Using social network analysis to inform on the process of one-male-unit formation of hamadryas baboons (Papio hamadryas) in captivity.

Hamadryas baboons (Papio hamadryas) live in a complex multilevel social system with the one-male-unit (OMU) at the core. OMUs consist of an adult alpha male with one or several adult females, their dependent offspring and, sometimes a few follower males. Previous research has documented that OMUs form in four distinct ways in wild populations. In December 2015, Oakland Zoo introduced two juvenile males into the hamadryas baboon exhibit. At the time of this study, these males were approaching sexual maturity. The complex social structure of this species and the changing social dynamics that might result as they reach sexual maturity provide a unique opportunity to utilize social network analysis (SNA) methods to examine OMU formation in a captive setting with an eye toward potential management strategies. SNA is a visualization method of looking at social data that allows researchers to understand sociality in terms of the importance of each individual, any subgroups, as well as the larger overall group dynamic. Behavioral and proximity data were collected over 6 months (July-December 2019). These data were then transformed into networks to analyze the two now subadult males' behavior over time. We found that one of the subadult males began the formation of his first OMU following one of the four pathways found in wild studies. Despite changing group dynamics, overall group cohesion remained unchanged. This study reveals hamadryas OMU formation patterns in captivity following the initial unit pathway as well as suggests potential welfare management issues that might arise.