Why do crabs and lobsters have shells?

Because they’re arthropods – the same animal group that includes insects and arachnids. If it has at least six legs, a segmented body, and wears its skeleton like a suit of armor, it’s an arthropod!

Hermit crabs are perhaps the most entertaining creatures in a tide pool. They scuttle quickly about on the bottom of pools and tidal flats scavenging for food. When danger approaches, they withdraw into their shells, blocking the entrance with their thick claws. Hermit crabs are also harmless–if you pick one up and hold still for a bit, they will move out of their shell to explore your hand.

These crabs, who look like tiny lobsters, inhabit discarded snail shells. Their soft, twisted abdomen has been converted into a hook that reaches into an empty snail shell. It then carries the protective shell on its back.


Picture Credit : Google