bluuebunny/crossref_metadata_2025 huggingface dataset:
Infant Development in a Captive-Bred Aye-Aye (Daubentonia madagascariensis) over the First Year of Life
Authors: Feistner Anna T.C. , Ashbourne Caroline J.
Published: September 2008

An adult wild-caught female aye-aye (Daubentonia madagascaríensis) and her captive-bred offspring were studied for 2 weeks pre partum and 52 weeks post partum. Data on activity, substrate use, approach-leave interactions and social interactions were recorded in 30-min samples. Observations on the mother were started 10 days pre partum, and 2 h of data were collected on each of 9 days up to birth. Observations in each week were split evenly over 5 days and between two 4-hour blocks of time during the aye-ayes’ active (dark) period. Ten h of data were collected in weeks 1-24, 5 h in weeks 25-40 and 2.5 h in weeks 40-52. Infant development and patterns of interaction with the mother, in terms of responsibility for proximity, grooming, play and food-sharing behaviour are described. Comparison with other prosimians indicates that aye-aye infants develop relatively slowly. The infant aye-aye first emerged from the nestbox in week 8, tried solid food in week 14, but did not feed herself regularly until week 20, and was still food begging and attempting to suckle at a year of age. This long period of dependence is inferred to be related to the aye-aye’s unique percussive and extractive foraging techniques, which require fine motor coordination and skill, and which take time and practice to develop proficiency.
Tap-Scanning and Extractive Foraging in Aye-Ayes, Daubentonia madagascariensis
Authors: Erickson Carl J.
Published: September 2008

The trees on which aye-ayes forage contain complex communities of organisms. Aye-ayes appear to use tap-scanning behaviour, in combination with complex perceptual and inferential capabilities, to exploit these communities as a source of food. In doing so, they alter them, perhaps to their own advantage.
Preliminary Observations on Hand Preference for Tapping, Digit-Feeding and Food-Holding in Captive Aye-Ayes (Daubentonia madagascariensis)
Authors: Feistner Anna T. C. , Price Eluned C. , Milliken Garrett W.
Published: September 2008

Aye-ayes possess highly adapted hands, using their specialized third digits to investigate potential food sources by tapping and the third or fourth digits to transfer food to the mouth. Observations were conducted on 11 captive aye-ayes (10 wild-caught; 1 captive-bred) following presentation of food or novel objects, and hand use for holding, tapping and digit-feeding was scored. Eight of the individuals showed significant hand preferences for one or more of the 3 measures, although there was no consistent pattern. These preliminary results are compared to those from other lemur species.
Aye-Ayes: Specialists on Structurally Defended Resources
Authors: Sterling Eleanor J.
Published: September 2008

During the course of a 2-year field study on aye-ayes (Daubentonia madagascariensis), data were collected on dietary composition, food acquisition and structural properties of food resources. Aye-ayes in this study sampled remarkably few species from a variety of food types. A majority of these resources were heavily structurally defended and therefore difficult of access for other mammals. Aye-ayes used their modified finger and anterior teeth to harvest most of these resources.
Positional Behaviour in Captive Aye-Ayes (Daubentonia madagascariensis)
Authors: Curtis Deborah J. , Feistner Anna T.C.
Published: September 2008

The aye-aye shows numerous special features in its postcranial skeleton, partly in association with its unusual feeding habits and partly in association with locomotor specialisation connected with the possession of claws. This study examined the positional behaviour of 3 captive adult aye-ayes in order to throw light on these morphological specialisations. Locomotion was dominated by quadrupedal walking and climbing. Given the relatively large body size of aye-ayes, an unexpectedly high frequency of head-first descent was observed. This may provide an explanation for two characteristics of aye-ayes: robusticity of the shoulder girdle and high compressive and bending strengths of the humerus. Agile leaping was also observed, contrasting with previous reports that this species is characterised by slow, cautious movement. Specific morphological features that are shared with slow-moving lorisids may be attributable to a combination of frequent headfirst descent and postural suspension.
Phylogeny of the Lemuridae Revisited: Evidence from Communication Signals
Authors: Macedonia Joseph M. , Stanger Kathrin F.
Published: September 2008

Phylogenetic relationships among the extant lemurid prosimians were assessed cladistically using stereotyped vocal, olfactory, and visual communication characters. Among our results are 3 findings of particular importance. First, our data are consistent with those from several recent studies of highly repeated DNA fragments in supporting a close phyletic affinity between Lemur catta and the genus Hapalemur. Moreover, our results indicate that L. catta is nested within the Hapalemur clade as the sister taxon to Hapalemur griseusi’Hapalemur aureus. We interpret character states shared between Hapalemur simus and L. catta as primitive retentions by L. catta. Second, our findings agree with the DNA data in proposing a sister group relationship for Eulemur coronatus and Eulemur rubriventer. Third, our results question the validity of assigning Varecia variegata to the Lemuridae. For the characters we examined, Varecia more resembled indrids than lemurids, and the position of Varecia could be swapped with any of our outgroups (Indri, Propithecus, Daubentonia) without affecting tree topology. Previous workers sometimes have linked Varecia with various lemurids on grounds of ambiguously defined characters or on incorrect data gleaned from the literature. In those studies, the placement of Varecia in the Lemuridae usually has depended more on the minimization of character state conflicts (i.e. parsimony), than on demonstrable synapomorphies. In addition, data from DNA research have failed to demonstrate any pattern that links Varecia with Lemur, Hapalemur, oτ Eulemur. Results of the present study suggest that shared Varecia-indrid character states may be symplesiomorphic retentions in the Indridae, and that Varecia could be phyletically more primitive than either the indrids or lemurids.
Intergroup Grooming Relations between Alpha Females in a Population of Free-Ranging Rhesus Macaques
Authors: Judge Peter G. , de Waal Frans B.M.
Published: September 2008

