Coconut crab claws are insanely strong

You don’t want to be around this crab when it gets grabby.

In a study published Wednesday in PLOS One researchers found that the coconut crab, which already had the title of the largest land crab on Earth, also has the strongest grip of any crustacean.

Lead author Shin-ichiro Oka and his colleagues figured this out by testing the strength of 29 coconut crabs in Okinawa, Japan. Coconut crabs are native to the island, and live across islands around the Pacific. For the strength test, the researchers gently held back the crab’s other legs and placed a pressure sensor on the crab’s left claw, causing the crab to react by grabbling a stick of stainless steel with as much force as it could muster.

The results were impressive. Both male and female crabs pinched with equal force, with the strength of the pinch increasing proportionally to body size. The researchers calculated that based on their observations, the largest coconut crabs (weighing in at about 8.8 pounds) would be able to exert a pinching force of about 3300 Newtons—stronger than any other crab. Other animals are stronger, including alligators and crocodiles, which can chow down at forces of 16,700 newtons. But in the world of pinchers, the coconut crab is king.

The pinching power allows the coconut crabs to take advantage of food sources that are impenetrable to other animals, including other crabs, and, of course, coconuts, which the crabs can dig into by removing the tough husk to get to the sweet flesh within.

Unfortunately, while coconut crabs have a healthy population on Okinawa (where they are protected by government regulations) their fate isn’t secure everywhere.

“The coconut crab resources are decreasing in the world, because of over harvesting and changing their habitat,” Oka said in an e-mail. He and other researcher plan to continue studying the life history of the crab, including future studies that will dig deeper and explore the mechanism behind the crabs’ impressive pinching abilities.