(NEXSTAR) – Video of a giant tortoise hunting down and eating a baby bird is leaving biologists a little shell-shocked.
The video, filmed in July on Fregate Island in the Seychelles, has been released as part of a recent study published in the scientific journal Current Biology. In the clip, the tortoise (Aldabrachelys gigantea) is seen “deliberately” hunting a tern chick that had fallen from its nest and landed on a log.
Tortoises are not strict herbivores, though there have been anecdotal reports of them “squashing” crabs or birds under their shells, according to the study. Tortoises will also eat bones, shells or even dead frogs if they happen to come across their rotting flesh. But purposeful hunting? That kind of behavior has only been documented by witnesses a handful of times and never caught on film until now.
“For me, it was amazement,” said University of Cambridge biologist Justin Gerlach after seeing the video, which was filmed by the study’s co-author Anna Zora, a deputy conservation and sustainability manager on Fregate Island.
“Anna witnessed it first-hand, but I saw the video later. She told me she had seen a tortoise ‘hunting a bird’ and, naturally, I thought she must have been mistaken because we all know they don’t do that. But then watching the video, it’s undeniably and amazingly hunting,” he told Nexstar.
Gerlach said it’s hard to say how widespread this kind of behavior is among the tortoise population on Fregate Island. He seems to think, however, that it may just be a result of conservation efforts that have allowed the terns to recolonize the island.
“For this one, I think what we are seeing is a result of restoration of the ecosystem … These may be behaviors that existed in the past but have been impossible since humans disturbed the environment.”
This behavior can’t be entirely new, however. As seen in Zora’s video, the tortoise has its jaw widened and its tongue retracted, which are not typical feeding behaviors, but rather “aggressive” behaviors, the study points out.
“The direct approach to the chick on the log suggests that the tortoise had experience of being able to capture a chick in such a situation,” reads a press release for the study, published at Cell.com.
As for any repercussions to the ecosystem, Gerlach said there likely wouldn’t be any for the terns, seeing as they have virtually no chance of survival after falling from their nests. But it certainly changes how the tortoise and its diet will be studied.
“It will probably change the way anyone who watches the video thinks about tortoises,” added Gerlach.