Intergroup affiliation among female rhesus macaques, Macaca mulatta, was examined in the captive free-ranging colony of Morgan Island, S.C., USA. The provisioned colony has many social groups (35) and is maintained at a relatively high population density (21 animals/ha) with a relatively low adult male to female ratio (1:8.8). Focal and ad libitum samples were collected on 32 adults (3 males and 29 females) from two groups. Although infrequent, grooming was observed between adult females from different groups, and alpha females were the main participants in these interactions. Colony records indicated that none of the intergroup grooms was between females formerly from a common group. Relations between familiar neighboring groups may be maintained by a combination of both affiliative and aggressive behavior.
Significance of Silica in Leaves to Long-Tailed Macaques (Macaca fascicularis)
Authors: Lucas Peter W. , Teaford Mark F.
Published: September 2008

Leaves of two plant species eaten by Macaca fascicularis in Bukit Timah Nature Reserve, Singapore, were collected and colour-tested. Leaves matching those eaten by M. fascicularis were examined by energy-dispersive X-ray micro-analysis. The leaves of Streblus elongatus (Moraceae) and Gluta wallichii (Anacardiaceae), together forming 19.6% of the leaf diet of the macaques, contained silica. In G. wallichii, this is in the base of hairs that project from the underside of the leaf, whereas S. elongatus leaves have short sharp siliceous trichomes which are densely packed on the undersurface of leaf veins. We predict from an indentation analysis that chewing on the latter species could cause dental microwear at low occlusal forces. The leaves are reportedly common in the diet of three other primate species in peninsular Malaysia and the finding could have general significance for studies of dental wear.
Comparative Study of Oestrogen Excretion in Female New World Monkeys: An Overview of Non-Invasive Ovarian Monitoring and a New Application in Evolutionary Biology
Authors: Pryce C.R. , Schwarzenberger F. , Döbeli M. , Etter K.
Published: September 2008

Oestrogen was measured in urine samples collected from captive females representing 7 species of New World monkey to provide an overview of the applicability of such information in the non-invasive monitoring of ovarian function and to assess the potential applicability of such information in phylogenetic studies. Species available for study were the pygmy marmoset, common marmoset, red-bellied tamarin, cotton-top tamarin, golden lion tamarin, Goeldi’s monkey and the owl monkey. Oestrone conjugates were measured in serially collected urine samples to demonstrate ovarian cyclicity. Urine samples obtained during the luteal phase were subjected to HPLC to identify immunoreactive oestrogens; oestrone and oestradiol-17β accounted for almost all of the immunoreactive oestrogen detected while oestriol content was negligible. Urine samples obtained during the follicular phase and luteal phase were subjected to glucuronidase hydrolysis, sulphatase hydrolysis and acid solvolysis, which revealed that the major immunoreactive oestrogen metabolite was: (1) oestradiol sulphate in the pygmy marmoset and common marmoset, (2) residual oestradiol in the red-bellied tamarin, (3) residual oestradiol and oestrone glucuronide in the cotton-top tamarin, and (4) oestrone glucuronide in the golden lion tamarin, Goeldi’s monkey and owl monkey. A phylogenetic tree based on the above shifts in oestrogen excretion suggested that clawed New World monkeys are specialized and that the lineages leading to the study species split off in the following order: Goeldi’s monkey, golden lion tamarin, cotton-top tamarin, red-bellied tamarin, common marmoset and pygmy marmoset.
Foraging Synchrony in a Group of Yakushima Macaques (Macaca fuscata yakui)
Authors: Agetsuma Naoki
Published: September 2008

The synchrony of behaviour among individuals in a group of Yakushima macaques was evaluated in relation to group size and food resources. The degree of synchrony was greater when the group was small (5–8 individuals) than when it was large (15–19 individuals). Diet did not affect the degree of synchrony. However, the duration of the ‘active phase’, in which most members of the group synchronized feeding and moving, was shorter when they fed mostly on fruit and seeds (fruit- and seed-eating season) than when they fed mostly on leaves and fallen seeds (leaf- and fallen-seed-eating season). When the group was large, the monkeys ranged over a greater area and foraged in fewer trees during the fruit- and seed-eating season than during the leaf- and fallen-seed-eating season. However, this tendency was not so clear when the group was small. These results suggest that the extent to which the distribution of food resources determines patterns of foraging increases with group size and that monkeys in a larger group reduce levels of intragroup food competition in order to obtain sufficient food.
Hand, Mouth and Eye Preferences in the Common Marmoset (Callithrix jacchus)
Authors: Hook-Costigan M.A. , Rogers L.J.
Published: September 2008

