10 January 2017
A male Japanese monkey has been filmed trying to mount and mate with a Sika deer.
Researchers saw the primate attempting to mate with at least two deer in November 2015, during the macaque breeding season.
The macaques regularly bathe in hot springs in snow-covered parts of Japan, and live side-by-side with the deer.
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."
It's not the first example of inter-species mating. In 2014, reports of an Antarctic fur seal coercing king penguins into sexual relations made headlines worldwide.