Locomotor behavior of wild orangutans (Pongo pygmaeus wurmbii) in disturbed peat swamp forest, Sabangau, Central Kalimantan, Indonesia

This study examined the locomotor behavior of wild Bornean orangutans (P. p. wurmbii) in an area of disturbed peat swamp forest (Sabangau Catchment, Indonesia) in relation to the height in the canopy, age-sex class, behavior (feeding or traveling), and the number of supports used to bear body mass. Backward elimination log-linear modeling was employed to expose the main influences on orangutan locomotion. Our results showed that the most important distinctions with regard to locomotion were between suspensory and compressive, or, orthograde (vertical trunk) and pronograde (horizontal trunk) behavior. Whether orangutans were traveling or feeding had the most important influence on locomotion whereby compressive locomotion had a strong association with feeding, suspensory locomotion had a strong association with travel in the peripheral strata using multiple supports, whereas vertical climb/descent and oscillation showed a strong association with travel on single supports in the core stratum. In contrast to theoretical predictions on positional behavior and body size, age-sex category had a limited influence on locomotion. The study revealed that torso orthograde suspension dominates orangutan locomotion, concurring with previous studies in dipterocarp forest. But, orangutans in the Sabangau exhibited substantially higher frequencies of oscillatory locomotion than observed at other sites, suggesting this behavior confers particular benefits for traversing the highly compliant arboreal environment typical of disturbed peat swamp forest. In addition, torso pronograde suspensory locomotion was observed at much lower levels than in the Sumatran species. Together these results highlight the necessity for further examination of differences between species, which control for habitat.     

Effects of body size and social context on the arboreal activities of lowland gorillas in the Central African Republic

The objectives of this 27 month study were to document the positional behaviors used by lowland gorillas (Gorilla gorilla gorilla) in the Central African Republic and to compare the effects of body size dimorphism on the use of arboreal substrates. During this study, despite their great size, all gorillas used trees regularly. Predictions concerning the relationship of body size to arboreal behavior were generally upheld. Small branch and suspensory activities were rare for silverbacks. Females used smaller and multiple substrates and suspensory postures more frequently than males. Although females foraged in the periphery of trees, males stayed close to the cores and rarely used terminal branches. In addition to body size, this study found that party size, social rank, and tree structure all influence an animal's substrate choice and subsequent positional activities. Lone males typically remained in the cores of trees where substrates are large. Group males may have been forced to use all parts of trees because others were present. Lone males used small crown trees which provided easy access to terminal branch foods. Males and females foraging together used larger trees (containing more feeding sites) than single sex groups. Female positional behavior may have been affected by the presence of males. When apart from males, females used the cores of trees and larger substrates more than when foraging with males. As habitat and social context both influence substrate use, they should be considered essential components of body-sized based interpretations of the behavior of fossil or extant species. © 1995 Wiley-Liss, Inc.     

Spatial structure in Mangabey groups

The spatial order of mangabey age-sex classes in progressions across canopy gaps was found to resemble strongly that of baboons. Greater peripherality of adult males (particularly dominant males) and centrality of independent juveniles characterized intragroup spatial structure whether the predominant group activity was feeding, social interaction, or movement. The similarities in spacing, despite striking differences in the number and nature of predators, between arboreal, forest mangabeys and terrestrial, open-country baboons suggest that intragroup spatial structure responds to factors other than predation.     

Locomotor and postural behavior in Alouatta palliata and Cebus capucinus

Positional behavior of two platyrrhine monkeys, Alouatta palliata and Cebus capucinus, was observed at La Pacifica and Santa Rosa National Park, Costa Rica. Frequency data for locomotion, postures, support diameters, orientation of supports, and use of canopy were recorded on focal males and females. Alouatta palliata is a frequent user of arboreal quadrupedalism (47%) and climbing (37%), with bridging (10%) representing the next most frequent type of locomotion. Intraspecific comparisons show the smaller-sized females of Alouatta to prefer very small diameter supports, the lower canopy, and to climb more frequently than the larger males—a pattern opposite to that which has been documented to occur with increasing body size across species. A more limited study on Cebus capucinus shows this species to be highly quadrupedal (54%) with moderately high locomotor frequencies for climbing (26%) and leaping (15%).     

