Coconut Crab Claws Have The World’s Strongest Pinch Among Crustaceans

Lorenzo Tanos

Coconut crabs' claws already look fearsome enough as it is, but appearance merely tells part of the story. According to a new study, these claws may actually be the most powerful in the entire animal kingdom.

The Christian Science Monitor describes coconut crabs as native to the Indian and Pacific Oceans, and capable of growing to lengths up to three feet and weighing close to nine pounds. They are the largest terrestrial crabs in existence, and while they usually feed themselves with hard-shelled coconuts and other forms of vegetation, they may even feed on kittens and other small animals.

Just how strong are coconut crab claws? As the Christian Science Monitor pointed out, it's already quite an awesome feat to open up a coconut without the help of any tools. And with that in mind, researchers sought to test the strength of coconut crab claws and see how much force they exert when pinching.

As it turns out, they have the world's strongest pinch among crustaceans, exerting up to 3,300 newtons, or over 4.5 times more forceful than most humans can grip. According to a separate report from Reuters, that translates to up to 742 pounds, or 336.5 kilograms of force and makes coconut crabs more powerful than most land-predators. Crocodiles are still far more forceful, as their bites exert about 16,460 newtons, but coconut crab claws are much closer in force to the bites of lions, tigers, and hyenas, who only exert about 4,450 newtons when snapping their jaws shut.

"We expected the force would be very strong. But the actual powers exceeded our expectation. And we were also surprised that their pinching force was approximately 90 times of their body weight."

The Reuters report further quoted Oka, who said that the claws are used for both accessing otherwise difficult-to-reach food sources and beating other predators to that food and also for self-defense purposes. They may also fight each other for prey and use their claws accordingly to ward off other crabs. Coconut crabs' claws are believed to have evolved over time, as the animals had transitioned into a terrestrial existence.

"In particular, the ability of these crabs to open coconuts demonstrates the impressive force of their claws."
"One of the things that crabs have is a very large concentration of muscle fibers that have a unique property, being exceptionally long sarcomeres."

[Featured Image by fearlessRich/Wikimedia Commons/Cropped and Resized/CC BY-SA 2.0]