Emotionally engaged? Bin Yang, James R. Anderson, and Bao-Guo Li/Current Biology 26

It’s a tear-jerker worthy of Hollywood – and one of the first examples of compassionate care and grief in a wild monkey. The alpha male of a group of snub-nosed monkeys and his dying partner spent a final, tender hour together beneath the tree from which she had fallen minutes earlier, cracking her head on a rock.

Before she succumbed, he gently touched and groomed her. And after she was dead he remained by her side for 5 minutes, touching her and pulling gently at her hand, as if to try and revive her (for a full account of what happened, see “A monkey tends to his dying mate – as it unfolded”, below).

“The case we’ve reported is particularly important because of the exclusively gentle nature of the interactions, and the special treatment of the dying female shown by the adult male,” says James Anderson of Kyoto University, Japan. “The events suggest that in the case of strongly bonded individuals at least, monkeys may show compassionate behaviour to ailing or dying individuals.”


The study follows a recent report of a quasi-funeral for an adult captive chimpanzee at a sanctuary in north-west Zambia, and evidence of death-related behaviour in crows.

Together, the reports add to evidence that humans may not be the only species to display grieving behaviour following bereavement, or to show respect for dead individuals with whom they have forged ties. They also hint that animals have some recognition of the finality of death.

“It seems likely that in long-lived species such as many primates, repeated exposure to death within the group leads to an understanding of the irreversibility of death,” says Anderson. “I believe the adult male and other members of his unit understood the dead female was no longer alive.”

Anderson says that while it’s dangerous to anthropomorphise, when strong bonds formed between individuals are broken by death, those individuals can feel the impact emotionally.

“It seems quite reasonable to conclude that monkeys and apes may suffer grief in bereavement,” he says. “There’s now enough evidence from observations of responses to dying group members in species such as chimpanzees, elephants and dolphins to suggest that empathy and compassion occur in these species, and now in snub-nosed monkeys.”

A monkey tends to his dying mate – as it unfolded James Anderson of Kyoto University, Japan, and colleagues have been monitoring a population of some 150 snub-nosed monkeys on the mountainous slopes of the Zhouzhi National Nature Reserve in Shaanxi province, China. The incident in which the alpha male apparently tended to his dying mate occurred in one of a dozen or so sub-groups into which the population was split, all of them led by single males. On the day, the researchers had noticed that the female, "DM", appeared weak and isolated from the rest of her group, comprising three other adult females, two juveniles and two infants, as well as the single male, "ZBD". They also noticed bleeding from DM's nostrils. At 1 pm, the male approached his partner, who had joined the group three years earlier. He gently touched her hand twice and warned the others to stay away. Thirty minutes later they climbed a tree and sat on a branch 25 metres up, where he groomed and gazed at her. Disaster struck half an hour later when she suddenly fell to the ground, remaining largely motionless except for sporadic twitching and faint groans. He and the other females tended and groomed her for a further 50 minutes, but eventually the others retreated, leaving the pair alone. DM then stood up and tried to follow, but collapsed and died at 3.35 pm. ZBD remained with her for a further five minutes, touching her and pulling her hand, but to no avail. Finally, he rejoined the others down by a river 50 metres away, but continued gazing back to where she lay until the troop headed off out of sight at close to 5 pm. One of the researchers buried the body around a kilometre away. But the next day, the troop returned to where she had died, with ZBD sitting and looking for her for at least two minutes before heading off with the rest of the group. "It's rare to observe the responses of primate group members to the natural death of any adult. Sick or injured individuals tend to simply "disappear" — maybe they die in a hidden place, or are finished off by predators at night," says Anderson.

“This report provides compelling evidence that non-human animals experience deep grief and loss,” says Marc Bekoff, an ethologist at the University of Colorado, who says he has witnessed similar “grieving ceremonies” in wild coyotes, elephants, dogs, red foxes, cats, crows and magpies.

“As I watched some magpies respond to a dead corpse, I saw them stand around the body, fly away, bring back pine needles to lay around the dead body, softly peck at it, almost imperceptibly bow their heads, then fly off,” says Bekoff. “We don’t know exactly what’s going on in the heads and hearts of these animals, or whether they have a concept of death that tells them their friend is gone forever, but I don’t see any reason at all to say they’re not grieving.”

Rare reports of primate responses to death are important for our understanding of the evolutionary origins of some “mourning” behaviours, says Edwin van Leeuwen of the University of St Andrews, UK. Last month, he reported the case of the chimpanzees at the Zambian sanctuary reacting when they discovered a group member dead. The behaviour involved “quiet attendance and close inspections punctuated by rare displays” (see “A chimp funeral for a friend, below”).

The origin of, and motivation for, such behaviours remains unknown. “Is it to console the wounded, the dying, or for reasons that have more to do with a survivor’s own well-being, such as reducing anxiety?” van Leeuwen asks.

One important clue, common to both reports, is that the deceased animals were adults who had strong social links with their peers and acquired status within the group.

This, according to van Leeuwen, reflects research suggesting that mourning evolved to mark the passing of socially important individuals. The behaviours follow naturally from actions necessary to sustain group cohesion, he says.

Bekoff agrees. “It could be adaptive, by bringing group members together to foster cohesiveness, and they might know that they need to reorganise in the absence of a former group member,” he says. “But it’s hard to say how each factors in.”

Not everyone is convinced. “A hard-nosed approach would be to describe what happened in terms of confusion on the part of the animals closest to this monkey [that] fell out of the tree,” says Matthew Cobb at the University of Manchester, UK. “Attempts to rouse or provoke a sick or dying individual do not necessarily tell us anything about the internal state of the ‘caregiver’. The explanation may be much simpler, and less romantic.”

Journal reference: Current Biology, DOI: 10.1016/j.cub.2016.03.062

Read more: Death in dolphins: do they understand they are mortal?; The animal roots of human morality; Bereaved animals grieve – if their lifestyle allows it; Do animals have emotions?

A chimp funeral for a friend His name was Thomas, and judging by the reaction to his death at the age of 9, he was extremely popular with his 42 peers. His dead body was discovered in 2010, two days after he had gone missing, by staff at the Chimfunshi Wildlife Orphanage Trust sanctuary in Zambia. They immediately summoned researchers, who filmed what happened next. Over the subsequent 30 minutes or so, more than half the group approached Thomas's body at least once. Most sat quietly and apparently respectfully close to the corpse. But some were more animated. Pan, a male with whom Thomas had formed an especially strong bond, scattered fellow chimps by shaking large branches at them, and peered closely at the body. Violet, the alpha female in the group, screamed loudly over the body, swaying back and forth as she did so. She tried to revive Thomas by hitting him with a branch. Noel, an adult female who had adopted Thomas after his mother died in 2006, had an equally unusual but much gentler reaction. At one point she touched the body and brought her hand to her lips, as if in a kiss. Later, she explored Thomas's face with her mouth and hands, and most remarkably, she spent several minutes cleaning Thomas's teeth with a grass stem. She kept doing so even when others had been tempted away with offerings of food. "This tells the story of the adoptive mother who would rather stay with the dead body of her adopted son than receive abundant food," says Edwin van Leeuwen of the University of St Andrews, UK. "Moreover, she engages in elaborate teeth-cleaning with a tool, an intimate behaviour seldom seen even between living chimpanzees." [journal_reference title="American Journal of Primatology" title_link="http://dx.doi.org/10.1002/ajp.22560" doi="10.1002/ajp.22560"]