Frances J. White’s research while affiliated with University of Oregon and other places

Hair plucking has been observed in many captive primate species, including the great apes, however, the etiology of this behavioral pattern is poorly understood. While this behavior has not been reported in wild apes, an ethologically identical behavior in humans, known as trichotillomania, is linked to chronic psychosocial stress and is a predominantly female disorder. This study examines hair plucking (defined here as a rapid jerking away of the hair shaft and follicle by the hand or mouth, often accompanied by inspection and consumption of the hair shaft and follicle) in a captive group of bonobos (N=13) at the Columbus Zoo and Aquarium in Columbus, Ohio. Plucking data were collected using behavior and all-occurrence sampling; 1450 social and self-directed grooming bouts were recorded during 128 hours of observation. Twenty-one percent of all grooming bouts involved at least one instance of plucking. Urine samples (N=55) were collected and analyzed for the stress hormone cortisol. Analyses of urinary cortisol levels showed a significant positive correlation between mean cortisol and self-directed plucking for females (r=0.88, p<0.05) but not for males (r=-0.73, p=0.09). These results demonstrate an association between relative self-directed hair plucking and cortisol among female bonobos. This is the first study to investigate the relationship between hair plucking and cortisol among apes. Overall, these data add to our knowledge of a contemporary issue in captive ape management.

Research on wild apes is not only fundamental for elucidating human origins but for their conservation as well. Despite their relative size, apes are difficult to observe in the wild prior to habituation, limiting our ability to accurately assess demography and kin relations. Non-invasive genetic sampling provides an indirect source of this information. Here, we present findings of a pilot genetic survey of a wild community of bonobos that are in the initial stages of being studied. Fifty-three fecal samples were collected over eight days near the Iyema field site in the Lomako Forest, DRC. DNA was first extracted and quantified using a qPCR assay. Samples with a sufficient amount of DNA were genotyped at 11 microsatellite loci and sexed using an amelogenin assay. Thirty-three of 53 samples yielded a sufficient amount of DNA for complete genotyping. We identified 19 individuals, including six males and 13 females. Mean allelic richness across all loci was 5.7 and expected heterozygosity was 0.69. Estimates of population size indicate between 26 and 66 individuals are present in the study area, but more than one community may be present. These results contribute to our ongoing efforts to study and monitor the bonobos at Iyema to better understand their demography, behavior, and conservation. Our study also highlights the utility of genetic analyses in pilot and survey research.

Accurate estimates of population sizes are essential to effective biomonitoring and conservation strategies. Genetic capture-recapture methods have been used to confidently assess abundance in African apes without having to completely habituate communities. The objective of this study was to use this method on a semi-habituated bonobo community at the Iyema field site, located in the Lomako Forest Reserve, Democratic Republic of Congo. Previous behavioral research has resulted in an estimated community size of 20 - 50 individuals. We collected 53 fecal samples for DNA analysis. DNA was extracted and quantified from each sample and then genotyped at 11 polymorphic microsatellite loci. Unique individuals were sexed using an amelogenin assay. We estimated community size using the software program Capture and the R Package Capwire. Capture estimated 23 - 34 individuals are present in this community. Using Capwire, the equal capture model (ECM) indicated approximately 26 community members whereas the two innate rates model (TIRM) indicated approximately 38 individuals are present (95% Confidence Interval: 26-65). Finally, we tested both Capwire models and found TIRM to better fit our data (LR=8.72, bootstraps=500, p<0.05). All three estimates fall within the previous estimates for the community although more intensive sampling is required to obtain a more accurate community size estimation.

War is awful for people and for wildlife. The “Great African War” of the 1990s and 2000s was the worst in modern African history. An estimated 3.9 million people died while wildlife clearly suffered. The purpose of this chapter is to look at the effects of the war and subsequent political instability on the people and nonhuman primates living in the Lomako Forest. To do this, we compared the prewar and postwar ranging and community demographics data of two bonobo communities living near the N’deli site in the Lomako Forest. One community was not directly observed in the study area after the war while the second moved outside of their former range and saw a decrease in community number and average group size. We also compared the prewar and postwar demographics of four monkey species living in the forest. For all of the species, average group size was lower while for three out of the four species the population density decreased as well. Overall, the population density of monkeys living in Lomako went from 165 to 83.6 individuals/km2. These results suggest an increase in hunting pressures faced by nonhuman primates because of an increasingly hungry human population with little income. Finally, we comment on the ethics of habituating primates in politically unstable regions.

