Primate Behavior Studies: Essential to Primate Welfare

A special session of the 2006 Animal Behavior Society annual meeting

In Memory of Sylvia Taylor, DVM     

The Primate Anthology: Essays on Primate Behavior, Ecology, and Conservation from Natural History

The Primate Anthology: Essays on Primate Behavior, Ecology, and Conservation from Natural History. Russell L. Ciochon and Richard A. Nisbett. eds. Upper Saddle River, NJ: Prentice Hall, 1998. 246 pp.     

Physiological Changes during Recovery from a Primate Dorsal Column Lesion

The evoked potential (EP) over primary somatosensory cortex (SI) was monitored before and after a complete lesion of the primate dorsal column (DC) pathway on one side. The EP was elicited by electrocutaneous or mechanical stimulation of either foot, and was recorded from the contralateral cortical surface for periods of up to 3 months after the lesion. The amplitudes of the three major peaks (P20, N50, and P90) of the cortical somatosensory EP were significantly reduced following interruption of the contralateral DC. Over weeks following the lesion, there was a significant increase in amplitude of the P90 component of the EP that was not evident in the other peaks. The postlesion increases in P90 amplitude were correlated with improved performance on a task that required grasping with either foot, suggesting that behavioral recovery from a DC lesion results in part from neural plasticity, as opposed to a simple relearning of the task.     

Applying Quantitative Genetic Methods to Primate Social Behavior

Increasingly, behavioral ecologists have applied quantitative genetic methods to investigate the evolution of behaviors in wild animal populations. The promise of quantitative genetics in unmanaged populations opens the door for simultaneous analysis of inheritance, phenotypic plasticity, and patterns of selection on behavioral phenotypes all within the same study. In this article, we describe how quantitative genetic techniques provide studies of the evolution of behavior with information that is unique and valuable. We outline technical obstacles for applying quantitative genetic techniques that are of particular relevance to studies of behavior in primates, especially those living in noncaptive populations, e.g., the need for pedigree information, non-Gaussian phenotypes, and demonstrate how many of these barriers are now surmountable. We illustrate this by applying recent quantitative genetic methods to spatial proximity data, a simple and widely collected primate social behavior, from adult rhesus macaques on Cayo Santiago. Our analysis shows that proximity measures are consistent across repeated measurements on individuals (repeatable) and that kin have similar mean measurements (heritable). Quantitative genetics may hold lessons of considerable importance for studies of primate behavior, even those without a specific genetic focus.     

Increasing Group Size Alters Behavior of a Folivorous Primate

Group size influences many aspects of mammalian social life, including stress levels, disease transmission, reproductive rates, and behavior. However, much of what is known about the effects of group size on behavioral ecology has come from comparisons across multiple groups of different sizes. These findings may be biased because behavioral differences across groups may be more indicative of how environmental variation influences animal behavior, rather than group size itself. To partially circumvent this limitation, we used longitudinal data to examine how changes in group size across time affect the behavior of folivorous red colobus monkeys (Procolobus rufomitratus) of Kibale National Park, Uganda. Controlling for food availability, we demonstrated that increasing group size resulted in altered activity budgets, based on 6 yr of data on a group that increased from 57 to 98 members. Specifically, as group size increased, individuals spent less time feeding and socializing, more time traveling, and increased the diversity of their diet. These changes appear to allow the monkeys to compensate for greater scramble competition apparent at larger group sizes, as increasing group size did not show the predicted relationship with lower female fecundity. Our results support recent findings documenting feeding competition in folivorous primates. Our results also document behavioral flexibility, an important trait that allows many social mammals to maximize the benefits of sociality (e.g., increased vigilance), while minimizing the costs (e.g., increased feeding competition).     

Introduction to Special Issue on Primate Hybridization and Hybrid Zones

International Journal of Primatology -     

Nonhuman Primate Behavior: A Note on Recent Research

Recent publications dealing with nonhuman primate social behavior suggest that Service's discussion of that topic in The Hunters is in need of extensive revision, and that Damas's (AA 71:315–316) recently expressed admiration for the discussion is unfortunate. Short paragraphs based on readily available references summarize findings that have appeared since The Hunters was published and indicate where Service's generalizations concerning species specific social organization, sexual seasonality, dominance orders, and territoriality are in greatest need of updating. [Primate social behavior; hunter-gatherers; ecological studies]     

The Primate Series

The Primate Series. 1997. Seven videos, 10-53 minutes each (244 minutes total), color. Videos by Anne Zeller. For more information contact Documentary Educational Resources, 101 Morse Street, Watertown, MA 02472.     

Primate Crop Feeding Behavior,Crop Protection,and Conservation

Many species across a range of primate genera, irrespective of dietary and locomotory specializations, can and will incorporate agricultural crops in their diets. However, although there is little doubt that rapid, extensive conversion of natural habitats to agricultural areas is significantly impacting primate populations, primate crop foraging behaviors cannot be understood solely in terms of animals shifting to cultivated crops to compensate for reduced wild food availability. To understand fully why, how, and when primates might incorporate crops in their dietary repertoire, we need to examine primate crop foraging behavior in the context of their feeding strategies and nutritional ecology. Here I briefly outline current debates about the use of terms such as human–wildlife conflict and crop raiding and why they are misleading, summarize current knowledge about primate crop foraging behavior, and highlight some key areas for future research to support human–primate coexistence in an increasingly anthropogenic world.     

Feasibility and Uncertainty in Behavior Genetics for the Nonhuman Primate

The analysis of phenotypic covariances among genetically related individuals is the basis for estimations of genetic and phenotypic effects on phenotypes. Beyond heritability, there are several other estimates that can be made with behavior genetic models of interest to primatologists. Some of these estimates are feasible with primate samples because they take advantage of the types of relatives available to compare in primate species and because most behaviors are expressed orders of magnitude more often and in a greater variety of contexts than morphological or life-history traits. The hypotheses that can be tested with these estimates are contrasted with hypotheses that will be difficult to achieve in primates because of sample size limitations. Feasible comparisons include the proportion of variance from interaction effects, the variation of genetic effects across environments, and the genetics of growth and development. Simulation shows that uncertainty of genetic parameters can be reduced by sampling each individual more than once. Because sample sizes are likely to remain relatively small in most primate behavior genetics, expressing uncertainty in parameter estimates is needed to move our inferences forward.     

Avoiding Predators: Expectations and Evidence in Primate Antipredator Behavior

Predation and antipredator behavior are important but poorly studied influences on the evolution of primate societies. I review recent evidence of predation and antipredator strategies among primates. I describe patterns of antipredator behavior and attempt to explain the variation among primate taxa and among antipredator strategies. I use predation by chimpanzees on red colobus and antipredator strategies by the colobus as a case study of how a primate prey species may respond to the threat of predation.     

Genetic Markers in Primate Studies: Elucidating Behavior and Its Evolution

The application of genetic techniques has provided valuable new insights into primate evolution and behavior. Important techniques include the polymerase chain reaction (PCR), where in exponential amounts of a target DNA sequence are produced via enzymatic amplification. This allows DNA to be analyzed from fecal droppings, which is particularly beneficial in field studies. Fragments containing hypervariable microsatellites can be amplified and subsequently typed. Also parts of the mitochondrial DNA can be amplified and subsequently sequenced. These methods have been applied with great success to determine familial relationships and, on a smaller scale, relationships among lineages and social groups, and the redefinition of the interface between social behavior, social structure and population genetics. Moreover, it has become possible, to a degree, to study genetic variation as it relates directly to adaptive evolution, as the maintenance of genetic variation has become accessible to analysis.