Feeding Consequences of Hand and Foot Disability in Wild Adult Chimpanzees (<Emphasis Type="Italic">Pan troglodytes schweinfurthii</Emphasis>)

Many wild primates experience long-term limb disability, and their ability to cope with disability has implications for survival and fitness. We quantified the arboreal feeding and postural behaviors of adult chimpanzees to study the consequences of physical limb disabilities. We collected behavioral data for a total of 8 mo on chimpanzees at Sebitoli, Kibale National Park, Uganda, focusing on the time spent feeding, common feeding tree species, body postures, and substrate use. Of the 51 chimpanzees we observed, 16 (31%) exhibited limb anomalies, which varied in form and severity. Disabled chimpanzees climbed as high as chimpanzees without disabilities and did not differ from nondisabled chimpanzees in the amount they used feeding tree species. Adult chimpanzees with severe hand disability spent significantly more time feeding than nondisabled individuals. In addition, manually disabled adults did not suspend themselves from branches during feeding as frequently as nondisabled adults and used larger substrates for gripping and sitting than nondisabled adults. These results indicate that disabled individuals compensate to carry out feeding activities in trees.     

Positional behavior of Siberian chipmunks (Tamias sibiricus) in captivity

Arboreal and semi-arboreal mammals have remarkably diverse positional behavior and associated morpho-functional adaptations related to the three-dimensional nature of their arboreal habitat. In this context, we investigated the positional behavior of captive Siberian chipmunks (Tamias sibiricus), small bodied semi-arboreal sciurids, in an aviary-type wire-mesh cage containing both terrestrial and arboreal supports. We sampled four adult individuals during a five-month period using focal animal sampling every 30 s. Results showed that animals preferred 8–10 cm horizontal supports and always avoided vertical supports. Locomotion occurred on both terrestrial and 8–10 cm arboreal supports whereas postural behavior occurred primarily on 8–10 cm arboreal supports. Quadrupedal walk dominated during locomotion, and occurred primarily on terrestrial horizontal supports, as is observed for other squirrels. The predominance of quadrupedal locomotion is consistent with the postcranial morphology of chipmunks. In contrast, clawed locomotion occurred on wire mesh and on >13 cm arboreal vertical supports. Finally, pronograde and orthograde sitting, both on 8–10 cm arboreal supports and on terrestrial supports, were the predominant postures, implying general predisposition to selection of stable postures on stable supports for food item manipulation and ingestion.     

Behavioral thermoregulation in a sexually and developmentally dichromatic neotropical primate,the black-and-gold howling monkey (Alouatta caraya)

Behavioral thermoregulation in primates may provide a means for the conservation of heat during periods of low ambient temperature and/or food shortage as well as a way to dissipate heat under hot conditions. This article focuses on behavioral thermoregulation in a sexually dichromatic primate, the black-and-gold howling monkey (Alouatta caraya). Two models have been proposed to explain the evolution of sexual dichromatism in this species: thermoregulation and sexual selection. Five hypotheses associated with thermoregulatory behaviors are tested. These are as follows: (1) energy-conserving postures are used mainly under low ambient temperatures; (2) sunny resting places are selected during periods of low temperature; (3) exposure of the less-insulated ventral region to sunlight decreases with increasing temperature; (4) black-colored adult males use energy-conserving postures, sunny places, and exposure of the ventral region to sunlight less frequently than do blonde-colored adult females; and (5) smaller individuals use energy-conserving postures, sunny places, and exposure of the ventral region to sunlight in significantly greater frequency than do larger individuals. Over a 12-month period, behavioral data were collected on a free-ranging habituated group of 15–17 howlers of all age-sex classes. Ambient temperature was measured each hour. The results indicate that during resting, howlers showed a consistent use of heat-conserving postures, showed a preference for sunny places, and exposed their ventral region to sunlight under low ambient temperatures. A preference for shady places, heat-dissipating postures, and exposure of the back were observed under high ambient temperatures. Despite sex differences in adult color patterns and differences in size between age classes, no significant age or sex differences in thermoregulatory behaviors were detected. Failure to confirm a thermoregulation model implies that sexual selection may be responsible for sexual dichromatism in this species. Am J Phys Anthropol 106:533–546, 1998. © 1998 Wiley-Liss, Inc.     

