enrichment

Linda Brent, Ph.D.

Chimp Haven, Inc.

Southwest Foundation for Biomedical Research

Thomas M. Butler, D.V.M., M.S., DACLAM 

Southwest Foundation for Biomedical Research

Baboons

for nonhuman primates
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Baboons

Introduction

Nonhuman primates maintained in captivity have a valuable role in education 

and research. They are also occasionally used in entertainment. The scope of 

these activities can range from large, accredited zoos to small “roadside” exhibits; from national primate research centers to small academic institutions with 

only a few monkeys; and from movie sets to street performers. Attached to these 

uses of primates comes an ethical responsibility to provide the animals with an 

environment that promotes their physical and behavioral health and well-being. Thus, an obligation is entailed that those individuals/institutions caring for 

captive primates should make every effort to ensure adequate veterinary care and 

husbandry are provided, that the animals are housed in appropriate facilities, 

and that as broad a range of species-typical behaviors are able to be expressed by 

the animals as is possible for the captive environment.

This book serves as an introduction to the basic behavior and environmental 

enrichment of several species of nonhuman primates that are more commonly 

used in education, research and entertainment. In many ways, this book is 

meant to be a “how to” manual; it is not intended to be a broad scientific review 

of the primate behavior and enrichment literature. The fundamental premise 

taken throughout each chapter is that for an enrichment program to be effective, there must be a basic understanding of the biology and behavior of the 

primate species. The species addressed in this series are: baboons, capuchins, 

chimpanzees, macaques, marmosets and tamarins, and squirrel monkeys. Each 

species-section can be read as a stand-alone document without need to reference 

the other sections. This then allows the user to distribute the different sections 

to personnel caring for the specific animals. 

Each section is divided into five parts: 1) Background, comprised of the habitat 

of the primate, the physical features of the primate, its psychological and/or 

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ii

social behavior, and its mating and reproductive behavior; 2) Social World; 

3) Physical World; 4) Special Cases, describing any age-related considerations 

and concerns associated with individual housing; and 5) Problem Behaviors. 

The content of this series has been provided by members of the Association of 

Primate Veterinarians (APV) and the American Society of Primatologists (ASP) 

who have special expertise in the species addressed. This book is intended to be 

a primer because it is, indeed, an introduction to the subject of environmental 

enrichment for primates housed in a diversity of conditions. A list of references 

and/or other resources (principally on-line) is provided at the end of each chapter that provide additional guidance. The use of scientific references has been 

limited, but should the reader desire more information about a specific subject, 

the links at the end of the sections will provide direction to obtaining additional 

detailed information. Readers are also directed to the National Research Council 

publication, the Guide for the Care and Use of Laboratory Animals (1996) and 

the U.S. Department of Agriculture’s (USDA) Animal Welfare Regulations to 

review the regulatory requirements of the Public Health Service and the USDA 

for the provision of environmental enrichment.

The APV and ASP wish to thank the Office of Laboratory Animal Welfare, in 

particular Ms. Carol Wigglesworth and Dr. Axel Wolff; the U.S. Department of 

Agriculture/Animal Care, in particular Dr. Chester Gipson; and Ms. Dale Feurer, editor, and Ms. Lori Wieder, graphics and layout production, for their assistance with this project. The authors acknowledge the helpful contributions of 

Dr. David J. Shepherdson, Conservation Program Scientist, Metro Washington 

Park Zoo; Ms. April D. Truitt, Director, Primate Rescue Center, Inc.; and Ms. 

Kathleen Conlee, Program Officer, Humane Society of the United States. Special thanks also go to the chapter authors Dr. Christian Abee, Dr. Kate Baker, 

Dr. Linda Brent, Dr. Thomas Butler, Dr. Jeffrey Fite, Dr. Dorothy Fragazy, Dr. 

Jeffrey French and Dr. A. Michele Schuler, and to the reviewers from the American Society of Primatologists and the Association of Primate Veterinarians.

—Kathryn Bayne, M.S., Ph.D., D.V.M., DACLAM, CAAB

Editor, Working Group

This project is dedicated to the memory of Dr. Sylvia Taylor, Veterinary 

Medical Officer, Animal Care, U.S. Department of Agriculture, who 

was a proponent of providing enrichment to nonhuman primates and 

was generous in sharing her knowledge and expertise in this regard. 
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Baboons

Background

Habitat

Baboons live in many parts of Africa, primarily in dry savannah woodlands. 

