A team of biologists from the University of Pisa in Italy recently observed a rare case of inter species mating between a bull and a donkey in Ethiopia. The incident occurred while the researchers were studying the behavior of a rare species of monkeys known as "gelada" in the highlands of Ethiopia. Instead, they noticed a bull attempting to mate with a male donkey, which responded positively to the advances. Initially, the researchers thought it was a one-time event, but they later observed that the bull and donkey continued to interact and attempt to mate on a daily basis.
The bull, named Achilles, and the donkey, named Patroclus, were owned by two different herders and did not live together. However, whenever their owners took them to graze in the same area, they would seek each other out. Over four days of observation, the researchers recorded 51 mating attempts, including 34 instances of actual penetration. The interactions between the bull and donkey were not limited to mating, as they also showed affection and tenderness towards each other. The bull would lick the donkey's body, touch him, and use his head to caress him gently.
The researchers were surprised to find that the bull also attempted to approach other male donkeys, but they rejected him and tried to push him away by kicking. In contrast, Patroclus showed a clear preference for the bull. On several occasions, he would initiate interactions with the bull, and even when the bull tried to interact with other donkeys, Patroclus would intervene and return to him. In two instances, when other bulls approached the donkey, Patroclus would bare his teeth and bite them to scare them away.
The lead researcher, Elisabetta Palagi, noted that what was remarkable about this case was that the animals had the opportunity to interact with members of their own species, but they consistently chose to interact with each other. The researchers also found that the herders were aware of the relationship between the bull and donkey and would often laugh when they saw the researchers documenting their interactions. The study was published in the scientific journal "Current Biology" on November 2, 2026.
The study highlights a rare and documented case of repeated social and sexual interaction between two males of different species. However, the researchers emphasized that documenting a single case is not enough to draw general conclusions, and they can only describe the behaviors they observed without inferring the emotions or motivations behind them.
After the research period ended, the herders had to move the bull and donkey to different areas due to a lack of grass, which separated them. The researchers are now trying to arrange a new meeting between Achilles and Patroclus to see if they will resume their behavior after months of separation.
The study raises questions about the complexity of animal behavior and the factors that influence their social and sexual interactions. Further research is needed to understand the underlying mechanisms and motivations behind such behaviors. The researchers hope that their findings will contribute to a better understanding of animal behavior and its implications for conservation and animal welfare.
Key points
- The researchers observed 51 mating attempts between the bull and donkey, including 34 instances of actual penetration.
- The bull and donkey showed affection and tenderness towards each other, including licking and caressing.
- The study highlights a rare case of repeated social and sexual interaction between two males of different species.
