Out on the plateaus of the Ethiopian Highlands, a team of biologists set out to study high-altitude gelada baboons, a type of grazing monkey. Instead, they got a front-row seat to an unanticipated tryst: a bull and a male donkey engaged in a display of interspecies sex.
Researchers observed the bull (Bos indicus) repeatedly mount the same male donkey (Equus asinus) a total of 51 times over four days in March. The animals did not live together, and they only encountered each other when their separate owners brought them and other animals to a shared field to graze, the scientists reported November 2 in the journal Current Biology.