They are the largest and most terrestrial, or ground dwelling, of the cheek pouch 

monkeys (Cercopithecines). There are five types of baboons--olive, yellow, red, 

chacma and hamadryas--which may interbreed to form hybrids in captivity 

and, in some places, in the wild. Olive and Yellow baboons are found in many 

areas of equatorial Africa and are typically called savannah baboons. Hamadryas 

baboons inhabit the highlands of Ethiopia. Red or guinea baboons live in gallery 

forest and woodland savannas of West Africa. Chacma baboons reside in southern African woodland to semi-desert habitats. Home ranges of baboons may 

cover approximately 10,000 acres.

Physical Features 

Baboons walk on all four limbs, and their forelimbs and hindlimbs are approximately the same size. Males (44 to 53 lbs.) are much larger than females (26 to 

35 lbs.) and have long canine teeth. The tail is moderately long and is typically 

held in a characteristic U-shape. Baboons have prominent ischial callosities, 

which are bright red in some species. They have a prominent muzzle. The life 

span of a baboon ranges from 20 to 30 years. 

Behavior 

Baboons have a number of distinct vocalizations, including:

• Alarm bark – loud, rapid, sound to indicate potential threat or challenge

• Lipsmack – short, repeated clicking of the lips or tongue, associated with 

friendly behavior and approaches to a dominant individual or infant
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• Grunt – low, snort-like sound, often associated with group unity or 

communication

• Ooer – moo-like sound made by infants in distress

• Gek – quick “aaack” indicating disturbance

• Scream – shrill, loud, high-pitched sound made when aggressive or fearful 

Other gestures that indicate a threat or aggression include brow raises that display white eyelids, yawns directed at a specific individual, hitting the ground or 

object rapidly (slapping), teeth grinding, and staring intently at another individual.

Baboons travel and feed during the day and sleep in trees or cliffs at night for 

protection from predators. Being very good scavengers, baboons can survive in 

areas that other primates cannot. They spend about half of their waking hours 

looking for, processing, and eating food. They may dig up roots and eat insects, 

lizards, small mammals, and even crabs or fish if near water. In captivity, they 

spend more time in social interaction and much less time feeding. Captive baboons can be fed a complete, commercially available diet, supplemented with a 

variety of other fruits and vegetables. 

 

Mating and 

Reproduction 

The female’s skin 

on her rump, or 

perineal area, swells 

greatly according 

to her menstrual 

cycle. This is usually referred to as 

sex skin. Hamadryas females have 

a particularly large 

sex skin swelling. 

During the period 

of maximal swelling, 

she will ovulate and 

be most receptive 

to mating. The sex Prominent sex skin on a baboon (photo by E. Glover, Southwest 

Foundation for Biomedical Research (SFBR)).
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Baboons

skin becomes flat and takes on a bright red or purple hue when she becomes 

pregnant. Gestation lasts from 18 to 24 weeks. Infants are born black with pink 

faces and bottoms. They need the mother’s protection, milk and transportation 

to survive. At about four to six months, the infant begins to change to the color 

of the adults. They are generally weaned by colony managers around five to six 

months of age, and although the natural weaning process will vary among baboon species, it generally occurs between one to two years of age. They become 

sexually mature at about three to five years.

Social World

Baboons live in a strict society. They clearly know their rank in the group and 

the rank of others, and behave toward others as appropriate for their dominance 

status. Baboons are very protective of infants and tolerant of juveniles, and 

males may carry and groom infants on occasion. Friendships have been reported 

between particular males and females.

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A social group of baboons (photo by E. Glover, SFBR).
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Baboons are incredibly social animals and should not be kept isolated. Infants 

should be kept with their mothers for at least a year to develop normal social 

skills. Compared to most other primates, baboons are fairly easy to put together 

into groups. Preferably, subspecies should be kept together, or at least in groups 

with similar structure as found in the wild, which can differ among and within 

species, probably based on the nature of the habitat in which the animals are 

found. Groups that combine a single male with multiple females are most common in captivity, but all-male groups also can be formed. Groups with multiple 

females and males are more difficult unless there is enough space for them to 

avoid aggression, especially fights over mates.

Physical World

Housing

In general, 

baboons are 

quite hardy and 

adaptable. They 

can be successfully housed in a 

variety of captive 

conditions, from 

indoor cages to 

large outdoor 

semi-free ranging enclosures. 

Sturdy cages are 

required because 

baboons are 

strong and will manipulate the cage a great deal. Cages should be constructed 

to prevent the baboons from pulling off pieces of the cage and eating them. 

Baboons favor high perches. While some facilities have successfully used old tires 

and ropes for resting areas and swings, others have reported that the baboons eat 

Baboon sleeping off the ground on a high shelf (photo by E. Glover, SFBR).

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the items and become sick. Alternative 

swings and resting areas can be constructed from metal or polyvinyl chloride. Large areas and/or visual barriers are 

necessary so that low-ranking individuals 

can avoid others. If aggression within the 

group is a problem, elevated resting areas 

or hiding areas should be added to help 

mitigate the aggression.

