemplary Cell Calibration GUI of the BioDAQ software tool. 
           [0078]      FIG. 28  is a single screen view of an exemplary Measurement Assessment GUI of the BioDAQ software tool. 
           [0079]      FIG. 29  is a single screen view of an exemplary Data Viewer GUI of the BioDAQ software tool, illustrating the average cumulative food consumption of two groups of laboratory animals with respect to room lighting and time. 
           [0080]      FIG. 30  is another single screen view of the exemplary Data Viewer GUI shown in  FIG. 29 , illustrating the cumulative food consumption of each laboratory animal included in the experiment with respect to room lighting and time. 
           [0081]      FIG. 31  is another single screen view of the exemplary Data Viewer GUI shown in  FIG. 29 , illustrating the cumulative food consumption and individual feeding bouts of one laboratory animal with respect to room lighting and time. 
           [0082]      FIG. 32  is another single screen view of the exemplary Data Viewer GUI shown in  FIG. 29 , illustrating the cumulative food consumption of one laboratory animal with respect to room lighting and time, whereby the cumulative food consumption measurement is reset after each room lighting change. 
           [0083]      FIG. 33  is another single screen view of the exemplary Data Viewer GUI shown in  FIG. 29 , illustrating the cumulative food consumption of one laboratory animal with respect to room temperature and time. 
           [0084]      FIG. 34  is a schematic diagram of an exemplary system for monitoring the feeding habits of animals. 
           [0085]      FIG. 35  is a schematic diagram of another exemplary system for monitoring the feeding habits of animals. 
           [0086]      FIG. 36  is a schematic diagram of yet another exemplary system for monitoring the feeding habits of animals. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0087]    The invention is best understood from the following detailed description when read in connection with the accompanying drawing, which shows exemplary embodiments of the invention selected for illustrative purposes. The invention will be illustrated with reference to the Figures. Such Figures are intended to be illustrative rather than limiting and are included herewith to facilitate the explanation of the present invention. 
         [0088]    Generally, an ingestive behavior monitor according to exemplary aspects of this invention is comprised of a series of integrated physical and electrical components which quantitatively record ingestive behavior in the substantial absence of human interaction. The system monitors the mass of food sources presented to the animal in its home cage. The system detects interaction between the animal and the food by measuring the stability of the mass measurement. As the animal interacts with the device to obtain food, the act of ingestion is detected. 
         [0089]    A precision strain gauge is contiguously interfaced mechanically with the food device. The mass is sampled periodically, approximately once per second, to derive a history of the mass. By evaluating this history mathematically, the monitor is able to record the animals&#39; ingestive behavior in a date/time/mass/duration data stream with a resolution of 1 second, for example, through time. The monitor may be installed in an accredited animal room or laboratory used to house research animals for acute or chronic studies. The instrument is designed to impart low impact to the general facility environment. The instrument can withstand the normal procedures used in general day to day maintenance of the colonies housed in the room. Though other materials are contemplated, many components of the food intake monitor device are composed of stainless steel and polycarbonate and can be cleaned using the same procedure used for washing typical animal husbandry equipment. 
         [0090]    When used herein, the term “feeding bout” refers to the period when the animal is actually removing food from the hopper; the term “feeding event or meal” refers to the period when the animal is actively eating, generally composed of one or more feeding bouts interspersed with brief periods of rest, chewing, etc.; the term “inter-bout interval” (IBI) refers to the time period that defines the end of a feeding event; the term “trip” refers to the level of activity which indicates that the animal is feeding; and the term “noise” refers to the level of activity which indicates that the hopper mass measurement is unstable and is used to qualify a meal starting or ending mass measurement. 
         [0091]    Referring generally to the Figures, one aspect of this invention provides a system for monitoring the intake of food by animals.  FIG. 1A  provides a partial end view of an exemplary embodiment of an animal cage according to an aspect of this invention, and  FIG. 1B  is a partial cross-sectional side view of the animal cage shown in  FIG. 1A . 
         [0092]    According to one embodiment, a molding such as a stainless steel channel is wrapped around an opening in a cage to prevent an animal from chewing the cage material (optionally plastic) and acts as a mounting surface for an adapter assembly. The molding does not significantly alter the dimensions or integrity of the cage and does not prevent a clear view of the animal. Accordingly, the molding provides a secure mounting surface for mechanism connection and covers cage edges to prevent gnawing. Also, multiple mechanisms are easily swapped using the molding (e.g., food monitoring, blank, manual recording, and other mechanisms). Also, the molding facilitates quick exchange of mechanisms. 
         [0093]    Referring specifically to the embodiment illustrated in  FIGS. 1A and 1B , an animal cage assembly according to one aspect of this invention is generally designated by the numeral  10 . Animal cage assembly  10  includes an animal cage  12  and a molding  14 . Generally, the animal cage  12  provides an enclosure for an animal such as a laboratory mouse or rat. Animal cage  12  is optionally formed from a plastic material, preferably transparent or translucent, but may be alternatively formed from any of a variety of plastic and non-plastic materials. Exemplary animal cages are currently available from Allentown Caging Equipment Company, Route 526, P.O. Box 698, Allentown, N.J. 08501-0698, and such cages are disclosed in U.S. Pat. No. 5,894,816 to Coiro et al., the disclosure of which is incorporated by reference herein in its entirety. 
         [0094]    Animal cage  12  has a side wall  16  and a base  18  that together define an interior  20 . Defined in at least one side wall  16  of the animal cage  12  is an aperture  22 . The purpose of aperture  22  will be described later in greater detail. 
         [0095]    As mentioned previously, the molding  14  is provided to protect the edge surfaces of the side wall  16  of the animal cage  12  that are defined by the aperture  22 . Molding  14  also serves to support the side wall  16  of the animal cage  12  in the area of the aperture  22 . And as will be described later in greater detail, molding  14  provides a mounting surface by which components or assemblies or mechanisms can be mounted to the animal cage assembly  10 . 
         [0096]    Molding  14  has a plurality of flanges  24 A,  24 B,  24 C, and  24 D. Also, molding  14  has a perimeter  26 . As is best illustrated in  FIG. 1B , the perimeter  26  of the molding  14  is positioned against an interior surface of the side wall  16  of the animal cage  12  in the area of the aperture  22 , with the flanges  24 A through  24 D extending through the aperture  22  from the interior surface of side wall  16  outwardly beyond an exterior surface of the side wall  16 . The flanges  24 A through  24 D are then bent or otherwise deformed in a direction away from the center of the aperture  22  so that they are positioned against an exterior surface of the side wall  16  of the animal cage  12 . The molding  14 , so positioned with respect to the aperture  22 , thereby forms a frame or edge molding in which the exposed surfaces of the flanges  24 A through  24 D are exposed yet protect the edges in the side wall  16  of the animal cage  12  defined by the aperture  22 . In other words, the flanges  24 A through  24 D and the perimeter  26  of the molding  14  substantially cover the edge surfaces of the side wall  16  defined by the aperture  22 . 
         [0097]    The molding  14 , as assembled with the animal cage  12  to form the animal cage assembly  10 , performs at least three (3) functions. First, molding  14  (by virtue of perimeter  26  and flanges  24 A through  24 D) substantially prevents an animal within the animal cage assembly  10  from chewing, gnawing, scratching, or otherwise damaging the animal cage  12  in the area of the aperture  22 . Second, molding  14  provides a structural support or reinforcement to the side wall  16  of the animal cage  12  in the area of the aperture  22 . Third, molding  14  (again by virtue of perimeter  26  and flanges  24 A through  24 D) provides one or more mounting surfaces by which a component or assembly or mechanism can be mounted to the animal cage  12  in the area of the aperture  22 . Other functions of the molding  14  will become evident in view of the following description. 
         [0098]      FIGS. 2A ,  2 B, and  2 C are front, side and top views, respectively, of an exemplary embodiment of a frame component configured for use in an animal cage according to an aspect of this invention. The frame or molding component serves as a grommet that is fitted around the aperture in a cage. In addition to the functions recited previously (e.g., providing a secure mounting surface to accept various pieces to be mounted to the cage and covering plastic edges so that plastic can not be gnawed by an animal), the molding component is substantially flat to the cage to allow normal stacking of cages for storage and cleaning. Also, more than one molding component can be added to a cage. 
         [0099]    Referring specifically to the embodiment illustrated in  FIGS. 2A ,  2 B, and  2 C, the molding  14  is shown before its assembly with the animal cage  12  to form the animal cage assembly  10 . Though molding  14  illustrated in  FIGS. 2A through 2C  differs from that shown in  FIGS. 1A and 1B , like numbers have been used to indicate the features of the molding  14  in  FIGS. 1A ,  1 B,  2 A,  2 B, and  2 C. 
         [0100]    As illustrated in  FIG. 2A , the perimeter  26  of molding  14  defines an interior aperture  28  flanked by flanges  24 A through  24 D. As shown in  FIGS. 2B and 2C , flanges  24 A through  24 D extend in a direction that is substantially perpendicular to the plane in which the perimeter  26  of the molding  14  resides. This orientation of flanges  24 A through  24 D is a pre-mounted orientation (i.e., before the flanges  24 A through  24 D are bent or folded in a radially outward direction in order to engage the molding  14  to the animal cage  12  to form the animal cage assembly  10 ). 
         [0101]    As is exemplified by comparing  FIGS. 1A and 1B  to  FIGS. 2A through 2C , a shape of the molding  14  (as defined by the perimeter  26  and the flanges  24 A through  24 D) can be selected to match virtually any shape of an aperture formed in the side wall (or any other wall) of an animals cage. In other words, a molding can be configured to conform to an aperture of any shape. Although a four-sided molding  14  is illustrated in  FIGS. 1A through 2C , molding  14  can be provided with fewer or a greater number of sides with fewer or a greater number of flanges. Additionally, the shape of the molding can be defined by arcuate geometries such as those of a circle, an oval, an ellipse, or any other configuration. 
         [0102]    No matter what shape is selected for the perimeter  26  of the molding  14 , one or more flanges can be positioned at various positions along that perimeter in order to engage the molding to an animal cage  12  at the location of an aperture  22 . Also, the molding&#39;s perimeter need not define an enclosed aperture such as aperture  28  and may instead be open at one end or elsewhere depending on the intended use of the molding and the positioning of an aperture such as aperture  22  in the animal cage  12 . 
         [0103]    While a wide variety of materials can be selected for the molding  14 , a malleable metallic material is preferred. According to one exemplary embodiment, the molding  14  can be formed from a stainless steel material such as 304 stainless steel. Alternatively, other metallic or non-metallic materials can be selected for the molding  14 , depending upon the use of the molding and other criteria. Also, the thickness of the material from which the molding  14  is formed is optionally about 0.028 inch, though a wide variety of dimensions can be selected based on the material chosen to form the molding and other criteria. In another embodiment, the flanges of the molding  14  are configured to snap or clip onto the side wall in the area of the aperture  22 . It is also anticipated that the molding might be constructed of several pieces and assembled into place, for example with a perimeter piece and one or more flanges that are fastened to the perimeter piece or cage rather than as a single piece that is formed into place. 
         [0104]      FIGS. 3A through 3K  illustrate an embodiment of an adapter assembly that can be releasably engaged to an animal cage assembly according to an aspect of this invention. Generally, the adapter assembly is one example of a mechanism that can be connected to and disconnected from a cage. Preferably, the adapter assembly can be coupled to the cage while it sits on a flat surface without tilting or lifting the cage. One or more adapter assemblies may be releasably engaged to a single animal cage, as desired by the user. The adapter assembly is also referred to below as a Peripheral Control Unit (PSC). 
