A video from July 2020 has surfaced showing a 66-pound female Aldabra tortoise pursuing and eventually killing a baby tern on Frégate Island in the Seychelles. The journal Current Biology states its the first recorded visual evidence of a tortoise hunting another animal.
Even though tortoises are considered to be herbivores, meaning their diet relies entirely on consuming plant material, the study mentions instances where they have been observed feeding on bones and snail shells, or the decaying flesh of a dead animal. A tortoise species known as the Manouria emys have also been known to eat frogs in captivity, while the Galápagos giant tortoise has reportedly squashed birds with the shell on its back.
These examples, however, don’t suggest the tortoise exhibited predatory behavior. That is, until now. “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,” Justin Gerlach, zoologist at the University of Cambridge and co-author of the study, told Insider.
The video, which can be seen below, shows the Aldabra tortoise slowly approaching the tern chick that didn’t seem to initially perceive it as a threat. Gerlach believes the uptick in tortoise and tern populations on Frégate Island may be directly linked to this once unforeseen behavior among tortoises.
The video is cut off once the bird is killed, but the journal entry reveals the entire interaction lasted seven minutes, with the tortoise swallowing the tern’s lifeless body whole.