Motor and sensory preferences were measured for 8 common marmosets (Callithrix jacchus). Three types of motor function were examined: spontaneous feeding, mouth use when chewing and visuospatial reaching. Eye preference was used as an index of sensory lateralization. The marmosets displayed individual preferences for the performance of the motor tasks, but no group biases were revealed. Correlations between preferences displayed on the motor tests suggest that one hemisphere may control spontaneous feeding and lateralized mouth use while the other controls visuospatial reaching, but no consistent preference was present. In an eye preference test, 7 subjects displayed right-eye preferences, suggesting hemispheric specialisation for this function.
Mandibular Advancement for Obstructive Sleep Apnea: Dose Effect on Apnea, Long-Term Use and Tolerance
Authors: Gindre Louise , Gagnadoux Frédéric , Meslier Nicole , Gustin Jean-Marie , Racineux Jean-Louis
Published: September 2008

Background: Previous studies have documented an effect of mandibular advancement (MA) on pharyngeal airway size and collapsibility. Objectives: We aimed to describe the course of the apnea-hypopnea index (AHI) and the snoring index (SI) during progressive MA and to evaluate the long-term efficacy, tolerance and usage of MA therapy after progressive MA titration in sleep apnea patients. Methods: Sixty-six patients with obstructive sleep apnea syndrome underwent sequential sleep recordings during progressive MA titration. Long-term effectiveness, compliance and side effects of oral appliance (OA) in the titrated position were evaluated by questionnaires. Results: OA therapy was started at 80% of the maximum MA. Seventy percent of the patients had only one increment in MA with a marked decrease in mean AHI from 36 to 10. In the remaining cases, further increments in MA were associated with a progressive reduction in AHI and an increase in the number of patients responding to treatment. OA in the titrated position resulted in a 70% decrease in AHI, with 54% of patients showing complete responses, 29% partial responses and 17% no response. Daytime sleepiness and quality of life improved, too. Seventeen months after the start of treatment, 82% of the patients declared that they were still using OA almost all nights. Reported side effects including subjective occlusal changes were frequent but mild. Conclusions: Improvement in AHI during OA is dependent on the amount of MA. Sequential sleep recordings facilitate MA titration. Long-term MA therapy in the titrated position is effective and well tolerated. Reported side effects are frequent but mild.
A Comparison of Radiographic and Anatomical Evidence of Tooth Development in Infant Apes
Authors: Winkler L.A.
Published: September 2008

This study assesses dental development in a sample of 8 known-age infant orangutans and chimpanzees in order to examine discrepancies between radiographic analyses of tooth development and the actual developing teeth. All crania were radiographed and any developing teeth then extracted for comparison. The height of deciduous teeth was measured both on the radiographs and on the extracted teeth to assess the accuracy of radiographic tooth measurements. A comparison between the radiographic and actual measurements of the deciduous teeth reveals substantial discrepancies. For permanent teeth, the degree of radiographic underestimation of tooth development was found to vary depending on the tooth being studied, its stage of development (early stages are particularly problematic) and the radiographic techniques used. Examination of the dissected teeth also revealed earlier times of onset of calcification for I22, C11, P3–43–4 and M2 than reported in previous studies. For the canine and M22, upper and lower homologues appear to begin development at different times, but there is no apparent difference in onset times between other upper and lower homologues.
Phylogenetic Relationships among Two Species of Golden Monkey and Three Species of Leaf Monkey Inferred from rDNA Variation
Authors: Wang Wen , Su Bing , Lan Hong , Zhang Ya-ping , Lin Shi-ying , Liu Ai-hua , Liu Rui-qing , Ji Wei-zhi , Hu Hong-guang , Xie You-xin , Wu Deng-hu
Published: September 2008

Restriction maps of rDNA repeats of five species of Colobinae and three out-group taxa, Hylobates leucogenys, Macaca mulatta, and Macaca irus, were constructed using 15 restriction endonucleases and cloned 18S and 28S rRNA gene probes. The site variation between Rhinopithecus roxellana and Rhinopithecus bieti is comparable to that between Preshytis françoisi and Preshytis phayrei, implying that R. bieti is a valid species rather than a subspecies of R. roxellana. Phylogenetic analysis on the 47 informative sites supports the case for Rhinopithecus being an independent genus and closely related to Preshytis. Furthermore, branch lengths of the tree seem to support the hypothesis that the leaf monkeys share some ancestral traits as well as some automorphic characters.
Emissary Canals in the Hominoidea and Their Phylogenetic Significance
Authors: Braga José
Published: September 2008

Two emissary canals of the skull base (the retroarticular and condylar canals) have been examined in a sample of 1,453 great apes. Our results imply that emissary vein patterns are distinct for orang-utans and African apes. In orang-utans the temporal sinus is frequently present and the retroarticular canal is often present. Orang-utans show a different external venous system in which the condylar canal is very rare. In orang-utans the retroarticular canal resembles the more primitive structure in prosimians and is probably homologous with it. In the African apes, as in humans, the temporal sinus regresses and the condylar vein is well developed. The complete absence of a retroarticular canal can be considered as a synapomorphy supporting the human-African ape clade and excluding Pongo. The enlargement of the condylar vein is much more frequent in the common chimpanzee. The dominance of the condylar vein over the temporal sinus appears to occur progressively during great ape evolution.
Centrilobular Fibrosis: An Underrecognized Pattern in Systemic Sclerosis
Authors: de Souza Romy B.C. , Borges Claudia T.L. , Capelozzi Vera L. , Parra Edwin R. , Jatene Fabio B. , Kavakama Jorge , Kairalla Ronaldo A. , Bonfá Eloisa
Published: September 2008

