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PubMed1998

Comparative locomotion and habitat use of six monkeys in the Tai Forest, Ivory Coast.

The relationships between locomotion, body size, and habitat use in six sympatric Old World monkeys are examined to test whether the associations found are consistent with those demonstrated in previous studies (Fleagle and Mittermeier [1980] Am. J. Phys. Anthropol. 52:301-314; Gebo and Chapman [1995] Am. J. Phys. Anthropol. 97:49-76). Colobus polykomos, C. badius, C. verus, Cercopithecus diana, C. campbelli, and Cercocebus atys were studied for 14 months in the Ivory Coast's Tai Forest. Analyses reveal that (1) larger monkeys tend to frequent those strata containing the greatest densities of large supports while smaller monkeys are more diverse in their canopy use; (2) high frequencies of leaping are not necessarily confined to the understory, and understory specialists are not necessarily frequent leapers; (3) body size does not consistently predict leaping or climbing frequencies; (4) in general, climbing is more frequent during foraging and leaping is more common during travel; (5) larger supports are used during travel while smaller supports are used during foraging; and (6) larger monkeys do not always use larger supports than do smaller monkeys. Some of the factors contributing to the manner that locomotion, body size, and habitat use are related in cercopithecid monkeys are discussed.

Animals↗
PubMed1997

"Stepping-sticks" and "seat-sticks": new types of tools used by wild chimpanzees (Pan troglodytes) in Sierra Leone.

In Tenkere, Sierra Leone, a community of wild chimpanzees (Pan troglodytes verus) spent long hours eating the fruits and flowers of the Kapok (Ceiba pentandra) tree. The branches of this species are covered in sharp thorns which make movement in their high canopies problematic for the chimpanzees. In an apparent attempt to increase their mobility and to ease the discomfort of lengthy bouts of eating in these trees, some of the Tenkere chimpanzees have been observed using stick tools as foot ("stepping-sticks") and body ("seat-sticks") protection against the painful thorns. This form of tool-using is culturally unique to the Tenkere chimpanzees, as at other sites where these apes have been observed eating parts of kapok trees, there are no published records of this tool technology. In three of the stepping-stick tool use incidents, the chimpanzee used the tool(s), held between their greater and lesser toes, in locomotion. This form of tool use is the first recorded case of habitually used tools that can be justifiably categorized as being "worn" by any known wild population of Pan troglodytes.

Animals↗
PubMed1997

Foraging ecology and use of space in wild golden lion tamarins (Leontopithecus rosalia).

In this paper we describe the use of space and feeding ecology of seven groups of golden lion tamarins observed for a total of 2,164 hr in Poço das Antas Reserve, Rio de Janeiro, Brazil. Relative to habitat availability in the home ranges of these groups, lion tamarins spent more time than expected in relatively undisturbed swamp forests and less time than expected in more degraded hillside and pasture habitats. Home range area was correlated with group biomass but not group size. Golden lion tamarins fed primarily on fruits and small animal prey, but relied heavily on floral nectar during seasonal periods of relatively low fruit availability. Compared to other New World monkeys, lion tamarins used larger home range areas and exhibited longer daily path lengths than would be predicted by group biomass alone. We suggest that this pattern of foraging and use of space may be explained by the relatively greater availability of cryptic prey and their microhabitats in forests that are flooded and/or have closed canopies than in forests that are in earlier stages of succession where prey may be more susceptible to desiccation during the dry season.

Animals↗
PubMed1998

Lowland gorillas and seed dispersal: the importance of nest sites.

Lowland gorillas eat the fruit and disperse the seeds of many tree species in the Lopé Reserve, Gabon. This study aimed to show whether deposition of seeds at gorilla ground nest sites conferred any advantage for germination and seedling establishment as compared to the fate of seeds deposited in gorilla dung on trails or under parents. Four tree species were chosen for study, which had a range of fruit types and fruiting patterns but which were all important foods for gorillas. Data showed that gorillas removed significant quantities of seeds from all four species and deposited them in dung at nest sites or on trail. Nest sites were not always favorable for germination, but the most favorable sites permitted the best survival and growth of any of the seedlings, including those deposited in dung on trail or scatter-dispersed under or away from parent canopies. Initial performance in the first few weeks after deposition was not always indicative of long-term survival and growth, so data collection over 1-2 years was absolutely essential. The main factors affecting seedling fate at nest sites appeared to be vegetation cover and desiccation. It is suggested that the nesting habits of gorillas are an additional factor encouraging the successful establishment of seedlings over and above the obvious advantages of large body size, gut capacity, and extended day ranges.

