Spider monkeys actively choose to eat fruit infested with insects

Some species of spider monkey living in the Amazon rainforest actively choose to eat fruit infested with larval insects, as a way of introducing more protein into their diet.

“Spider monkeys eat mostly fruit pulp,” says Thiago Cavalcante of Brazil’s National Amazon Research Institute. “This is generally pretty poor in protein.”

To find out how white-cheeked (Ateles marginatus) and black-faced (Ateles chamek) spider monkeys ensure a healthy mix of nutrients, Cavalcante and his colleagues watched them eating in forest along the Amazon’s Tapajós river and examined their leftovers.

“Spider monkeys are really messy…