Intergeneric Hybrid Baboons

Though belonging to genera that have been distinct for several million years, gelada and common baboons—Theropithecus gelada and Papio hamadryas sensu lato, respectively—interbreed occasionally, even in the wild. A female hamadryas at Bihere Tsige Park, Addis Ababa, Ethiopia, apparently favored a gelada male over eligible conspecifics and produced several offspring with him. The F₁hybrids were large but developmentally normal. In skull and tooth form, and to a lesser extent in postcranial proportions, they were intermediate between the parental forms but lacked most of their parents' derived, (sub)species-specific epigamic characters. A female infant born to a subadult F₁was sired by a hamadryas. The backcross infant appeared normal and was still flourishing at about 2.5 years. Though perhaps impeded by natural selection against poorly adapted hybrids, theoretically interspecific hybridization could exceed mutation as a source of novel, preadapted genes in the wild.