Anthropology Colloquium: Jacinta Beehner

Friday, May 5, 2023

4:15 pm — 6:15 pm

Hybrid (see description for details)

Open to the Public

Jacinta Beehner of the University of Michigan presents her work: "The 'Hoo-Haa Effect' - An Unfortunate Name for a Series of Related Effects in Female Primate Reproduction"

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Abstract: In 1978, Thelma Rowell discovered that in a group of patas monkeys, novel males could stimulate immediate mating activity in the group’s females. Later, a report on hamadryas baboons similarly observed that novel males caused adolescent females to mature early, pregnant females to abort, and lactating females to resume fertility; each phenomenon accompanied by signals of fertility. In this talk, I will summarize 15 years of data demonstrating that all three phenomena occur in wild geladas (Theropithecus gelada) as well. I will further speculate on the fitness benefits for females. Geladas live in family units where dominant “leader” males sire nearly all offspring in the unit. Leader males are replaced every 3 years; and following takeovers, infants are at risk of infanticide. My colleagues and I found that immature females that experienced a takeover, matured earlier than those that did not. Moreover, earlier maturation predicted earlier first birth and first successfully weaned infant. Next, we confirm with new data that females abort pregnancies after takeovers. Finally, we found that lactating females that experienced a takeover resumed cycling far earlier than those that did not. Because these females did not conceive earlier, we call these “deceptive” cycles. Importantly, deceptive cycles were associated with higher infant survival for these females. To unite these phenomena, Rowell coined the term, “the Hoo-Haa effect”. Although I do not plan to resurrect this particular term, I propose that these phenomena share a similar mechanism that deserves further study.

This is a hybrid event, taking place online and in person in Room 5417 at the CUNY Graduate Center. For both in-person and online registration, please visit:


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