Unpublished video reveals giant turtle acting as a bird predator

Researchers studying nature in the Seychelles Islands filmed a giant tortoise hunting and devouring a baby tern in a single bite. Scientists say this is the first time that this species, considered herbivorous, has been filmed hunting another animal.

“It’s totally amazing and scary,” said Justin Gerlach, an ecologist who lives on an island in Peterhouse, Cambridge, England. “The turtle is deliberately chasing the bird, kills it, and then eats it. So, yes, it’s a hunter.”

Scientists’ astonishment is due to the fact that giant tortoises, now found only in the Seychelles and Galapagos Islands, were considered herbivores. In fact, their vegetarian diets are believed to have shaped their ecosystems, much like elephants or bison.

Complementing the diet

In an article published Monday in the journal Current Biology, Dr. Gerlach and Anna Zora, co-author of the Frégate Island Foundation, explain that there is evidence that giant reptiles may supplement their diets from time to time. Turtles sometimes consume snail shells and bones from dead birds, goats and even other turtles. But it’s the first time they’ve seen them hunting.

There were rumors of turtles chasing seabird chicks, which became helpless after they fell from their nests. But until the video was captured, Dr. Gerlach assumed that such an observation was, at best, a misunderstanding.

“Nobody looked for it, why would you look for it? Turtles don’t hunt,” said Gerlach. “A researcher would never waste his time looking for a predatory turtle.”

Now, he wonders what else scientists will be able to learn from these creatures, which can live for more than 200 years and weigh over 226 kg.

“It’s a big mystery what they (the researchers) found here,” said James Gibbs, a herpetologist at the State University of New York and the Galapagos Conservancy who was not involved in the research.

When Dr. Gibbs watched the video, he was surprised at how slowly and strangely the attack unfolded. “It’s a very interesting combination of diligence and incompetence,” he said.