The macaques have previously been observed grooming the deer or riding them in a playful manner.
The curious behaviour is outlined in a study published in the journal Primates.
The monkey seemed to be a low-status male, who guarded his “love interests” by chasing away other male monkeys who came near.
Co-author Alexandre Bonnefoy commented: “The male mounted the deer and displayed some copulation behaviours, which included about 15 sexual movements over a period of 10 seconds, before dismounting.”
Everything but tech support.