Early this year, we all pretended to be shocked when we saw a video of monkeys having sex with deer in Japan. New research actually studies the behaviour.
Scientists headed to the Meiji Memorial Forest in Japan from November 2012 to January 2013 and again from November 2014 to January 2015 to watch Japanese macaques get freaky. What they found the second time was females humping the backs of sika deer.
The encounters were "sexual in nature," according to the paper, published last week in the Archives of Sexual Behaviour. "To our knowledge," the authors write, "this is the first quantitative report of heterospecific sexual behaviour between a non-human primate and a non-primate species under free-ranging conditions." (Humans, of course, bone other animals all the time.)
The researchers observed 13 monkey-deer sexual interactions (and eight failed attempts) during the few months, in which the female monkeys would mount the deer and rub up against them. These mounts lasted somewhere between 3 seconds and 42 seconds each, and each encounter involved around 0.5 to 2.3 mounts, on average.
They weren't exactly sure why the interactions were happening, but the paper offered a few hypotheses. Maybe the females were practicing their sexual behaviours on the deer. Or perhaps they would rather hump deer than the more aggressive male macaques. Maybe the males prefer older females, leaving the young females without sexual partners. Or maybe these were the result of playful interactions turned sexual.
People on the internet seems surprised by this interaction, forgetting that humans are the species that came up with the centaur and the satyr. Deceased horse boner Kenneth Pinyan, aka the infamous Mr. Hands, was also a human.
Anyway, science knows that monkeys bone deer now, and can't quite understand why. Surprise surprise!