A video of a large land-dwelling crab known as a coconut or robber crab hunting and killing a seabird has gone viral.
The incident was witnessed and captured by a researcher, Mark Laidre of Dartmouth College, while he was studying the giant crabs in the remote Chagos Islands in the Indian Ocean, New Scientist reported.
Coconut crabs can grow up to the size of a dog and can even climb trees, and tear through solid matter with their claws which are as strong as a lion's jaws. They live alone in underground burrows dug by them in sand or loose soil.
Its large size and the quality of its meat means that the coconut crab is extensively hunted and is very rare on islands with a human population
In the video taken by Laidre, the crab can be seen climbing a tree and attacking the seabird in its nest which is situated on a branch close to the ground.
According to Laidre, the crab broke one of the bird's wings which made it fall out of its nest. It then attacked the bird with its claws, breaking its other wing.
Once the bird was rendered immobile, other coconut crabs arrived and tore the bird apart. Laidre described the scene as "pretty gruesome".
Laidre said he was fascinated by a story told to him by a witness in 2014. "An adult red-footed booby had landed near the entrance to a coconut crab's burrow," Laidre recounted. "As the bird stood there, the crab slowly emerged from its underground lair, approaching the bird from behind. The crab then grabbed the bird by one leg and dragged it, struggling, back into its burrow."
According to Laidre, the witness never saw the bird again, the Washington Post reported.
Coconut crabs are said to be the largest land-living arthropods in the world. They can weigh up to 4kg and grow up to one metre wide and can be the largest animal in their environment. They are commonly found in coral atolls across the Indian and Pacific Oceans.
The crabs feed on coconuts and fleshy fruits but like other crabs they are known to scavenge off corpses.
According to Laidre's surveys, birds are less likely to live on islands where coconut crabs live, and vice versa, the Guardian reported.