Adult monkeys are seen feasting on a 10-day old infant from their group in rare example of cannibalism among primates

Capuchin monkeys have been observed eating the remains of an infant monkey for the first time, a rare instance of cannibalism among New World primates.

Researchers studying Panamanian white-faced capuchins in Costa Rica witnessed a 10-day-old infant fall from a tree.

It’s mother attempted to rescue the offspring but it soon died and she quickly abandoned the corpse.

That’s when a 2-year old male approached and began nibbling on the dead baby’s fingers.

Then the group’s 23-year-old alpha female – the infant’s great aunt – arrived and began eating the lower extremities, as well.

Cannibalism is sometimes adopted by animals during periods of food scarcity or high-population density, as it provides access to high‐quality proteins, fats and other nutrients.

But it also carries a high risk of disease transmission and other drawbacks.

The consumption of male partners by females during mating is widespread in arachnids.

Cannibalism isn’t unknown among other monkey species, either, usually as part of infanticide by alpha males looking to establish a reproductive monopoly.

In the wild, a pregnant chimpanzee may sometimes isolate for weeks before and after giving birth to prevent her baby from being eaten alive by other members of the community.

But it’s rare among New World monkeys: There have been only eight cases recorded in just six species among the more than 100 found in the Americas.

And it’s never been observed among capuchin monkeys, which are native to the rainforests of Central America.

‘We’ve never seen anything like this before,’ primate behavioral ecologist Katharine Jack, co-author of a new report In the journal Ecology and Evolution, told New Scientist.

White-faced capuchins are omnivorous — they’re known to dine on lizards, squirrels, birds, and even baby coatis — but they usually only eat things they’ve killed themselves.

‘They don’t scavenge at all,’ said Jack.

Typically, capuchins bite the face of their victims, ‘possibly to avoid being bitten or to silence the prey,’ the authors wrote.

There is usually a struggle for access to the prey and the entire animal is consumed.

In this case, dating from April 2019, an adult male seen being chased away after the infant’s fall is believed to have struck the fatal blow.

But only the alpha female and the young male consumed the infant — and they left its face, upper limbs, and torso intact.

While the other group members expressed interest — sniffing, touching, and threatening the corpse— none made an attempt to eat it.

‘Given that this is the only observation of cannibalism recorded in over 37 years of study on this population, we consider it to be a rare behavior in this species,’ the authors wrote.

The researchers say further study is needed to fully understand the unusual behavior, but they noted that female capuchin monkeys are known to carry deceased offspring for many hours.

In this instance, the baby’s mother presented herself but made no attempt to carry it off when it was unable to cling to her.

As a first-time parent, researchers theorized, she may not have understood what to do.

Without its mother carrying off the dead infant, the other monkeys were presented with an unusual situation.