Bull and Donkey Form Sustained Bond in Ethiopia
Researchers documented a male bull and male donkey in Ethiopia forming a lasting sexual and social partnership, published in Current Biology.
Updated on Nov. 2, 2026 in Large Animals
Ecologists recorded a sustained sexual and social bond between a domesticated bull named Achille and a male donkey named Patroclo on an Ethiopian plateau. The research, published in Current Biology, describes the pair grazing together and interacting closely despite having different owners.
Why it matters
The case documents close, sustained same-sex-style bonding between domesticated animals of different species, expanding what is recorded about social behavior in livestock. It offers a field-observed example that researchers can compare against other animal pair-bonding studies.
Achille mounted Patroclo 51 times during the four days the pair was observed together, and the observers recorded four separate days apart for comparison. Neither animal was seen interacting sexually with other animals in the same field during the together period.
The players
Achille
A domesticated bull living on an Ethiopian plateau who was the subject of the observed bond with a donkey.
Patroclo
A male donkey on an Ethiopian plateau who received Achille's mounting and grazed with him across the observation period.
Current Biology
A peer-reviewed scientific journal that published the case study describing the bond.
The details
Achille, a bull, and Patroclo, a male donkey, live on an Ethiopian plateau and often graze together despite having different owners. Patroclo was receptive when Achille mounted him and aggressive toward other bulls nearby, and the pair licked or rubbed against each other after sexual interactions.
Timeline
Observed over four days together and four days apart, as part of the field study.
Research published today, November 2, 2026, in Current Biology.
Health Landscape
The case extends peer-reviewed field research on animal social behavior published in Current Biology. It adds a documented example of sustained pair-bonding in domesticated livestock to a literature that has largely focused on wild species.
For owners of working animals, the case shows that livestock can form close, lasting bonds with other species that may affect how grazing groups are arranged. It suggests keeping in mind animal social preferences when pairing animals on shared pasture.
The takeaway
Animals can form strong social bonds across species boundaries, which is worth keeping in mind when managing shared grazing. Observing how your own animals interact may reveal preferences that affect their wellbeing.
Further reading
Explore more on Large Animals and how livestock behave in the wild and on farms.
