A coconut crab has been filmed methodically stalking, killing and eating a seabird in behaviour that has shocked scientists with an attack that has been described as ‘gruesome.’
The deadly crab was filmed as it climbed a tree and crept up on a sleeping sea bird in its nest on the remote Chagos Islands in the Indian Ocean.
It then plunged its powerful claw, which has the strength of a lion’s jaw, into the bird, breaking it’s wing and sending it crashing from the tree to the sand below.
The killer crustacean follows the injured, struggling bird and breaks its other wing as the bird lunges about desperately and squawks in terror.
Once the bird was lying helpless on the ground, five other coconut crabs arrived and tore the bird apart and eat it.
Researcher Mark Laidre from Dartmouth College, New Hampshire in America, filmed the macabre sight which may shed new light on the behaviour of this species and he spoke to New Scientist about the incredible discovery.
‘It was pretty gruesome,’ Mr Laidre said.
It is the first time these enormous creatures have been seen actively hunting large, back-boned animals, and suggests they might dominate their island ecosystems.
Chagos is ideal for studying coconut crabs: it is in pristine condition, is surrounded by one of the largest marine reserves on Earth and has lots of coconut crabs, making them easier to find and observe.
Mr Laidre is now planning follow-up studies to investigate whether this new form of hunting is widespread on the island.
A researcher in Japan previously proved last year that the the crab can pinch with a force of up to 3300 newtons, stronger than any other crustacean and comparable to a big predator’s bite, like a lion.
Shin-ichiro Oka at the Okinawa Churashima Foundation Research Center in Japan said: ‘The claws of coconut crabs can generate a force 80 to 100 times the mass of their body.’
‘The crab in the video seems to be about 2 kilograms, so it would be able to easily break the bird’s bones.’