Enrichment

Feeding is a popular enrichment activity for baboons, who are very motivated 

by food. Due to their strict dominance 

hierarchy, only the most dominant male 

and female may eat food items provided 

to a group. To avoid this type of monopolization, it is best to scatter smaller 

food items all around the enclosure. In 

addition to feeding commercially available, nutritionally balanced diets, baboons can be offered food enrichments such 

as grains, fruits, vegetables, vegetation, bark, coconuts, peanut butter, dry fruit, 

honey, candy, cereal. The feeding of treats should not compromise the baboon’s 

appetite for the nutritionally balanced food, so the quantity of treats provided 

should be monitored closely. Baboons will also ingest items that are not healthy 

for them, such as rocks, wire, metal or other harmful materials. Bloat has been 

reported if baboons eat too many orange peels or gas-producing vegetables (e.g., 

broccoli), and they may become impacted if they eat too much hair, hay or 

wood.

 

Objects containing food must be heavy or they will be destroyed quickly. Puzzles 

made of sturdy materials, such as polyvinyl chloride (PVC), can be filled with 

treats. Toys on short chains can be coated with honey and dipped in grain, then 

frozen and hung on the cage, for a treat. Once the baboons eat the food, they 

can then play with the toy that remains. Frozen blocks of juice or water with 

fruit inside can be given to the baboons in the cage or enclosure, or hung from 

the roof with a chain. Locking nuts are necessary so the baboons do not unscrew 

the devices. Also, sturdy clips should be used to attach the device, and puzzles 

Baboon using a recycled and modified soap 

barrel for perching (photo by E. Glover, SFBR).
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should be removed 

when empty to keep 

the baboons from 

breaking them.

Since baboons manipulate and chew 

many objects, very 

sturdy dog toys make 

good baboon toys 

(e.g., rigid plastic 

balls; large, thick 

rubber toys; hard 

nylon dog chews). 

Hard, nontoxic logs 

or wood pieces can 

be used for chewing and even as perches. Pieces at least two to three inches in 

diameter are best so that they are not immediately destroyed. Wood items must 

be replaced on occasion 

and should be monitored 

so that large pieces or 

slivers do not endanger 

the baboons. 

Other types of enrichment include videotapes, mirrors, and wind 

chimes, which are especially helpful enrichment 

for singly caged baboons. 

Several commercially 

available enrichment 

items, including fleece 

boards made for grooming and plastic balls with 

holes in them and filled 

with treats, are not as 

useful for baboons and 

Baboon with durable toy (photo by E. Glover, SFBR).

Baboon on a shelf in enclosure (photo by E. Glover, SFBR).
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Baboons

probably not worth the 

expense.

New items may receive 

a lot of attention, but 

baboons will quickly tire of 

them. Replacement of toys 

or devices at regular intervals is important to keep 

the animal’s interest high.

 

Special Cases

Older animals usually will become more isolated from the troop, but not always. 

Since they can’t climb as well as their younger counterparts, they should have 

plenty to do at ground level. Food and water must be accessible near the floor, 

and food will have to be softened by soaking in water if the older baboon has 

lost some teeth.

Infants are curious creatures and will explore any opening. It is essential to make 

sure that all possible openings are covered to prevent entrapment or escape.

Baboon with Kong® toy 

(photo by E. Glover, SFBR).

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Problem Behaviors

Like other monkeys, baboons can develop problem behaviors for a number of 

reasons. Being taken away from the mother and raised by humans is a major 

cause of later abnormal behavior patterns, as the infant must learn to cope with 

the loss of the mother and grow up in an artificial environment. Boredom, stress 

and, ultimately, problem behavior may result from confinement in small enclosures, lack of enrichment activities, solitary housing, or housing that does not 

afford the animal ways to avoid more dominant individuals or frightening situations.

Examples of abnormal behavior patterns to watch for are hair eating and regurgitation. Extra feeding with food or “toys” can help to alleviate these behaviors that 

are related to boredom and not enough time spent feeding. Orphaned baboons 

often develop self-directed behaviors, such as self-sucking and clinging. They 

need appropriate attachment figures if they cannot be kept with the mother. One 

possibility is a mobile surrogate made of fleece-wrapped, three-inch PVC hung 

from the top of the cage. Exposure to peers or other friendly adults is critical 

to the orphan for normal development. It is very difficult to eliminate problem 

behaviors developed during infancy, but some individuals may be helped by 

gradually introducing them to friendly, perhaps younger, social partners.

