The physical, behavioral and ecological diversity of baboons (genus Papio) makes them a fruitful source as analogies for understanding early human evolution. This project investigates a widespread but little known species, the kinda baboon (P. kindae), and probes the physiological and genetic bases of its distinctive behaviors and physical features. Besides being unusually small and juvenile in appearance, kinda baboons appear less sexually differentiated than other baboons. Behaving like females of other species, adult male kindas frequently initiate long grooming sessions, while females often give alarm barks, which is normally a male baboon activity. Unexpectedly, kinda baboons hybridize with neighboring chacma baboons (P. ursinus) which are almost twice their size, and are behaviorally more typical. This research project traces the causes of these species differences from the level of observable behavior and anatomy, through the level of development and hormonal control, to the level of the genome. Over 200 kinda, hybrid, and chacma baboons are trapped, sampled, and released unharmed in Kafue National Park, Zambia. Basic biological data such as weight and body measurements are collected along with blood samples. Specialist labs investigate these blood samples for the hormones and other biologically active components that influence growth, sexual differentiation, and behavior, and produce a high-resolution map of the kinda genome. Physiological differences that consistently distinguish kindas can then be tracked to the genetic level, by comparing fast-evolving candidate regions in kindas with homologous regions in other baboon species.
The project is innovative in combining proven, comparatively low-tech field techniques with cutting edge technology in genomics and hormonal physiology. Most immediately, it fills a major gap in our knowledge of a key primate genus. In the long term, it provides insights into behavioral variation and evolution in other species, including humans. In the wider sphere, the project will train graduate students, further scientific collaboration with Zambian Wildlife authorities, and promote the status of baboons in wildlife tourism.
Baboons (genus Papio) are large monkeys, found throughout most of Africa south of the Sahara, and parts of the Arabian peninsula. There are six recognized species, with geographical ranges that meet but do not overlap. Our project has been documenting the biology of the least known, and smallest, species, the kinda (rhymes with "Linda") baboon (Papio kindae) of south-central Africa. The kinda baboon hybridizes naturally with a much larger, neighboring species, the chacma baboon (Papio ursinus). During our NSF-supported fieldwork we trapped 67 kinda and 16 hybrid baboons at two locations in Kafue National Park, Zambia. From each animal we collected samples of blood, hair, and other tissues, body measurements and a dental cast, then released them back to the wild. This material has shown that the hybrids are intermediate in dental features and body size, shape and proportions. Our collaborators are using blood samples and other tissues to investigate the genetics and physiology of the kindas and hybrids, and compare them with other baboons. The physiologists have already discovered that kindas have a novel pattern of growth hormone expression that may contribute to their smaller size. Recent advances in DNA sequencing have permitted the NYU lab to examine far more genetic variation than originally anticipated, documenting the structure and dynamics of the baboon populations. This genetic material has also allowed inclusion of the kinda baboon in the work of the consortium -- led by co-PI Jeff Rogers at Baylor -- that is producing and analyzing complete genomic sequences for all baboon species. Meanwhile, ongoing observational fieldwork supervised by co-PI Jane Phillips-Conroy at Washington University, continues to document the unique behavior of the kinda baboons, and how this is modified by hybridization. Why is it important to comprehensively document another baboon species? We see significance at several different levels. For primatology, the study fills a major information gap, documenting unsuspected variation within a well-studied, iconic, genus. For general evolutionary theory, it provides a case study for understanding the nature of species, how they become distinct, and how they can remain so despite interbreeding at their margins -- issues that have come to the fore in recent years, as genetic evidence has documented how much marginal interbreeding occurs between "good" species. Genetic information from the baboons helps to answer questions such as: what genes tend to become fixed as species diverge? after speciation, how many genes cross the species border? are they a random sample, or are they filtered by selection? How do behavioral factors such as mate choice and differences in social communication bias the way genes flow from one species to another? For evolutionary anthropology, such questions are particularly relevant, because fossils and ancient DNA show that for the first two million years of its existence, the human genus (Homo) resembled Papio in its diversity. Several closely-related, but physically distinct, human species were contemporaries in Africa, Europe and Asia - early "modern" humans, Neandertals, Denisovans, and more. Like the baboons, they had separate evolutionary histories, yet they could, and sometimes did, interbreed and exchange genes. This process cannot be directly observed, because the era of coexistence ended 150000 to 30000 years ago, as our species (H. sapiens) spread from Africa, completely replacing the others. Anthropologists are increasingly appreciating that the baboon analogy can help us understand how distinct, neighboring human species might have interacted during the long, influential, interval of coexistence and limited admixture. Although human health and disease prevention are not our primary goals, we are pleased to share materials from our archived collections with biomedical researchers. Such collaboration has documented a previously-unknown, "wild" virus of potential zoonotic interest, and also shown that antibiotic-resistant bacterial strains can spread from humans and be harbored by nearby nonhuman primate populations. Finally, we believe that projects such ours can play an important role in public understanding of science. Organic evolution is the unifying theoretical theme of modern biology. Yet, as documented in a recent Science article, at the grade school level it is probably the most poorly taught of major scientific principles, largely because it is skirted by teachers fearful of opposition from anti-science activists. While no one study can correct this situation, accounts of important evolutionary phenomena such as natural speciation and behavioral adaptation may be more convincing when they are exemplified by familiar, appealingly human-like organisms like baboons.
