Trichuris Burdens in Zoo-Housed Colobus guereza

Trichuris spp. infect the majority of captive primate species along with an estimated 1049 million people worldwide, making it an important zoonosis [Stephenson, L. S., Holland, C. V., & Cooper, E. S. Parasitology, 121(Suppl.), S73–S95, 2000]. We investigated the efficacy of methods used to evaluate the prevalence of Trichuris spp. in 2 groups (n = 12) of socially housed Abyssinian colobus (Colobus guereza kikuyensis) at Paignton Zoo Environmental Park and the factors that may affect density. We collected individual and group fecal samples over 6 mo and estimated burden (egg counts/g of feces) of Trichuris spp. via the McMaster technique. Shedding was significantly higher in the afternoon than in the morning (matched-pairs t-test: t _[5] = −4.46, p < 0.01) and in dominant adult male colobus (Spearman rank: r _[5] = −0.94, p < 0.01; age: r _[5] = 0.89, p < 0.05). Parasitological studies of zoo-housed primates can be a useful tool to explore factors that may affect burdens of Trichuris spp. in them.     

Virus associated papillomas in colobus monkeys (Colobus guereza)

Numerous papillomas ranging in size from 1--10 mm were seen in four colobus monkeys (Colobus guereza). The lesions were confined to the fingers and toes and to the dorsal-lateral aspects of the hands and feet distal to the carpus and tarsus. Electron microscopy of two of the lesions revealed compactly arranged crystalline arrays of intranuclear virus particles in the epidermis. The particles were seen only in cells of the stratum granulosum and stratum corneum. By the negative stain technique, the non-enveloped spherical particles measured 52--58 mm in diameter. The arrangement of the capsomeres was consistent with an icosahedral symmetry. The observations suggested a viral etiology for the cutaneous papillomas similar to that of other mammalian species.     

Population size and habitat preference of the Omo River guereza (Colobus guereza guereza) in a multi-habitat matrix in the central highlands of Ethiopia

Primates - Given the current rate of habitat degradation and loss in the tropics, data on primate population densities and habitat use are indispensable for assessing conservation status and...     

Habitat quality,population dynamics,and group composition in Colobus Monkeys (Colobus guereza)

Data from an Ethiopian population of Colobus guerezashow that territory size is fixed by the high density of the population. Groups undergo fission when their size results in fewer than 10 trees per individual within the group’s territory. The daughter groups produced by fission emigrate into suboptimal habitat, which acts as a demographic sink. Comparative analyses using data from other East African populations demonstrate that mean territory size is inversely related to population density and that density, in turn, is a function of the size of the forest block. Since both group size and reproductive rates can be shown to be positively correlated with type of forest, it is concluded that this relationship reflects the fact that local population densities reach their ceiling more rapidly in small forest blocks because the animals’ access to alternative territories is limited. The number of males in a colobus group is shown to be a function of the number of females in it. Multimale groups have lower reproductive rates than one-male groups, probably because the stress generated by competition among the males causes temporary infertility among the females.     

Time Constraints Limit Group Sizes and Distribution in Red and Black-and-White Colobus

Researchers have shown that, in frugivorous primates, a major constraint on group size is intra group feeding competition. The relationship is less obvious in folivorous primates. We investigated whether colobine group sizes are constrained by time limitations as a result of their low energy diet and ruminant-like digestive system. We used climate as an easy to obtain proxy for the productivity of a habitat. Using the relationships between climate, group size, and time budget components for populations of Colobus and Piliocolobus at different research sites, we created 2 taxon-specific models. In both genera, feeding time increased with group size or biomass. The models for Colobus and Piliocolobus correctly predicted the presence or absence of the genera at, respectively, 86% of 148 and 84% of 156 African primate sites. Median predicted group sizes where the respective genera were present are 19 for Colobus and 53 for Piliocolobus. We show that the differences between the 2 genera are due mainly to intrinsic differences in the way each taxon’s digestive physiology interacts with climatic variables to influence resting time requirements. The models may help us explore their responses to climatic change in both the past and the future.     