Sex differences in adult chimpanzee positional behavior: The influence of body size on locomotion and posture

Focal animal instantaneous sampling of adult male and female chimpanzee positional behavior was conducted during a 7-month study in the Tai Forest, Ivory Coast, in order to determine whether there are sex differences in the locomotion, posture, substrate use, and height preference of sexually dimorphic adult chimpanzees, and if so, whether these differences support predictions based on body size differences. Results indicate that as predicted, adult male and female chimpanzees differ in their arboreal locomotor behavior, with the larger males using less quadrupedalism and more climbing, scrambling, and aided bipedalism than females during feeding locomotion. There is a sex difference in height preference as well, with female chimpanzees consistently using more arboreal behavior than males, primarily during resting. Although it has been previously demonstrated that separate primate species of differing body size differ in locomotor and postural activities (Fleagle and Mittermeier, 1980; Crompton, 1984), this study clearly demonstrates that body size differences within a species can also be correlated with differences in locomotor behavior. These findings may influence how we interpret sex differences in body size of extinct species. © 1993 Wiley-Liss, Inc.     

Seasonal variation in the positional behavior of red howling monkeys (Alouatta seniculus)

Recent studies on the positional behavior of primates reveal that significant seasonal variation occurs in both locomotion and postures that is related to changes in diet and foraging techniques. Howling monkeys (genusAlouatta), which also have a seasonally varied diet, are predicted to have correspondingly varied positional behaviors. Two groups of red howling monkeys were studied in a primary rain forest in French Guinana during the dry and wet seasons. During the dry season, when howler diet is based mainly on leaves, howlers traveled more frequently by quadrupedal walking on large supports, a mode of progression that is probably inexpensive energetically and relatively stable. During feeding, quadrupedal and tripedal stand contributed considerably, a posture probably associated with the equal distribution of leaves within a tree crown. In contrast, during the wet season, when fruit was abundant, howlers fed very frequently by sitting on large supports, probably because fruit consumption required more time for special manipulation. However, most seasonal changes in feeding postures, and in travel and feeding locomotion, were difficult to associate directly with dietary shifts. These behavioral changes may be more highly correlated with slight modifications in microhabitat use (horizontal and vertical daily ranges, similar and alternative arboreal pathways) that are not considered in this paper.     

Arboreal locomotor and postural behaviour of European red squirrels (<Emphasis Type="Italic">Sciurus vulgaris</Emphasis> L.) in northern Greece

The study of the locomotion and postures of arboreal squirrels may provide important contextual information on the evolution of the morphology and ecology of sciurids. In this context, we studied the positional behaviour and habitat use of four adult European red squirrels (Sciurus vulgaris L.) in a mixed coniferous forest in northern Greece. Our results show that, during the study period, S. vulgaris extensively used the forest canopy and the terminal branch zone. The use of small and medium supports of all orientations was also particularly frequent. The positional profile of the species was characterized by the dominance of quadrupedal, clawed and airborne locomotion along with seated and standing postures. Quadrupedalism and sitting appeared to promote terminal branch use for food access and manipulation, while claw climbing favored vertical ranging and retreat to trees after terrestrial foraging. Finally, leaping reduced energetic costs during travelling between food sites within the relatively dispersed forest. These results and those of previous research on the positional behaviour of other squirrels reveal several trends related to body size, arboreal or gliding habits and tropical or temperate forest distribution and contribute to the understanding of evolutionary novelty in multiple levels within the sciurid radiation.     