Background: The impressive association of lung involvement and gastroesophageal reflux in scleroderma raises the possibility of a cause-effect relationship. Objectives: To determine clinical, radiological and histopathological features of systemic sclerosis (SSc) patients according the presence or absence of centrilobular fibrosis (CLF). Methods: Twenty-eight SSc patients with lung involvement were submitted to open lung biopsy and the specimens classified for the presence of CLF (bronchocentric distribution of the lesions and intraluminal matter according to the classification of idiopathic interstitial pneumonia). HRCT, pulmonary function tests and esophageal analysis were also performed. Subsequently, cyclophosphamide was introduced for the nonspecific interstitial pneumonia subgroup and antireflux treatment was intensified for isolated CLF patients. Results: Isolated CLF was found in 21% of the biopsies and also found associated to nonspecific interstitial pneumonia in 84% of these patients. The other 3 cases had usual interstitial pneumonia, pulmonary hypertension and respiratory bronchiolitis-associated interstitial lung disease. The histopathological analysis revealed that all 6 patients with isolated CLF had the bronchocentric distribution and intraluminal basophilic content, with foreign bodies detected in one third of them. The central distribution of lung involvement on HRCT was found in 67% of these patients with a consistent patchy distribution (100%). Ground glass (67%) and consolidation (33%) were the predominant patterns found. The constant clinical finding in all isolated CLF cases was dyspnea, esophageal abnormalities and a moderate lung impairment (FVC: 63.83 ± 16.31%; DLCO: 61.66 ± 18.84%). Lung function parameters in isolated CLF patients remained stable after 1 year of exclusively intensive antireflux treatment (FVC, p = 0.23; DLCO, p = 0.59). Conclusions: The novel description of CLF pattern in SSc lung disease with peculiar histological, tomographic and clinical features will certainly contribute to a more appropriate therapeutic approach.
Functional Morphological Similarities in the Locomotor Skeleton of Miocene Catarrhines and Platyrrhine Monkeys
Authors: Rose M. D.
Published: September 2008

Noncercopithecid Miocene catarrhines share numerous features of their postcranial skeleton with extant platyrrhines, particularly pitheciines, cebines, and atelines. For any given fossil taxon, these similarities do not extend throughout the skeleton. Also there may be similarities to more than one platyrrhine taxon, within different parts of the postcranium, or even within a single bone. These similarities are of two types. Features that are most likely to be retentions from the primitive anthropoid condition are present in many Miocene taxa. They are part of functional complexes associated with the performance of quadrupedal and possibly orthograde climbing activities. Other features, especially present in nonhominoid primitive catarrhines, are related to the performance of suspensory behaviors, and reflect a partial convergence on the suspensory ateline condition.
Locomotor Differentiation and Different Skeletal Morphologies in Mangabeys (Lophocebus and Cercocebus)
Authors: Nakatsukasa Masato
Published: September 2008

The postcranial morphology of the arboreal white-cheeked mangabey (Lophocebus albigena) differs from that of partly terrestrial Cercocebus mangabeys (C. torquatus, C. galeritus). Its humerus has a reduced greater tuberosity, weak muscular insertions on the humeral shaft, less salient trochlear keels, a thinner diaphysis and less retroflexed medial epicondyle. The femur of L. alhigena is characterized by a lowered greater trochanter, a thinner shaft, a flattened distal epiphysis and a wide and shallow patellar surface. The forelimb is short relative to other limb segments. L. alhigena has attained these skeletal features by deducting the ancestral terrestrial adaptations, such as skeletal robusticity and joint restriction. Influences of phylogenetic inertia on the development of skeletal morphology are discussed.
Organization of the Epaxial Muscles in Terrestrial and Arboreal Primates
Authors: Kamakura Hiroo , Hirasaki Eislii , Nakano Yoshihiko
Published: September 2008

The erector spinae muscles of the patas monkey, hamadryas baboon, and spider monkey were dissected and the origins and insertions were described in detail. In the two terrestrial monkeys, a well-developed thoracolumbar segment of the muscle was observed. This trait seems to correlate to the sagittal movement of this region required in the pronograde quadrupedal locomotion. On the other hand, the erector spinae muscle of the spider monkey is quantitatively not so well developed and the arrangement of the muscle bundles was simpler than in the terrestrial monkeys. The arboreal habit of the spider monkey seems not to demand powerful extension in the thoracolumbar junction, and spinal rotation seems to be more important.
Distribution of Muscle Fibre Types in the Thoracic and Lumbar Epaxial Muscles of Japanese Macaques (Macaca fuscata)
Authors: Kojima Ryuhei , Okada Morihiko
Published: September 2008

