Wild African elephants may have domesticated themselves

Wild elephants are one of the few known species to show signs of self-domestication. The phenomenon has only previously been documented in humans and bonobos, a closely related primate.

Humans have bred animals to maximise traits such as friendliness, sociability and a docile temperament in a process called domestication. Some researchers believe humans and bonobos have gone through a similar process but that they have naturally done it to themselves.

Limor Raviv at the Max Planck Institute for Psycholinguistics in the Netherlands wondered if other species have self-domesticated too. She decided to start with African savannah elephants (Loxodonta africana), a species with which she was already familiar. She and her colleagues looked at how the elephants compared with bonobos (Pan paniscus) and humans on 20 different measures.

They found that all three species display similar behaviours and share certain physical features. Like bonobos and humans, elephants are social, play, have a long childhood and care for the offspring of others in their group. Wild African elephants’ also share a shortened jawbone – a trait shared by many domesticated animals – and show restraint in aggression toward others.

Next, the researchers looked for commonalities between the genome of domesticated animals and the genome of wild elephants. By drawing on studies of 261 mammals such as cattle, dogs, cats and horses, they built a list of genes frequently associated with domestication. They then identified 674 genes as having a high likelihood of being passed down from earlier elephant generations.

The team found that 79 of those African elephant genes were associated with domestication in other species, further strengthening the idea that elephants evolved these traits without the direct intervention of people. This is significant, says Raviv, because elephants and humans are not closely related, suggesting domestication can evolve convergently in multiple branches of the mammal evolutionary tree.

Raviv suspects Asian elephants (Elephas maximus) may also show signs of self-domestication, but genome data was only available for African elephants at the time of the research. She says it is possible that other highly intelligent, social animals like dolphins, whales and parrots have also evolved self-domestication

Melinda Zeder at the Smithsonian National Museum of Natural History in Washington DC takes issue with the term self-domestication. Domestication is a mutual process between two species, which means no species could do it alone, she says. “There are parallels to domestication that are interesting to explore, but by branding it as domestication, they’re muddying the waters.”

Raviv says though self-domestication might seem like “a pretty wacky idea”, it is still worth investigating the phenomenon, even if another explanation is afoot. Raviv and her team are now looking for signs of self-domestication in seals, dolphins, whales and bats.