An international team who set out to study an Ethiopian baboon ended up documenting a close bond between a bull and a male donkey that went beyond the two just getting it on. Despite having partners of their own species and both sexes available and meeting only while grazing, the two stayed close and often had contact - like licking and nuzzling - as well as the bull mounting the donkey. The donkey didn't try to avoid this, unlike the rare occasions when the bull mounted another donkey. The study authors say it's an open question whether their reciprocal sexual behaviour has other benefits, or is just the result of a close social relationship.
This donkey and his bull lover aren't just in it for the sex