Histochemical properties are investigated in the thoracic and lumbar epaxial muscles of Japanese macaques, Macaca fuscata. Whole transverse sections of the muscles were removed at the different levels of the thoracic and lumbar vertebrae and muscle fibre types were classified into type I and type II fibres on the basis of their histochemical profiles. In the lumbar region the iliocostalis and longissimus muscles have many type II fibres. In the thoracic region the iliocostalis muscle has more type I fibres than the longissimus muscle. The intermammillares and mammilloaccessorii muscles which lie medially and deep to the longissimus muscle in the lumbar region have an extremely large number of type I fibres. These differences in the distribution of muscle fibre types among and within muscles suggest that functional differentiation exists among and within the muscles.
Developmental Changes in the Fibre Composition of Elbow, Knee, and Ankle Extensor Muscles in Cercopithecid Monkeys
Authors: Jouffroy F.K. , Médina M.F.
Published: September 2008

Developmental changes of muscle fibre composition in the various heads of the elbow, knee, and ankle extensors have been studied in three genera of cercopithecid monkeys. In order to circumvent the technical hindrances of usual histoenzymological procedures (fresh muscles need to be frozen at once at -80 °C), immunofluorescence methods were used and technical adjustments were successfully carried out to make the study of formaldehyde-preserved muscles possible. Clear responses to antibodies against adult fast myosin in newborn macaques demonstrated that, at birth, adult myosins have already replaced the fetal isoforms, thus providing a reliable marker for the study of postnatal evolution of the muscle fibre composition. For each one of the three joints, from birth to adulthood, the percentage of slow, fatigue-resistant fibres increases only in that head of the extensor muscle groups which is specialized in maintaining posture by counteracting gravity (the ‘postural’ head). Hence, the question is raised of the relationships between such cytological evolution, developmental changes in postural behaviour, and body weight increase.
Biomechanical Reasons for the Divergent Morphology of the Knee Joint and the Distal Epiphyseal Suture in Hominoids
Authors: Preuschof H. , Tardieu Christine
Published: September 2008

The obliquity of the femoral diaphysis accounts for the valgus position of the human knee joint and reduces bending moments in the frontal plane. A high angle of obliquity is considered a hallmark of hominid bipedality, but its functional importance has rarely been identified correctly. A biostatic investigation of the knee joint in various realistic positions unveils resultant joint forces which do not deviate greatly from the long axis of the femoral shaft. This is due to the length of the femur and to the shortness of the human foot. The flat epiphyseal suture is more or less perpendicular to these joint forces, and the equal size of the femoral condyles reflects the even distribution of forces between them. In great apes the resultant forces acting in the knee joint vary considerably in dependence on the degree of flexion and rotation of the knee joint. The resultant joint force may be in line with the femur shaft or diverge. The epiphyseal surfaces offer facets to all joint forces found in the course of the study. Due to the pronounced varus position of the knee joint, the joint itself and the adjacent part of the femur are under medially concave bending moments, which lead to higher compressive forces at the medial than at the lateral condyle. The enlarged medial condyle allows the distribution of medially displaced joint forces over a relatively large area, and the elliptic cross-section yields high bending resistance in the frontal plane. A human-like angle of obliquity is present in the early australopithecines, the values being mostly within the range of variation of children. The valgus position of the australopithecine knee joint is considered to be a functional, and epigenetic consequence of habitual bipedality. It is particularly pronounced because of the short length of the femur and the great bitrochanteric width.
Footfall Patterns in the Early Development of the Quadrupedal Walking of Japanese Macaques
Authors: Nakano Yoshihiko
Published: September 2008

The development of quadrupedal walking in infant Japanese macaques (Macaca fuscata) was studied on the basis of their footfall patterns. Lateral views of the walking of 5 monkeys were taken by a video-camera and the timing of touchdown and liftoff was recorded. The total number of trials was 435. The change of footfall patterns during development was complicated. Four stages could be discerned, as in behavioural studies. In the first stage, there was a wide variation. The dominant patterns were the diagonal sequence which included any type of couplet in the second stage and trot in the third stage. There were two groups of footfall patterns in the fourth stage which were the diagonal sequence – diagonal couplet and the lateral sequence – lateral couplet. It seems that the stages reflect aspects of the development of both the neural system and the musculoskeletal system.
Centre of Gravity of the Body during the Ontogeny of Chimpanzee Bipedal Walking
Authors: Kimura Tasuku
Published: September 2008

Bipedal walking was studied in chimpanzees between 1 and 19 years of age by measuring the external energy generated by the movement of the centre of gravity of the body. The ‘recovery’ of external energy in infant chimpanzees less than five years of age is smaller than in juveniles from 5 to 19 years of age. During the single stance phase, the short, flexed hindlimb of chimpanzees younger than 5 years is not able to lift the body centre of gravity high enough, so that these infants have a considerable energy output during bipedal walking. Extension of the hindlimb is one of the bases for energy economy in human bipedalism. The development of this low-energy-cost mechanism is an important component of the evolution of human bipedalism.
Characteristics of Ground Reaction Forces in Normal and Chimpanzee-Like Bipedal Walking by Humans
Authors: Li Y. , Crompton R.H. , Alexander R.McN. , Günther M.M. , Wang W.J.
Published: September 2008

