Features

Crab A Lil’ Attitude

crab-faceBy Marsha Pardee

Feelin’ crabby — like your head is bunched between your shoulders and you want to pinch somebody else’s head off? Well, it’s more than just an attitude for some, and for those poor souls, there is simply no adjusting.

I’m speaking of the true crabs of the world, those that live and thrive along the shores or in the shallows and deeps of the seas. Can you imagine what it would be like to have ten legs (two of which you have to eat with), be terminally flat-chested and humpbacked with no neck or head to speak of, and have eyeballs that stick out on stalks? You would spend your life hiding in holes or crevasses to keep from being eaten, and have to scrounge around the sea floor scavenging bits of day-old debris. I’d be a little crabby too under the circumstances.

But regardless of what would appear to be a seriously sad state of affairs to us, crabs are pretty well adjusted creatures. Not only do they deal with their seemingly dire set of circumstances, but they have flourished in their underwater realms. They have also managed to come up with some very colorful and creative ways to stay alive. As they say, if you are going to have an attitude, then you might as well make the most of it.

I’ll start this soppy soap opera with a crabby version of the birds and the bees and some other basic processes. Then I’ll lead you through what we think we know about the lifestyles and attitudes of the different types of cantankerous crabs.

GET A LIFE!

As if living in the body of a crab wasn’t enough to get you down, here’s something that will really break a woman’s heart. Many female crabs only have sex ONCE IN THEIR LIFE!! And yep, you guessed it, the boys constantly run around. But at least when they do get their chance, the males will court them appropriately and cuddle them for a few days first, with the one-time deed actually lasting for several hours.

Now don’t think I’m a pervert, but in my earlier studious years, I once clocked blue crab sex, and am pleased to say that for the poor females, the pair I watched mated for 12 hours straight. Once the act is complete, females may store the sperm for successive batches of babies and they never have need of a man again. Anatomically speaking, male and female crabs are pretty well equipped and easy to differentiate. If you looked at the abdomen, which is the underside of a crab, it would appear that the back of the crab wraps up under the belly. Where it overlaps contains the sex organs of the crabs. Premature females have a V-shaped flap that turns into an “apron” for holding eggs once she has had her once-in-a-lifetime encounter. Males have a prong-shaped flap that resembles, well you know . . . a male.

I’ve never really thought of a crab as being cuddly, but in fact they are — at least with each other that is, and only when they are trying to procreate. The male crab will literally cuddle the female beneath him, carrying her around for up to week or more prior to their mating. When she finally undergoes her pre-terminal molt (yes, another horror story I’ll get to later), then they are capable of copulating. The male will continue to cuddle and protect her until her shell hardens again. Then he is off for another tryst and she is left to raise the kids.

ccc-with-eggsHow do we know some of these sordid details? Much of the information comes from fishermen. One of my favorite books is Beautiful Swimmer by William Werner, which eloquently describes the life and times of the beleaguered blue crabs in the Chesapeake Bay. In Werner’s accounting, he tells of a fishing method (called trot lining) commonly used by the local fishermen. With this technique, fishermen bait a staked line with a male crab (called a jimmy) to attract the young females. A single male can attract hordes of females in this manner over time. When hormones are running high, the fishermen can harvest a new female every few hours.

Enough about blue crab gigolos, what happens to the poor women? Well, if they’ve been arrested on the trot line, I’m afraid they are served a life-time sentence — on somebody’s plate that is, as a delectable soft-shell crab dinner. But if they get to live happily ever after, they go on to being “sooks,” and bear large batches of babies. In my estimation, they take the female domesticate role a bit too far, with their aprons and red painted pinchers, but whatever it takes to keep the world in blue crabs.

When they are ready, the female crabs extrude their eggs, while releasing the stored sperm to fertilize them. The eggs are carried in the apron-shaped abdomen, which looks much like a sponge attached to her belly. Here the female broods her eggs, cleaning and oxygenating them until they are ready to be released. The eggs hatch into what is a called a zoea larvae, which looks more like something from outer space than the beginnings of a crab. The larvae go through several molts (shedding their skins) before metamorphosing (really big changes in appearance) into megalops larvae (yes, it looks like it sounds) and finally into their final torturous form.

In actuality, there is not much to the body of a crab. Basically, they have ten legs which puts them in the Order Decapoda along with lobsters and shrimp. Two of the ten legs are formed into pinchers or claws used pretty much like our hands to get food to their mouths. Everything else is sandwiched between top and bottom shells. The top shell is called the carapace and its underside the abdomen. The only other movable parts are their stalked eyes and mouth parts, located front and center on the carapace between their two claws. The whole package is typically round or oblong, looking somewhat like a Jamaican patty or pastie with legs and a couple of eyeballs.

