Coconut crabs are the strongest crustaceans, it turns out – at least when it comes to lifting, pinching and cracking things.
The largest land crabs on Earth, coconut crabs, scientific name Birgus latro, can lift around 66 pounds with their pincers. They can also pinch with some 750 pounds of force, putting them on the list of strongest terrestrial animals. Only alligators and a few other animals have a similar bite force, the Los Angeles Times reports.
These astounding coconut crab facts came from research conducted by the Okinawa Churashima Foundation in Japan that measured the pinching power of 29 coconut crabs on Okinawa Island. The crabs differed in weight, from less than a pound to five pounds, with pinchers extending around seven to 400 pounds of force.
While conducting the challenge of measuring and weighing the crabs, the researchers themselves got a taste of the crabs’ pinching prowess.
The strength of a crab’s claws is strongly proportional to body mass, so the study authors calculated the pinching force of the largest coconut crab. The giant crustacean, weighing nine pounds, would have a pinching strength of 750 pounds of force.
To compare, a human’s bite from the molar exerts an average of 265 pounds of force, and an Olympic boxer’s average punch measures 770 pounds of force. Though, a punch would be more of a push than a clamping force.
Coconut crabs are believed to have developed their large, strong claws for survival, as they lost the need to carry their shells over time. They descended from hermit crabs, which carry hard snail shells on their backs for protection.
Without their shells, the crabs were able to grow bigger and developed a hard, calcified abdomen as protection. The crabs also use their claws as a deterrent to competitors, and to fight animals for food. These pinchers can give them access to food their competitors can’t, like hard-bodied fruits, carrion, the inside of trees, and even animals with shells.
The study was published in the journal PLOS One.