Bipedal walking by common chimpanzees is known to differ both kinematically and kinetically from human bipedalism, in particular by the adoption of flexed-knee gaits and characteristically single-peaked vertical ground reaction force curves. This study provides a test of the proposition that the two former mechanical characteristics are functionally related. Further, it examines the pattern of forces occurring during normal human bipedal walking at slow, normal and fast velocities; and during walking imitating bipedal walking of the common chimpanzee, by both male and female human adults and children. The data suggest that naturally reared chimpanzees walk with greater lateral forces than do adult humans walking erect. Women show greater variance in force parameters than do men; and children more than do adults, but men walk with greater vertical accelerations of the centre of mass, and sharper peaks of sagittal acceleration and deceleration than women. Data from both forceplate and pressure-pad records suggest that young children (and a chimpanzee for which force-plate data was available) accelerate using the heel, rather than the anterior part of the foot. A principal component analysis of Fourier coefficients for the force curves shows that forces produced by adults imitating chimpanzee gaits are intermediate between those produced in normal human gait and those produced by ‘real’ chimpanzees, confirming a functional connection between knee and hip kinematics during bipedal walking and the shape of the vertical ground reaction force curve. Human flexed-knee, flexed-hip walking is found to produce in-phase fluctuations in potential and kinetic energies, preventing the energy exchange which obtains in erect walking. Finally, computer simulations of bipedal walking indicate that kinematics are more influential determinants of ground reaction forces than are body parameters.
The Trajectory of the Point of Application of the Resultant Force of Body Mass at Different Walking Speeds. Statistical Analysis of Human Walking
Authors: Adachi Kazutaka , Nishizawa Satoshi , Endo Banri
Published: September 2008

Parameters of walking at ordinary, fast and slow speeds in 30 male and 30 female young adults were investigated. More than 10 trials were made for each speed by each subject. The number of subjects and trials was large enough to permit a statistical analysis. The focus of the study was the movement of the point where the resultant foot-ground force intersects the ground. Its pathway, or trajectory, begins at touchdown from the middle part of the heel, then runs quickly on a straight line to the heads of the first or second metatarsal bones, turns medially and moves slowly towards the base of the first toe, ending at the tip of the first or second toe, or between them. This result confirms that the ankle joint works like a hinge during the stance phase, and that the human foot structure is relatively robust. Remarkably high positive correlations between stride length and stature, as well as iliospinal height were found in male subjects. However in females these clear correlations were not found, except at fast walking speeds, although were not so notable as in males. Correlations calculated from the data from all female subjects indicated significantly quite high values, as in males, but it is almost impossible to estimate exact stature or iliospinal height reliably from stride length because of its relative high variation. The sexual difference in walking speed is not due to stride duration, but to stride length.
Utilization of Available Films and Records of Primates with Central Nervous System Lesions
Authors: Vilensky Joel A. , Gilman Sid
Published: September 2008

For many decades, ablation experiments were used to evaluate the function of central nervous system structures in primates. The use of this technique has greatly diminished with the development of neuronal unit recording. Nevertheless, the available films and written descriptions from prior ablation studies can still be used to further our understanding of: (1) the functional organization of the primate brain; (2) the differences in function between similar cerebral structures in primates and other mammals, and (3) ontogenetic changes in the functional characteristics of cerebral structures. We are in the process of making some of the films and records from these prior studies available to interested scientists.
Comparison of Locomotor Patterns and the Cerebellar Complex in Ateles and Macaca
Authors: Hirasaki Eislii , Matano Shozo
Published: September 2008

Kinetics and kinematics of the quadrupedal walking of Ateles and Macaca were studied, and the results were compared with those of vertical climbing. Macaca seems to use similar strategies for locomotion in climbing and walking horizontally, whereas Ateles apparently changes strategies. Next, volumetric comparisons of three cerebellar nuclei (M, I, L), the ventral pons (VP), the inferior olivary principal (Pr) and accessory (Ac) nuclei, and the vestibular nuclear complex (VES) were made by using size indices of each nucleus. Higher values are recognized clearly in the medial zone group (M, Ac, VES) of Macaca, whereas almost similar values are shown to exist in the lateral zone group (L, Pr, VP) of both species. Relationships between the kinesiological results and the development of the cerebellar system are discussed.
Application of the Minimum Jerk Model to Formation of the Trajectory of the Centre of Mass during Multijoint Limb Movements
Authors: Suzuki Masataka , Malsunami Ken’ichi , Yamazaki Yoshihiko , Mizuno Naoki
Published: September 2008

Smoothness of movement is an inherent characteristic of the motor repertoire of primates. According to the minimum hand jerk model, a major feature of motor coordination in two-joint upper limb movements by humans in the horizontal plane is the production of the smoothest possible movement of the end effector, the hand (‘hand version’). In the present study, this model was extended to the formation of the trajectory of the centre of mass (CMt) of the whole arm system (‘CMt version’), and its importance for the shaping of multijoint movements was tested against the classical ‘hand version’. During point-to-point movements between many pairs of targets in the work space, the movements of the CMt showed lower changes of torque than in movements of the hand on a straight path. Furthermore, the CMt version of the minimum jerk model reproduced the curved hand trajectory that can be observed in actual human performance. Under the assumption that the smoothness criterion is induced by a high-level motor coordination, our results suggest that CMt-based planning can be an alternative strategy for joint coordination. It offers the advantage of the simplified scaling of joint torques which are suitable for execution of planned movements.
Biomechanical Analysis of the Development of Human Bipedal Walking by a Neuro-Musculo-Skeletal Model
Authors: Yamazaki Nohutoshi , Hase Kazunori , Ogihara Naomichi , Hayamizu Noriyuki
Published: September 2008

