Scientists have documented hundreds of the "infant corpse carrying" behavior of primates before. Sometimes, primates would carry and groom the cadaver of their offspring for weeks or months as the bodies slowly decay or become mummified. A new study suggests that this strange behavior is more common among the species than previously thought.

More so, Phys.org reported that this behavior could be some form of primates dealing with the grief associated with losing their child. Scientists involved in the study created the largest database of the responses of primate mothers to the deaths of their infants to describe the strange behavior and find clues into the evolution of emotions.

Bizarre Infant Corpse Carrying Behavior of Primates

For their study, titled "Why Do Some Primate Mothers Carry Their Infant's Corpse? A Cross-Species Comparative Study," published in Proceedings of the Royal Society B, the team compiled data from anecdotes reported in over 120 publications about the behavior of primates.

They took the most rigorous quantitative analysis of the 406 cases across 50 species to understand primates' infant corpse carrying behavior. Although some scientists question whether primates are aware of a death or not, the new study suggests that they come to learn about death after some time.

 Dr. Alecia Carter, the study co-author from University College London's Anthropology Department, said that the study showed that primates learned about death in the same way as humans, although it might take time to understand its results, not unlike humans. But what they are not sure of is whether primates understand that death is universal.

Researchers said that the study shows how grief is processed among primates and whether they would also experience severe depression after the death of an offspring, as humans do. But Carter noted that some primates might need the tie to deal with the loss of a child, showing strong maternal bonds in primates, humans, and generally in mammals.

Live Science reported that around 80% of the monkeys in the study were documented performing the infant corpse carrying behavior. The team saw that the behavior is more common in great apes and Old World monkeys.

Primate species are also a determinant of behavior. Those who have diverged a long time ago, such as lemurs, do not carry the dead bodies of their offspring but grieve on their own way by returning the corpse or performing "mother-infant contact calls."

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Factors That Influence the Infant Corpse Carrying Behavior

Elisa Fernández Fueyo, a study co-author from University College London, told Insider that they were surprised to find out that three factors could influence primates' infant corpse carrying behavior. They pointed out that the length of time the mother spent carrying the corpse of her infant would depend on the strength of the mother-infant bond.

The first factor is the mother's age. Younger primates were most likely to carry the dead body of their young compared to older female primates. Secondly, the way the baby died could also determine whether the mother would pick up the cadaver or not. Primates would less likely carry the body of their dead offspring if it died in a traumatic event, like being attacked by a predator or an accident.

Lastly, the age of the babies when they die is also a factor in the strange behavior. The younger the infant died, the longer their mother would carry them.

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