- Researchers filmed a giant tortoise stalking and killing a baby tern on an island in the Seychelles.
- The video is the first direct evidence of tortoises hunting.
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When a baby tern falls from its nest, the bird instinctively knows it must try to get off the ground at all costs, perhaps by climbing onto on a rock or log. Otherwise, lizards and crabs can easily make a meal of the flightless bird.
A slow-moving, mostly plant-eating tortoise is not usually at the top of a tern's list of worrisome predators. However, conservationist Anna Zora stumbled across a gruesome meeting of a tortoise and a tern in July 2020, on Frégate Island in the Seychelles, an archipelago more than 1,000 miles off the eastern coast of Tanzania. The tern ended up becoming lunch.
It's the first direct evidence of a tortoise hunting another animal, according to a study published Monday in the journal Current Biology.In the video, a female Aldabra giant tortoise, weighing about 66 pounds, approaches a baby tern that had climbed onto a log after falling out of its nest. The tortoise moves toward its prey, its neck extended and jaws open wide, climbing onto the log as it snaps at the chick. The bird tries pecking the tortoise's beak, then flutters further down the log. Its cries of distress echo through the woods.Then the moment the tern stops pecking, the tortoise strikes, biting down on the bird's head and killing it.
In a new paper published in Current Biology, Anna Zora and Justin Gerlach offer the first direct evidence of a giant tortoise hunting on FrÃ©gate Island in the Seychelles. This video of the tortoise killing a tern chick is truly something to watch.
"'Shocked' is probably the right word," Justin Gerlach, a zoologist at the University of Cambridge and co-author of the study, told Insider.
Gerlach knew tortoises wouldn't turn down meat if they could get it, but the video is proof that this tortoise, at least, deliberately went after prey.
"I haven't seen the behaviour myself - my co-author Anna Zora mentioned it to me and I assumed 'hunting' was just a misunderstanding. But when she showed me the video I was amazed - absolutely no question of what is going on," he said.
The video cuts off after the bird's death, but Zora watched the tortoise then swallow its prey whole. (Tortoises have no teeth, merely a beak with serrated edges.) The entire process took seven minutes.
Tortoises will happily consume meat
Although tortoises eat mostly plants, they're not strictly vegetarian, and this isn't the first report of a tortoise consuming meat or calcium-rich animal parts like bones or shells, Gerlach said. One species of tortoise eats frogs in captivity. In the wild, they will go for carrion or slow-moving prey like snails.
"But previously, it's always been impossible to tell if the tortoise had directly killed the animal, or if it had just happened to sit down on one and find it conveniently squashed dead," Gerlach said in a press release. Although herbivores make protein from the the amino acids they get from plants, meat is, of course, concentrated protein."So no, they don't need it, but if it's there ready made that's quite attractive," Gerlach said of tortoises, adding, "any herbivoure is going to eat a bit of a dead animal if it comes across it."
Hunting might be common among Frégate Island tortoises
"We simply haven't looked for it because we never thought it was a possibility," he said.