Like the sea-dwelling turtle, the land-based tortoise makes up for its glacial locomotion by existing in a hard protective shell that predators find difficult to penetrate. Unless, of course, that predator is a chimpanzee. In that case, a tortoise is vulnerable to being attacked, bashed against a tree, and having their meat sucked out like a shucked oyster.

This alarming demonstration of the food chain was recently observed for the first time at Loango National Park in Gabon, a country in central Africa. The chimps had become habituated to human researchers over several years. Writing in Scientific Reports, researchers documented 34 instances of the chimps picking up a tortoise and successfully smashing the underside, or plastron, of the shell against a tree to break it. (The top is called a carapace.) Freeing the tortoise from its defensive armor, the chimps proceeded to climb trees and dine out on the squirming reptiles.

Though chimps possess astonishing strength, not all of them were able to successfully crack the shells. When a few females and one juvenile tried, male chimps finished the job for them. The chimps also shared the meat among members of their group. One even ate half of a tortoise, then stuck the other half in a tree for later, an indication he was planning for the future.

Researchers aren't totally sure why chimps target tortoises for snacking. There are other food sources like fruit available in the environment. One possibility is that from May to October, tortoises make a tremendous amount of noise scurrying among the leaves, drawing attention to themselves as possible prey. Morbidly, it's also worth noting that their shells have nerve endings. That means that getting cracked open against a tree by a chimp is exactly as painful as it sounds.

[h/t Smithsonian]