Pattern, Distribution, and Function of Greeting Behavior Among Black-and-White Colobus

Various species of primates engage in greeting, a ritualized pattern of nonaggressive behavior that usually occurs during a reunion. Black-and-white colobus (Colobus guereza) perform overhead mounting, mounting, and embracing behavior soon after an aggressive act and in nonagonistic situations. We studied the pattern, distribution, and function of the greeting behavior in 2 captive groups of black-and-white colobus. Overhead mounting was the most frequent pattern, accounting for >60% of all greetings (N=333). In nonagonistic situations, younger subordinate individuals greeted an older dominant individual more frequently than vice versa. A dominant male in a small multimale group frequently initiated contacts with adult females, though he was the oldest in the group. Conversely, the dominant male in a large 1-male group never greeted group members. Immediately after performing the greeting, the greeter groomed the recipient in more than half the cases. In the large group, greeting frequency correlates positively with the age difference between the pair; however, there is no correlation between the relatedness, affiliation frequency, or aggression frequency of a pair in either the small or large group. The results are consistent with the hypothesis that greeting behavior functions as a tension-reducing mechanism in nonagonistic situations. There is no evidence, however, that greeting functions to express social status or to attract a mate. In addition, the frequent greeting by the adult male in the small multimale group may indicate that individuals affirm social bonds via greeting behavior.     

Use of sleeping trees by black and white Colobus monkeys (Colobus guereza) in the Kakamega Forest,Kenya

Groups of black and white colobus monkeys, or guerezas (Colobus guereza), observed in the Kakamega Forest, Kenya, had weak fidelity for sleeping sites. Groups often slept in trees near commonly used food sources, which might reduce the time and energetic costs of travel. Although the home range of each group overlapped with four to seven others, groups seemed to avoid sleeping near other groups, which would give them immediate and exclusive access to nearby food sources in the morning. The number of times a species of tree was slept in was positively correlated with its density. This may have occurred because so many suitable sites were available that proximity to feeding trees could be obtained whether or not groups slept in the feeding trees. Groups slept in tall trees, which provide stable sleeping sites and which may provide protection from both aerial and ground predators. Groups were more tightly clustered on nights with greater visibility, which might reduce the risk of predation. Am. J. Primatol. 45:281–290, 1998. © 1998 Wiley-Liss, Inc.     

Artificially generated cultural variation between two groups of captive monkeys, Colobus guereza kikuyuensis

The majority of studies of social learning in primates have tested subjects in isolation and investigated the effects of learning over very short periods of time. We aimed to test for social learning in two social groups of colobus monkeys, Colobus guereza kikuyuensis. Subjects were shown video footage of familiar monkeys either pushing or pulling a plastic flap to obtain a food reward, while they were given simultaneous access to the same apparatus. Action frequencies showed a significant difference between the two groups, with the pull group performing a higher proportion of pulls to pushes, compared with the push group. Copying persisted even in later sessions during which the demonstration footage was not being shown. We conclude that we successfully generated two contrasting behavioural traditions in these groups of monkeys. We do not know how long this contrast in behaviour would have persisted had we been able to continue testing for an even longer period of time, but further studies using similar designs and even longer test periods would have the power to confirm whether stable behavioural variation can be sustained between groups of monkeys, supported by social transmission.     

Intergroup Relationships in Western Black-and-White Colobus, <Emphasis Type="Italic">Colobus polykomos polykomos</Emphasis>

We investigated patterns of intergroup relationships in western black-and-white colobus, Colobus polykomos, in Taï National Park, Côte d'Ivoire, between 1993 and 1999. They live in one-male multifemale units, and demonstrate male dispersal and occasional dispersal by females. Solitary males and all-male bands are absent or very rare. Our aim was to investigate the function of female and male aggression during intergroup interactions. The species is particularly interesting because, in contrast to predictions from socioecological models, female aggression occurs during intergroup interactions in combination with female dispersal. Home ranges of neighboring groups overlapped considerably and groups lacked an area of exclusive access. Intergroup interactions occurred once every 6.6 observation days. Encounters were either peaceful (12%), or involved displays and threats (25%) or chases and fights (63%). Females interacted in 74% and males in 98% of aggressive intergroup encounters. We found little to no indication that male and female aggression correlated with the presence of food, importance of a location, or presence of infants or receptive females. However, females were more often aggressive during the months when the group depended strongly on seeds from Pentaclethra macrophylla. We also observed forays by males to other groups. Forays occurred on average once every 20 observation days. In 75% of the forays, the intruding male chased members of the target group. In 25% of the forays 1–3 females joined their male but females never attacked the target group. Our main study group was the target of such forays significantly more often when young infants were present in the group than when not. We conclude that female aggression between groups was related to food procurement and that male forays might be related to infanticide.     

