Hermit crab racing

Hermit crabs were some of the most fascinating creatures we had on Yadua. Not because of any complex social behaviours, but probably more because they were one of the few animals we could really watch close up

Unlike most crabs they don't have their own shell, and so they will find and acquire one from a dead animal, or even anything remotely shell-like, instead. As a hermit crab grows bigger it therefore also has to find new, larger shells to house itself. All this can lead to a rather comical arrangement of shapes and sizes: some with pretty boring round shells; others that have an array of fantastic spikes on them; the smallest little crabs struggling to get around in oversized shells; and the giant crabs badly in need of a new home

From our point of view there were two different sorts of hermit crabs, those that lived on land, and those in the sea, especially on the reefs and in the shallows

We rarely got to pay too much attention to the marine version unless in the unlikely event of there not being much else on the reef to capture our attention, though sometimes you could sit by the shallows and watch a couple wrestling over a new shell they had found. I particularly remember a big and a little crab having a disagreement over an empty cone shell (cone shells are a particularly venomous mollusc, and so this would have been a useful shell to own). Both obviously wanted it, but the little one couldn't get near for fear of the bigger crab, which in turn was never going to fit into this little shell, though it kept trying

The land hermit crabs were much more a feature of our camp, though, and if you looked hard enough there would always be a few around. Any sudden movement close by and the crab would instantaneously suck itself back inside its shell, bulky claws and all. However, if you were patient you could pick one up and watch as it slowly decided the outside world might be safe again and emerged limb by limb

One of our pastimes in camp, which I hope isn't seen as being at all cruel, was to race hermit crabs. Pretty simply this involved putting a handful of crabs in the middle of a circle, choosing your "horse" and then waiting for the first to cross the outer line of the circle. Bit by bit each crab would emerge from its shell and slowly wander off, though without warning any of them might decide it was safer inside, leaving your apparently winning steed sitting curled up right before the finish line

Katie, Gordon and his father and brother (who came to visit) even developed an improved version of this, with the crabs instead inside a piece of bamboo, meaning that with nowhere else to go they would actually move in a roughly straight line (or do a U-turn and head back the way they started)

Unfortunately, I don't seem to have any good pictures of hermit crabs from the island, but I'm sure if you want to see what they look like you could easily find pictures somewhere on the internet