Just monkeying around? Adolescent female monkeys mount deer and rub themselves on the deers’ backs, apparently to practise sex when they are too young to be chosen by adult males.

Earlier this year, researchers reported observations of a single male Japanese macaque mounting sika deer and trying to mate with them.

In Minoo, Japan, researchers started recording monkey-deer liaisons in 2014, but there, it’s female macaques that have been observed mounting the deer. Noëlle Gunst and colleagues at the University of Lethbridge, Canada, recorded five adolescent female macaques mounting deer a total of 258 times in a two month …