Social networks analysis tools were used to investigate the social structures of two African ungulate species. Captive herds of addra gazelle (Gazella dama) and roan antelope (Hipptragus equinus) were observed. Social networks were constructed of each herd's affiliative (socially cohesive) interactions and nearest-neighbor (closest individual within 2 body lengths) associations during three time periods. I evaluated whether network measures could be explained by individual, dyadic or sub-group attributes at three levels of social network organization. Both roan and addra males were very central to their networks, and in some time periods so were juveniles. Roan and addra partner preferences differed, with addra tending to affiliate by age class while roan were more variable in their partner preferences. Matrilinealy-related sub-groups were also identified in addra. This networks analysis approach has broad applicability for characterizing animal social organizations as well monitoring captive populations.