         [0105]    As will be described in greater detail with specific reference to  FIGS. 3A through 3K , the adapter assembly includes a load cell enclosure that can take the form of a metal box that mounts on the cage and holds a food hopper. The enclosure houses a load cell, a servo and other devices and is universally fitted to an L-bracket component of the adapter assembly for both rat and mouse hoppers, for example. The load cell enclosure contains a strain gauge and a receptacle such as a sensor cable receptacle. The enclosure has a centrally located hole which allows a post to connect to the food hopper. Fasteners located on the enclosure are used to secure the device to the feeding device. 
         [0106]    The adapter assembly (or other part to be mounted) is fitted with several parts, including a clip at the top and a hook near the bottom. The adapter assembly is mounted first by the hook and then engaged in place by the clip. The hook can be adjusted forward and backward to account for the different draft angles possible in different cages that may be offered by different manufacturers. Although not shown, alternate embodiments would allow the clip to be adjusted forward and backward, instead of the hook, to account for different draft angles or have the clip and hook displaced horizontally from the center of the aperture instead of vertically or have the hook at the top and the clip at the bottom. Additionally, although the illustrated embodiment shows a single hook and clip, it is anticipated that some embodiments may use multiple hooks or clips similarly arranged. This mounting mechanism can be used to mount food delivery devices, water delivery devices, exercise equipment or any other device that may be used in connection with laboratory animals. 
         [0107]    A coupling allows rapid mounting of a hopper onto the load cell. The coupling optionally has ‘spurs’ or other features configured to substantially resist rotation or torque of the hopper. A cage mount module of the adapter assembly optionally includes a stainless steel L-bracket mounted to a support, such as a polycarbonate block, with an integrated cage mounting clip and a manual gate. 
         [0108]    A gate that can be automatically controlled by the system is preferably provided with a pivoting action that pushes the animal away from the opening of the hopper containing food. When the gate is open (e.g., down) the gate can be positioned to lock the hopper in place, thereby capturing the hopper without bolting it. The gate of the adapter assembly is controlled by a cam and an arm attached to a servo. The gate can be configured to fall open naturally. The gate is optionally locked in place so that the servo can be turned off with the gate opened or closed, as desired. 
         [0109]    The hopper is optionally fitted with various meshes. For example, wire-based parts can be fabricated to increase or decrease the ‘ease’ of feeding. The ease of feeding can therefore be adjusted to correspond with an animal&#39;s inclination to eat and the ease or difficulty of the feed offered. The ease or difficulty of the feed offered is dependent upon the size of the food relative to the size of the openings in the mesh and the orientation of the mesh. The same hopper can be fitted with an inter-changeable mesh. A wire format is optionally used to be ‘gentler’ on the animal. 
         [0110]    Accordingly, the adapter assembly optionally has one or more of the following features: a) the gate is opened by gravity; b) the gate can be locked closed independent of the actuator mechanism (e.g., manual override); c) an animal&#39;s weight will act to open the gate, not close it; d) the gate&#39;s closing action pushes an animal away safely, reducing any possibility of injury (e.g., not a guillotine); e) passive locking (e.g., lowering the gate keeps the hopper from being removed); f) the gate&#39;s axle provides a hand-hold for the animal; g) the gate/vestibule is too small for the animal to sleep or nest on; h) an adapter component can be formed from translucent material, thereby minimizing environmental impact and allowing observation; i) the coupling prevents the hopper from turning or limits such turning; j) the mounting mechanism is universal for mice and rats (and other laboratory animals); k) a dummy mechanism (e.g., a mechanism without a strain gauge) can be used for manual studies or acclimation; l) the assembly optionally has inter-changeable hopper faces; m) the gate position is optionally locked when closed, allowing the servo motor to be turned off while the gate remains in either position; n) a switch can be used to provide an assessment of the animals motivation for food; o) signaling means, such as visible or audible stimuli, to facilitate training the animals; p) signaling means, such as visible or audible stimuli, to indicate to humans; r) a switch mechanism that a human may use to send a signal to the system; and s) a mechanism to uniquely identify a specific animal or hopper, such as an implanted RFID tag. 
         [0111]    Referring specifically to the embodiment illustrated in  FIGS. 3A through 3K , an adapter assembly according to one aspect of this invention and according to one embodiment of this invention is generally designated by the numeral  30 . Generally, the adapter assembly  30  includes a mounting assembly  32  configured for mounting the adapter assembly  30  to an animal cage assembly such as animal cage assembly  10  shown in  FIGS. 1A and 1B , a base assembly  34  configured to house a strain gage (as will be described later), and a hopper assembly  36  configured to contain food (not shown) for feeding an animal contained within an animal cage assembly  10 . Though adapter assembly  30  is specifically configured to contain food and facilitate and control the feeding of laboratory animals, a wide variety of alternative assemblies can be mounted to the animal cage assembly  10 . 
         [0112]    Adapter assembly  30  includes, among other components, an arm  38  connected to a servo (not shown in  FIG. 3A ), which arm  38  is positioned for moveable contact with a cam  40  that is coupled for rotation of a shaft  42 , as will be described later in greater detail. The rotation of the shaft  42  causes pivotal movement of a gate (not shown in  FIG. 3A ) between an opened position for allowing an animal within the animal cage assembly  10  to have access to food within the hopper assembly  36  and a closed position preventing such access. 
         [0113]    The animal is prohibited from opening the gate when the gate is in the closed position. In the closed position, the cam  40  is mechanically grounded against the arm  38 , thereby preventing the animal from rotating the gate to an opened position. In this configuration, the servo motor may be turned off, as the relative positions of the arm  38  and cam  40  prevent the gate from moving, irrespective of the servo-motor status. 
         [0114]    Referring to  FIG. 3B , the mounting assembly  32  of the adapter assembly  30  includes structures by which the adapter assembly  30  can be releasably connected to the animal cage assembly  10 . More specifically, the mounting assembly  32  of the adapter assembly  30  is releaseably engageable to the molding  14  of the animal cage assembly  10 , thereby releaseably mounting the adapter assembly  30  at a position corresponding to the aperture  22  formed in the side wall  16  of the animal cage  12  of the animal cage assembly  10 . 
         [0115]    In the embodiment illustrated in  FIG. 3B , the mounting components include a clip  44  and a hook  46 . The clip  44  is mounted to an adapter component (to be described later in connection with  FIGS. 10A through 10E ) by means of a plate  48  and fasteners  50  (one shown). The upper portion of the clip  44  is therefore moveable with respect to the adapter component of the adapter assembly  30 . 
         [0116]    The hook  46  of the mounting assembly  42  is mounted to the adapter component by means of fasteners  52  (one shown). As is indicated by the slots formed in the hook  46  and positioned just to the right of the fasteners  52 , the position of the hook  46  with respect to the adapter component is adjustable. Such adjustability of the position of the hook  46 , which changes the lateral positioning of the hook  46  with respect to the stationary clip  44 , facilitates adjustment of the adapter assembly  30  for mounting to a variety of animal cage assemblies. More specifically, and as is illustrated in  FIG. 1B , the side wall  16  of the animal cage  12  is provided with a draft and is therefore positioned in a plane that is not perpendicular to the base  18  of the animal cage  12 . In view of the different draft angles that may be provided on the side wall  16  of the animal cage  12 , the adjustability of the hook  46  with respect to the clip  44  facilitates the attachment of the adapter assembly  30  to an animal cage assembly  10  independent of the specific draft of the sidewall  16  of the animal cage  12 . In other words, whether the sidewall  16  of the animal cage  12  is perpendicular to the base  18  or at some angle with respect to a plane perpendicular to the base  18 , the adapter assembly  30  can be adjusted for suitable attachment to that animal cage  12 . 
         [0117]    The mounting assembly  32  of the adapter assembly also includes a gate  54  coupled to the shaft  42  by means of fasteners  56  (one shown). Though the operation of the gate  54  will be described later in greater detail,  FIG. 3B  illustrates that the gate  54  will pivot with respect to the remainder of the mounting assembly  32  upon rotation of the shaft  42  about its axis. Accordingly, the gate  54  can be moved from the open position (shown in  FIG. 3B , providing a laboratory animal with access to food within a hopper) and a closed position (not shown) in which such access is denied. Mounting assembly  32  of adapter assembly  30  is also provided with a front plate  58  with an aperture corresponding to the aperture formed in the adapter component. 
         [0118]    The base assembly  34  of the adapter assembly  30  includes a housing for a strain gage that is used to measure the weight of food contained within the hopper assembly  36 . More specifically, the housing of the base assembly  34  includes an enclosure  60  and a cover  62  defining an interior. The enclosure  60  is mounted to an L-bracket  64 , which provides interconnection between the base assembly  34  of the adapter assembly  30  and the mounting assembly  32  of the adapter assembly  30 . Mounted within the enclosure  60  is a load cell  66  and a bracket  68  (details of which will be described in connection with  FIGS. 14A through 14C ). A ball nose spring plunger  70  extends within the bracket  68  in order to provide a frictional and releasable engagement of a coupling to be described later. Also, a series of fasteners, including set screws  72 , fasteners  74  and spring washers  76 , are engaged within or to the bracket  68 . 
         [0119]    Providing a releasable connection between the hopper assembly  36  and the base assembly  34  of the adapter assembly  30  is a coupling  78  having two (2) dowel pins  80  to prevent rotation of the coupling  78  with respect to the housing assembly  36  and with respect to the base assembly  34 . The coupling  78  releasably mounts the hopper assembly  36  over the base assembly  34  in such a way as to transmit the weight of food contained within the hopper assembly  36  to the strain gauge or load cell  66  mounted within the enclosure  60  of the base assembly  34 . It is in this manner that the weight of the food within the hopper assembly  36  can be monitored. 
         [0120]    Referring specifically to the hopper assembly  36  of the adapter assembly  30 , the hopper assembly  36  includes a puck or support  82  mounted by means of fasteners  84  to a bottom surface of a hopper  86 . A screen (details of which will be described in connection with  FIGS. 5A to 5D ) is mounted within the hopper  86 . A stop  90  is provided within the base of the screen  88  in order to capture a mesh (to be described later) within the screen  88 , which mesh holds food within the hopper assembly  36  yet provides a laboratory animal with access to the food when the gate is open. Further details of the hopper assembly  36  are described later in connection with  FIGS. 4A through 4C . 
         [0121]    Referring now to  FIG. 3C , the base assembly  34  of the adapter assembly  30  is connected to the L-bracket  64  by means of fasteners  92 , and fasteners  94  connect the cover  62  to the enclosure  60 . Also, the enclosure  60  includes a connector or receptacle  96  to which a cable can be connected to transmit signals from the load cell  66  within the enclosure  60  to a receiver. 
         [0122]    A spring plunger  91  is coupled to the cam  40  of the mounting assembly  32  in order to capture the cam in a selected position to hold the gate  54  of the mounting assembly  32  in a pre-selected position. More specifically, the spring plunger  91  permits retention of the cam  40  in a position selected to hold the gate  54  in the closed position so that the animal is prevented from escaping when the hopper is removed for replacement or cleaning. In addition to the spring plunger  91 , the cam may be captured in a selected position using a screw, pin, magnet or any other article or surface capable of capturing the cam. Additionally, with the gate  54  held in the closed position, the servo motor can be turned off. Also, the mounting assembly  32  includes a dowel pin  93  positioned to limit the rotational movement of the cam  40  with respect to the adapter of the mounting assembly  32 . 
         [0123]    Referring to  FIG. 3D , the adapter (designated by the numeral  95 ) is retained between the L-bracket  64  and the front plate  58  by means of fasteners  97 . Also illustrated in  FIG. 3D  is a central aperture  99  through which the coupling  78  (not shown) is configured to extend. The apertures formed in the L-bracket  64  adjacent the fasteners  92  are provided to facilitate the rapid assembly and disassembly of the L-bracket  64  with the enclosure  60 . In particular, the slotted apertures adjacent the fasteners  92  permit the rapid removal of the enclosure  60  from the L-bracket  64  to facilitate the cleaning of the enclosure  60 , as the user may clean the sensitive enclosure  60  separate from the other components of the system. 
