Living Crab Shell

I found this shell whilst snorkelling in Mexico on my last day there. I washed the sand off in the shower before wrapping in a plastic bag to transport home as an unique souvenir gift for my mum.

The next morning, I discovered that I'd accidentally also transported a little shell crab within, and without sea water, it had tried to escape.

Sadly, i learned from my mistake, not to take anything away from it's natural surroundings.

I did wonder how these shells actually grow... and I now think that I remember (maybe David Attenborough) being told that the crabs leave their shells behind only when they find a larger one to move into... 
so I'm now guessing that the shell is also effectively a living creature, and the crab occupant is responsible for helping the shells to grow from inside out...

Heyho, I didn't mean to be a murderer, but I'll treasure the shell (gift to mum), even if it did slice my finger whilst washing it.

wink emoticon