杏吧原创

Capuchin monkeys have been observed eating the remains of a young capuchin infant, offering an extremely rare example of cannibalism among the primates that live in the Americas.

鈥淲e鈥檝e never seen anything like this before,鈥� says Katharine Jack at Tulane University in Louisiana.

Researchers have been observing and collecting data on white-faced capuchins in the Santa Rosa National Park in Costa Rica since 1983 鈥� one of the longest ongoing studies on primates in the world.

In April 2019, Mari Nishikawa from the University of Tokyo, Japan, and other researchers were observing capuchins in the park when they heard several screams. They witnessed a 10-day-old infant fall from a tree just before its mother and another female chased a male monkey off.

Infanticide isn鈥檛 uncommon in these primates. It often occurs when a new alpha male enters a group and wants to gain reproduction monopoly over the females. Jack says non-alpha males sometimes kill infants too, such as the subordinate male chased off in this case.

The mother attempted to rescue the infant, but its back legs appeared paralysed, perhaps as a result of a bite from the male, and it soon died. The mother abandoned her dead infant, after which a 2-year old male approached and began nibbling on the fingers. This prompted the group鈥檚 alpha female 鈥� the great aunt of the infant 鈥� to arrive and begin eating the cadaver as well.

The episode was strange for a number of reasons, says Jack. For starters, capuchins typically only eat things they have killed themselves. 鈥淲e鈥檝e never seen a capuchin consume something that鈥檚 dead,鈥� she says. 鈥淭hey don鈥檛 scavenge at all.鈥�

When they do eat meat 鈥� coati pups for instance 鈥� capuchins usually consume the head and face first, but the cannibalism was just the opposite, as they started with the infant鈥檚 fingers and feet.

Furthermore, other primates in the group approached the body, sniffing and examining it, but didn鈥檛 join the meal. Many of them curled their lips back in a gesture that we might interpret as disgust, although Jack notes it is impossible to attribute this emotion to the capuchins.

鈥淚t seemed like it was something very novel to them, the way they behaved and reacted to the situation,鈥� she says.

Cannibalism is a rarity among the primates native to the Americas. While chimpanzees and other primates elsewhere have been observed cannibalising their own 鈥� often infants or placentas 鈥� there are fewer than 10 cases of cannibalism among primates in the Americas, recorded in just six species among the more than 100 found in the Americas.