1. Psychedelic yadokari from Okinawa.         2. Biggun - bigger than my fist - yadokari from Ishigaki.

    The PANTHEIST* : On Crawly Crustacea             (Def: see right col.)

As a nature lover, I often find myself enamored by the wonders of beautiful or strangely adapted creatures of our world. To my eyes, some of the most beautiful and at the same time, some of the weirdest critters on the planet belong to those long-legged, insect like sea-dwellers (well – mostly!) – the Crustaceans – that is crabs, shrimps and the like.

Now, I must admit here that I have a strange fascination with Crustaceans which could possibly be explained by the fact that I am allergic to them – can’t eat any of 'em! Well… actually my allergy is not that strong – a couple of shrimps generally results in nothing more than an itchy mouth. But a morsel of famous Queensland mudcrab is enough to produce more drastic symptoms – swollen tongue, throat and face etc… I guess I’m lucky not to have the `hypersensitive` version whose victims can end up in the emergency ward from miniscule contamination from shrimp or crab flesh.

Anyway, to return to my obsession – a `Painted Crayfish` (Panulirus versicolor - below) must surely be one of the most beautifully decorated creatures in Nature. The amazing detail of colour in their camouflage is a sight to behold in their natural habitat on the coral reefs of the Indo-Pacific. (Or even in an aquarium tank for that matter).

But for myself, and I suspect many Nature Lovers would share this trait, weirdness (in animals at least) is somehow more attractive than sheer beauty. For this reason I find myself intrigued by those terrestrial (land dwelling) crabs – the hermit crabs and of course the giant robber crab (also known as coconut crab). While these robot-like crawlies lose out big-time in the `natural beauty` stakes (Shhh... don’t tell the militant hermit crabby club I said that – their assassins will be crashing through my door faster than you can say Osama Bin-Crabbin!), they more than compensate with weirdness of form and lifestyle.

And lucky for me, where I live, there are plenty of crabby companions to play with! As a current resident of the island of Okinawa in Japan, I am probably one of the few privileged 'Westerners' to be acutely aware of the secret subtropical paradise islands of the Ryukyu Archipelago. These islands are situated roughly between 700 & 1200 km SW of the main islands of Japan – quite close to Taiwan infact. Okinawa, the largest island, and closest to Japanese Mainland, is quite beautiful but somewhat overpopulated in the southern half, being mostly covered by various conjoined cities. Moving progressively south in the Ryukyus, we encounter the islands of Miyako, Ishigaki and Iriomote, along with a host of tiny islands. All of them offer dense subtropical jungle, crystal water beaches and coral reefs. They are dominated by a geology of ancient reef limestone which creates the famous craggy outcrop rock formations seen in Phang Nga Bay of Thailand and the Philippines among other places. As such, the weathering of the coastline provides an endless array of habitats for such things as Hermit Crabs – known locally as ‘yadokari’ (宿借 - rent hotel); and the giant Robber Crabs or ‘yashigani’. Despite their long-term status as delicacy for the local people and probably thanks to a relatively small human population - Yashigani have survived and can still be found in the jungles of Ishigaki and Iriomote particularly.  A Yashigani / Robber Crab page will be forthcoming - stay tuned!!

Okinawan Hermit Crabs - Yadokari 

(literally 'Rent-hotel' in Japanese - 宿借) 

Hermit Crabs: In the scorching Ryukyu summer, Yadokari can be readily found on or near any of the myriad beaches. Of course kids love to play with them, as do many adults, and I am sure the Ryukyu Yadokari play an important Nature lesson for many Japanese kids and adults alike. Luckily for the crabs they are quite well protected in their shells and seem to cope with minor harassment quite well. Indeed, I have engaged in the relatively harmless pursuit of Yadokari races on many occasions (though fitting the saddle is a nightmare!!).

These curious critters spend just a short larval stage in the oceans, before living out their lives on land in a borrowed (or is that stolen?) snail shell. Beach specimens are generally less than 5cm long, though larger ones are sometimes found. Apparently, hermit crab populations are often limited by the availability of snail shells, presumably large ones in particular (greater than say 7cm long), which are not so common on the beach. But, occasionally - and it will usually be somewhat removed from the beach - one can find the larger specimens of up to 12-15cm in shell size (like the one on the right at the top of the page). These crabs usually occupy a heavier, more sturdy shell than small to medium sized crabs. There have been reports of some crabs utilizing aluminium drink cans and the like for want of a decent shell. These ‘grand-daddy’ (or grand-ma) crabs apparently spend most of their lives roaming the jungle, and eating god knows what - detritus and vegetable matter. The females return to the sea only to deposit their eggs in the lapping waves.

Aparently yadokari may live about 10 years in the wild, and up to 20 years in captivity!!. Although it’s very difficult to determine their age because they have variable growth rates depending on the size of the shell occupied – for example – a crab in a tight shell will grow more slowly than a crab occupying a roomy shell.

One of the most uniquely curious sights of Nature I have witnessed was that of a hermit crab changing its shell. When the crab becomes too big for it's shell, or if another shell is preferred for some crabby reason, the crab will carefully inspect the empty shell by sight (presumably) and with its feelers. The empty shell is delicately turned over and around, many times, every which way, viewed and felt, inside and out. One presumes the crab is checking for existing tenents (sometimes with a view to violent eviction), as well as holes or damage of some sort that might render the shell an unsuitable dwelling. Then again – this process could just be the crabby equivalent of a young lady in a dress shop!! (forgive me Germaine for what I am about to write)... 

    “Which one looks best darling… does this one make me look fat??”.

No – seriously – the process is most curious and entertaining to observe, though it must be done with absolute stillness for if the crab senses any movement from the observer, it will withdraw into its shell instantly and refrain further inspection until the intruder has gone, or turned once again into a statue. 

If the empty shell passes its roadworthiness inspection, well then... it’s time for a test drive!! The empty shell is carefully positioned alongside the old one, then the wary crab whips its vulnerable naked rear-end out of the old and into the new. If it's a good fit, Mr or Miss Yadokari will then take the new shell for a test-drive!! - Just like Mrs Beckham at the local Porsche dealer!!; or me at the shonky used-car lot!! Usually it's just a short walk before circling back to the old shell, which is reinspected – just to make sure it isn't better than the new one. If the shells are similar, the crab may even swap back and forth a few times before making a final decision!!

Now... no doubt I am guilty of a certain amount of `humanization` (or 'anthropomorphism') of the crabs behavior, for they are wild and relatively `simple` creatures, but watching the shell changing activity of these Yadokari, it's virtually impossible for a Human observer to avoid thinking about our own behavior when buying a new car, house or clothes. The parallels are amazing, and I couldn't help wondering exactly what is going on in this crabs brain, or could all this apparently intricate, decision-making behavior be totally instinctive? Impossible questions of course... How much of this behavior is instinctive; how much is learned; is there any free choice being exercised by this primitive critter??

Anyway... when the matter has finally been decided, Yadokari-San will scuttle off to continue its crabby business. For larger crabs shells are often a scarce resource, creating strong competition for new, bigger shells amongst yadokari. Crabs that are obviously in need of a larger shell are a common sight and can sometimes be observed fighting with others, trying to forcibly remove them from their shell in order to steal it. These crab fights can be quite noisy, with both animals chirping loudly (for a hermit crab), and I presume viciously!! Apparently this scarcity of shells is a population limiting factor for wild Yadokari..

MORE TO COME  - STAY TUNED......