Italian researchers in Ethiopia observe unusual bond between a donkey and a bull
University of Pisa scientists studying monkeys in Ethiopia accidentally spotted a close sexual and social bond between a male donkey and a bull. The study, published in Current Biology, is described by its authors as the first such report in the literature.
Researchers from the University of Pisa in Italy have documented an unusual relationship between two males of different species in Ethiopia: a bull named Achille and a donkey named Patroclo. The study, published in the journal Current Biology, is described by the authors as the first report of its kind in scientific literature.
A chance discovery
The pair was noticed by André da Cruz, a PhD student at the University of Pisa, while the team was studying geladas, also known as bleeding-heart monkeys, in Ethiopia. During a lunch break he glimpsed something in the distance: a bull mounting a donkey. His colleagues initially did not believe him.
The animals belonged to different owners. They came into contact only because their herds used the same pasture as part of their daily routine.
What was observed
The researchers watched the animals for four days when both were grazing in the same area, and for four more days when only one was present. They recorded 51 instances of Achille mounting Patroclo. The animals also licked and rubbed each other, often before and after these events. According to the authors, such contact appears to prolong the social interaction beyond the sexual act.
Other donkeys tried to avoid the bull and showed threatening facial expressions toward him, whereas Patroclo often presented his hindquarters to Achille and nibbled him. Neither animal tried to mount members of its own species, although Achille did show courtship behaviour toward some female cattle.
Scientists' interpretation
Co-author Dr Elisabetta Palagi of the University of Pisa said there was no sign of force and that the data point to a special relationship. The two males searched for each other, and when Achille approached another animal, Patroclo went to him and tried to distract him. Da Cruz added that Patroclo was highly aggressive toward bulls other than Achille.
Palagi described the case as a sexual interaction separated from reproduction. It is unclear whether the sexual and social aspects always existed together or one led to the other, but the bond appears to bring benefits, including attention and potentially support.
Josh Luke Davis, author of A Little Gay Natural History, said interspecies relationships are not necessarily unusual and cautioned against reading too much into the finding.
