During the proceptive period of mating (the female-driven pre-copulation courtship of the animal world) it seems male capuchins just can't be bothered. Females engage in several behaviors in order to get the attention of the males, like shaking branches, whining, and grabbing or touching the male and then running away. Sounds familiar, right, ladies?
But in one subspecies, the tufted capuchin, a couple females were observed overhand-lobbing stones at the males to get a little bit of love. And it totally worked. While females only threw stones at "high-ranking" males—the schlubby underlings remained completely unscathed—the males that were hit ended up copulating with the females who threw the stones. According to researchers Tiago Falótico and Eduardo Ottoni, it seems the behavior is totally catching on:
"The pattern of occurrence of the behavior, restricted to just one group and with an increasing number of females performing it, suggests that social learning played an important role in behavioral transmission. That is, the behavior was independently 'invented' by one or more females, and then copied by others as a form of 'enhanced' display."
I love the idea of a female tufted capuchin down on her mating luck, smashing a nut out of a fruit and realizing that she could use the same tool to pester a male into impregnating her. Or maybe it wasn't so calculated; perhaps she threw the rock out of frustration and the male's response was, "Welp, looks like I'm giving you babies now."
Capuchins are considered the most intelligent of the New World monkeys (not apes). They were the first species discovered to use stones and other tools to complete a variety of actions in the wild and have even been taught (in experiments) how to use money, developing a quite rational response to price shocks and exhibiting human-like perceived loss aversion.
So maybe they're onto something with this stone-throwing business.