The global demand for ivory has threatened African elephants for years. Poaching - which hunts the largest and oldest individuals for their tusks, generally female - is estimated to have killed 100,000 individuals between 2010 and 2012. As a consequence, the average age of adult elephants has decreased significantly.
Despite a 70% drop in individuals, the team demonstrates how elephant mothers shape the social life of their daughters
However, a new study, published in the journal Current Biology, reveals that poaching does not prevent groups of elephants, highly structured in matriarchal societies, from reorganizing and remaining stable when they lose their family or companions.
Scientists at Colorado State University (USA) have analyzed the behavior patterns of adult elephants in the Samburu National Reserve in northern Kenya for 16 years. Despite the decrease of 70% of the individuals, the team shows how elephant mothers shape the social life of their daughters who take over from their mothers.
"What most surprised us was the solidity and resistance of the social structure of the elephants in the face of the loss of many of their old matriarchs, who represent the social nucleus," says Shifra Goldenberg, lead author of the study and researcher at the university U.S.
In many other societies, by eliminating the main connectors, the system collapses. In other cases, young elephants insert themselves into new families when they kill their entire family. However, in the case of the Samburu elephants, "young females actively rebuild their social bonds when they lose an important social partner," Goldenberg notes.
Following in the footsteps of their mothers
The scientists also observed that the social position of the young elephants was very predictable. "Shortly after the killings, we were surprised to see some elephants associating with each other, but according to our long-term records, the mothers of these calves already knew each other," explains the researcher.
The new social ties of the young people were therefore not so surprising for the experts, among whom Iain Douglas-Hamilton, founder of the Save the Elephants association, has participated. "The calves accessed the social networks of their mothers to recreate the same social structure, essential for the society of the elephants," emphasizes Sinc Goldenberg.
But while their social ties appear to be quite resilient despite poaching, the long-term demographic effects of the loss of mother or family remain to be seen. "This question is going to be really critical to quantify the indirect effects of poaching on elephant populations," concludes Sinc Georges Wittemyer, co-author of the study and researcher at the American university.
Photo: Two young elephants from different families interact under the watchful eye of an older relative. / Shifra Goldenberg