Chimpanzees in an African reserve have been spotted cracking open tortoises like they're nuts.
In what's believed to be a world-first, scientists have observed primates at Loango National Park in Gabon pick up the slow prey and smash their shells on tree trunks. This allows them to scoop out the tasty meat inside.
As far as researchers know, everywhere else in the world chimps and tortoises coexist peacefully.
"We have known for decades that chimpanzees feed on meat from a variety of animal species, but until now the consumption of reptiles has not been observed", said Tobias Deschner, primate researcher at the Max Planck Institute for Evolutionary Anthropology.
According to a paper published on Thursday in journal Scientific Reports, the chimps in Laongo have long feasted on hard-shelled fruit that's not common elsewhere.
"They see this is a hard-shelled object with some interesting thing inside and I need to crack it open," Deschner told the Associated Press.
"If I can do that with the fruit and have the same problem with a hard-shelled animal with something inside that I want to get access to, then I can say 'OK, why not do it in exactly the same way?'"
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Not only is it practical, Deschner says it's a significant evolution in the local chimpanzee culture.
"They all use exactly the same way of doing it... This suggests to me that they really look at how others are doing it and then copy the movements."
Weak chimps were seen giving their tortoises to stronger adults, who'd share the spoils with the whole group.
One was even spotted stashing a half-eaten tortoise into a tree and coming back the next day for leftovers - proving they can plan ahead.
"We see chimpanzees disappearing all over Africa due to habitat destruction and poaching," said Deschner. "With each population that goes, there is a unique culture that is lost."
- But like humans, it appears not all chimps are created equal. A primate in a Norwegian Zoo in March had to get stitches after getting high and attempting to gnaw off his own arm.