Animals↗
PubMed1998

Sleeping sites, sleeping places, and presleep behavior of gibbons (Hylobates lar).

The sleeping habits of wild white-handed gibbons (Hylobates lar) were investigated to assess the risk of predation and predation-avoidance behavior. Sleeping sites were distributed throughout home ranges, including areas where they overlapped with neighbors, and appeared to be selected independently of habitat characteristics. Individuals did not build night nests or otherwise manipulate the vegetation around the sleeping place but slept on open branches. Group members usually slept in separate trees, and, except for females with infants, they never shared a sleeping place. Sleeping trees were entered several hours before dusk and were used for about 14-17 h. The majority of sleeping trees were used only once, and fewer were selected repeatedly by the same or other group members. Usually females with infants went into a sleeping tree first, then juveniles, and last were mostly subadult and adult males. Intragroup competition over access to a sleeping place was observed once. Average time difference between the first and last group member to enter a sleeping tree was 13 min. The sequence of departure from sleeping trees was more variable. Gibbon sleeping habits seem to primarily reflect adaptations to minimize predation risk. The predation-risk hypothesis was indirectly supported by observations of mobbing pythons, alarm calls given in response to birdes of prey flying low over the canopy, and more importantly by 1) the predominant use of large sleeping trees, which were among the tallest trees available, particularly by adult females with small infants and juveniles, 2) an unpredictable long-term pattern of reuse of sleeping places, and 3) inconspicuous presleep behavior.

Animals↗
PubMed1984

Energy expenditure estimation in recipients of marrow transplants.

The resting metabolic expenditure of seven allogeneic marrow transplant patients supported by total parenteral nutrition was monitored by respiratory indirect calorimetry using a portable apparatus with a plexiglass canopy. The averaged measurements of resting metabolic expenditure using indirect calorimetry were highly correlated with calculated basal energy expenditures, ideal body weights, fat-free weights, and actual body weights. No consistent correlation was demonstrated between resting metabolic expenditure and body temperature. It is concluded that indirect calorimetry using a portable system is feasible and that measurements of energy expenditure so obtained correlate well with calculated estimates employing the basal energy expenditure equation.

Adult↗
PubMed2002

Patterns of lateralized hand use in an arboreal primate, Simias concolor.

Studies of hand use in nonhuman primates suggest that several species exhibit hand preferences for a variety of tasks. The majority of studies, however, focus on the lateralized hand use of captive nonhuman primate populations. Although captive settings offer a more controlled environment for assessing hand preferences, studies of wild populations provide important insights into how handedness is affected by natural environmental conditions and thus potential insights into the evolution of handedness. To investigate handedness in a population of wild nonhuman primates, we studied patterns of lateralized hand use during feeding in four simakobu monkeys (Simias concolor), an arboreal species inhabiting the Mentawai Islands, Indonesia. Our data show that individual variation in hand preferences for feeding existed among our study animals. In addition, each simakobu expressed a significant hand preference for supporting itself on a branch during feeding, an uncoordinated bimanual task. This bias was most prevalent when the branch used for support was a main branch rather than a terminal branch. When both hands were employed in a coordinated bimanual feeding activity (bimanual manipulation), only two subjects showed a significant bias for feeding. Our data suggest that these individuals are more likely to express significant hand preferences when feeding from stable, rather than precarious, positions within the canopy.

Animals↗
PubMed2004

Use of spatial, visual, and olfactory information during foraging in wild nocturnal and diurnal anthropoids: A field experiment comparing Aotus, Callicebus, and Saguinus.

