Wednesday, October 22, 2008


One of the many species of creatures under my care at work are Caribbean Land Hermit Crabs Coenobita clypeatus. These fascinating creatures are not the easiest animals to observe unless you suffer from insomnia because they are strictly nocturnal. I have just finished adding various animals to an exhibit we are doing called 'In the Dark' and my Hermit Crabs are one of the species we are showcasing. The exhibit illustrates how different species adapt senses other than sight to a life in the dark. All the animal's cases are lit with moonlight spectrum lights during the day and daylight spectrum during the night so they are at their most active when the Museum is open.
Just before I moved the Hermit Crabs up to their temporary new location I was giving their tank a spring clean. When I lifted the water bowl out I found this underneath...........

One of my lovely crabs was in a state of undress! As with many crustaceans, when a Hermit Crab grows it has to shed its exoskeleton to reveal a new one underneath, this process is called ecdysis. The crab is incredibly vulnerable at this point because the new exoskeleton is very soft, as you can see in the picture below.

When the moult is complete the crab will then eat the old exuvium in order to re-absorb the calcium it contains.

Once I had made this delightful discovery I had to be very careful not to disturb the crab and to carefully replace the water bowl to recreate the hide out he had made for himself. I must confess I felt a bit like I had walked in on some one who was naked! All that soft pink exposed! Anyway he did indeed survive my rude interruption and a few days later when the exoskeleton had hardened he reappeared above ground in all his new splendour! I put a new shell in the tank incase he felt the need for a move and within a few minutes he had swapped to the bigger shell - I missed that! No sooner had he moved to the other shell than one of the smaller crabs moved into the recently vacated one! (And yes, I missed that move too! Well I do have to work, I can't spend all my time watching the crabs moving house!! ;) )

Photo Credits - CJT


Rambling Woods said...

You have the most interesting posts Celeste. I didn't know that about crabs or knew something about them needing larger shells. Amazing and it does look like we are peeping toms looking at it like that...

Your EG Tour Guide said...

I'm so glad you took photos to show us what you saw. It's rare, that's for sure.

Celeste said...

Rambling Woods - Happy you liked the post Michelle, I did feel rather ashamed of photographing the poor little crab in his exposed state but I just thought it was so fascinating.

Your eg tour guide - That is what I thought too which is why I intruded on the crabs private moment!

2sweetnsaxy said...

Wow. You have the most interesting posts and great pics! :-)

Laughing Orca Ranch said...

I'm loving your blog. I enjoy blogs where I can learn new things. I never knew that about Hermit Crabs. Funny about the naked skin, too. Poor little thing.
How cool of you to catch it in the 'act', though.

I wonder if I grow larger (gah!) that I can get a bigger house, too? lol!

New Mexico, USA