The Socioendocrinology of Nile Lechwe

Nile lechwe Kobus megaceros are restricted in distribution to the seasonal floodplains and surrounding habitats of the White Nile basin in southern Sudan and eastern Ethiopia. The most recent census was in 1983, when population size was estimated at 30,000 to 40,000, and the species was considered “threatened” by the World Conservation Union (IUCN). The current population size in the wild has probably decreased due to political instability and population growth. Little is known about the biology and behavior of this species, which has not been the subject of a field study.

Caroline Pitt, a research coordinator with the Behavioral Biology Division of the San Diego Zoo's CRES, is studying the social relationships and endocrine profile of Nile lechwe in the East Africa exhibit at the Wild Animal Park, in conjunction with Fred Bercovitch, CRES associate director. Studying the interactions between hormones and social behavior has been called socioendocrinology. One area of focus for this project is examining coat color development in males and how this is related to social interactions, hormones, and reproductive success. Nile lechwe exhibit a trait known as sexual dichromatism, in which males and females are different colors. As males mature, they develop from a tan coloring identical to that of females into a dark chocolate color with a white “saddle” running down the neck and shoulders. Tracking the growth and development of the male Nile lechwe in the current herd at the Wild Animal Park is being accomplished through a combination of behavioral data, fecal hormone analysis, and digital photography. Additionally, herd and mating system dynamics, and the interplay between hormone levels and activity patterns, is being investigated.

This study should have implications for conservation education, colony management, fostering ex situ conservation, and understanding the dynamic links between hormones and behavior in the Nile lechwe. Information gained from this project could be used to lay the groundwork for future research to take place in the native habitat of this species.

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Listen to an iZoofari Chat with Caroline as she discusses her study.