Early in their evolution, the ancestors of anthropoid primates radiated from a nocturnal to a diurnal niche. Foraging during the night differs from foraging during the day in terms of the availability of light and color cues, and in the movement of odor molecules through the canopy. In this study, we compared the ability of nocturnal and diurnal New World monkeys to use perceptual cues (i.e., the sight or smell of food) and spatial information (place predictability) in within-patch foraging decisions. An experimental field study was conducted on wild groups of night monkeys (Aotus nigriceps), tamarins (Saguinus imperator imperator and S. fuscicollis weddelli), and titi monkeys (Callicebus cupreus) at the Zoobotanical Park/UFAC, Rio Branco, Brazil. Our research design included the construction of feeding stations located in the home range of the study groups. Each feeding station consisted of eight visually identical feeding platforms located in a circular arrangement. In all test settings, two platforms at each feeding station contained a food reward (banana), and the remaining six platforms contained a sham reward (yellow plastic or inaccessible banana). In the night-monkey experiments, each feeding platform was illuminated by a 40-W red bulb to aid the researcher in observing their behavior. When the location of reward sites was predictable over time, individuals in all four species successfully relocated food rewards based solely on spatial information. Each species was also successful in using visual information to distinguish real from sham food rewards. However, only night monkeys and one group of emperor tamarins used olfactory information alone to locate food rewards. Overall, the species' performances did not clearly differentiate Aotus from diurnal New World primates in these experiments.

Animals↗
PubMed2005

Galago locomotion in Kibale National Park, Uganda.

Very few locomotor studies have been conducted on galagos. This is surprising given their interesting anatomy and ecology, as well as their increasing species diversity. In this study we investigated locomotion and postures in two sympatric galagos species (Galagoides thomasi and Galago matschiei) living in Kibale National Park, Uganda. G. thomasi uses arboreal quadrupedalism and leaping, while G. matschiei is more leaping-oriented. Both species utilize small oblique branches in the mid-canopy. These similarities in substrate use are most likely due to the similar body sizes and anatomies of the two species, as well as to the structure and availability of trees in Kibale National Park. Lastly, we compare the locomotor patterns of G. thomasi and G. matschiei with those observed in the few other quantitative locomotor studies available for galagos.

Animals↗
PubMed2006

Plant choice in the construction of night nests by gorillas in the Bwindi Impenetrable National Park, Uganda.

We investigated the choice of plants in nest sites and individual night nests of a group of gorillas (Gorilla beringei) in Bwindi Impenetrable National Park, Uganda. Most of the nests were built on the ground in secondary forest or canopy gaps. The gorillas used 62 plant genera in their nests out of a possible 108 plant genera available in the immediate environment. This group of Bwindi gorillas chose nest sites nonrandomly with respect to habitat type and selected nest sites in which Pteridium spp. or Mimulopsis spp. were the dominant plants. The Bwindi gorillas selected Pteridium spp. and Ipomea spp. to construct their individual night nests in greater quantities compared to their proportional availability in the immediate environment.

Animals↗
PubMed2007

Use of traps to capture black and gold howlers (Alouatta caraya) on the Islands of the upper Paraná River, Southern Brazil.

Howlers (genus Alouatta) are widely captured with the use of anesthetic projectiles; however, no capture protocol involving the use of traps has been described to date. In the present study we describe the first efficient capture program for black and gold howlers (Alouatta caraya) using traps, which was implemented on the islands of the upper Paraná River in southern Brazil. We constructed two trap models with either manual or automatic activation (trap A with two entrances and guillotine-type doors; trap B with one entrance and a guillotine-type door). The traps were suspended in the canopy by means of vertical climbing techniques, and were baited regularly and abundantly with bananas and mangoes. We captured 70 howlers (86% using manual activation and 14% using automatic activation) on four different islands. We restrained 41 of these animals and measured their body mass, which averaged 5.30 kg+/-1.79. Given our results, we suggest that the system described in the present study represents an alternative capture program for howlers in areas that have low food diversity and no other mammal species that will compete for the bait, as has been observed in riparian environments, islands, and forest fragments.

Alouatta↗
PubMed2002

Comparison of responses to alarm calls by patas (Erythrocebus patas) and vervet (Cercopithecus aethiops) monkeys in relation to habitat structure.

We studied responses to alarm calls of sympatric patas (Erythrocebus patas) and vervet (Cercopithecus aethiops) monkeys in relation to habitat structure, with the intention of understanding the relationship between the environment and predator avoidance. Patas and vervet monkeys are phylogenetically closely related and overlap in body size. However, while patas monkeys are restricted to nonriverine habitats at our study site, vervets use both nonriverine and riverine habitats, allowing us to "vary" habitat structure while controlling for effects of group size, composition, and phylogeny. Patas monkeys in the nonriverine habitat responded to mammalian predator alarm calls with a greater variety of responses than did vervets in the riverine habitat, but not when compared with vervets in the nonriverine habitat. Ecological measurements confirm subjective assessments that trees in the riverine habitat are significantly taller and occur at lower densities than trees in the nonriverine habitat. Despite the lower density of trees in the riverine habitat, locomotor behavior of focal animals indicates that canopy cover is significantly greater in the riverine than the nonriverine habitat. Differences in responses to alarm calls by the same groups of vervets in different habitat types, and convergence of vervets with patas in the same habitat type, suggest that habitat type can be a significant source of variation in antipredator behavior of primates.

