Introduction

Studies of behavioral endocrinology provide opportunities to examine the reproductive biology and stress responses of animals. In the case of endangered species, the study of reproductive biology has the two-fold value of contributing to both applied and pure research. In the wild, conservation efforts are enhanced by the assessment of reproductive function and population growth dynamics. It can be used as a diagnostic tool to improve the breeding management plans of captive animal populations. Exchange of information between researchers and managers of captive and wild populations can assist the efforts of both groups (Wildt & Wemmer, 1999). From the standpoint of pure research, studies of reproductive biology help us to understand the evolution of sexual behavior from both proximate and ultimate perspectives, including sex differences in behavior, sexual selection, and the diversity of reproductive mechanisms observed in the animal kingdom. Additionally, studying stress is important because it may affect the reproductive abilities and well-being of individuals which may impact lifetime reproductive success and survivorship.

The reproductive biology of gorillas has been the focus of much research with both captive and wild populations. From an applied perspective, difficulties in captive breeding led to the need for improved understanding of reproductive function. While the lowland gorilla has been kept in captivity since the late 1800s, it was not until 1956 that efforts to have captive gorillas reproduce began and initially the results were poor.