A catastrophic hurricane brought more than 100 monkeys living on a Caribbean island closer together, helping them to survive the storm’s aftermath.
For decades, scientists have tracked the alliances, power struggles and social relations of the feral rhesus macaques (Macaca mulatta) on Cayo Santiago, a small island near Puerto Rico. After Hurricane Maria devastated the island in 2017, Camille Testard at the University of Pennsylvania in Philadelphia and her colleagues sought to understand how the disaster affected the monkeys’ social interactions.
The scientists calculated that relatively few adult macaques died in the six months after the storm. But Maria stripped away nearly two-thirds of the island’s vegetation, potentially increasing competition for shade and food.
The authors compared observations of the animals’ behaviour from before and after the storm and found that monkeys became more social after the hurricane: they more frequently sat close together and groomed each other. Timid, isolated monkeys sought these connections more than did outgoing monkeys, becoming friends with the friends of their friends.
Researchers think these connections might have provided social support and valuable opportunities to rest in the newly scarce shade.