Jacob Kraus Publishes Paper in the International Journal of Primatology

By Abby Harlan
April 1, 2026

Jacob Kraus, visiting assistant professor of biology at Washington and Lee University, recently authored a paper published in the March 2026 edition of the International Journal of Primatology.

The paper, "Age-Sex Class Variation in the Activity Budget and Diet of Rhinopithecus bieti in Association with Monthly Temperature," explores how primate behavior and diet relate to energy and nutritional needs, especially those needs associated with differences in body size, age and sex. The study specifically analyzes the effects these factors have on Asian colobines species when impacted by changes in climate.

Kraus and his co-authors gathered data for more than 32 months on an isolated population of black-and-white snub-nosed monkeys at Mount Lasha in the Yunling Provincial Nature Reserve in Yunnan, China. They utilized scan sampling between May 2008 and August 2016 to investigate how temperature affected activity patterns and diet both between and within different age and sex groups of this species. While the study discovered minimal differences in feeding patterns amongst the monkeys, it did observe significant behavioral differences between the sexes and age groups depending on if the temperatures were warmer or colder. The results suggest that yearly fluctuations in climate increase differences in physical needs among age and sex groups, leading to bigger changes in activity than in diet.

Kraus joined the W&L faculty in 2025 after serving as a visiting assistant professor of biology at Bates College. He earned a Bachelor of Arts in biology from Reed College and a Ph.D. in integrative biology from the University of Wisconsin-Madison. His research and teaching interests include animal responses to seasonal changes in climate and resource availability, biostatistics, behavioral and wildlife ecology and primatology.

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