         [0124]    Referring now to  FIG. 3E , a servo  100  extends from within the enclosure  60  to transmit movement to the arm  38 , which in turn transmits movement to the cam  40  for rotation of the shaft  42  and ultimate pivotal motion of the gate  54 . Also illustrated in  FIG. 3E  is the orientation of the hook  46  with respect to the clip  44 . More specifically, the clip  44  extends outwardly from the mounting assembly  32  of the adapter assembly  30  farther as compared to the hook  46 . The slots formed in the hook  46  permit linear adjustment of the hook  46  with respect to the adapter  95  by loosening and then re-tightening the fasteners  52 . 
         [0125]    The enlarged view into the enclosure  60  shown in  FIG. 3F  reveals additional details of the structure and orientation of the bracket  68 , connector  96 , and other components housed within the enclosure  60 . 
         [0126]    To assemble the base assembly  34  to the remainder of the adapter assembly  30 , the fasteners  92  coupled to the enclosure  60  are loosened and the enclosure is positioned with the sensor cable receptacle  96  facing the user. The base of the L-bracket  64  is held closest to the user. The base is then lowered so the fasteners  92  pass through the circular portion of the keyholes on the L-bracket  64 . The L-bracket  64  is then slid forward so that the aperture  99  is centered on the opening in the enclosure  60  and the fasteners  92  are in the slots of the keyholes. The fasteners  92  are tightened to secure the L-bracket  64  to the enclosure  60 . To remove the enclosure  60  for maintenance or cage washing, the foregoing steps are reversed. The coupling  78  is first removed prior to removal of the enclosure  60 . 
         [0127]    Referring now to  FIGS. 3G and 3H , the relationship between the screen component of the hopper assembly  36  and the hopper component of the hopper assembly  36  is illustrated. Specifically, the screen  88  is positioned within the hopper  86  in such a way as to contain food within the hopper assembly  36  while permitting access to that food by an animal within an animal cage such as animal cage assembly  10 . Also, a mesh component  102  is captured by surfaces of the screen  88  and a stop component  104 . The mesh  102  is therefore releasably engaged with respect to the screen  88  so that it can be removed and replaced, as needed. Also, the releasable engagement between the mesh  102  and the screen  88  facilitates the use of various mesh configurations that can be selected based on the animals being fed, the nature of the food being provided to the animals, and other considerations. Further details of the mesh  102  will be provided with reference to  FIG. 6 , and further details of the screen  88  will be described with reference to  FIGS. 5A through 5D . The manner in which the mesh  102  is captured with respect to the screen  88  will be described with specific reference to  FIG. 5D . 
         [0128]    Referring to  FIG. 3H , a different embodiment of a mesh component, designated as mesh  106 , is utilized. Though mesh  106  is similar to mesh  102  in that it is optionally formed from a bent wire material, mesh  106  differs from mesh  102  in that the elongated runs of the wire run in a substantially horizontal direction as opposed to the vertical direction of the runs of the mesh  102 . In either embodiment, meshes  102  and  106  are captured by surfaces of the screen  88  for releasable engagement. 
         [0129]    As is illustrated in  FIGS. 3G and 3H , the screen  88  is optionally spot welded to the hopper  86 . This attachment forms a substantially permanent or long-lasting connection between the screen  88  and the hopper  86 . Other means of connection between the screen  88  and the hopper  86  are contemplated as well, whether they are substantially permanent or temporary for interchangeability. 
         [0130]      FIGS. 3I and 3J  are end and side views, respectively, of an embodiment of the adapter assembly coupled to an animal cage assembly. The relationship between the adapter assembly  30  and the animal cage assembly  10  is illustrated in  FIGS. 3I and 3J . As shown in  FIG. 3I , the boundaries of the adapter assembly  30  do not extend past the height and the width of the animal cage  12 . Accordingly, the animal cage assemblies may be stacked side by side, stacked on top of each other, or placed on a level table. For example, if the base of the adapter assembly  30  extended past the base of the animal cage  12 , and both were placed on a level table, the adapter assembly would prop up a single side of the animal cage  12 , perhaps disturbing the animal. 
         [0131]    As illustrated in  FIG. 3J , the clip  44  is configured to engage against the flange  24 A and perimeter  26  of the molding  14  of the animal cage assembly  10 . In such an arrangement, the hook portion of the hook  46  engages the flange  24 C and perimeter  26  of the molding  14 . Such engagement by the clip  44  and hook  46  releasably engages the adapter assembly  30  to the animal cage assembly  10 . The adjustability of the hook  46  with respect to the clip  44  facilitates the attachment of the adapter assembly  30  to an animal cage assembly  10  independent of the draft of the sidewall  16  of the animal cage  12 . Accordingly, despite the fact that the side wall of the animal cage  12  shown in  FIG. 3J  maintains a draft angle, the adapter assembly  30  is positioned substantially parallel to the base of the animal cage. The hook portion  46  also substantially prevents the adapter assembly  30  from shifting. 
         [0132]    As illustrated in  FIG. 3K , a switch mechanism  193  is attached to the arm  38  of the adapter assembly  30 . The switch mechanism  193  is activated by any slight movement of the gate  54 . The switch  193  is in mechanical contact with a dowel  191  on the cam  40 , via hook portion  192 , and in electrical connection with the computer module which monitors the activity of the switch. The switch provides an evaluation of the animal&#39;s motivation to eat the food contained in the hopper. In use, the animal pushes or pulls the gate thereby activating the switch. The user may configure the system to open the gate  54  after the animal activates the switch mechanism  193  by contacting the gate a pre-determined number of times. 
         [0133]    Furthermore, the switch enables the user to create a hurdle for the animal to obtain the food by requiring that the switch be activated a pre-determined number of times before the gate will open. For example, the user may require that the switch be activated five times for the gate to open to allow the animal to eat a first time. Moreover, if the animal wants to eat a second time in a single day the user may require that the switch be activated ten times for the gate to open to allow the animal to eat. 
         [0134]    In use, when the animal contacts the gate  54 , the cam  40  slightly rotates towards the arm  38 . By virtue of the frictional contact between the dowel  191  of the cam  40  and the hook  192  of the switch mechanism  193 , the arm  194  depresses the switch mechanism  193 , thereby activating it. The switch mechanism  193  relays an electrical pulse to the computer which monitors the status of the switch mechanism  193 . The switch mechanism  193  may be any type of detection mechanism, e.g. a vibration sensor, accelerometer, switch, etc. 
         [0135]      FIGS. 4A ,  4 B, and  4 C are side, front, and bottom views, respectively, of an embodiment of a hopper assembly configured for use in the adapter assembly shown in  FIG. 3A . According to one exemplary embodiment, a food hopper is a stainless steel cube with a slotted feeding interface and a post coupling. A mouse hopper holds solid food, for example 50 grams of solid food, while a rat hopper holds a larger supply of food (150 grams, for example). The screen configuration is optionally changeable using a clip mechanism to allow for different types of food. 
         [0136]    Referring specifically to the embodiment illustrated in  FIGS. 4A through 4C , an exemplary hopper assembly  36  is illustrated. Specifically, the puck or support component  82  of the hopper assembly  36  is fastened to a bottom surface of the hopper  86  by means of two (2) fasteners  84 . Together, the screen  88  and the hopper  86  of the hopper assembly  36  define an access opening  108 , which allows selective access to food within the hopper assembly  36  for a laboratory animal. Further details of the screen  88  are shown in  FIGS. 5A through 5D , and further details of the puck component  82  are shown in  FIGS. 8A and 8B . 
         [0137]      FIGS. 5A ,  5 B,  5 C, and  5 D are side, front, top, and enlarged views, respectively, of an embodiment of a screen component configured for use in the hopper assembly shown in  FIG. 4A . Referring specifically to the embodiment illustrated in  FIGS. 5A through 5D , screen  88  of the hopper assembly  36  is optionally formed from sheet metal bent into a selected configuration. As is best illustrated in  FIG. 5A , screen  88  includes plural flanges  110  along its edges to facilitate connection (e.g., by spot welding) to the interior surface of the hopper  86  (not shown in  FIG. 5A ). Also, screen  88  has a lip portion  112  and brackets  114  positioned and shaped to releasably engage a mesh such as mesh  106  in juxtaposition with the aperture  108 . Accordingly, and as is illustrated in  FIG. 5D , portions of a wire-formed mesh  106  are captured between the lip portion  112  and the brackets  114  at an upper edge of the aperture  108 . The stop component (shown in  FIGS. 3G and 3H ) and designated by the numeral  104  supports a lower portion of the mesh  106  to maintain the mesh  106  in the space between the lip portion  112  and brackets  114 . Though not shown in  FIG. 5D , the stop  104  would be positioned to the right of the bottom portion of the mesh  106  in the base of the screen  88 . Removal of the stop  104  would permit removal of the mesh  106  for cleaning, replacement, or other purposes. 
         [0138]    Referring to  FIG. 6 , which provides a front view of an embodiment of a mesh component configured for use with the screen component shown in  FIG. 5A , mesh  102  is optionally formed from an elongated segment having end portions  116 , elongated runs  118 , and bends  120 . While a metallic wire is optionally selected as a material for the mesh  102 , other metallic or non-metallic materials are contemplated as well. It has been discovered, however, that a rounded or circular cross-sectional shape of the elongated runs  118  of the mesh  102  provides a surface well adapted for contact by laboratory animals while feeding. In other words, the elimination of sharp edges from the mesh  102  is better suited for this purpose. It should be understood by one skilled in the art that the mesh component may be formed by a die-casting or injection molding process. 
         [0139]      FIG. 7  is a front view of another embodiment of a mesh component configured for use with the screen component shown in  FIG. 5A . Like mesh  102 , the mesh  106  illustrated in  FIG. 7  also has end portions  116 , elongated runs  118 , and bends  120 . The primary difference between the mesh  102  shown in  FIG. 6  and the mesh  106  shown in  FIG. 7  is that the elongated runs  118  of the mesh  102  run substantially vertically while the elongated runs  118  of the mesh  106  run substantially horizontally. 
         [0140]      FIGS. 8A and 8B  are side and bottom views, respectively, of a support component configured for use in the hopper assembly shown in  FIG. 4A . Referring specifically to the embodiment illustrated in  FIGS. 8A and 8B , the puck component  82  of the hopper assembly is provided with a slot  122  to accommodate the dowel pins  80  of the coupling  78  ( FIG. 3B ), thereby preventing rotational movement of the puck  82  with respect to the coupling  78 . Puck  82  also includes an aperture  124  extending through it to receive the coupling  78 . Mounting holes  126  are provided for engagement of fasteners  84 , which interconnect the puck  82  to the hopper  86 . 
         [0141]      FIGS. 9A ,  9 B, and  9 C are side, front, and top views, respectively, of another embodiment of a screen component, generally designated by the numeral  128 , that can be used in a hopper  86  of the hopper assembly  36 . Screen  128  differs from screen  88  in that it is a one-piece component as opposed to the assembly of the screen  88  and the mesh  102  or  106 . Like screen  88 , screen  128  is optionally formed from sheet metal that is cut or otherwise formed to a desired shape and bent into a desired configuration. Screen  128  includes a series of flanges  130  to facilitate interconnection of the screen  128  and interior surfaces of the hopper  86 . In order to provide a laboratory animal with access to food within the screen  128  of the hopper assembly  36 , the body of screen  128  defines a plurality of apertures  132  (five (5) such apertures  132  being illustrated in  FIGS. 9B and 9C ). As illustrated by  FIGS. 9A-9C , for example, a screen for use in a hopper can take a wide of variety forms and configurations. Such a screen can also be formed form a wide variety of metallic and non-metallic materials. 
