Primate intelligence gives me cognitive dissonance. It’s fascinating that monkeys can recognize numbers, construct tools and even follow to-do lists. But it also bruises my ego, just slightly, knowing that monkeys aren’t that different from my parents, friends or heroes. (Michael Phelps excluded. He’s the übermensch.)

Those who believe that the 25-cent peep show is restricted solely to humans, guess again. A January study at Duke University Medical Center revealed that male rhesus macaque monkeys will “pay” to gaze at images of female monkey posteriors. The animals gave up quantities of fruit juice for prolonged views of either female hindquarters or the faces of high-ranking males in their society.