A Comparison of Anubis Baboons, Hamadryas Baboons and Their Hybrids at a Species Border in Ethiopia

During a 6-month field study at the Awash River, Ethiopia, more than 180 hybrid baboons in three groups were found in a zone of about 20 km between anubis groups and hamadryas groups. The genetical structure of the hybrid zone was preliminarily described using a simple morphological hybrid index. An ecological borderline, not coinciding with either boundary of the hybrid zone, was found at the Awash Falls. Only one anubis group had advanced downstream beyond the falls, sharing this habitat with the hybrid and hamadryas groups. An ecological comparison was made between this anubis group, an anubis group from above the falls, one hybrid group, and one hamadryas group.