Amboseli baboon

What can you learn from a estrous swelling?

Author: Courtney Fitzpatrick



Although females of many taxa display sexual signals as they become ready to be fertilized, little is known about what other types information, if any, may be contained in those signals. Female baboons display one of the most conspicuous signals of fertility in the animal world; exaggerated estrous swellings. These swellings appear on the animal’s hind end during the follicular phase of the sexual cycle, are largest around the period of ovulation, and quickly disappear during the luteal phase. By characterizing several different sources of variance in swelling size, our new study reveals the potential information content in this charismatic trait. Read More

Early reproductive aging is a uniquely human trait

Author: Susan Alberts

A young female baboon in Amboseli

Our recent paper addresses the question of reproductive cessation in humans and other primates in PNAS. Reproductive aging in human females –  characterized by declining fertility in the 30’s, followed by complete reproductive cessation in mid-life – is an evolutionary puzzle because, all else being equal, mid-life reproductive cessation is inherently disadvantageous. One important question regarding the evolution of early reproductive aging is whether it is unique to humans or shared with other species. This has been the topic of much speculation but no definitive answer to this question has previously been available; comparative data from nonhuman primates are particularly important in answering this question because of the close phylogenetic relationship between humans and nonhuman primates. Read More

Social behavior influences gene expression

Author: Jenny Tung

Amboseli baboons

A baboon’s social life can have a powerful impact on how successful he or she is in life. We know from previous studies in Amboseli, for instance, that social status, social bonds, and social competition can be important in predicting health, survival, and reproductive success. Now, recent work by Dan Runcie and ABRP investigators has found that a baboon’s social environment can also influence how genetic differences affect gene expression, suggesting that gene regulation in Amboseli may often be subject to so-called gene-environment interactions. Read More

Collaborating institutions

Princeton, Duke, and Notre Dame

Princeton University

Duke University

University of Notre Dame


The Amboseli baboons

Located near Amboseli National Park in Kenya, ABRP is one of the longest-running studies of wild primates in the world. ABRP is directed by Dr. Jeanne Altmann at Princeton University, and Dr. Susan Alberts at Duke University. The Associate Directors are Dr. Beth Archie at the University of Notre Dame and Dr. Jenny Tung at Duke University. Click the links at left to learn more about the project and our research.

Amboseli via Google earth