> Among primatologists, bearded capuchins are famous for using stone tools to obtain food. They’ve been observed placing palm nuts on a hard surface and smashing them with rocks to reveal the tasty kernels inside. Wild females have also been seen using sticks or blades of grass to pick their noses and eat any boogers they extract.

why would eating boogers be a selective advantage? They eat each other's boogers as well? the wild males are never observed participating?