Tortoise has always been considered a harmless and herbivore reptile species. But ironically to our surprise, for the first time, researchers caught a female Aldabra giant tortoise hunting and eating a baby bird by clamping its jaws directly around its head on Frégate Island.
The video of the gruesome meeting of a tortoise and a tern, taken on Fregate Island in Seychelles, an archipelago more than 1,000 miles off the eastern coast of Tanzania, in July 2020, shows a slow-moving herbivore giant tortoise (a member of the species Aldabrachelys gigantea), which is not usually present in a tern’s list of worrisome predators, pursuing a flightless lesser noddy tern chick and then making it his launch by clamping its jaws directly around its head.
“I couldn’t believe what I was seeing. It was horrifying and amazing at the same time,” says biologist Justin Gerlach from the University of Cambridge.
“It was looking directly at the tern and walking purposefully toward it. This was very, very strange, and totally different from normal tortoise behavior.”
According to a study published in the journal Current Biology, this encounter (lasted seven minutes in total) is the first direct evidence of a tortoise hunting any other animal.
Previously all tortoises were thought to be vegetarian, but this encounter in which the tortoise pursued the chick along the top of a log at one point, indicates that this type of interaction happens frequently. And that these creatures just take their sweet time hunting, and their prey has to be a pretty easy catch.
“The direct approach to the chick on the log suggests that the tortoise had the experience of being able to capture a chick in such a situation,” the researchers write in their paper. “This indicates that this type of interaction is not infrequent for this individual. The observation of other tortoises hunting and consuming birds suggests that this behavior has been adopted by several individuals.”
Researchers think this new hunting behavior has been driven by the conditions on Seychelles’ Fregate island but still don’t have a proof for that. However, Justin Gerlach now wants to study how often the island’s tortoises hunt and figure out how many have learned to do so.