Birgus latro, or the Coconut Crab, has a crushing force few animals on the planet can rival. The crab, which lives on islands throughout the Indian and Pacific Oceans, can grow up to 18 inches long and weigh upto 4 kilos.
Using a stainless steel force-measuring stick, Japanese researcher Shin-ichiro Oka calculated the crushing force of the crabs’ large claw. Oka estimates that based on body size, the largest-known coconut crab could crunch with roughly 742 pounds of force — about 90 times their body weight. “The pinching force of the largest coconut crab is almost equal to the bite force of adult lions,” says Oka.
The pinch-force of the crab exceeds that of any other known crustacean. Among terrestrial animals and when adjusted for body size, the crab’s size to crush ratio is second only to the bite of the saltwater crocodile, which has a bite force that rivals the dinosaur, Tyrannosaurus Rex.
So why does a crab need such a powerful tool? The crab sometimes eats coconuts, which require a massive amount of force to break open. Also, it has no shell to protect it, just a calcified outer skin, so the mega-claw acts as a threatening defensive weapon.