         [0142]      FIGS. 10A through 10E  illustrate an adapter component configured for use in the adapter assembly shown in  FIG. 3A . The adapter optionally takes the form of a translucent, polycarbonate block sandwiched between a stainless steel front plate and the L-bracket, thereby providing isolation for the hopper. 
         [0143]    Referring specifically to the embodiment illustrated in  FIGS. 10A-10D , adapter  95  defines a central aperture  134  through which an animal can have access to food within the hopper assembly  36 . Adapter  95  includes four (4) mounting holes  136  to accommodate fasteners such as fasteners  97  shown in  FIG. 3D . Adapter  95  also includes mounting holes  138  provided in a side surface to receive dowel pins such as the dowel pin  93  shown in  FIG. 3C . An aperture  140  is also provided in the adapter  95  to accommodate the shaft  42  shown in  FIG. 3B . 
         [0144]    A recess  141  is provided in a top surface of the adapter  95  in order to receive the clip  44  as illustrated in  FIG. 3B , and mounting holes  142  are provided in the area of recess  141  so that fasteners  50  can be used to engage the plate  48  and clip  44  of the mounting assembly  32  to the adapter component  95 . Mounting holes  144  are provided in the bottom surface of the adapter  95  in the vicinity of a recess  146 . The recess  146  accommodates the adjustable hook  46  as shown in  FIG. 3B , and the mounting holes  144  accommodate fasteners  52  (also shown in  FIG. 3B ). 
         [0145]      FIG. 11A  is a side view of an embodiment of a hook component configured for use in the adapter assembly shown in  FIG. 3A . The hook attaches to the bottom of the opening  146  of adapter  95  and is slotted to allow for adjustment to the angle of the mounting surface of cage. Referring to  FIGS. 11A through 11C , an embodiment of a hook component  46  is illustrated. Hook  46  includes a mounting portion  148  and a hook portion  150 . The mounting portion  148  facilitates adjustable mounting of the hook  46  to the adapter  95 , and hook portion  150  of hook  46  provides releasable engagement between the mounting assembly  32  of adapter assembly  30  and an animal cage assembly  10 . The mounting portion  148  of the hook  46  includes elongated apertures or slots  152  (two (2) shown in  FIG. 11B ) to accommodate fasteners  52 . The slots  152  are elongated in order to provide advantageous adjustment of the position of the hook  46  with respect to the adapter  95 . As described previously, such adjustments of the hook  46  makes it possible to adjust the adapter assembly  30  for attachment to a variety of animal cages that may have different drafts or wall configurations. 
         [0146]      FIG. 12  is a side view of an embodiment of a clip component configured for use in the adapter assembly shown in  FIG. 3A . The clip attaches to the top of a cage opening and allows for rapid mounting and dismounting to the cage opening. According to one embodiment, the clip is made from SS spring steel. 
         [0147]    Referring to  FIG. 12 , the clip  44  has a mounting portion  154  separated by a bend  155  from an engagement portion  156 . The mounting portion includes at least one aperture (not shown) to accommodate a fastener  50  for coupling clip  44  to adapter  95  of mounting assembly  32 . The engagement portion  156  can be pivoted or flexed with respect to the mounting portion  154  to facilitate engagement of the clip  44  to a surface of an animal cage. In order to allow such flexure of clip  44 , the clip is optionally formed from stainless steel spring steel or another suitable or equivalent material. 
         [0148]    A recess  158  formed in the engagement portion  156  accommodates an edge of an aperture formed in an animal cage. More specifically, referring to  FIGS. 1A and 1B , the recess  158  is configured to engage against the flange  24 A and perimeter  26  of the molding  14  of the animal cage assembly  10 . In such an arrangement, the hook portion  150  of the hook  46  shown in  FIGS. 11A through 11C  would engage the flange  24 C and perimeter  26  of the molding  14 . Such engagement by the clip  44  and hook  46  releasably engages the adapter assembly  30  to the animal cage assembly  10 . 
         [0149]    A second recess  160  is optionally formed in the engagement portion  156  of the clip  44  in order to provide clearance for a structure of the animal cage such as a lid portion of the animal cage. The clip  44  is optionally formed by compressing stainless steel spring steel between a punch component and a die component that is contoured to form the desired shape of the clip. Other forming methods, including molding, bending, and cutting for example, can be utilized. 
         [0150]      FIGS. 13A ,  13 B, and  13 C are front, side and end views of an embodiment of a gate component configured for use in the adapter assembly shown in  FIG. 3A . The gate pivots on a shaft (swinging upward), thereby gently pushing an animal away from the hopper. A cam is attached to the end of the shaft on the outside of the adapter which allows for manual movement. A spring plunger is attached to the cam which locates in a hole in the adapter&#39;s side for locking the gate in the closed position. A dowel pin is located in the adapter&#39;s side to limit the travel of the cam and to position the gate in the closed position. In the closed position, the animal has no access to the food in the hopper and is prevented from escaping through the opening. In the open position, the gate lays flat on the base of an interior channel of the adapter and overlaps on top of the hopper&#39;s tray to prevent an animal from pulling the coupling out of the load cell, to prevent escape, and to keep spillage of food contained. 
         [0151]    The gate can be operated manually by moving the cam up and down or automatically with a servo mounted on the side of the enclosure. The servo arm is activated via computer software to operate at timed intervals, thereby allowing or disallowing access to the food hopper. In an exemplary embodiment, for example, the servo arm receives a signal from the computer software to close the gate after a predetermined amount of food has been consumed thus restricting the total amount the animal is permitted to consume. The food restriction function of the adapter assembly is a beneficial tool in biology wherein food restriction can increase the longevity of the animal. The adapter assembly is not limited to feeding the animal once per day. The food may be offered to the animal in intervals throughout the day or the food may be offered the entire day. The user determines the appropriate feeding time(s) and feeding time duration. 
         [0152]    On a mouse assembly, for example, the shaft acts as a launching pad for the animal providing leverage for entering and eating once inside the adapter tunnel. The gate moves slowly when closing with no pinch points to safely push the animal out of the adapter tunnel. On a rat assembly, for example, the opening in the adapter is larger. A locking pin which is slid through two holes in the adapter is installed for small animals to prevent escape and can be removed to provide maximum access to the food hopper when the animal has grown. 
         [0153]    Referring specifically to the embodiment illustrated in  FIGS. 13A through 13C , the gate  54  of the mounting assembly  32  provides a substantially flat surface  162  flanked by flanges  164 . The surface  162  of gate  54  provides a platform when in the open position on which an animal can step and which can receive food that falls from the hopper as an animal feeds. When in a closed position, however, the surface  162  of the gate  54  provides a blocking function that prevents the animal from accessing the food in the hopper, thereby preventing or ending a feeding event or feeding bout. 
         [0154]    The shape of the gate  54  is advantageously selected in order to be animal-friendly. Specifically, the edges of the gate  54  are rounded and provided with flanges  164  so as to prevent entrapment of an animal as the gate  54  moves from the closed to opened positions or from the opened to closed positions. Also, the shape and operation of the gate  54  serves to push an animal safely away from the feed hopper to end a feeding cycle. Such pivotal action of the gate  54 , coupled with the shape of the gate  54 , minimizes the risk of harming the animal. 
         [0155]    Gate  54  also includes apertures  166  to accommodate fasteners, such as fasteners  56  shown in  FIG. 3B , which connect the gate  54  to the shaft  42  of the mounting assembly  32 . More specifically, the apertures  166  in the surface  162  of the gate  54  permit coupling of the gate  54  to the shaft  42  so that rotation of the shaft  42  causes pivotal rotation of the gate  54  about an axis of the shaft  42 . 
         [0156]      FIGS. 14A ,  14 B, and  14 C are front, side and top views, respectively, of an embodiment of a bracket component configured for use in the adapter assembly shown in  FIG. 3A . Referring specifically to the embodiment illustrated in  FIGS. 14A through 14C , bracket  68  defines a blind hole  168  that releasably receives the coupling  78  that extends from the base assembly  34  of the adapter assembly  30  up to the hopper assembly  36  of the adapter assembly  30 . The blind hole  168  is flanked by slots  170  that receive dowel pins  80  of the coupling  78 , thereby resisting or preventing rotational movement of the coupling  78  with respect to the bracket  68 . Such resistance to rotation of coupling  78  (both by virtue of the slots  170  in the bracket  68  and the slot  122  of the puck  82 ) prevents or limits the rotational movement of the hopper  86  with respect to the remainder of the adapter assembly  30 . Such limitation of rotational movement reduces the opportunity for the hopper  86  to contact other structures, thereby reducing the possibility of an inaccurate reading of the strain gage. 
         [0157]    Bracket  68  also includes a mounting hole  172 , which accommodates the ball nose spring plunger  70  shown in  FIG. 3B . As described previously, the ball nose spring plunger  70  provides frictional engagement with the coupling  78  to resist the removal of the coupling  78  from the bracket  68 . While coupling  78  remains removable from the bracket  68 , the ball nose spring plunger  70  helps to retain the coupling  78  in the bracket  68  when the hopper assembly  36  is removed from the top of the coupling  78 . In other words, the ball nose spring plunger  70  provides increased friction between the coupling  78  and the bracket  68  as compared to the friction between the coupling  78  and the puck  82  of the hopper assembly  36 . 
         [0158]    The bracket  68  also includes threaded holes or apertures  174  to receive set screws such as set screws  72  shown in  FIG. 3B . The set screws  72  are provided to adjust the position of the bracket  68 , or to stabilize the bracket  68 , with respect to a surface of the enclosure  60  or the cover  62 . 
         [0159]      FIG. 15A  is a partial cross-sectional side view of an embodiment of a coupling assembly configured for use in the adapter assembly shown in  FIG. 3A . The coupling optionally includes a cylindrical rod which connects the strain gauge cell to the hopper or water device. It is optionally symmetrical so that either end of the rod can be inserted into the strain gauge cell and/or food hopper. 
         [0160]    Referring to  FIG. 15A , which illustrates an exemplary embodiment of the coupling  78 , the coupling  78  is optionally formed from a shaft  176  having holes through which dowel pins  80  are pressed. Though shaft  176  of coupling  78  is optionally formed from a rod material to provide a round or rounded cross-sectional shape, the coupling  78  can be formed from a wide variety of materials having a wide variety of shapes. For example, dowel pins  80  are provided through shaft  176  to co-act with slots in the puck  82  and the bracket  68  to prevent rotational movement. Alternatively, the coupling  78  can be provided with a shaft having a non-circular cross-sectional shape to prevent such rotation without the need for dowel pins  80 . For example, coupling  78  can be provided with a shaft  176  formed from a square shaft or a shaft having another cross-sectional shape that is non-round. 
         [0161]      FIGS. 15B and 15C  illustrate another exemplary embodiment of a coupling assembly configured for using in the adapter assembly shown in  FIG. 3A . This embodiment of the coupling  187  is optionally formed from a polymeric material to reduce potential damage to the bracket  68 . Under an applied torsion load, the polymeric material of the coupling  187  will elastically yield, thereby substantially reducing the stress applied to the bracket  68 . The coupling includes flange portions  188  to co-act with slots in the puck  82  and the bracket  68  to prevent rotational movement. 
         [0162]    A seal  189  is provided at one end of the coupling  187 . Though not shown in  FIG. 15C , the outer diameter surface  189  is preferable configured to extend beyond the outer surface of the coupling&#39;s body. The frictional contact between the seal  189  and either the bracket  68  or the puck  82  enhances the containment of the coupling  187 , depending upon the orientation of the coupling. A seal on both sides of the coupling  187  is also contemplated to further enhance the containment of the coupling. Furthermore, the utilization of the seal  189  eliminates the need for hole  172  and ball nose spring plunger  70 , which also provide frictional engagement with the coupling  78  to resist the removal of the coupling  78  from the bracket  68 . 
