Some monkeys also hunt and eat meat, study finds

Bearded capuchin monkeys do not only crack hard-shelled fruit with stones and anvils. They also hunt and eat small vertebrates, and researchers say the behavior may shed light on the evolution of human diets.

An international study published in PLOS One examined two wild groups of Sapajus libidinosus at Fazenda Boa Vista in Brazil’s northeastern state of Piauí. Over 45 months and more than 5,000 hours of observation, researchers recorded 446 instances of vertebrate consumption, an average of 6.34 predation events per 100 hours.

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Not a diversion but an important source of energy.

The prey included lizards, and occasionally snakes and iguanas, as well as rodents, birds, bats and opossums. Males hunted more often than females, and adults hunted more often than young monkeys. The monkeys also ate more small vertebrates when fruit and insects became less available.

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The acquisition of energy in a short time is certainly an advantage when the prey is shared with other group members, or there is a risk that someone else may take it.

Elisabetta Visalberghi of Italy’s National Research Council said the prey were “not a diversion but an important source of energy.” The monkeys removed and ate the brain and internal organs before other parts, consuming the nutrient-rich tissue quickly while taking longer to process muscle. Researchers said rapid energy acquisition could help when prey is shared with other group members or might be taken by another animal.

The findings, researchers said, provide new clues about how early humans may have developed subsistence strategies. Small vertebrates could have supplied important nutrients to hominins when other resources were scarce, before the emergence of a pattern centered on regularly exploiting animals as large as or larger than the predator.

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Observing how capuchins integrate small vertebrates into their diet can help us better understand some stages in the evolution of human predation.