The internet loves a weird animal friendship. A bird and monkey hugging, or a tiger cuddling a pig while resisting the urge to eat it. These relationships are often hallmarked by their G-rated quality, like cartoon animal friends who only get up to mischievous hijinks. We don’t often imagine the pair having sex, but that’s exactly what’s happening between a bull and a male donkey in Ethiopia.

According to a study published in Current Biology by University of Pisa researchers, ethologist Elisabetta Palagi and her team stumbled upon a whirlwind romance between a bull and a donkey, while studying monkeys in the Ethiopian highlands. The bull, named Achille, was seen repeatedly mounting a male donkey named Patroclo.

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Scientists Observed a Bull and Male Donkey Having Sex 51 Times in Just Two Weeks

Achille and Patroclo belong to different owners, live on separate farms, and only meet up as they’re released for grazing.…