Eastern gorillas remain close to adult members of their group when they die, but they also observe, touch, groom and lick the carcasses of other individuals outside the group.
This is the conclusion of an international group of scientists who have recorded for the first time this behavior that could have possible implications in the spread of diseases such as Ebola.
Animals react differently to the death of their neighbors. Social insects remove or bury bodies, sharks have necrophobia and stay away from corpses. Californian charas, a bird of western North America, organize funerals with songs, and are attended and cared for by elephants, giraffes, cetaceans and primates. In the latter case, what happens to the individuals who die and who do not belong to the group?
An international team of scientists, led by theDian Fossey Gorilla Fund, has observed and recorded for the first time the behavior of a group of mountain gorillas (Gorilla beringei beringei) to the death of a 35-year-old dominant male, named Titus, and a 38-year-old female, named Tuck, who belonged to the group and who had died of diseases related to their advanced age in the Rwanda Volcanoes National Park.
In parallel, they observed another group of eastern lowland gorillas (Gorilla b. graueri) to the death of an unknown male in the Kahuzi-Biega National Park in the Democratic Republic of the Congo.
As certain interactions between gorillas can lead to violence, the scientists conjectured that individuals would become more involved and spend more time with the corpses of members of their own group than with the stranger. However, the results, published in the journalPeerJ, surprisingly reveal that the behaviors of both groups were very similar, and at the three funerals the groups veiled the bodies of the deceased.
"The animals in all three cases showed a variety of affiliative and agonizing behaviors towards the corpses," emphasize the researchers in their work.
In front of the three corpses, the rest of the gorillas not only remained seated near the deceased as a sign of mourning, but also sniffed, touched, groomed and licked them. In the case of mountain gorillas, the individuals who shared closer relationships with the deceased stayed longer with the body.
One of them, a young male, whose mother had left the group, came to spend two days in contact with the male Titus, even sleeping next to him, according to the observations of the researchers. One of the youngest sons of the female Tuck groomed her body and even tried to be breastfed by the deceased, despite having already been weaned. For scientists, this behavior would show theanguish over the loss of the mother.
Source of disease
According to the research team, this work is not only interested in how animals perceive and process death, but also has important implications for conservation.
A detailed inspection of the corpses would show that the bodies present a serious risk of disease transmission. According to experts, contact between healthy individuals and infected corpses could be the main route of spread of diseases such as Ebola, which has affected and killed thousands of gorillas in Central Africa.
Porter A, Eckardt W, Vecellio V, Guschanski K, Niehoff PP, Ngobobo-As-Ibungu U, Nishuli Pekeyake R, Stoinski T, Caillaud D. 2019. “Behavioral responses around conspecific corpses in adult eastern gorillas (Gorilla beringei spp.) "PeerJ 7: e6655 https://doi.org/10.7717/peerj.6655