Scientists have long wondered why female Barbary Macaque monkeys yell out during sex. So they set about to study the phenomenon by counting monkey thrusts and measuring monkey ejaculate (no, seriously). And the answer? Female monkeys yell to help their male partners come--the more they yell, the more vigorously their partners thrust, and the more likely their partners are to climax. Nice job and all on the research, scientist dudes, but we could have told you that just from watching porn.