The researchers captured the moment when a former vegetarian broke through the hierarchy to eat meat – and what made it even more “awful” was the fact that he was a turtle.
Scientists have captured the moment on video when a giant Seychelles tortoise – thought to be a vegetarian species – attacked and ate a baby tern, in what they say is the first documentation of deliberate hunting on any wild turtle species. .
“This is completely unexpected behavior and has never been seen before in wild turtles,” said Justin Gerlach, director of studies at Peterhouse, Cambridge, and affiliated researcher at the University of Cambridge’s Museum of Zoology, in a statement on Monday. ).
“The giant tortoise chased the baby tern along a log, finally killing the baby tern and eating it,” said Gerlach, who led the study, published Monday in the journal Current Biology.
“It was a very slow encounter, with the turtle moving at its normal slow walking pace – the entire interaction lasted seven minutes and was pretty awful.”
Anna Zora, conservation manager at Frégate Island and co-author of the study, captured the moment, which happened in July 2020.
“When I saw the turtle moving strangely, I sat down and watched, and when I realized what it was doing, I started filming,” Zora said in the statement.
Gerlach told the CNN that the way the turtle moved toward the baby suggested it was “experienced.”
“He’s moving very deliberately – he’s not just wandering, he’s looking at this tern and he’s walking right towards it, clearly intending to do something. This suggests to me that you are doing this with intent. He knows what he’s doing, he’s done it before,” he said.
Although turtles are considered vegetarian, they have been spotted eating carrion “in a timely manner” as well as snail bones and shells for calcium.
“It is quite common for herbivores to eat some dead animal as a source of free protein, essentially. But this is the first video evidence of them deliberately killing to eat,” he said.
Still, the team cannot say for sure how common this behavior is among turtles and plans to study them further.
Giant tortoises are the largest herbivores on the Galapagos and Seychelles Islands and eat up to 11% of the vegetation, researchers said. Gerlach added that the turtle’s behavior is unlikely to significantly affect tern populations.
Experts said the new hunting behavior was caused by the “unusual” combination of a tern colony with nesting trees and a population of giant turtles on Seychelles’ Frégate Island, which is home to about 3,000 turtles.
It’s not the first time that unusual lethal attacks between animal species have been seen in the wild – chimpanzees were first observed killing gorillas in the wild in 2019.
“It’s probably not uncommon for animals to surprise our expectations by eating unexpected things, which can be unique,” explained Gerlach.
“We should try to avoid having too many assumptions about what animals will do or what they are doing. And that really shows the value of observation. Just by watching and recording what animals are doing, you can find things totally unexpected, things that we couldn’t otherwise discover – it has to be by chance,” he said.
(Translated text. Read the original in English.)