A male monkey in Japan has been filmed trying to mate with a female deer—likely the first observation of two distantly related species having a nonviolent sexual encounter.

The deer have also been seen eating the monkeys’ feces, and the primates, in turn, have been seen grooming and even riding the deer, says Cédric Sueur, an animal behaviorist at Hubert Curien Multidisciplinary Institute in France. (See a woodpecker atop a weasel and other animals riding animals.)