Crabs are strange creatures. We love to eat them, and at the same time there are parts of the world where they are worshipped. What are these enigmatic creatures of the sea actually? Here are some crab facts that will make you better-informed about them.
- Crabs actually have ten appendages (legs). Therefore they are known as decapods (deca = ten, poda = leg). Out of these, the first pair of appendages are modified into claws, which are biologically known as chelae.
- Crabs are crustaceans. Crustaceans are creatures that do not have an endoskeleton like most animals have, but they have an exoskeleton. The exoskeleton of the crab is like a shield on its body, known as a carapace.
- Crabs are also arthropods. The Phylum Arthropoda includes animals that have segmented appendages, among other features. Even insects like the cockroach, butterfly, housefly, mosquito, spider, etc. belong to this phylum.
- In crabs, the thorax and the abdomen are not separate as it is the case in most creatures of the world. The thorax and the abdomen are joined together in crabs, which is termed as cephalothorax. But there are crabs in which this fusion does not take place. For example, the species known as Raninoida.
- Male and female crabs can be identified externally. You have to look at their abdomens. The male crabs have narrow abdomens, while the female crabs have broader abdomens.
- The sizes of crabs can range from a small marble to that of several meters. The smallest known crab is the Pea Crab, named for its size; while the largest crab is the famous Japanese Spider Crab that has a walking leg span of as many as 3 to 4 m, and can go out to 8 m when outstretched.