Few animals have a less intimidating public image than the tortoise, known best for its vegetarian diet, slow pace of life and the ability to live for more than 100 years.

       But a new study has found, for the first time, that these animals are also hunters who will kill and eat other animals if given the perfect opportunity.

       However, their lack of speed and weapons mean they are one of the least efficient predators on the planet because of their physical limitations.

       Dr Justin Gerlach, a researcher at the University of Cambridge’s museum of zoology, was involved in a conservation project on Fregate, a private island in the Seychelles.

       His colleague, Anna Zora, caught on camera the first direct evidence of a tortoise hunting when she stumbled across an adult female in pursuit of a chick that had fallen out of its nest in the trees above and was standing on a log.

       The bird, a tern, was too young to fly and was scared of leaving the log and hopping on to the ground because it would likely have been eaten by a lizard or crab.

       Ms Zora saw the whole event unfold before her after she was returning home from a day of counting the island’s tern population on July 30 2020, at about 5pm.

       A 1.5ft-long female giant tortoise had seen a chick on a log after falling from its nest and made a beeline for it at walking pace. But this was no coincidence or friendly greeting as the large reptile approached with its mouth open and tongue retracted, a classic sign of tortoise aggression.

       The tortoise was unrelenting in its pedestrian pursuit of the bird and kept pushing forwards, constantly trying to bite the young tern, who was becoming increasingly distressed.

       “The chick retreated along the log and was pursued by the tortoise, which continued to attempt to bite,” the researchers wrote in their paper, published in the journal Current Biology.

       “The chick tried to defend itself by pecking at the tortoise without making contact, and fluttering its wings.”

       But as the bird reached the end of the log and ran out of space, it was faced with a decision: ignore its hardwired fear of the forest floor, hop off the log and run away from the current threat; or stay on the log and take its chances with the rampaging tortoise.

       It opted for the latter and the consequences were fatal. The tortoise’s next attack landed, its jaws clamped around the head of the bird and killed it instantly. The victorious tortoise climbed down from the log, picked up the carcass which had tumbled to the floor and swallowed it whole.

       The whole event took seven “horrifying” minutes, Dr Gerlach said, with the actual pursuit and killing taking 92 seconds.

       Dr Gerlach said that in nature, even the most stout herbivore will eat meat if it stumbles across an already dead animal. He also said that previously, there had been only anecdotal reports of tortoises crushing and eating other animals, but no hard evidence.

       The recording from Ms Zora shattered both these assumptions.

       ‘Any herbivore will eat a bit of meat’

       “Eating other animals was not surprising,” Dr Gerlach told The Telegraph. “Pretty much any herbivore will eat a bit of meat if it comes across it. It’s a bit of free extra protein, so eating carrion is expected. But actually, the killing was astonishing to see.

       “This video clearly shows deliberate pursuit and killing of another animal, which can only be described as hunting. It fits the definition of hunting. It’s more than simple opportunism in that it saw the chick from a distance and made a direct approach to it. It didn’t just find itself next to the chick and take a lucky bite.”

       The bird’s reluctance to run away on the ground meant that the lack of tortoise speed was no issue and it was able to catch the baby bird. Researchers think that the tortoise knew chicks often fall from their nests and will avoid the floor at all costs, leaving them stranded on a log.

       “This indicates that this type of interaction is not infrequent for this individual,” the researchers wrote. “In most ecosystems, potential prey would be too fast or agile for giant tortoises. For birds, only flightless chicks that will not attempt to run away would be vulnerable.”

       The finding, despite overhauling what we know about tortoises, poses more questions than it answers. Future studies will seek to find out how common this behaviour is on the island, how often an individual hunts, and what the benefits are of a tortoise moonlighting as a predator.

       Until these questions are answered, the researchers say it is best to still think of tortoises as herbivorous, but with capacity for this “exceptional” behaviour.

       “It wouldn’t be advisable for zoos to feed meat [to tortoises], even to this species, as it’s really difficult to get a good nutritional balance in captivity, and most easily available foods tend to be high in protein anyway (assuming that it’s the protein they are after),” Dr Gerlach said.