How Chimpanzees Mourn Their DeadS

Chimpanzees are our closest primate relative, and have a number of behaviors we once thought were human only: they empathize, cooperate, and have a sense of self. But how do they deal with the most distressing event possible — death?

Two studies this being published in Current Biology this week show a remarkable amount about how chimpanzees mourn, and the effect that death has on them — sometimes in ways very similar to us, sometimes shockingly different.

In what is an incredibly rare occurrence, cameras recorded the death and mourning of two groups of chimps — one with an elderly female, and the other with the death of two infants. When an adult chimp dies unexpectedly or traumatically, the tribe's reaction is often loud and violent. Both times here, the reaction from those close to the dead was very different.

At a UK safari park, three chimps gathered around another, elder female of the group as she neared death. Pansy was more than 50 years old, and had been slowing down for some time. For days before her death, the group was very quiet, and paid her lots of attention. Just before she died, the group continually groomed and caressed her, which researchers think was partly to test for signs of life. When she died, the group left, but her adult daughter came back, and spent the night with the body.

The next day the keepers removed the corpse, and the other chimps remained subdued. For a number of days they avoided sleeping on the platform where she died — usually a prized location, and remained generally quiet for long period afterwards.

At the opposite end of the age spectrum, a group of researchers were studying chimpanzees in Guinea, and observed the death of two infants from flu-like respiratory infections. The mothers responded by carrying around the bodies of their children for weeks or months, to the point where the corpse was mummified. They would take them everywhere, groom them, and take them to sleep. Slowly, over the course of this period, the mothers would begin to let the other chimps come in contact with the dead babies for longer and longer periods. They would increase the length of time they could handle being separate from the bodies, even allowing other young chimpanzees to play with them (like in the video below). They appeared to slowly and gradually accept the passing of their younh.

Our furry cousins obviously have an inkling of death, grief, and empathy, and understanding their view on mortality raises interesting questions about our own. How different is a mother chimpanzee's veneration for their dead child different from Victorian trend of post-mortem photography? How far is it from burying the dead? The chimpanzees seem to have no distaste or repulsion to the dead, even keeping them around for months. Why don't they have any aversion to the potentially disease causing bodies? Is there a chimpanzee afterlife they believe in?

James Anderson of the University of Stirling says of the safari park chimps:

"Several phenomena have at one time or another been considered as setting humans apart from other species: reasoning ability, language ability, tool use, cultural variation, and self-awareness, for example, but science has provided strong evidence that the boundaries between us and other species are nowhere near to being as clearly defined as many people used to think. The awareness of death is another such psychological phenomenon. The findings we've described, along with other observations of how chimpanzees respond to dead and dying companions, indicate that their awareness of death is probably more highly developed than is often suggested. It may be related to their sense of self-awareness, shown through phenomena such as self-recognition and empathy towards others."

[Papers published in Current Biology, Press Release]