Arboreal Postures Elicit Hand Preference when Accessing a Hard-to-Reach Foraging Device in Captive Bonobos (<Emphasis Type="Italic">Pan paniscus</Emphasis>)

Arboreal, and in particular suspensory, postures may elicit a preference for the strongest limb to be used in postural support in large bodied primates. However, selection may have favored ambilaterality rather than a preference for a particular hand in chimpanzees (Pan troglodytes) fishing arboreally for ants. To investigate the influence of arboreality on hand preference we recorded handedness in seven captive bonobos (Pan paniscus) manipulating a foraging device during terrestrial and arboreal postures in a symmetrical environment, observing 2726 bouts of manipulation. When accessing the foraging device in the arboreal position the bonobos adopted predominantly suspensory postures. There was no population level hand preference for manipulating the foraging device in either the terrestrial or arboreal positions. However, four of seven individuals that interacted with the foraging devices showed a significant preference for one hand (two were left handed, two were right handed) when manipulating the foraging device in the arboreal position whereas only one individual (left handed) showed a preference in the terrestrial position. This suggests that individuals may have a preferred or strongest limb for postural support in a symmetrical arboreal environment, resulting in a bias to use the opposite hand for manipulation. However, the hand that is preferred for postural support differs between individuals. Although our sample is for two captive groups at the same zoo, our findings suggest that the demand of maintaining arboreal postures and environmental complexity influence hand preference.     

Locomotor ecology of wild orangutans (Pongo pygmaeus abelii) in the Gunung Leuser Ecosystem, Sumatra, Indonesia: a multivariate analysis using log-linear modelling

The large body mass and exclusively arboreal lifestyle of Sumatran orangutans identify them as a key species in understanding the dynamic between primates and their environment. Increased knowledge of primate locomotor ecology, coupled with recent developments in the standardization of positional mode classifications (Hunt et al. [1996] Primates 37:363-387), opened the way for sophisticated multivariate statistical approaches, clarifying complex associations between multiple influences on locomotion. In this study we present a log-linear modelling approach used to identify key associations between orangutan locomotion, canopy level, support use, and contextual behavior. Log-linear modelling is particularly appropriate because it is designed for categorical data, provides a systematic method for testing alternative hypotheses regarding interactions between variables, and allows interactions to be ranked numerically in terms of relative importance. Support diameter and type were found to have the strongest associations with locomotor repertoire, suggesting that orangutans have evolved distinct locomotor modes to solve a variety of complex habitat problems. However, height in the canopy and contextual behavior do not directly influence locomotion: instead, their effect is modified by support type and support diameter, respectively. Contrary to classic predictions, age-sex category has only limited influence on orangutan support use and locomotion, perhaps reflecting the presence of arboreal pathways which individuals of all age-sex categories follow. Effects are primarily related to a tendency for adult, parous females to adopt a more cautious approach to locomotion than adult males and immature subjects.     

Forest Structure and Support Availability Influence Orangutan Locomotion in Sumatra and Borneo

