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t is always kind of magical when you see a crab change shells for the first time. Magical and gross. Heavy on the gross. One thing that most people don't realize is just how much hermit crab there is inside their shells. The abdomen of a hermit crabs wraps all the way around and follows the shell as it spirals. Click below to watch a very clear video of a hermit crab changing shells.

Notice how at the beginning of the video this little Ecuadorian hermit crab has both pinches deep in the opening of the shell. This is a pretty classic posture for crab who is shell shopping. They can only get a rough idea of how close it is to the right size by inserting their big pincher.

Also pay attention to just how moist his abdomen is as he changes from one shell to the other. This is because of the shell water that is kept inside his shell. The water is a specific mix of fresh water and salt water and the easiest way for him to get that water into his shell is for him to have access to pool deep enough to let the water in. If you look closely you can see his 4th and 5th pair of legs. They are called "shell legs" and are very small, they help with cleaning and anchoring mostly and cannot be walked on.

Always offer your crabs a variety of hermit crab shells. I'll be talking more about shells and sizing in an upcoming article. Enjoy the video, it is not mine but a really nice one recently uploaded to youtube.