         [0163]      FIG. 16  is a cross-sectional side view of an embodiment of a cam component configured for use in the adapter assembly shown in  FIG. 3A . Referring to the embodiment of cam  40  illustrated in  FIG. 16 , the cam  40  has a shape configured to provide requisite movement with respect to the arm  38  based on contact between the arm  38  and cam  40 , as shown in  FIG. 3A . The cam  40  is provided with an aperture  178  to accommodate the shaft  142 , and a fastener can be inserted by means of an aperture  180  in the cam  40  in order to secure the engagement between the cam  40  and the shaft  42 . Also, the use of a fastener through the aperture  180  of the cam  40  prevents rotational slippage of the cam  40  with respect to the shaft  42 . The cam  40  is also provided with an aperture  182 , preferably threaded, to receive the spring plunger  91  as shown in  FIG. 3C . 
         [0164]      FIGS. 17A and 17B  are front and side views of an embodiment of a blocker assembly configured for use with the animal cage shown in  FIG. 1A . Clip and hook components of the blocker assembly attach to the cage opening to block the opening and prevent an animal from escaping when an adapter assembly is removed. 
         [0165]    Referring to  FIGS. 17A and 17B , a blocker assembly, generally designated by the numeral  200 , is illustrated. Blocker assembly  200  is configured for use with a cage assembly such as animal cage assembly  10  in order to block an aperture such as aperture  22 . The blocker assembly  200  therefore provides a barrier to prevent the escape of an animal through an aperture in the animal cage when the adapter assembly  30  or other equipment is removed from the cage. The blocker assembly  200  also illustrates that any of a number of assemblies or components can be mounted to a cage assembly such as assembly  10  to provide a wide variety of functions. For example, any of a variety of feeding assemblies can be coupled to the animal cage. Also, a variety of barriers can be provided as can exercise equipment and other equipment useful for laboratory experiments. 
         [0166]    The blocker assembly  200  includes a clip  244 , like clip  44  of adapter assembly  30 , for engagement with a surface of an animal cage. The clip  244  is positioned for cooperation with a hook  246  of a blocker  295 . The clip  244  is coupled to the blocker  295  by means of an assembly of a plate  248 , a support  249 , and a fastener  250  that couples the clip  244 , plate  248 , and support  249  together. The blocker  295  of the blocker assembly  200  is provided with a contiguous surface  296  that is configured to block an animal. The surface  296  can also comprise a screen, mesh or any other suitable material. 
         [0167]    Referring to  FIG. 18 , another exemplary embodiment of an adapter assembly  230  is illustrated. The adapter assembly  230  is similar to the adapter assembly  30  illustrated in  FIG. 3B  with the exception of modifications to the L-bracket  220  and the hopper assembly  236 . 
         [0168]    Referring now to  FIGS. 18 ,  19 A and  19 B, L-bracket  220  is similar to L-bracket  64  described with reference to  FIGS. 3B-3D , however L-Bracket  220  includes a cylindrical wall  222  protruding from the mounting surface  224  of the L-bracket. The cylindrical barrier  222  is positioned to limit food particles and/or liquid leaked from the hopper from entering the blind hole  168  formed in the bracket  68  illustrated  FIGS. 14A through 14C . As mentioned above, blind hole  168  receives the coupling  78  that extends from the base assembly  34  up to the hopper assembly  36 . 
         [0169]    It is envisioned that a significant accumulation of liquid within the blind hole  168  could potentially disturb the electronic components of the base assembly  34 . Furthermore, food pellets or particles entrapped within the blind hole  168  could complicate the insertion and/or removal of the coupling  78  from the blind hole  168 . It may be difficult for the user to remove food particles from the blind hole  168  or the interior of the base assembly  34 . Thus, by virtue of the cylindrical barrier  222 , the food particles and water would collect on the mounting surface  224  of the L-bracket without entering the blind hole  168 , facilitating easy clean-up of the adapter assembly  230 . The barrier  222  should be of sufficient height to limit food particles from entering the blind hole  168 , but low enough to allow the hopper  236  to mate with the base assembly  234 . The cylindrical barrier  222  may be welded, fastened or formed on mounting surface  224  of the L-bracket. 
         [0170]    Referring now to  FIGS. 18 ,  20 A and  20 B, another exemplary embodiment of a screen  288  is illustrated. The screen  288  holds food within the hopper assembly  236  yet provides a laboratory animal with access to the food when the gate is open. The screen  288  generally comprises a plurality of formed wires  292  coupled to opposing headers  294 . The opposing headers  294  are designed to snap onto the top end of the hopper  286 , as shown in  FIG. 18 . The screen  288  is specifically shaped to allow the animal access to the contained food from the top, side or bottom of the hopper. 
         [0171]    The wire format is optionally used to be ‘gentler’ on the animal. As mentioned above, rounded or circular cross-sectional shape of the wires provides a surface well adapted for contact by laboratory animals while feeding. In other words, the elimination of sharp edges from the wires  292  is better suited for this purpose. 
         [0172]    An animal consumes food by gnawing pieces off of the food pellets accessible between the wires  292 . The distance between the wires  292  may be designed to be larger than the animal muzzle, but smaller than the food pellet. The diameter of the wires  292  as well as the distance separating the wires may be tailored to the size of the food or to increase or decrease the ‘ease’ of feeding. The ease of feeding can therefore be adjusted to correspond with an animal&#39;s inclination to eat and the ease or difficulty of the feed offered. The ease or difficulty of the feed offered is dependent upon the size of the food relative to the distances between adjacent wires  292 . A hopper may be fitted with an inter-changeable screen. 
         [0173]    In one exemplary embodiment, the wires  292  are formed from Stainless Steel, although it should be understood that the wires may be formed from a variety of metallic or non-metallic materials and may be extruded, molded or die-cast. Each wire  292  may be welded to the headers  294 , as shown by the weld spots  295  illustrated in  FIG. 20B . The wires may also be fastened to the headers  294  using any fastening means known in the art. 
         [0174]    Referring now to  FIG. 21 , another exemplary embodiment of an adapter assembly  330  is illustrated. The adapter assembly  330  is similar to the adapter assembly  230  illustrated in  FIG. 18 , however in this embodiment, the food hopper assembly  236  is replaced with a water hopper assembly  336 . In practice, the water hopper assembly  336  contains water or any other liquid used to hydrate the laboratory animal. The water hopper assembly  336  is adapted to operate with the base assembly  34  and the gate  54  in the same manner as the food hopper assembly  236 . 
         [0175]    Similar to the previously described food hoppers, the water hopper assembly  336  is coupled to the base assembly  34  via coupling  78 . The coupling  78  releasably mounts the water hopper assembly  336  over the base assembly  34  in such a way as to transmit the weight of liquid contained within the water hopper assembly  336  to the strain gauge or load cell  66  mounted within the enclosure  60  of the base assembly  34 . It is in this manner that the weight of the liquid within the water hopper assembly  336  can be monitored. 
         [0176]    Referring now to the detailed drawings of the water hopper assembly  336  illustrated in  FIGS. 22A-22C , the water hopper assembly  336  generally includes a body portion  337 , and a spring loaded valve assembly  342  coupled to the body portion  337 . The body portion  337  includes a reservoir  338  sized to contain a sufficient volume of water to hydrate an animal. The reservoir  338  may be sized to hold any pre-determined volume of liquid. The top end of the reservoir  338  is optionally open to the atmosphere, as shown, such that laboratory personnel can quickly and easily refill the reservoir or determine if the reservoir needs to be replenished. An integral support  350  is disposed at the bottom surface of the body portion  337 . An aperture  352  formed in the integral support  350  is sized to releasably carry the coupling  78 , as shown in  FIG. 21 . 
         [0177]    The spring loaded valve assembly  342  is positioned to face the interior of an animal cage for the purpose of feeding and configured to release a controlled supply of liquid to the animal. The valve assembly  342  comprises a valve housing  343  clipped, clamped, snapped, fastened or integral with the body portion  337  of the hopper assembly  336 . A compressible spring  336  positioned within the housing  343  bears on an end of a moveable nipple  344  (or valve) to seat the shoulder  351  of the nipple  344  with the valve seat  353  of the body portion  343 . 
         [0178]    In use, when the gate is in the open position, the laboratory animal depresses the nipple  344  of the valve assembly  342  to obtain water or any other liquid is from the reservoir  338 . More specifically, as the animal depresses the nipple  344 , the spring  346  held in the valve housing  343  compresses, and a gap develops between the valve seat  353  and the shoulder  351  of the nipple  344 . Liquid from the reservoir flows through the gap (not shown) under the force of gravity, and between the nipple  344  and the valve housing  343  towards the mouth of the laboratory animal. The spring constant of the spring is desirably low enough to permit the animal to easily depress the nipple  344 . 
         [0179]    When the drinking bout is complete, the animal releases the nipple  344 , permitting the spring  346  to return to its expanded state and the shoulder  351  of the nipple  344  seats with the valve seat  353  thereby prohibiting liquid flow. The closed state of the valve assembly is illustrated in  FIG. 22A . The open state of the valve assembly  342  is not shown. To limit liquid from unintentionally escaping from the reservoir  338  an seal  352  is positioned on the shoulder  351  of the nipple  344 , such that the elastomeric seal closes the interface between the shoulder  351  of the nipple  344  and the valve seat  353 . The seal  352  may be an o-ring or a washer, for example, or any other item capable of sealing the interface between the shoulder  351  of the nipple  344  and the valve seat  353 . 
         [0180]    An opening  340  is formed in the body portion  337  of the hopper assembly  336  to provide adequate clearance for the head or snout of the laboratory animal. The size of the opening  340  may be tailored to suit the size of the animal&#39;s head. A sloped wall  348  is positioned at the base of opening  340  to catch any unconsumed liquid. Liquid that is delivered from the valve assembly  342  but not consumed by the animal travels along the sloped wall  348  and pools at the base of the sloped wall  348 . Accordingly, the load cell can account for the weight of the liquid pooled at the base of the sloped wall  348 . It is in this manner that the weight of the liquid that was actually consumed by the animal can be accurately monitored. 
         [0181]    The body portion  337  of the water hopper assembly  336  may be machined, molded, formed or die-cast and formed from any non-toxic material capable of retaining liquid. In this exemplary embodiment, the body portion  337  is injection molded and composed of polycarbonate material. The body portion  337  may be composed of a transparent material so that laboratory personnel can quickly determine the volume of water within the reservoir. Although not shown, the exterior surfaces of the body portion  337  may include graduated indicia corresponding to the liquid level within the reservoir  338 . 
         [0182]    Referring generally to the figures, exemplary procedures for assembly of the cage device will now be described. 
         [0183]    To close the gate mechanism on the cage mount module so that the gate plate lies in a vertical position and is locked: 
         [0184]    (1) Grasp the cage mount module in one&#39;s left hand. Using one&#39;s right hand&#39;s thumb and pointer finger, pull out on the knurled knob of the gate locking mechanism and continue to hold it pulled. 
         [0185]    (2) Move the gate into the vertical position while pulling on the knob until the cam hits the stop pin. Release the tension on the knob. 
         [0186]    (3) The post inserts into the hole in the adapter. Turn the knurled knob until it springs back into the slot and locks. 
         [0187]    To open the gate, reverse the foregoing procedure. 
         [0188]    To attach the load cell enclosure to the cage mount module: 
         [0189]    (1) Grasp the cage mount module with four fingers under the keyhole plate and with your thumb on the spring clip. Press down on the spring clip and hold it down. 
         [0190]    (2) Holding the device at an angle of approximately 45 degrees to the cage, with the spring clip at the top and closest to the top of the cage grommet, engage the groove in the spring clip by inserting the rounded aspect of the clip into the opening. 