Animals↗
PubMed2003

Mechanisms of force and power production in unsteady ricochetal brachiation.

Brachiators travel by swinging beneath handholds, and it is not obvious how these animals manage to accelerate and decelerate in a horizontal direction, especially when moving rapidly. Most previous analyses focused on brachiation in highly constrained laboratory conditions that induced steady-state locomotion. Emerging understanding of brachiation suggests that much of gibbon locomotory behavior and morphology must be considered within the context of the complexities of the natural environment: the forest canopy is three-dimensional, with high variation in handhold availability and properties. The goal of this paper is to quantify the active mechanisms by which gibbons can dynamically control their velocity. Force production and kinematics were analyzed from a white-handed gibbon Hylabates lar during ricochetal brachiation. Both the mechanisms of force production and power input may be inferred for accelerating and decelerating brachiation by combining force data with kinematics. Examples of steady-state, accelerating, and decelerating ricochetal brachiation are highlighted. Gibbons are able to produce net horizontal impulses by releasing early (resulting in a loss of potential energy, but an accelerating horizontal impulse) or delaying release (associated with an increase in potential energy, and a decelerating horizontal impulse). Torque about the shoulder, leg-lifting (or dropping), and elbow flexing (or straightening) are discussed as potential mechanisms for controlling energy within the brachiating system. Of these possibilities, leg-lifting and arm-flexing were observed as mechanisms of adding mechanical energy. Net energy loss, and substantial torques about the shoulder, were not observed.

Acceleration↗
PubMed2004

Multivariate analysis of organismal and habitat parameters in two neotropical primate communities.

This paper investigates the interrelations of some organismal and habitat parameters in two platyrrhine primate communities in French Guiana and Ecuadorian Amazonia. Fifteen habitat and organismal parameters and body weight were retained after a preliminary analysis, on the basis of frequent use and constraints reflected in anatomical specializations. The 16 parameters for 13 platyrrhine species were used for a series of principal components analyses (PCAs). All PCAs on separate or combined communities provided comparable results. The Atelinae, Ateles, Alouatta, and Lagothrix, were clustered together with Pithecia, associated with canopy, mature forest, frugivory, and (to a lesser degree) climb/suspensory locomotion. On the other hand, the three species of Cebus usually formed a loose cluster, located in the center of the cloud of species. Lastly, the Callitrichinae, involving two species of Saguinus and Cebuella, were relatively dispersed and frequently associated with liana forest, lianas, understory, and faunivory. However, Cebuella was consistently isolated and associated with liana forest, lianas, body weight, understory, and vertical supports. In this way, clusters appeared to conform to the major platyrrhine taxonomic groups, supporting the fact that basic ecological and behavioral adaptations have evolved in a phylogenetic context. In addition, the analyses revealed that body weight, forest type and layer, feeding behavior, and locomotion are the most important variables that have apparently shaped or driven the adaptive zones of extant platyrrhines.

Alouatta↗
PubMed2004

Circadian rhythms in diet and habitat use in red ruffed lemurs (Varecia rubra) and white-fronted brown lemurs (Eulemur fulvus albifrons).

Daily variation in niche use among vertebrates is attributed to a variety of factors, including thermoregulatory, reproductive, and nutritional requirements. Lemuriform primates exhibit many behavioral and physiological adaptations related to thermoregulation and sharp, seasonal reproduction, yet they have rarely been subjects of a quantitative analysis of circadian (or daily) rhythms in niche use. In this study, I document daily rhythms in diet and microhabitat use over an annual cycle in two sympatric, frugivorous lemurs, Varecia rubra and Eulemur fulvus albifrons. Data on diet, forest site, and forest height were recorded at 5-min time points on focal animals and divided into three time blocks for analysis (06:00-10:00 hr, 10:00-14:00 hr, and 14:00-18:00 hr). I employed multivariate tests of independence to examine daily rhythms in diet and microhabitat use according to sex, season, and reproductive stage. Throughout the day, V. rubra is frugivorous and dwells in the upper canopy, with notable departures (especially for females) during the hot seasons, gestation, and lactation. E. f. albifrons has heterogeneous daily rhythms of food choice and microhabitat use, particularly across seasons, and both sexes are equally variable. These daily rhythms in diet and microhabitat use appear related to thermoregulatory and nutritional requirements, seasonal food availability and circadian rhythms of plant (and possibly insect) palatability, predator avoidance tactics, and in the case of Varecia, to reproduction. Daily rhythms of food choice in V. rubra support two previously suggested hypotheses explaining why primates consume more nonfruit items late in the day, whereas those of E. f. albifrons are too variable to lend support to these hypotheses.

