Emily Chan
On our planet, evolution has spawned countless creatures of all shapes, sizes, and colors. But throughout Earth’s long history of evolving life, no other critter has shown up quite as frequently as crabs.
In 2020, a meme went viral, suggesting that all living things will eventually look like crabs. The joke is rooted in truth, though.
Crabs keep turning up in nature, and nobody knows why. The phenomenon has puzzled scientists for years, and it’s called “carcinization.”
Carcinization refers to the process of several independent groups of crustaceans evolving to take on a crab-like form. The term was coined in 1916 by an evolutionary biologist named L.A. Borradaile.
Carcinization is a recurrent theme in the evolution of crustaceans. Luckily, the trend does not seem to be in the stars for humans.
The main features that a crustacean develops to become a crab include a wide, flat, rounded shell, and a folded, tucked-in tail.
The tails of carcinized crabs are mostly concealed beneath their bodies. It’s important to note that not all crabs are true crabs.
For instance, the blue crab and Dungeness crabs, which are part of the Brachyura group, are considered true crabs because of their classic crab-like shape.
On the other hand, Anomura, such as hermit crabs and king crabs, only developed a similar shape through carcinization.
Sign up for Chip Chick’s newsletter and get stories like this delivered to your inbox.
