Off the coast of Panama, on an island uninhabited by humans, a culture unlike any other has arisen. On Jicarón Island, white-faced capuchin monkeys (Cebus capucinus imitator) rule, unmolested by predators.

The footage showed the capuchins walking and pounding their stone tools with baby howlers on their backs. But cameras did not capture the moments of abduction, which scientists said likely happened up in the trees, where howlers spend most of their time.