The taste for porn cuts across species. Our close cousins in the animal kingdom, rhesus macaques, will give up their beloved cherry juice for a few more seconds to look at images of their females' hindquarters, according to a team of Duke University neurobiologists.
'The males sacrificed fluid for the opportunity to view female perinea [hindquarters],' wrote the US researchers in the latest issue of Current Biology.
The team gave the male macaques two choices: a drink of cherry juice, or different quantities of the juice, in exchange for looking at a range of pictures, including what can only be termed as primate pornography.
Unsurprisingly, the juice-to-picture exchange rate was highest for photos of female rears (pictured).
'Virtually all [male] monkeys will give up juice to see female hindquarters,' says Robert Deaner, who led the Duke team, of his male subjects in an interview with science weekly Nature.
Dr Deaner and his colleagues also found pictures of the faces of their leaders and other high-status male monkeys are highly valued. They theorised that dominant males have a direct impact on who gets to mate with whom, so everyone has an interest in those who wield such power.