Digestibility of a high-fiber biscuit-based diet by black and white colobus (Colobus guereza)

The acceptability and digestibility of a high-fiber biscuit-based diet was investigated using two adult male Colobus guereza animals. Although the animals were initially reluctant to accept the biscuit, it was eventually readily consumed. Apparent digestion coefficients for the diet (average composition, dry matter basis: 16% crude protein, 25% neutral detergent fiber (NDF), 9.5% acid detergent fiber (ADF), 1.2% acid lignin) determined by total fecal collection were 0.871 for dry matter, 0.813 for NDF, 0.693 for ADF, and 0.208 for acid lignin. Fiber digestive capabilities in C. guereza generally exceeded those reported in ruminant species based on predictive equations. Use of acid lignin and Cr₂O₃ as markers underestimated dry matter digestibility by 3.9 and 6.0%, respectively.     

Group Size and Composition of Colobus guereza in Kyambura Gorge, Southwest Uganda, in Relation to Chimpanzee Activity

We documented and assessed the influence of chimpanzee activity on group size and composition of Colobus guereza in Kyambura Gorge, southwest Uganda, from July to September, 1994 and in February and March 1996. The population density of colobus is very high: 347 individuals per km ². Density differed outside activity centers of chimpanzees (525 individuals per km ² ) and within the centers (186 per km ² ). We identified a total of 24 colobus groups, ranging between 3 and 13 individuals. Of the 24 groups, 22 were one-male groups. Groups were smaller and the percentage of subadults and juveniles was lower in groups within chimpanzee activity centers. Estimates of home ranges are between 1.7 and 6.2 ha, but neighboring home ranges overlapped 80%. Only a territory of approximately 0.5 ha was defended by the alpha male.     

Characterization of a novel simian immunodeficiency virus from guereza colobus monkeys (Colobus guereza) in Cameroon: a new lineage in the nonhuman primate lentivirus family

Exploration of the diversity among primate lentiviruses is necessary to elucidate the origins and evolution of immunodeficiency viruses. During a serological survey in Cameroon, we screened 25 wild-born guereza colobus monkeys (Colobus guereza) and identified 7 with HIV/SIV cross-reactive antibodies. In this study, we describe a novel lentivirus, named SIVcol, prevalent in guereza colobus monkeys. Genetic analysis revealed that SIVcol was very distinct from all other known SIV/HIV isolates, with average amino acid identities of 40% for Gag, 50% for Pol, 28% for Env, and around 25% for proteins encoded by five other genes. Phylogenetic analyses confirmed that SIVcol is genetically distinct from other previously characterized primate lentiviruses and clusters independently, forming a novel lineage, the sixth in the current classification. Cercopithecidae monkeys (Old World monkeys) are subdivided into two subfamilies, the Colobinae and the Cercopithecinae, and, so far, all Cercopithecidae monkeys from which lentiviruses have been isolated belong to the Cercopithecinae subfamily. Therefore, SIVcol from guereza colobus monkeys (C. guereza) is the first primate lentivirus identified in the Colobinae subfamily and the divergence of SIVcol may reflect divergence of the host lineage.     

Integration of Gorilla Females into Heterosexual Captive Groups

In captivity, gorilla females are exchanged between zoos. Integration processes might be accompanied by aggression from resident females towards the immigrant. Group size as well as individual factors are thought to influence frequency of aggression. For the present study, four introductions of females into three different captive groups were observed. It was hypothesized that establishment of a relationship between silverback and the new female is important for the integration process. Resident females were expected to be reluctant against new competitors for male service. Expectations were met, except for a juvenile immigrant. Resident females initiated most aggression, but male aggression also often increased against the new females. However, males and the resident immatures showed affiliations and closest proximity towards the immigrant. With one exception, the new females were responsible for establishing proximity to the male. Only one male supported the immigrant in conflicts and showed a high rate of control interventions. The role of the silverback is eminent, however, age and social experience of all involved individuals influence interactions.