Fregate Island is a privately-owned, luxury resort in Seychelles, and is used for ecotourism. Sea birds have recolonized the area. Fregate Island is providing a new insight that the giant tortoise might be one of nature’s vegetarians.
A video shows the astonishing moment an Aldabra giant tortoise hunts and kills a tern chick on the island. The tern chick fell from a nest in the trees above.
“That was probably something that occurred much more commonly in the distant past, when they would have been many islands with tortoises and with seabirds, but over hundreds of years, humans wiped out both the sea birds and tortoises,” Gerlach is reported in The AfricaNews, as saying.
“And it’s only the restoration work that’s been done on places like Fregate that has allowed the habitats to recover, allowed the populations to recover. And I suspect what we’re seeing is something that used to occur in the past, but no human has seen for 200 years.”
It’s the first time this behaviour has ever been documented and changes what scientists thought they knew about the species. A study of the slow-speed hunt has been published in the scientific journal Current Biology.
The research was led by Dr Justin Gerlach, director of studies at Peterhouse, Cambridge.
“Everybody knows, or everybody thought they knew, that tortoises are vegetarians,” he says. “Pretty much any herbivorous animal will eat a bit of meat that they come across. It’s a bit of free protein. So why wouldn’t they do so? But that’s just feeding on a bit of carrion. It’s not hunting. It’s not killing prey. And so this is totally unexpected.”
The bird’s natural instinct is that the ground is dangerous, so it refuses to leave the top of a log. But with no escape route, the tortoise is able to corner its prey – albeit very slowly.
Gerlach says the tortoise appears to be an experienced hunter. “So it seems to be an aggressive action and it seems to be deliberate. There’s nothing very casual about this. So that all adds up to a tortoise that’s done this before,” he says.
There are more than 3,000 Aldabra giant tortoises on Fregate Island, the second largest colony in the world.
“I remember one of the guys saying to me, ‘oh no! We need to save the chick’ and I stopped him, I said, look, if you were in the Savannah with a lion running after a gazelle, would you go and save the gazelle?” Zora says.
“It’s a little bit the same concept. Nature can be cruel.”