Age and seasonal influences on the body mass and the testicular morphology of brown bears (Ursus arctos) in Croatia

Abstract

Ursus arctos. From the wintering to the embryonic diapause, this species capable of physiological prowess has not finished to amaze us. In this study, we document and analyse a completely different facet of their physiology: the reproductive dynamics of the male bear. A statistical study of data collected during the previous years on the Croatian brown bear population will allow us to highlight several elements. Indeed, the evolution of different testicular measurements (index, mass, length and width), linked to the kinetics of the body mass, will show the close links between these different factors. The evolution of these elements will also be studied considering two specific periods: a whole life but also during the seasons (spring-autumn). The resulting curves will be described and interpreted. Then, we will make new assumptions about the working dynamic of the reproductive cycle of male brown bears.