         [0191]    (3) While holding the grove of the clip in and up against the upper edge of the cage grommet, rotate the bottom of the cage mount module until the lower hook lip is above the lower edge of the cage grommet. Release the spring clip by slowly releasing the pressure of your thumb. 
         [0192]    (4) Insert the post through the centered hole, passing through the cage mount module&#39;s steel plate and into the opening of the strain gauge cell. 
         [0193]    (5) Insert the food hopper with the slotted face towards the adapter&#39;s opening of the cage mount module. 
         [0194]    (6) Open the gate to the feeding position by reversing the instructions provided above for closing the gate. 
         [0195]    To remove the module, grasp module as above, depress the spring clip with the thumb, rotate the bottom of the module away from the cage grommet to a 45 degree angle, and lower the hook groove to free its engagement with the upper edge of the cage grommet. 
         [0196]    The system for monitoring the intake of food by animals described herein is adapted for use with various electronics hardware components and software modules. For example, the system is configured for use with a remote node, a sensor cable, a network module, a connector block, an input/output module, a remote node serial number, a data collection computer, and a TCP/IP network, for example. 
         [0197]    The remote node is optionally an electronics package mounted near the cage rack. A single remote node can monitor up to 32 cages, for example. The remote node continuously measures the weight of the food hoppers. When the weight of a hopper becomes unstable, indicating that an animal is feeding, the remote node records the previous stable weight as the starting weight. As long as the weight is unstable, a meal is considered to be in progress. Once the weight has been stable for the inter-bout interval, the meal is considered to be concluded. Once the meal is concluded, the start and end weights are used to calculate the meal weight and the start and end times are used to determine the meal duration. 
         [0198]    A desirable embodiment comprises a single sensor cable connecting a strain gauge cell to the remote node. Other embodiments, such as multiple cables to a strain gauge cell, or a single cable for multiple strain gauge cells, or a wireless connection are also contemplated. 
         [0199]    The network module can be provided as a component of the remote node which connects to the network. This is optionally the topmost module and has LEDs labeled A through D in one embodiment. The LED&#39;s on the remote node reflect various aspects of the system operation. For example, in an exemplary embodiment, the ‘D’ light indicates that the system is operational. The ‘A’ light indicates message activity between the remote node and a central station. The ‘B’ light blinks whenever a meal is recorded and the ‘C’ light is on whenever stored meals are available for download by the central station. Each remote node can be assigned to one network module. 
         [0200]    The connector block is optionally provided as a component of the remote node where the sensor wire(s) are attached. These modules can be removed and inserted without powering down the remote node. The connector block can typically have up to 8 sensors connected to it, or more. There are typically one to four connector blocks in a remote node, and in some cases one to eight or more. 
         [0201]    The input/output (I/O) module can be provided as a component of the remote node that converts signals received from the sensors into a form usable by the network module. The I/O modules may be removed and inserted without powering down the remote node. There are typically one to four I/O modules in a remote node, and in some cases up to eight or more. Typically, there are the same number of I/O modules as connector blocks. 
         [0202]    The remote node serial number is a unique number assigned to each remote node based on a serial number that may be printed on the side of the network module. The serial number is also utilized in conjunction with a license key that is provided with the system to provide control over the distribution of the application and to various features within the exemplary embodiment. In the exemplary embodiment, the license key is unique to the serial number of the remote node network controller and the application will only function if the license key is correct. 
         [0203]    The data collection computer serves as the primary operator interface and permanent data storage location. It may be a laptop or desktop or other form of computer. The TCP/IP network provides communication between the data collection computer and the remote node. Its form can be a (crossover) cable between the remote node and the data collection computer. More complicated networks may involve other parts of an existing computer network, including VPNs and connections to remote sites. 
         [0204]    The communications channel between the remote nodes and the central station PC can be any channel that will support TCP/IP. This includes Ethernet (typical facility computer networks) and the internet. The bandwidth required is approximately 3 to 5 kbits/S per remote node. The system also works well over a VPN between facilities. When the communications is disrupted, the remote nodes will continue to monitor and record and will upload their meal data to the computer automatically when communications is restored. 
         [0205]    Referring now to  FIGS. 34-36 , three different exemplary embodiments of systems for monitoring the intake of food by animals are illustrated. In the first exemplary embodiment illustrated in  FIG. 34 , the Researcher workstation, the Node Server and the Structured Query Language database (SQL db) are integral components of the data collection computer, labeled PC 1 . One or more Peripheral Control Units (PSC) are connected to or in communication with the Node and the Node is connected to or in communication with the Node Server. 
         [0206]    In the second system embodiment illustrated in  FIG. 35 , the Researcher workstation is an integral component of the data collection computer, labeled PC 2 . In this embodiment two Node Servers are connected to or in communication with the Researcher Workstation, an SQL database is connected to each Node Server, three Nodes are connected to or in communication with the two Node Servers and multiple PSC&#39;s are connected to or in communication with the Nodes. In this embodiment, the user interface function and data gathering functions are split into distinct hardware platforms, thus, the Node Server and the Structured Query Language database (SQL db) are separate from the Researcher Workstation. 
         [0207]    In the third system embodiment illustrated in  FIG. 36 , the Node Server is an integral component of the data collection computer, labeled PC 3 . In this embodiment a Researcher Workstation, two Nodes and the SQL database are connected to or in communication with the Node Server, and multiple PSC&#39;s are connected to or in communication with the Nodes. Similar to the embodiment illustrated in  FIG. 35 , the user interface function and data gathering functions are split into distinct hardware platforms, thus, the Researcher Workstation and the SQL db are separate from the Node Server. 
         [0208]    With regard to the three systems illustrated in  FIGS. 34-36 , communications between the data collection computer (i.e. PC 1 , PC 2  and PC 3 ) and the Nodes is TCP/IP, thus, communication may be established over the Internet or Intranet, for example. Furthermore, communications between the Nodes and the PSC units may be short distance analog, digital signaling or TCP/IP. 
         [0209]    According to the exemplary embodiment illustrated in  FIGS. 20-33 , a laboratory animal food consumption analysis and reporting software tool is installed on the data collection computer. The software tool is hereinafter referred to as the BioDAQ software tool or BioDAQ system. The BioDAQ system is configured to record, synthesize and display food consumption data. The functionality of the software tool will be explained with reference to the following figures. 
         [0210]    Referring to  FIG. 23 , a single screen view of an exemplary ‘Startup’ graphical user interface (GUI)  500  of the BioDAQ software tool is illustrated. The Startup GUI  500  is the entrance screen to the software program. The user is prompted to enter the IP address and the license key of the remote node into text boxes  502  and  504 , respectively. Once the remote node information has been entered, the GUI  500  alerts the user that the particular remote node has been located by displaying a ‘Y’ (i.e. Yes), as shown, at indicator  506 . Similarly, the GUI  500  alerts the user that the license key of the remote node entered into textbox  504  is valid by displaying a ‘Y’ (i.e. Yes), as shown, at indicator  508 . If so desired, the user may reboot the remote node by selecting the Reboot Remote icon  510 . Once the Remote IP and License Key numbers are entered correctly, the user may proceed to setup the experiment by selecting the Experiment Setup icon  512 . Although not shown, after selecting the Experiment Setup icon  512  another GUI appears prompting the user to open an existing experiment or create a new experiment. After an existing experiment is selected or a new experiment is designated, the Network Population GUI  516  shown in  FIG. 24  appears. An experiment may be defined as any analysis of the feeding habits of at least one laboratory animal. The user may exit the software program by selecting the Exit icon  514  shown in  FIG. 23 . 
         [0211]      FIG. 24  is a single screen view of an exemplary Network Population GUI  516  of the BioDAQ software tool. In this exemplary embodiment, the experiment optionally includes thirty-two Peripheral Control Units (PSC) releasably attached to animal cages. The PSC&#39;s are each connected to or in communication with the remote node. A matrix of thirty-two individual PSC icons  517 , hereinafter referred to as the PSC matrix  518 , correspond to each of the thirty-two PSC&#39;s that are connected to the remote node. As mentioned above, one or more PSC&#39;s (also referred to as adapter assemblies  30 ) may be releasably engaged to an animal cage. It should be understood that the thirty-two PSC icons  517  do not necessarily refer to thirty-two animal cages, rather, the thirty-two PSC icons  517  refer to thirty-two different PSC&#39;s that are attached to any number of animal cages. Thus, for example, if thirty-two PSC&#39;s are included in the experiment and two PSC&#39;s are attached to each animal cage, there are 16 animal cages. Furthermore, each cage is not limited to a single animal, as multiple animals may reside in one cage. However, in a typical experiment, one animal resides in one cage and one PSC is attached to one cage. 
         [0212]    The PSC numbers are listed on the left and right side of the cage matrix  518 . For example, the top row of individual PSC icons  517  displayed in the PSC matrix  518  denote PSC&#39;s  1 - 8  and the left-most column of individual cage icons  517  denote PSC&#39;s  1 ,  9 ,  17  and  25  from top to bottom. In this exemplary embodiment, PSC&#39;s  1 - 9  are shown in the ‘ON’ position and PSC&#39;s  10 - 32  are shown in the ‘OFF’ position. The ‘ON’ indicator denotes that the particular PSC will be included in the experiment and the ‘OFF’ indicator denotes that the particular PSC will not be included in the experiment. The status of any PSC may be toggled from ‘ON’ to ‘OFF’ and vice-versa by selecting the respective PSC matrix icon  517 . The user may include all of the PSC&#39;s in an experiment by selecting the ‘ALL ON’ icon  520 . Similarly, the user may exclude all of the PSC&#39;s from an experiment by selecting the ‘ALL OFF’ icon  522 . The user may return to the ‘Startup’ GUI  500  by selecting the ‘Abandon Selection’ icon  524 . 
         [0213]    The user may select the ‘Set Measurement Parameters’ icon  528  to define the unique measurement parameters of the experiment. Accordingly, selection of icon  528  launches the Set Measurement Parameters GUI  530  illustrated in  FIG. 25 . 
         [0214]    Referring now to  FIG. 25 , the measurement parameters of the experiment are established in the ‘New Parameter’ section  532  of the Set Measurement Parameters GUI  530 . In this embodiment, the adjustable parameters are ‘Feed’ and ‘Noise’. ‘Feed’ refers to the minimum weight change sensed by the load cell to initiate recordation of a feeding bout. ‘Noise’ refers to the maximum weight change sensed by the load cell to stop recordation of a feeding bout. In this example, when the load cell senses a weight change of 1.0 grams or more, the BioDAQ software tool starts recording a feeding bout. Furthermore, when the load cell senses a weight change of 0.1 grams or less over the course of a feeding bout, the BioDAQ software tool stops recording the feeding bout. The ‘Feed’ and ‘Noise’ parameters may be set for an individual PSC or all of the PSC&#39;s. 
         [0215]    To set the ‘Feed’ and ‘Noise’ parameters for one particular PSC, for example PSC  1 , the individual PSC icon  547  within the PSC matrix  548  is selected. The selected PSC, e.g. PSC  1 , is automatically displayed in the ‘Selected Cage’ display  549 , as shown. The ‘Feed’ and ‘Noise’ parameters of PSC  1  are then entered into textboxes  542  and  544 , respectively. Finally, the ‘Update  1  Cage’ icon  534  is selected to formally set the parameters for the PSC. To set the ‘Feed’ and ‘Noise’ parameters for all of the PSC&#39;s, the ‘Feed’ and ‘Noise’ parameters are entered into textboxes  542  and  544 , respectively. Next, the ‘Update All Cages’ icon  536  is selected to formally set the parameters for all of the PSC&#39;s, e.g. PSC&#39;s  1 - 32 . 