The occurrence of female dominance among the Lemuriformes has prompted extensive research into the mating strategies and mate choice of several species, particularly ring-tailed lemurs. Female mate choice has been suggested to be particularly significant when understanding these complex mating strategies. The focus on female dominance, however, may obscure the complexities of intersexual affiliations that can have consequences for later mating opportunities. While males may use short-term strategies to increase their chances of breeding with females, continuous residence with females provides the opportunity for the use of long-term reproductive strategies. We studied intersexual relationships among adult individuals using grooming and proximity as measures of affiliation. Subjects were a group of semi-free-ranging ring-tailed lemurs (N=17) on St. Catherines Island, Georgia. Data were collected on social behavior using all occurrence sampling. Focal animal sampling was also used to collect behavioral and proximity data. When excluding related individuals, male-female grooming occurred less frequently than male-male and female-female dyads. However, social grooming was not equally distributed across all male-female dyads. The lowest ranking females were groomed by every adult male whereas the high ranking females were only groomed by certain males. Low ranking females were also observed to be in closer proximity to males more often than high ranking females; 20% and 6% of proximity scans, respectively. These data highlight asymmetries in intersexual relationships among these lemurs. These relationships should be considered when studying reproductive strategies and mate choice.

Research on wild apes is not only fundamental to elucidating human origins but to their conservation as well. Despite their relative size, apes are difficult to observe in the wild prior to habituation, limiting our ability to infer demography, relatedness, and kinship. Non-invasive genetic sampling provides an indirect source of this information. Here, we present preliminary findings of a genetic “survey” of a wild semi-habituated community of bonobos. 58 fecal samples were collected from nesting parties at the Iyema field site in the Lomako Forest, DRC. DNA was first extracted and quantified using a qPCR assay and samples that yielded >0.01 ng of DNA were further genotyped at 11 microsatellite loci and sexed using an amelogenin assay. 34/58 samples yielded a sufficient amount of DNA for complete genotyping. We identified 20 individuals, including 7 males and 13 females. Genetic diversity was high; mean allelic richness across all loci was 5.2 and expected heterozygosity was 0.70. We detected several kin relationships between individuals, including 7 parent-offspring dyads. Mean relatedness among males was only slightly higher when compared to the relatedness among females, which is consistent with results reported from wild chimpanzee communities. Our genetic survey indicates that this community has retained high genetic diversity. These results also validate our methods for the use of non-invasive genetic sampling of the bonobos at Iyema and are essential to our long-term research and conservation goals at the Iyema field site.

Our closest living relatives, bonobos and chimpanzees, along with small-scale human societies figure prominently in debates about human nature. Here we emphasize and explain behavioural variation within and among these three species. In the logic of behavioural ecology, individuals have been selected to adjust their behaviour along evolved reaction norms that maximize fitness given current socio-ecological conditions. We discuss variation in three behavioural contexts: relationships between the sexes, hierarchy and inequality, and intergroup interactions. In each context, behavioural variation can be related to two broad socio-ecological conditions: (i) the defensibility of contested resources, and (ii) differences in bargaining power. When defensibility of resources and differences in bargaining power are great, interactions are rife with conflict; when they are minimal, interactions are more harmonious. These socio-ecological conditions therefore constitute key catalysts and obstacles of cooperation. We conclude that human nature should be seen as consisting of evolved reaction norms.

The langurs (subfamily: Colobinae) of Southeast Asia have undergone many phylogenetic revisions. Incongruent results from recent genetic work suggest Trachypithecus pileatus and Trachypithecus geei are the result of ancient hybridization between Semnopithecus and Trachypithecus species. Geographically, these species are located between the distributions of Semnopithecus to the west and Trachypithecus to the east. The phylogenetic positions of T. pileatus and T. geei are thus uncertain, and they may represent a distinct genus from both Semnopithecus and Trachypithecus. In order to resolve their phylogeny, more data is needed on these poorly-known species. Forty-five 3D cranial landmarks were collected using a Microscribe-3DX on a sample of 172 adult crania from wild populations of Semnopithecus and Trachypithecus species, as well as 24 adult crania of Trachypithecus pileatus. Pairwise permutation tests with 1000 replications were run between subgroups of shape data to quantify and assign statistical significance to the differences between the subgroups. All subgroups were significantly different from each other in shape (Semnopithecus and Trachypithecus p=0.00, Procrustes distance=0.062277; Semnopithecus and T. pileatus p=0.00, Procrustes distance=0.08815; Trachypithecus and T. pileatus p=0.00, Procrustes distance=0.04415). Species within a genus were also signficantly different from each other, but their Procrustes distances fell within the range of permuted Procrustes distances. The Procrustes distances between T. pileatus and both Semnopithecus and Trachypithecus were not in the ranges of permuted Procrustes distances. This data suggests Trachypithecus pileatus and probably T. geei represent a distinct lineage and in conjunction with recent genetic work, may warrant a new genus designation.