Hermit crabs give new meaning to the term "mobile home"-they carry their houses on their backs wherever they go. These crustaceans constantly have to replace their shells as they grow, and they take over those abandoned by sea snails, dog whelks and other creatures. Hermit crabs also form protective bonds with other animals, such as sea anemones, and the two creatures work together to thrive on the ocean floor.
Only Four?: Most crabs walk along the ocean floor with eight legs, but hermit crabs do it with only four. They use their other four legs to help grip the insides of their adopted shells and hold the shells securely on their backs.
Doorstop: This crab has one bigger claw that is usually much bigger than the other one. If an enemy approaches, the crab ducks into its shell and covers the opening with its larger claw.
Screwed in Tight[]
Friendly anemones help protect the hermit crabs from danger.
Behind its head and legs, a hermit crab's body is little more than a spiral of fleshy tissue with legs poking out of it. The crabs protect their vulnerable skins by taking up residence in the empty shells left behind by sea snails and other shelled animals. However, as the crabs grow, their bodies can no longer fit in their shells. No problem. They simply find a bigger one, crawl inside and twist their bodies into place. They hold on to their shells so tightly that they can rarely be removed without injuring them.
Not So Crabby: Some hermit crabs let small sea anemones take root on their shells. An anemone's stinging tentacles helps protect the crabs from attackers, and the mobile shells help anemones find more food than if they were stuck in one place.
Dead or Alive: A hermit crab's diet isn't exactly appealing. These creatures munch on all the pieces of dead plants and animals they can find on the ocean floor. Once in a while, a crab might snag a live shrimp, or even a small crab.
Home Invasion[]
- A hermit crab that has outgrown its shell is near the bursting point and needs a new home immediately. It comes across another hermit crab, and notices that its shell would be a perfect fit. It attacks without hesitation.
- After several minutes of snapping with claws and pulling, the attacker manages to rip the other crab from its shell. The victor crawls in and makes itself at home. The other crab goes off to find a new shell, but it is an easy target for hungry fish until it does.
Trivia[]
- Hermit crabs are mentioned on several other cards:
- The Sea Anemones card also brings up the symbiotic relationship some species of anemone have with some hermit crabs.
- It is listed on the bottom of the back of the Spiny King Crab card, in the section "Crabby Cousins", as one of their relatives.