Monkeys hunt lizards and snakes when fruit runs low, study finds
When fruit becomes scarce, bearded capuchin monkeys start hunting — and their behaviour may offer clues to how early humans developed a taste for meat.
A long-term study in northeastern Brazil found that bearded capuchins (Sapajus libidinosus) hunt and eat small vertebrates more often when fruits and other plant foods are less available. The findings were published August 26 in PLOS One.
Researchers led by Noemi Spagnoletti of Sapienza University of Rome and Susana Carvalho, Scientific Director at Gorongosa National Park, Mozambique, followed two groups of monkeys at Fazenda Boa Vista in Piauí state for 45 months between 2006 and 2010, logging over 5,000 hours of observation.
They recorded 446 instances of vertebrate predation. Nearly half were lizards, over a quarter were rodents, with birds, snakes, iguanas and opossums also on the menu. The team recorded around 6.4 hunting events per 100 hours.
Hunting increased in the dry season when fruit was scarce. One group that had to find all its own food hunted at 1.88 times the rate of another group that was provisioned with nuts and corn.
Males hunted more often than females and were more likely to tackle dangerous prey like snakes. Both solitary and group hunts were observed, including sharing prey between members.
The monkeys also showed a clear preference — eating the brain and viscera first, apparently prioritizing fat-rich tissues.“These results suggest that capuchins turn to vertebrate prey during times of plant food scarcity, a pattern that has been suggested for ancestral humans during climate fluctuations,” Spagnoletti said.
Carvalho said the work highlights the value of long-term field observation: “Hunting small prey could have been an important source of nutrition for human ancestors, during periods of food scarcity, providing a steppingstone to the exploitation of larger prey — the fossil record now needs re-analyzing to look at evidence of small vertebrate predation.”