A new computer simulation method, using a neuro-musculo-skeletal model, is used to clarify the process of acquisition of erect bipedal walking during human ontogeny. Walking was autonomously generated as a dynamic interaction called ‘mutual entrainment’ between the neural oscillation and the pendular movement of differently proportioned bodies. Walking patterns of humans with 8 different sets of alternative body proportions, varying from those of 8-month-old children to those of 22 years old adults, were simulated. The development of bipedal walking is characterized as the change from a forced oscillation controlled by the nervous system to the natural oscillation of pendular motion, determined by body proportions. Body proportions are the fundamental factor in the development of bipedal walking.
Relative Position and Extent of the Nasal and Orbital Openings in Gorilla, Pan and the Human Species from the Study of Their Areas and Centres of Area
Authors: Schmittbuhl M. , Minor J.M. Le , Schaaf A.
Published: September 2008

In order to quantify the relative position and extent of the nasal and orbital openings in hominoid primates, a new methodology based on image analysis was developed and applied to a series of 134 hominoid skulls (52 Gorilla gorilla; 30 Pan troglodytes; 44 Homo sapiens, and, as comparison material, 8 Pongo pygmaeus). The areas and the centres of area of the orbital and nasal openings were determined automatically. The orbitonasal triangle connecting these three centres of area was then constructed. This triangle was used to quantify the elongation of the face. It was most elongated in Gorilla, shortest in the human species and intermediate in Pan; the elongation in Pongo was close to that in Gorilla. The proportions of the areas of the orbital and nasal openings in the face were related to the extent of the bony structures of the midface and were thus used to quantify the facial robustness. A robust face was demonstrated in Gorilla, but a gracile face in the human species. Robusticity in Pan was intermediate.
Mothers in a Wild Group of Moor Macaques (Macaca maurus) Are More Attractive to Other Group Members When Holding Their Infants
Authors: Matsumura Shuichi
Published: September 2008

Social interactions between mothers that were holding their infants and other group members were studied in a wild group of moor macaques (Macaca maurus). Affiliative approaches to infants (AAI) by group members that were accompanied with particular behaviours, such as mouthing and touching or affiliative grunts, were observed frequently. Females approached mothers with infants more frequently than did males in all age classes. Female reproductive status, parity and dominance relationships between interactants had little effect on the frequency of approaches. Mothers received more grooming and performed less grooming when they were holding their infants than when they were not. A high level of social tolerance in macaque species with relaxed dominance styles might allow the free expression of AAI. Dominance styles among females and AAI could be linked via a positive feedback relationship since AAI might play a role in relaxing the dominance style among females.
Mate Preferences of Wild Muriqui Monkeys (Brachyteles arachnoides):Reproductive and Social Correlates
Authors: Strier Karen B.
Published: September 2008

Muriquis (Brachyteles arachnoides) are unusual among polygamous primates in the nonaggressive, egalitarian relationships that exist among group members. Yet, despite their relative freedom to express strong preferences in their choice of mates, 18 sexually active females and 10 sexually active males routinely copulated with multiple partners during a 60-month period from July 1990 to June 1995 at the Estação Biologica de Caratinga on Fazenda Montes Claros, Minas Gerais, Brazil. Females with different reproductive and social histories differed in the ways they expressed their promiscuity. The number of different partners was positively related to copulation frequencies for long-term female residents, but not for recent female immigrants or mature or young males. Mother-son matings and matings between recent female immigrants and males from their natal group were rare. Preferential mating occurred between recent female immigrants and young males, while experienced long-term female residents tended to copulate more frequently with mature males. Prior reproductive experience appears to be a less important determinant of muriqui mating patterns than the constraints imposed by avoiding close inbreeding and the preferences exhibited by close social associates.
Uncertain Conservation Status of Squirrel Monkeys in Costa Rica, Saimiri oerstedi oerstedi and Saimiri oerstedi citrinellus
Authors: Boinski Sue , Sirot Laura
Published: September 2008

Central American squirrel monkeys, Saimiri oerstedi, have never been abundant. This species is apparently extinct in Panama and nearly so in Costa Rica. Less than 4,000 are estimated to survive in Costa Rica. In recent years only a limited number of squirrel monkey troops have been documented outside of two Costa Rican national parks, Parques Nacionales Corcovado and Manuel Antonio. Numerous factors contribute to a pessimistic prognosis for this species, most importantly, the continued deforestation and tourist development with concomitant demands on prime squirrel monkey habitat from hotels, restaurants, roads, and vacation villas in the Pacific Wet Lowland habitat of squirrel monkeys. We also highlight features of the natural history of this species most relevant to conservation efforts with the goal of enhancing the success of surveys and maintenance and breeding of captive groups.
Feeding Behaviour and Predation of a Bat by Saimiri sciureusin a Semi-Natural Amazonian Environment
Authors: Souza Luciente L. , Ferrari Stephen F. , Pina Ana Lúcia C.B.
Published: September 2008

