Tuesday, January 05, 2010

Hermit crab house swap

This is one of a load of photos I took at one of my favourite little spots in the caribbean. This area is a bay with a shallow sand slope with a fair bit of sea grass. There is a bar on the beach (nice) and a floating boat bar a little offshore so there are two jetties either side of the bay. The end result is that this is an excellent place to take beginner divers for the first "confined water" parts of an open water course. These are sessions teaching literally the first things you do in the water, in water you can stand up in and its essential skills like simply breathing from a regulator, clearing water from your mask when it floods and putting your regulator back in your mouth if it is knocked out. Whilst the instructors would do that, I would either help or (preferrably) explore the jetty pilings or sea grass for critters of which there are a surprising amount. Mostly we are talking about small sand/sea grass critters but I've seen plenty of big 'cuda, sting and eagle rays in there and the guys in the floating bar see shark reasonably regularly at night (unfortunately the boat traffic makes this not a great place to night dive). Anway on this little foray I found one of my favourite things to watch. It would make for a great photo sequence but unfortunately we had to leave before I got to the climax so you only get the one photo.....

hermit crab houseswap

In the conch on the left is a hermit crab - it has temporarily retreated. The shell on the right is bigger, cleaner and a little nicer so the crab was in the process of thinking about shifting. When they do this it is hilarious. Being out of its shell is high risk for a hermit crab with that soft juicy abdomen exposed so the change itself needs to be quick. However that new shell has been sat on the sand there for a while so you know there is going to be some sand or grit or worse another creature somewhere in that spiral. What you get therefore is a convoluted process of slow, methodical positioning of the new shell, cleaning and shaking to get the sand out and then a frantic switch. This is always (in my limited experience) followed by some body language that can only be described as the closest a hermit crab can come to showing irritation and discomfort and then another frantic switch, more shaking to get those last bits of sand out and yet another frantic switch. This can go on for some time. Alas that time is often longer than confined water introductory sessions so I got this initial shot and settled to watch what was coming when I was recalled to the boat. Gah! Next time.

1 comment:

Wanderin' Weeta said...

I never thought of that irritation, from sand still in the shell. Like wearing a shirt with a scratchy label; no fun.

I've seen my hermits poke around inside the shell, then roll it over and over, making sure of it. Then they switch. Sometimes they switch back.

Sometimes it seems logical: the shell was just too big and awkward. But the last time I watched, the shell I'd offered looked perfect, and the silly guy switched back and refused to even try out the new shell again.

So maybe it had some stuff in it, something scratchy. I'll make sure I clean the next one better.