         [0216]    Multiple default values for both ‘Feed’ and ‘Noise’ may be stored in the BioDAQ system. The default values are uniquely defined by the user of the software. For example, the Feed and Noise parameters for mice may be set to 0.5 g and 0.05 g, respectively, and the Feed and Noise parameters for rats may be set to 1.0 g and 0.5 g, respectively. Thus, if either rats or mice are commonly used in experiments, it is simple for the user to set the appropriate ‘Feed’ and ‘Noise’ values using the default entries. By virtue of the default values, a user of the software tool is not required to manually populate the ‘Feed and Noise’ textboxes  542  and  544  for each PSC. It is envisioned by the inventors that the default value feature may simplify the process of setting measurement parameters and may eliminate the possibility of entering inaccurate information into the ‘Feed and Noise’ textboxes  542  and  544 . It should be understood that the default settings are not limited to rats and mice. 
         [0217]    To apply a default ‘Feed’ and/or ‘Noise’ value to a PSC, either icon  540  or icon  538  may be selected. Thereafter, either the ‘Update All Cages’ icon  536  is selected to apply the default ‘Feed’ and ‘Noise’ parameters to all of the PSC&#39;s, or, alternatively, ‘Update  1  Cage’ icon  534  is selected to apply the default ‘Feed’ and ‘Noise’ parameters to a single PSC. The current stored ‘Feed’ and ‘Noise’ parameters are shown in the ‘Current Parameter’ section  546  of the Set Measurement Parameters GUI  530 . 
         [0218]    After the measurement parameters are defined in the Set Measurement Parameter GUI  530 , the return icon  550  is selected to return the user to the Network Population GUI  516  illustrated in  FIG. 24 . The user selects the ‘Start Recording’ icon  526  in the Network Population GUI  516  to start the experiment. Although not shown, a reminder message appears to remind the user to open the animal cages gates to permit the animals to feed. Acknowledging the reminder message launches the ‘Record Food Intake’ GUI  552  illustrated in  FIG. 26 . 
         [0219]    Referring now to the ‘Record Food Intake’ GUI  552  illustrated in  FIG. 26 , the feeding activity data for each PSC connected to the Remote Node is displayed in the PSC activity display matrix  554 . Similar to the PSC matrix  518 , each PSC icon  555  of the PSC activity display matrix  554  represents an individual PSC. The current state of the feeding activity for each PSC is displayed on PSC icon  555 , as shown. In this exemplary embodiment, the BioDAQ system may display the feeding activity status for each PSC to Feed, Quiet, IBI (Inter-Bout Interval), or OFF, as denoted by the Feed, Quiet, IBI, and OFF indicators displayed on PSC icons  3 ,  1 ,  2  and  10 , respectively. 
         [0220]    The ‘Feed’ indicator signifies that the animal is actively feeding and a meal is in progress. The ‘IBI’ indicator signifies that a meal is in progress but the animal is not actively feeding, thus the hopper weight has not been unstable for the inter-bout interval. The ‘Quiet’ indicator denotes that a meal is not in progress and the animal is not actively feeding. The ‘OFF’ indicator signifies that the PSC is not included in the experiment. The different indicators may be color-coded for the purposes of differentiation. 
         [0221]    The individual feeding bouts reported by each PSC are recorded and illustrated in the feeding activity display  564  of the ‘Record Food Intake’ GUI  552 . Two feeding bouts are shown in the feeding activity display  564  illustrated in  FIG. 26 . Each feeding bout is displayed along a row of the feeding activity display  564 . Referring to the individual columns of the display  564 , the PSC number is displayed in the ‘Cage’ column of the feeding activity display  564 . The total food consumed during each feeding bout is displayed in the ‘Meal’ column. The starting weight of the food contained within the hopper prior to each feeding bout is displayed in the ‘Start wt.’ column. The duration of each feeding bout is displayed in the ‘Duration’ column. Finally, the time and date of each feeding bout is recorded in the respective ‘Time’ and ‘Date’ columns. 
         [0222]    In addition to recording and displaying feeding bout data, the environmental conditions are recorded and displayed in the ‘Record Food Intake’ GUI  552 . Specifically, the temperature is shown in display box  558 , the humidity is shown in display box  560 , the light level (recorded and shown as a percentage) is shown in display box  562  and the approximate time and date of recordation is shown in display box  556  of the ‘Record Food Intake’ GUI  552 . 
         [0223]    Although not shown, the BioDAQ software is capable of uploading the experiment data to any program capable of generating a spreadsheet, such as Microsoft® Excel. Selecting the ‘Write .xls file’ icon  568  on the ‘Record Food Intake’ GUI  552  automatically generates a spreadsheet. A Comment text box  570  is provided for recording any observations, notes or comments associated with the experiment record. The comments entered into text box  570  are saved along with the experiment records. 
         [0224]    Selecting the ‘Stop’ icon  566  stops recording of the experiment. Once the experiment has stopped the system returns to the  FIG. 23  ‘Startup’ screen GUI  500 . 
         [0225]    The BioDAQ software tool provides a calibration feature to improve the accuracy of each load cell. More specifically, to calibrate each load cell, the user selects the ‘Cal.’ icon  572  on the ‘Record Food Intake’ GUI  552  to launch the ‘Calibrate Cells’ GUI  590  shown in  FIG. 27 . 
         [0226]    Referring now to  FIG. 27 , to calibrate a load cell of a PSC, an individual PSC icon  592  within the PSC matrix  594  is selected. In the example illustrated in  FIG. 27 , the load cell of PSC  1  is selected for calibration. The selected PSC is automatically displayed in the ‘Selected Cage’ display  596 , as shown. Thereafter, in practice, the user places a known mass (e.g. 10 g) into the food hopper of PSC  1 . The known mass (e.g. 10 g) is entered into the ‘Bottom Grams’ textbox  600 . The user then selects the ‘Update Bottom’ icon  602 . After the ‘Mean Update’ indicator  608  changes color or displays a message, such as the ‘Y’ illustrated in  FIG. 27 , the user replaces the first known mass (e.g. 10 g) in the hopper of PSC  1  with a second known mass (e.g. 300 g). The user then selects the ‘Update Top’ icon  606 . After the ‘Mean Update’ indicator  608  changes color or displays a message, such as the ‘Y’ illustrated in  FIG. 27 , the load cell is calibrated. The current parameters of the load cell, such as the load cell voltages corresponding to the two known masses, are displayed in the Current Parameter section  610  of the ‘Calibrate Cells’ GUI  590 . A ‘Reset to Default’ icon  612  is provided in the event of an improper entry or an out of sequence calibration. If the ‘Reset to Default’ icon  612  is selected, the load cell is returned to its default calibration value. Moreover, a ‘Cancel’ icon  614  is provided to cancel a pending calibration operation. Any number of load cells may be calibrated in the ‘Calibrate Cells’ GUI  590  following the sequence of steps provided above. 
         [0227]    The BioDAQ software tool also provides a measurement assessment feature so that the user may actively and visually observe weight measurements (also referred to as readings) real-time. The measurement assessment feature may be used as a software trouble-shooting tool, as described further below. 
         [0228]    Referring back to  FIG. 26 , selecting the ‘Version’ icon  557  launches the ‘Measurement Assessment’ GUI  616  shown in  FIG. 28 . To assess the real-time weight measurements associated with each PSC unit, an individual PSC icon  620  within the PSC matrix  618  is selected by the user. In the example illustrated in  FIG. 28 , PSC  7  is selected, as shown by the ‘Selected Cage’ display box  619 . The weight measurements of PSC  7  are illustrated in a graphical display  622  that displays weight measurement data with respect to time. 
         [0229]    In this exemplary embodiment of the BioDAQ system, the weight measurement readings of the selected PSC are transmitted to the BioDAQ software tool approximately once per second. Generally, BioDAQ performs a series of calculations upon every ‘n th ’ sequential measurement reading. Each series of ‘n’ sequential measurement readings represents one measurement time interval. The user may define the measurement time interval by entering a numerical value into the ‘n’ readings textbox  630 . In this embodiment, ten readings are entered into the ‘n’ readings textbox  630 , as shown. Thus, since one measurement reading is transmitted to the BioDAQ software tool every second and ‘n’ is set to ten, the measurement time interval is ten seconds and BioDAQ perform a series of calculations every ten seconds. 
         [0230]    The BioDAQ software tool calculates three quantities by means of defined algorithms once every measurement time interval. First, the software tool calculates an average mass of the food within the hopper (referred to as Grams) by averaging the lowest measurement reading of the sequential series (referred to as Min Grams) and the highest measurement reading of the sequential series (referred to as Max Grams). Second, the measurement algorithm calculates a measurement range (referred to as Max Range) by subtracting lowest measurement reading of the sequential series (i.e. Min Grams) from the highest measurement reading of the sequential series (i.e. Max Grams). The third calculation will be described below with reference to the graphical display  622 . 
         [0231]    Referring still to  FIG. 28 , the Max Grams, Min Grams, Grams and Max Range values, which were described above, are displayed in the exemplary graphical display  622  once every measurement time interval. The Max Grams data points, which are denoted by ‘+’ symbols, and the Min Grams data points, which are denoted by ‘x’ symbols, represent the maximum and minimum weight measurement readings over each measurement time interval, respectively. A series of Grams data points form the Grams trace  624 . The Grams data points represent the numerical average of the Max Grams and the Min Grams data point values. The most-current value of Grams is shown in display box  626 . The Max Range data points, which are denoted by ‘□’ symbols, represent the numerical difference between the Max Grams (‘+’ symbols) and the Min Grams data point values (‘x’ symbols). The Max Range may be considered as a gauge of the measurement resolution. 
         [0232]    As mentioned above, the BioDAQ software tool calculates three quantities by means of defined algorithms once every measurement time interval, two of which have already been described. The third calculation performed by the BioDAQ software tool once every measurement time interval is referred to as Mean Grams. Mean Grams refers to the mean value of all of the Grams data points displayed on the exemplary graphical display  622 . In this example, ten measurement time intervals are illustrated in graphical display  622 . Thus, the Mean Grams trace  628  represents the mean value of the Grams data points  624  over ten measurement intervals. 
         [0233]    The In Meal trace  628  denotes if the reading was recorded during a meal or if the reading was recorded during a state of inactivity. In this exemplary embodiment, an In Meal trace  628  displayed along the 1.0 hash mark of the Meal axis (i.e. the vertical axis displayed to the right of the graph) denotes that a meal was in progress, and an In Meal trace  628  displayed along the 0.0 hash mark of the Meal axis, as shown in  FIG. 28 , denotes that a meal was not in progress at the time of the recording. 
         [0234]    The BioDAQ software tool continuously compares the computed value of Max Range with the stored values of ‘Feed’ and ‘Noise’ illustrated in  FIG. 25  to gauge each PSC&#39;s feeding state. In this exemplary embodiment, three PSC feeding states exist, i.e. Feed, IBI and Quiet, which were described above with reference to  FIG. 26 . First, a condition where the value of Max Range is greater than the Feed value indicates that a meal has started or a meal is in progress for a particular PSC. BioDAQ consequently displays a ‘Feed’ message in the corresponding PSC icon  555  shown in  FIG. 26 . Second, a condition where the numerical value of Max Range is greater than the Noise value but less than the Feed value indicates that a meal is in progress for a particular PSC. BioDAQ consequently displays an ‘IBI’ message in the corresponding PSC icon  555  shown in  FIG. 26 . Third, a condition where the numerical value of Max Range is less than the Noise value indicates that a meal has ended and the “inter-bout interval” (IBI) has expired for a particular PSC. BioDAQ consequently displays a ‘Quiet’ message in the corresponding PSC icon  555  shown in  FIG. 26 . 