The influence of habitat structure and support availability on support use is an important aspect of understanding locomotor behavior in arboreal primates. We compared habitat structure and support availability in three orangutan study sites—two on Sumatra (Pongo abelii) in the dry‐lowland forest of Ketambe and peat swamp forest of Suaq Balimbing, and one on Borneo (Pongo pygmaeus wurmbii) in the disturbed peat swamp forest of Sabangau—to better understand orangutan habitat use. Our analysis revealed vast differences in tree and liana density between the three sites. Sabangau had a much higher overall tree density, although both Sumatran sites had a higher density of larger trees. The two peat swamp forests were more similar to each other than to Ketambe, particularly with regard to support availability. Ketambe had a wider variety of supports of different sizes and types, and a higher density of larger lianas than the two peat swamps. Orangutans in all three sites did not differ substantially in terms of their preferred supports, although Sumatran orangutans had a strong tendency to use lianas, not observed in Sabangau. Differences in observed frequencies of locomotor behavior suggest the homogeneous structure of Sabangau limits the locomotor repertoire of orangutans, with high frequencies of fewer behaviors, whereas the wider range of supports in Ketambe appears to have facilitated a more varied locomotor repertoire. There were no differences among age‐sex classes in the use of arboreal pathways in Suaq Balimbing, where orangutans selected larger trees than were typically available. This was less apparent in Sabangau, where orangutans generally used trees in relation to their environmental abundance, reflecting the homogeneous nature of disturbed peat swamp forest. These results demonstrate that forest architecture has an important influence on orangutan locomotion, which may become increasingly important as the structure of orangutan habitat continues to be altered through human disturbance. Am. J. Primatol. 74:1128‐1142, 2012. © 2012 Wiley Periodicals, Inc.     

Diet and feeding behaviour of the black-and-white ruffed lemur (Varecia variegata variegata) in the Betampona Reserve, eastern Madagascar

The feeding behaviour and diet of the black-and-white ruffed lemur (Varecia variegata variegata) was investigated in the Betampona Reserve, eastern Madagascar. The highly frugivorous diet of this subspecies was confirmed - feeding on fruits accounting for 92.0% of feeding records. Most feeding at Betampona was observed at 10-25 m above the forest floor amongst flexible, small (0.5-5.0 cm diameter) and oblique/horizontal (0-45 degrees ) supports. The Varecia spent on average 21.7% (+/- 1.5) of their daily activity budget feeding and employ a variety of postures that enable them to harvest fruits in the rain forest canopy. The suspensory postures were the most important in allowing Varecia to compete with other smaller-bodied frugivores.     

Modification of aggression through socialization and the special case of adult and adolescent male rhesus monkeys (Macaca mulatta)

Significant differences exist in the frequencies with which age-sex classes of rhesus macaques engage in agonistic interactions with other age-sex classes. In the study reported here, individuals engaged in significantly more agonistic interactions within their own age-sex classes, but, adult females also showed significantly more aggression toward infants and young females whereas adult males directed significantly more aggression toward adolescent males. Infants directed aggression toward infants of both sexes, but adults showed significantly less aggression toward adults of the opposite sex. These findings are hypothesized to reflect (1) competitive conflict among those individuals in the group most similar to each other (members of the same age-sex class); (2) the protection and socialization of offspring by adult females; and (3) the modification of adolescent male aggressive expression by the selective interference of adult males. As a consequence of adult response to the agonistic behavior of adolescent males, maturing males (1) selectively target other older males, avoid aggression against females and immatures; (2) form alliances with other males; and (3) become progressively isolated from their matrilines.     

Locomotion and Posture During Terminal Branch Feeding

We investigated locomotor and postural behavior during terminal branch feeding in order to gain a better understanding of the motor capabilities of primates. We videotaped wild, juvenile bonnet macaques (Macaca radiata) in India as they fed on flower nectar in a simal tree (Bombax malabaricum). Kinematic analysis revealed that they select specific support surfaces and movements that, for their body design and postures, maximize lateral stability and minimize the chances of falling. These choices are made even though the distance and duration of travel to a selected target are frequently increased. Our discussion focuses on particular concepts of how primates contend with balance problems arboreally, potential reasons for changes in footfall patterns, and how the tail contributes to arboreal locomotion and posture. We concluded that balance problems due to the ratio of body size to branch size are usually avoided, at least among juvenile bonnet macaques, by placing the hands and feet on branches extending laterally from the central support branch and not on the central branch itself. The lateral branches permit a wide base of support, which increases lateral stability. Second, juvenile bonnet macaques have a striking ability to rapidly and repeatedly adapt their gait patterns to changing substrate design with minimal interruption to overall progression. Third, primate tails that are not morphologically specialized for prehension nevertheless have important prehensile and sensory functions in arboreal locomotion and posture.     

