杏吧原创

A group of chimpanzees stole a freshly killed animal from a leopard, then ate it. It is the first time the apes have been seen challenging such a large and dangerous predator. The finding could show how ancient apes and hominins first gained access to meat as a food source, and hints at the origins of cooperative hunting.

Michio Nakamura of Kyoto University in Japan and his colleagues study a group of wild chimpanzees living in Mahale Mountains National Park in Tanzania. On the morning of 15 November 2016, Nakamura and a colleague were observing the chimps when they noticed a leopard sitting nearby. It soon moved off, perhaps because some of the chimps made intimidating 鈥渨aa barks鈥�.

A little later the group鈥檚 alpha male, Primus, arrived and led some of the chimps to a nearby tree, in which a female named Christina was sitting. All of them looked at a patch of thick bush on the ground. Then Christina climbed down, went into the bush, and pulled out the body of an antelope called a blue duiker (). It was freshly dead, with wounds on its throat that were still oozing blood.

Over the next five hours, the chimps took turns to eat the duiker, consuming its intestines, right hind leg and left forelimb. Throughout this period, various lines of evidence indicate that the leopard was either continually present or kept returning to the scene 鈥� perhaps trying to recover the duiker. Chimpanzees intermittently made waa barks again, and at one point the leopard was sighted by one of the observers. Nevertheless, the chimps made no attempt to flee.

The chimps had the advantage of numbers, says Nakamura. , but in this case 鈥渢here were some ten chimpanzees, including one adult male, rushing to the scene,鈥� he says. The incident illustrates the advantages chimps gain from living in cooperative social groups, he says, pointing to their ability to mount coordinated hunts for prey like colobus monkeys.

Such 鈥渃onfrontational scavenging鈥� may also have been important when our hominin ancestors first began eating meat in a big way around 2 million years ago. Earlier hominins such as Australopithecus mostly ate plants. As well as actively hunting prey, groups of hominins may have chased predators like lions away from their catches.

It鈥檚 a fascinating observation, but we should not read too much into it because it is a one-off, says Alexander Piel of Liverpool John Moores University in the UK. He points out that we do not know for certain that the leopard killed the duiker, and that the chimps only ate a few parts of the body. 鈥淚 wonder if it was a sick animal,鈥� he says, meaning the leopard wasn鈥檛 interested.

Nevertheless, the incident should prompt a rethink of the relationship between primates and big predators, says Piel. 鈥淲e tend to think carnivore over primate,鈥� he says, but this and other incidents like suggests chimps can sometimes hold their own.

Nakamura and Piel both say that chimpanzees may be more prone to taking prey from leopards than previously thought. While this is the first such observation, leopards have been wiped out by human activity at many chimpanzee sites 鈥� so those chimps would not have the opportunity to steal a meal.