         [0235]    The measurement assessment feature may be used as a system trouble-shooting tool, i.e., the ‘Record Food Intake’ GUI  552  permits a user to easily compare real-time weight measurement readings with the stored values of Feed and Noise for each PSC. 
         [0236]    Referring back to  FIG. 26 , selecting any one of the PSC icons  555  displayed in the ‘Record Food Intake’ GUI  552  launches the ‘Data Viewer’ GUI  640  illustrated in  FIGS. 29-33 . The ‘Data Viewer’ GUI  640  provides a visual representation of animal feeding activity. The exemplary ‘Data Viewer’ GUI  6401  illustrated in  FIG. 29  graphically illustrates the average cumulative feeding habits of two distinct groups of animals, i.e. group A and group B, with respect to time and lighting conditions. For example, group A may represent control mice and group B may represent dosed mice. It is envisioned that it may be useful to display the feeding habits of different animals separately for the purposes of comparison. Moreover, it is also envisioned that it may be useful to display the individual feeding bouts or cumulative feeding habits of animals with respect to lighting conditions, temperature, or any other environmental conditions for the purposes of analysis. 
         [0237]    In the exemplary embodiment, the average cumulative food intake of Groups A and B is displayed over approximately 15 days, i.e. from Dec. 14, 2005 to Dec. 28, 2005. The average cumulative food intake of Groups A and B is tracked by traces  642  and  644 , respectively, and the status of the lights (i.e. Lights %) is tracked by trace  646 . Time is displayed on the horizontal axis of the graph; the lighting condition (i.e. Lights %) is displayed on the right vertical axis of the graph; and the cumulative food intake (i.e. Cumulative (g)) is displayed on the left vertical axis of the graph. Selecting the ‘Display Bouts A’ icon  648  displays trace  642 ; selecting the ‘Display Bouts B’ icon  650  displays trace  644 ; and selecting the ‘Display Lights’ icon  652  displays the trace  646 . The various traces may have different color, shading or shape, as shown in the trace legend  653 . The cumulative food consumption over the 15-day time period for both groups are displayed in the ‘Sum of last period’ display boxes  662  and  664  for Groups A and B, respectively. 
         [0238]    In this example, the Lights % is generally set to 85% each day and 0% each night. It can be observed that the animals consume more food at night than the day. Moreover, Group A consumed more food over the 15-day period on average than Group B. 
         [0239]    In the exemplary embodiment shown in  FIG. 29 , feeding data from eight of thirty-two PSC&#39;s is displayed in the exemplary ‘Data Viewer’ GUI  640   1 . The eight active PSC&#39;s are associated with, or members of, either Group A or Group B. It should be understood that one or more animals may be associated with each PSC. Each PSC is represented by two separate PSC icons  656  in a PSC Matrix  654  of the ‘Data Viewer’ GUI  640   1 . The top row of PSC icons  656  correspond to Group A and the bottom row of PSC icons  656  correspond to Group B. Selecting an individual PSC icon  656  on the top row denotes that the PSC is associated with Group A and selecting an individual PSC icon  656  on the bottom row denotes that the PSC is associated with Group B, as shown. The name of the group (i.e. A or B) is displayed on the individual PSC icons, as shown. In this example, PSC&#39;s  1 - 4  are members of Group A and PSC&#39;s  9 - 12  are members of Group B. Although not shown, it is conceivable that a PSC may be associated with more than one group. The total number of PSC&#39;s associated with each group is displayed in display boxes  658  and  660  on the ‘Data Viewer’ GUI  640   1 . The term ‘NA’ adjacent display box  658  refers to the total number of PSC&#39;s associated with group A and the term ‘NB’ adjacent display box  660  refers to the total number of PSC&#39;s associated with group B. 
         [0240]    The BioDAQ software tool calculates the average food consumption of the members of both groups A and B. The average cumulative food consumption of the four members of Group A is represented by trace  642  and the average cumulative food consumption of the four members of Group B is represented by trace  644 . It is envisioned that this feature may be useful if the groups comprise a large number of animals (and traces on the graph), which would make it difficult for a user to accurately interpret the graph. 
         [0241]    Referring now to the exemplary ‘Data Viewer’ GUI  6402  illustrated in  FIG. 30 , selecting the ‘Display Cages’ icon  670  displays the cumulative food consumption of the individual members of Group A and B. The four individual traces representing Group A are indicated by trace series  672  and the four individual traces representing Group B are indicated by trace series  674 . It is envisioned that this feature may be useful to view the feeding habits of a single animal or a group of animals associated with a single PSC. 
         [0242]    Referring now to the exemplary ‘Data Viewer’ GUI  6403  illustrated in  FIG. 31 , the cumulative food consumption and individual feeding bouts of Group B are illustrated with respect to time and lighting conditions. Selecting the ‘Display Bouts B’ icon  678  displays the individual feeding bout data points, denoted by ‘x’ symbols, which are scattered throughout the graph. In this example, Group B only includes one PSC, i.e. PSC  9 , as shown in the PSC matrix  654 . 
         [0243]    Referring now to the exemplary ‘Data Viewer’ GUI  6404  illustrated in  FIG. 32 , the cumulative food consumption of Group B is illustrated with respect to time and lighting conditions. However, in this exemplary ‘Data Viewer’ GUI  6404 , the cumulative food consumption measurement is reset at each Light % change event over a period of about three days (i.e. from Dec. 17, 2005 to Dec. 20, 2005). The cumulative food consumption measurement trace is designated by trace  692  and the Light % trace is designated by trace  646 . In this example, the cumulative consumption trace  692  resets to zero as the Light % trace  646  changes, and, in this example, the cumulative measurement trace  692  is reset to zero at about 7:00 and 19:00 on the dates Dec. 17, 2005-Dec. 20, 2005. This feature may be particularly useful for analyzing the cumulative food consumption for an animal or group of animals with respect to changing environmental conditions. The results of the analysis may provide insight into the habits and health of the animal. 
         [0244]    The Reset feature is controlled through the Reset drop down menu  686 , shown in  FIG. 32 . Selecting the ‘Light Changes’ option from the Reset drop down box  686 , as shown, resets the cumulative food consumption measurement at each light change, as previously described. Although not shown, the cumulative consumption measurement may be reset if the lights are turned on or off, by selecting those options in the drop-down menu  686 . Furthermore, selecting a particular time interval within the ‘repeat hours’ drop-down menu  688  resets the cumulative consumption measurement at specific time intervals and selecting a time within the ‘hour of reset’ drop-down menu  690  resets the cumulative consumption measurement at a specific time. 
         [0245]    Referring now to the exemplary ‘Data Viewer’ GUI  6405  illustrated in  FIG. 33 , the cumulative food consumption of Group B is illustrated with respect to time and temperature. Selecting the ‘Display Temp’ icon  694  displays the temperature trace  696  on the graph of the ‘Data Viewer’ GUI  6405 . The ‘Display Temp’ tool may be useful to analyze the food consumption with respect to the temperature of the feeding environment. Although only light and temperature data are shown and described herein, other environmental parameters, such as humidity, may be included in the ‘Data Viewer’ GUI. 
         [0246]    The BioDAQ software can be configured to disregard erroneous feeding bouts, such as when a PSC is being filled or refilled with food or calibrated by laboratory personnel. This feature of the software tool may be referred to as a bout filter. In particular, the software tool will disregard any feeding bout above the threshold value recorded in the ‘Max. Bout’ text box  680 . Similarly, the software tool will disregard any feeding bout below the threshold value recorded in the ‘Min. Bout’ text box  682 . 
         [0247]    The bout filter is configured through various settings within the drop down menu  684  shown in  FIG. 33 . By selecting ‘Include’ from the drop down menu  684 , as shown, the bout filter disregards feeding bouts above and below the Max. Bout and Min. Bout threshold values, respectively. By selecting ‘Exclude’ from the drop down menu  684 , the bout filter only includes feeding bouts above and below the Max. Bout and Min. 
         [0248]    Bout threshold values, respectively. The ‘Exclude’ feature may be useful for tracking fill, refill, or calibration events over time. Lastly, selecting ‘Not Filtered’ from the drop down menu  684  deactivates the bout filter, so that the Data Viewer displays every recorded feeding bout. In the exemplary Data Viewer GUI&#39;s illustrated in  FIGS. 29-33 , the bout filter is set to ‘Include’. 
         [0249]    Referring now to all of the figures, measuring and evaluating the ingestive behavior of laboratory animals is important in the study of animal behavior, metabolism, and perturbations thereof due to disease or therapeutic intervention. Although numerous advantages are achieved by remotely monitoring the health of animals, the presence of human interaction during the assessment of ingestive behavior may introduce error to the assessment through disturbance to the animal&#39;s native behavior by removing the animals from the cages or entering the room where the animals are feeding. 
         [0250]    The feeding and monitoring systems described herein bestow several advantages over the existing methods and systems for evaluating the feeding habits of laboratory animals. The animal feeding systems permit the user to measure and evaluate the ingestive behavior without disturbing the animal. Because the exemplary animal feeding systems are entirely automated, less manpower is required to measure and evaluate the ingestive behavior of laboratory animals. The act of feeding and measuring food consumption is also more consistent and repeatable by virtue of the exemplary feeding and monitoring systems. 
         [0251]    With regard to the health and safety of the animals, the exemplary feeding systems may be adapted to alert a user when an animal is not feeding properly, as opposed to relying on a human to identify a problem. The notion that a feeding system is capable of alerting a user to a feeding or health problem is founded on the idea that healthy animals generally eat a known quantity of food in a given period. Animals will eat approximately the same mass of food as the water they consume. Thus, if an animal eats ‘x’ grams of food in a twenty-four hour period, it will generally drink about ‘x’ grams of water in the same time period. A number of potential reasons exist to explain why an animal is not eating, such as, for example, the cage gate is closed, food is not available, water is not available, the animal is not acclimated to the food or the hopper, the animal is not hungry because of experiment protocol, or the animal is dead. Remotely monitoring the food intake permits a user to infer the health of the animal based solely on the food intake or food intake in conjunction with water intake. 
         [0252]    The exemplary monitoring systems bestow a single centralized monitoring system for the recordation and synthesis of feeding behavior. The lifetime feeding history of an animal may be recorded in the centralized system. Knowledge of the feeding habits and health of an animal over its lifetime may make the animal particularly useful and/or valuable for any variety of reasons. 
         [0253]    Although the invention is illustrated and described herein with reference to specific embodiments, the invention is not intended to be limited to the details shown. Rather, various modifications may be made in the details within the scope and range of equivalents of the claims and without departing from the invention. 
         [0254]    For example, the feeding mechanism is optionally provided with integrated behavioral paraphernalia such as a press bar, a light, or other stimuli. Also, the feeding mechanism is optionally provided with integrated environmental monitoring for ambient parameters such as in-cage temperature, humidity, light and other parameters. Additionally, the feeding mechanism is optionally provided with an integrated activity monitor, either discrete or by data-mining the feeding load cell. 
         [0255]    Additionally, and according to yet another aspect of this invention, the system can be configured to help a user to classify animals based on data retrieved and/or stored by the system. According to one embodiment, for example, the system can be configured to help a user to classify animals based on a few days&#39; data. In one exemplary application, for example, this ability to classify animals based on limited data makes it possible to classify animals as “naturally obese” or “not naturally obese.” 
         [0256]    For example, the remote node may optionally be eliminated and the data collection computer optionally communicates directly with the strain gauge cell, via a network, via a wired connection or wireless connection. In addition, another embodiment includes multiple remote nodes utilized with a single data collection computer. 
         [0257]    While preferred embodiments of the invention have been shown and described herein, it will be understood that such embodiments are provided by way of example only. Numerous variations, changes and substitutions will occur to those skilled in the art without departing from the spirit of the invention. Accordingly, it is intended that the appended claims cover all such variations as fall within the spirit and scope of the invention.