Good news for male capuchin monkeys wondering why females are always throwing rocks at them: They're actually attracted to you (the bad news probably goes unsaid here). Researchers studying the sex lives of monkeys in Brazil's Serra de Capivara national park found that amorous female capuchins whine and pull faces at potential mates, resorting to rock-throwing when at their most fertile, the BBC reports.
Capuchins are known for their use of rocks to do things like dig holes and crack nuts, but while some uses of stones spread from group to group, flirting by chucking rocks is likely to stay within the Serra de Capivara group. "It would be tricky for this behavior to transfer. In capuchins the females stay with their groups for the rest of their lives—it's the males that migrate to other groups," the lead researcher explains. Maybe they've had enough of the rock-throwing. (Read more capuchin monkey stories.)