Tag Archives: seashell homes

hermit crab in seashell

Hermit Crabs and Why They Must Fight For Those Seashell Homes!

hermit crab in seashell
Tiny Hermit Crab at Beach

If you read this blog, you have probably grown tired of me talking about hermit crabs, but here I go again!   Usually I am complaining that every awesome shell I come across out in the backwater is inhabited by a hermit crab.

This time I am going to tell (and show) you just how crazy things can get when hermit crabs fight for those seashell homes. It’s a crab vs. crab world down under the sea.

First of all, if you know next to nothing about crabs, here’s a bit of info.

Hermit crabs are not like regular crabs you find along the beach.  We don’t eat them.  Regular crabs scurry across the sand without taking their home along on their back.  It’s difficult to ever see the entire body of the hermit crab, as it is usually hidden within a shell.  A hermit crab will “hang” out of the shell sometimes (like in the photo above), but he will not come all the way out.  If you are lucky enough to be present when he swaps his old shell for a new one, you can get a quick glimpse of the back end of his body.

That shell it carries with it used to belong to a snail – land, or marine.  The hermit crab did not make the shell he lives in, and will stay in it only as long as he fits well inside.   Once the fit is too tight, he will have to find another shell to occupy.  His life depends on it.  The shell will have to be already empty… they don’t kill snails or mollusks to take a shell.  And they don’t fight other hermit crabs that are already inside a shell.

hermit crabs

Imagine that your present home will have to be abandoned as you grow.  You can’t stop growing, so it’s a constant hunt for a new place to live.  Without a shell to hide in, a hermit crab’s life is in peril.

In this NatGeo video, deceptively entitled “Hermit Crab vs. Conch”, a large Horse Conch chases down a tulip snail (banded tulip) and digests it. But the main story is about the hermit crabs who need to find new and larger real estate for their growing bodies. They realize that the horse conch will spit out the left over shell when he’s done eating the snail and they all want that house!

Did you see the shells those hermit crabs are scurrying around in? One was a pear whelk (yellow shell), and one was a shaped like a shark’s eye, or moon snail.

Here’s another amazing video of a hermit crab changing shells, but this one takes her “friends” with her!  Smart creature!  (This shell looks like some kind of knobbed triton.)

You may wonder why the crab doesn’t just find a big shell to live in so he won’t have to worry about trading out his home.  That won’t work because if the shell is too big, he can’t carry it around as easily.

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(Photo credits: Pixabay)

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