Crab Facts

16 facts. 11 of them are true, and the true ones are cited. Good luck.

A new one is selected every day at midnight UTC. It is the same fact for everyone.

The complete list

1. The word carcinization was coined in 1916 by the zoologist L. A. Borradaile, who described it as “one of the many attempts of Nature to evolve a crab.” [source]
2. The crab body plan has evolved independently at least five separate times within the decapod crustaceans. These animals did not inherit the shape from each other. They each arrived at it on their own. [source]
3. King crabs are descended from hermit crabs. Somewhere in the lineage, an animal that lived in a borrowed shell stopped borrowing and started building. [source]
4. Horseshoe crabs are not crabs. They are not even crustaceans — they are closer to spiders and scorpions. Their blood is blue, and is used by the pharmaceutical industry to test for bacterial contamination. [source]
5. A crab observed walking forward is not a crab. It is something else, and it wants you to relax.
6. The coconut crab is a hermit crab that gave up the shell, moved onto land, and became the largest terrestrial arthropod alive. It climbs trees. It opens coconuts. It can lift around 30 kilograms. [source]
7. Porcelain crabs are not true crabs either. They are anomurans, more closely related to squat lobsters — an independent run at the same silhouette. They also shed their limbs at the slightest provocation, which is where the name comes from. [source]
8. Crabs can be reasoned with, but only in writing, and only about matters already settled.
9. Carcinization runs in reverse too. Several lineages have decarcinized, abandoning the crab form after arriving at it. Nobody has satisfactorily explained why anything would do this. [source]
10. Crabs grow by molting — climbing out of the old shell entirely. For a short window afterward the animal is soft, enormous, and completely defenceless. Every increase in size is preceded by a period of being extremely easy to eat. [source]
11. The Japanese spider crab has the greatest leg span of any arthropod on Earth — up to about 3.7 metres from claw to claw. [source]
12. Given four hundred million years and a reliable supply of humidity, an ordinary filing cabinet will produce a crab. This has not been tested to completion.
13. Pea crabs live their entire adult lives inside oysters and mussels. They are among the smallest crabs in the world, and they are, technically, uninvited. [source]
14. Crabs experience time sideways. This is why they are never in a hurry and never late.
15. The yeti crab lives around deep-sea vents and cold seeps, and grows bacteria on the dense hair covering its claws. It waves the claws through the water to feed them, then eats the bacteria. It is farming. [source]
16. The Pentium II under our desk has begun to develop a carapace. We are monitoring the situation and have stopped opening the case.