More severe problems, such as self-biting, also have been reported in captive 

baboons. Intensive efforts are required to reduce or eliminate this problem. A 

daily program of enrichment, with documentation of items that seem to reduce 

the frequency of self-biting is required and may need to be continued for the life 

of the baboon. For individuals that increase self-aggressive behaviors when new 

enrichment items are provided, enrichment provided outside of the cage (such as 

in association with positive reinforcement training) can be more effective until 

the behavior is under control. Abnormal behaviors in baboons housed alone are 

greatly decreased when the animals are placed into social groups.

Some baboons are also very aggressive to one another, causing problems when 

they are put into new groups. This “hyper aggression” is more common in males 

and difficult to control, and it may be necessary to try multiple different partners, including females or even juveniles. It is important to observe the individual 

to determine what sets off the aggression, since it may be related to commotion 

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in the environment, feeding time, etc. This can help to indicate options that 

may reduce the behavior (e.g., moving to another cage, separating during feeding).

It is far more humane for the baboon and less work for the person to keep 

abnormal behavior patterns from developing. This can usually be accomplished 

by doing two things. First, keep infants with their mothers for about one year. 

Second, house baboons in social groups in large enclosures with enrichment to 

occupy their time.

Safety Issues

While they may have a reputation for being aggressive due to their size and large 

canines, baboons actually are mild-mannered and easy to work with compared 

to other primate species. They have elaborate threat displays that help to keep 

the peace in large groups, but actual aggression resulting in injury is not common. Given the size of baboons, it is not easy to “force” them into doing something, such as moving into a new cage. Greater success and a better relationship 

will develop if the baboons are treated with respect and positive interactions 

– and they will respond with cooperation and friendly behavior. 

Baboons can be trained with positive reinforcement to cooperate during a 

variety of management procedures, including transferring them to new areas, 

getting them to show parts of their body for inspection, and performing certain medical tests (i.e., blood pressure measurement). Given their keen interest 

in food rewards, ability to learn quickly, and generally relaxed attitude around 

humans, they make good pupils. People can maintain positive interactions with 

baboons by providing treats to the baboons and taking care not to frighten them 

by staring at them or moving suddenly.

Baboons should be sedated during physical examinations and other procedures 

that require physical handling, especially if they weigh more than about 11 to 15 

lbs. The best way to move them is via a system of chutes and doors. 

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References

Altmann J. 2001. Baboon Mothers and Infants. Chicago: University of Chicago 

Press.

Brent L, Koban T, Ramirez S. 2002. Abnormal, abusive and stress-related 

behaviors in baboon mothers. Biol Psychiatry 52(11):1047-56.

Brent L, Belik M. 1997. The response of group-housed baboons to three 

enrichment toys. Lab Anim. 31(1):81-5.

Brent L, Weaver D. 1996. The physiological and behavioral effects of radio on 

singly housed baboons. J Med Primatol. 25(5):370-4.

Easley SP, Coelho Jr. AM. 1991. Is lipsmacking an indicator of social status in 

baboons? Folia Primatol (Basel) 56(4):190-201.

Fortman JD, Hewett TA, Bennett BT. 2002. The Laboratory Nonhuman 

Primate. Boca Raton, FL: CRC Press. 

Kessel A, Brent L. 2001. The rehabilitation of captive baboons. J Med Primatol. 

30(2):71-80.

National Research Council. 1998. The Psychological Well-Being of Nonhuman 

Primates. Washington, D.C., National Academy Press.

Primate Lit: A Bibliographic Database for Primatology. 

http://primatelit.library.wisc.edu

Rowe N. 1996. The Pictorial Guide to the Living Primates. East Hampton, NY: 

Patagonias Press.

Smuts B. 2001. Friendship between the sexes: forming enduring relationships 

in an olive baboon troop. In The New Encyclopedia of Mammals, edited by D. 

MacDonald, 360-361. Oxford, England: Oxford University Press.

Common Names of the Baboons

Papio anubis or P. hamadryas anubis: Olive baboon, Anubis baboon

P. cynocephalus or P. hamadryas cynocephalus: Yellow baboon, Savanna baboon

P. hamadryas or P. hamadryas hamadryas: Hamadryas baboon, Sacred baboon

P. papio or P. hamadryas papio: Western baboon, Guinea baboon

P. ursinus or P. hamadryas ursinus: Chacma baboon

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Baboons
This series of booklets on enrichment for nonhuman 

primates was made possible through the cooperation of: 

~ Department of Health and Human Services

~ NIH, Office of Laboratory Animal Welfare (OLAW)

~ US Department of Agriculture, Animal Care

~ Association of Primate Veterinarians

~ American Society of Primatologists

For more information, contact OLAW at NIH

tel: (301) 496-7163, e-mail olaw@od.nih.gov

NIH Publication No. 05-5745

Department of Health and Human Services, 2005

enrichment for nonhuman primates