Program of the fifty-sixth annual meeting of the American Association of Physical Anthropologists to be held in New York City Vista International Hotel April 2–5, 1987

Male orangutans (Pongo pygmaeus) weigh about twice as much as females. Observations in northern Sumatra of adults of both sexes (one male, three females) feeding in the same trees reveal the effects of body size dimorphism on feeding behavior: The male tended to use larger branches than the females, and to employ above-branch postures (sitting and standing) with greater frequency. The females employed suspensory under-branch postures more often. When feeding techniques were variable, the male tended to pull in branches to detach food with the mouth, whereas the female plucked more fruit by hand. By controlling for postcranial morphology and habitat structure, these results provide the first rigorous quantitative test of predictions about the effects of body size on primate positional behavior, and raise further questions about sexual diethism in feeding postural behavior of primates of varying absolute size.     

Observations on the woolly monkey (Lagothrix lagothricha) in northern Colombia

Woolly monkeys,Lagothrix lagothricha, were briefly studied in a cloud forest in Bolivar, Colombia during the dry season. Results suggest that this species is wholly arboreal, lives in multi-male heterosexual groups and does not defend territory. Woolly monkeys are folivorous and frugivorous. Social and auto-grooming are both reported. All age-sex classes except natal-coated infants and adult males indulge in play. Agonistic behaviour is very rare. There seem to be various consistent patterns of greeting behaviour and scent-marking of the environment was observed. Woolly monkeys tended to approach the observers rather than flee from them. They were observed in close proximity toCebus, Alouatta, andAteles species.     

Locomotion and feeding postures of spider and howling monkeys: field study and evolutionary interpretation

Field observations demonstrate clear differences in locomotion and feeding postures between spider monkeys (Ateles) and howling monkeys (Alouatta). When feeding, Ateles employs sitting postures approximately half the time, and a variety of suspensory postures using the tail the other half. Ateles moves quadrupedally during 52% of locomotion, by tail-arm suspension 25%, and various mixed support-suspensory modes the remainder. Tail-arm suspension is practiced more rapidly on thinner supports, and on more negatively inclined supports than is quadrupedal movement. Howlers do not locomote by tail-arm suspension: movement is almost entirely quadrupedal and is slower than that of spider monkeys. The positional behavior of spider monkeys fits closely recent views of major adaptive changes in hominoid evolution emphasizing brachiation and speed during travel. Howler locomotion and also tissue composition appear related to diet and digestive mechanisms.     

The behavioral repertoire of the black-and-white ruffed lemur, Varecia variegata variegata (Primates: Lemuridae)

A stable social group of 7 semifree-ranging black-and-white ruffed lemurs (Varecia variegata variegata) was studied for 4 months to catalog the behavioral repertoire of this species. Observations focussed on particular aspects of behavior were conducted before and after this 4-month period to supplement information gathered. Behavior in 11 major categories is detailed: postures, terrestrial locomotion, arboreal locomotion, feeding behavior, vocalizations, scent-marking, affinitive social behavior, agonistic social behavior, play behavior, sexual behavior, and parental behavior. Ruffed lemurs frequently used body positions and locomotor patterns unusual among lemurids, including bipedal hanging and long-descent leaps. These behaviors reinforce dental evidence that Varecia are among the most frugivorous of the Malagasy lemurs. Low intragroup cohesion, infrequent social interaction, and antiphonal use of several long-distance vocalizations suggest that ruffed lemurs naturally exhibit fission-fusion sociality. Social structure based on interindividual familiarity probably extends across foraging parties for several of the diurnally active lemurs; however, thus far only Varecia seems likely to exhibit fission-fusion sociality analogous to that seen in spider monkeys and chimpanzees.