Why Do Some Monkeys Eat Other Monkeys?

Cannibalism within primates is an ugly side of the wild animal world. Let's dig deeper into this gnarly act.

They say we live in a "dog eat dog world," but deep in the woods of Costa Rica's Santa Rosa National Park, a tribe of Capuchin Monkeys proved just how true this saying is... in an all-too-literal way.

It's really quite horrific: cannibal monkeys were documented by researchers as they witnessed a group of primates eat a dead infant that had just fallen from the treetops, much to the horrified faces of the on-looking researchers.

The researchers have been studying this group of white-faced Capuchin monkeys for more than 37 years, and never did they see or record a case of cannibalism — until recently, that is. What happened is a grisly scene indeed: after the baby monkey fell motionless for a few minutes to his death, other monkeys started to gather around the dead infant corpse. Here are just a few "highlights" to the events that happened following the death of the infant:

Editor's Note: The following details may be uncomfortable for some readers.

? A male approached and began nibbling at the dead monkey's foot, chomping on its toes.
? An alpha female then pulled the body away from the juvenile male and gnawed at the corpse, and after about half an hour, the female had consumed the entire lower half: leaving only the head, chest, and arms.

For those who like to play detective, this has been ruled an infanticide, as determined by the researchers. By the reason that, "Immediately following the screams and the infant's fall to the ground, the adult male was chased from the same area by an adult female."

Why Do Monkeys Eat Other Monkeys?

As shocked as you might be right now, cannibalism within primates is something that happens in the animal kingdom, however rare it might be:

"Prior to this young capuchin's demise, only eight cases of cannibalism had been observed in Central and South American primates", said researchers of the white-faced capuchin monkeys.

In fact, the behavior from some of the other monkeys also suggested this was quite an unusual situation for capuchins.

But why does this happen?

While monkeys maintain a diet of mostly plants and small animals (like lizards, birds, and squirrels), they will partake in cannibalism under the right circumstances, due to observations by lead researcher Mari Nishikawa.

Actually, primates that turn to cannibalism might have a more practical reason: they just require the nutritional benefits. Since the female that was eating the dead infant monkey was pregnant at the time and the young male was recently weaned off his own mother, it's hypothesized that monkeys resort to cannibalism when in desperate need of extra nutrients.

Cannibalism was also observed in other primate species, such as a group of chimpanzees in Tanzania (chimps actually turn to cannibalism the most often out of all the Great Apes!).

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