Animals↗
PubMed1984

Locomotion and postures of red howlers in a deciduous forest-savanna interface.

Positional (postural and locomotor) patterns and substrates used by the seven adults of a free-ranging troop of red howling monkeys (Alouatta seniculus) were identified and sampled during their feeding and resting. Traveling patterns and substrates were noted but not quantified. Arboreal locomotor behaviors were pronograde quadrupedalism, some leaping, bridging, lowering, and pull up. Sitting and reclining were the most frequent postures. Tail suspension and arboreal bipedal stance were used when feeding. Predominant locomotor behaviors were those in which limbs appeared to be compression stressed. There were no limbs suspensions. The monkeys used the entire tree canopy, that of the low shrubs, and did a good deal of travel on the ground. The lack of forelimb suspension is attributed to the inability of these howlers to hang beneath supports and look forward at the same time; the impediment is created by the size of the vocal organs in the neck. The locomotion of these monkeys is offered to depict that of Aegyptopithecus zeuxis.

Alouatta↗
PubMed1984

Ecological distinctions between sympatric species of Saguinus and Sciurus.

Tamarins are small New World monkeys that have been described as "squirrellike." Squirrels, along with bats and birds, are the taxa most likely to utilize resources similar to those used by primates in the tropical forest canopy. In this paper we compare differences in ecology, diet, locomotion, and habitat utilization between sympatric populations of tamarins (Saguinus oedipus) and tree squirrels (Sciurus granatensis) in Panama. Data presented indicate that although there is some degree of resource overlap, patterns of habitat utilization differ significantly. Rather than being "squirrellike," the Panamanian tamarin exhibits a pattern of locomotor and feeding behavior consistent with that found in other arboreal primates.

Animals↗
PubMed1992

Evolution of feeding niches in New World monkeys.

The adaptive radiation of modern New World monkeys unfolded as the major lineages diversified within different dietary-adaptive zones predicated upon a fundamentally frugivorous habit. The broad outlines of this pattern can be seen in the fossil record, beginning in the early Miocene. Cebids are obligate frugivorous predators. The smallest forms (Cebuella, Callithrix) are specialized exudativores, and the largest (cebines) are seasonally flexible omnivores, feeding particularly on insects (Saimiri) or "hard" foods, such as pith and palm nuts (Cebus), when resources are scarce. The smaller-bodied atelids (Callicebus, Aotus) may use insects or leaves opportunistically, but pitheciins (saki-uakaris) specialize on seeds as their major protein source. The larger atelines (Alouatta, Brachyteles) depend on leaves or on ripe fruit (Ateles). Locomotion, body size, and dietary adaptations are linked: claws and small body size opened the canopy-subcanopy niche to callitrichines; climbing and hanging, the fine-branch setting to the atelines; large size and strength, semiprehensile tails, and grasping thumbs, the extractive insectivory of Cebus; deliberate quadrupedalism, the energy-saving transport of folivorous Alouatta. Body size increases and decreases occurred often and in parallel within guilds and lineages. Conventional dietary categories, particularly frugivory, are inadequate for organizing the behavioral and anatomical evidence pertinent to evolutionary adaptation. Related models of morphological evolution based on feeding frequencies tend to obfuscate the selective importance of "critical functions," responses to the biomechanically challenging components of diet that may be determined by a numerically small, or seasonal, dietary fraction. For fossils, body size is an unreliable indicator of diet in the absence of detailed morphological information. More attention needs to be given to developing techniques for identifying and quantifying mechanically significant aspects of dental form, the physical properties of primate foods, their mode of access, and the cycles of availability and nutritional value.

Adaptation, Physiological↗