A free-ranging group of Saimiri sciureus was studied in a semi-natural forest habitat in eastern Amazonia, where behaviour patterns were broadly similar to those recorded for the species in the wild. According to focal-animal samples, the monkeys spent the vast majority of their time foraging and feeding, in particular for arthropod prey, which contributed almost half of identified food items. The predation of a small-bodied bat was also observed, although the study animals did not appear to forage systematically for chiropterans in the manner recorded for Saimirí oerstedi.
Effects of Habitat Quality and Hunting Pressure on Arboreal Folivore Densities in Neotropical Forests: A Case Study of Howler Monkeys (Alouatta spp.)
Authors: Peres Carlos A.
Published: September 2008

This large-scale geographic comparison examines the effects of subsistence hunting pressure and several indirect indicators of habitat quality on the abundance of howler monkeys {Alouatta spp.), the best studied and the most folivorous of all platyrrhine primates. Alouatta population densities were obtained from a standardized series of line-transect censuses undertaken at 23 Amazonian forest sites (1987–1995), including annually flooded (várzea), unflooded (terra firme), and eastern Amazonian transitional terra firme forests. A total of 83 density estimates from elsewhere were compiled from a comprehensive review of field studies from southern Mexico to northern Argentina. Howler density and biomass in Neotropical forests is profoundly affected by degree of hunting pressure, structural heterogeneity of the forest canopy, and to a lesser extent, the rainfall seasonality, total rainfall, and latitude of a given site. Mild gradients of forest elevation were a poor predictor of howler densities. In evergreen forests of lowland Amazonia, distance to major white-water rivers, which covaries with forest heterogeneity and soil fertility, is the best single predictor of howler densities. In Amazonia, habitat-specific patterns of distribution and abundance of Alouatta and other arboreal folivores conform to geochemical gradients determined by watershed types and their consequences for soil fertility. Results presented here confirm suggestions for Old World generalist herbivores that howler monkeys face strong dietary constraints which are most likely related to quality, phenology and productivity of digestible foliage during periods of resource scarcity.
The Ecology, Biogeography and Conservation of the Uakaris, Cacajao (Pitheciinae)
Authors: Barnett Adrian Ashton , Brandon-Jones Douglas
Published: September 2008

With the sakis (Pithecia) and the bearded sakis (Chiropotes), the uakaris (Cacajao) constitute the cebid subfamily, Pitheciinae. The most recent revision recognized six Cacajao subspecies in two species, confined to the Amazon basin. Before 1970 most field information derived from 19th century travellers. Studies still lag behind those of other cebid genera. This paper summarises the known ecology of Cacajao, and identifies future research and conservation priorities. The relevance of Pleistocene refugia and metachromism in analysing its biogeography is discussed. Range size remains obscure but, with the exception of C. c. calvus, may be extensive, as all other subspecies appear to migrate in the dry season from flooded riverine forest to terra firme. Observed group size ranges from 5 to 50, indicating the operation of a fission-fusion society. Social organization appears to be multi-male and non-hierarchical. This accords with the minimal sexual dimorphism. The highly developed canines function primarily as fruit openers. Cacajao is a dietary specialist on hard-shelled fruit, and appears unique among Amazonian cebids in its dependence (at least seasonally) on riverine forests. Hunting may be a problem locally, but local taboos sometimes offer protection. They appear vulnerable to habitat disturbance. On the Rio Negro, the range of C. m. melanocephalus appears to have greatly diminished. To ensure protection of viable populations, the inferred dietary dependence on seasonal migration may require accommodation. Research priorities include the status, habitat preference, diet and social ecology of all taxa except C. c. calvus. A more complete knowledge of the biogeography of the genus would be valuable.
Tamarin Mixed-Species Groups: An Evaluation of a Combined Captive and Field Approach
Authors: Buchanan-Smith Hannah M. , Hardie Scott M.
Published: September 2008

The geographical distributions of the tamarins Saguinus mystax, S. imperator and S. lahiatus do not overlap, but each of these species is sympatric with S. fuscicollis, and mixed-species associations are formed. One way to examine the costs and benefits of association is to compare mixed-species tamarin groups and single-species tamarin groups in the field. However, the stability and permanency of Saguinus associations mainly preclude such opportunities and comparisons between single- and mixed-species groups from different sites are confounded by a number of factors. However, predictions derived from field observations can be tested in captivity under controlled experimental conditions. In this paper, we evaluate the usefulness of testing hypotheses in captivity and describe an experimental study of vigilance in which the behaviour of single-species groups and mixed-species groups of S. fuscicollis weddelli and S. I. lahiatus was compared in order to determine the influence of each species on the other. The results demonstrate that the patterns of vigilance are both different and complementary. As such, they provide support for improved detection of predators as being one advantage of forming mixed-species groups. The discussion focuses on how the combined approach of systematic testing of hypotheses in captivity, together with field studies, can be employed to examine the advantages and disadvantages of Saguinus associations.