EVER WANT TO JUMP OUT OF YOUR SKIN?
And I mean this literally. What if every time you gained a few pounds, you not only couldn’t fit into your clothes, but you couldn’t fit into your skin, either? What a painful thought, being squeezed into an entire suit of too-tight jeans. Well that’s life for a crab, as well as for any other crustacean out there. Crustaceans are basically soft-bodied organisms encased in a shell-like skin. This exoskeleton, as it’s called, is made up of a hard substance called chitin and calcium.

Crustaceans grow in increments, whereas they obtain a certain size and then need to shed their exoskeletons to get to the next size. This process is called ecdysis or molting. Talk about an excruciatingly painful looking event!!

Imagine having to crawl out of your own skin. First you would need to secrete a substance that would dissolve your inner skeletal lining. Then you would need to crack open a line along your back and pull your legs, arms, torso and head out of that crack. (Oh, and don’t forget those organs!) Then, you have to swallow a bunch of water to pump your body up to the new size. Mind you, you are totally soft now so you must seek a place to hide for a couple of days until you can harden up again. And watch out for falling rocks and predators — it’s easy to lose a leg or a life at this stage. And your attitude towards this lifelong process? A bit more complicated than just getting your knickers in a twist, I’d say, and probably more like perpetual PMS.

decorator-crabIT’S A DOG-EAT-DOG WORLD
For the inhabitants of the watery realms, the daily drama is eat or be eaten. It’s basically survival of the fittest down there, and makes our daily lives look like a cakewalk in comparison. Just think what it would be like to spend your days scurrying to and fro frantically searching for food, while keeping an eye on the nearest bolt hole in case a predator comes cruising by. Or having to prostitute yourself on some corner coral reef, in hopes of gleaning a few parasites from a passing fish. Or worse yet, burrowing up to your eyeballs in oozy mud or sand just to save your hide or find the odd clam to munch on.

Crabs are mainly scavengers of sorts, underwater vultures that feed on the leftover carrion of the sea. If by chance a dim-witted creature comes within grasp, they are capable of pinching someone’s head off, but for the most part they take what they can find. Some crabs are more ambitious, like the yellowline arrow crabs found on reefs, and set up cleaning stations to attract and groom passing customers. Their efforts are rewarded in mere morsels of flesh, mostly flakes of dead skin or parasites that they remove. A few species of crabs (like those known as the clinging crabs) are more herbivorous, and scrape rocks for algae and other small protein particles with their specially adapted claws.

Who are their enemies? Well just about anything with jaws and teeth that can crunch. In their larval stages, crabs are free floating plankton, with little mobility or protection on their own. They can be sucked in and slurped up by even the tiniest of other marine creatures. As they grow, their likelihood of life loss in this manner decreases. Once they have attained the real crab look, with their sharp claws and spiny and more rigid outer shells, they are better prepared to protect and defend themselves.

Most crabs live in the oceans of the world, but there are a few that have taken to land and even some freshwater species. In the sections below, I have written about some of the crabs that may cross your path (or rather you theirs) here in the Turks & Caicos and throughout the Caribbean. In doing so, I’ve tried to view life from their perspective and maybe with just a hint of what I imagine their attitudes must be about their peculiar set of circumstances.

FEELING INSECURE?

Feel like you’re hanging from your toenails, upside down on a sheer rock drop-off? Then you can probably relate to the Clinging Crabs that often do just that. Members of the Spider Crab family, these crabs have long spidery legs and are often seen literally hanging by their toenails in some rocky crevasse or reef.

There are a number of clinging crabs relatively common to this area, including the Green, Banded, Paved, Nodose, Red-ridged, Hairy and Channel Clinging Crabs. All are of the Genus Mithrax. With the exception of the Hairy and Channel Clinging Crabs, the others are less than one inch in size. The Hairy Clinging Crab reaches a size of four inches, while the Channel Clinging Crab gets up to at least seven inches in carapace length.

Because of its size, the Channel Clinging Crab is often a food source throughout the Caribbean. Its popularity inspired scientists to research into its culture capabilities, with the first ever Mithrax crab farm being located here in the TCI on the island of North Caicos. The marketing name chosen for Channel Clinging Crab was the Caribbean King Crab and its culture potential was developed by West Indies Mariculture, Ltd. The farm’s delicacy was the production of soft-shelled Mithrax crabs, which were truly mouth-watering. Unfortunately, the farm closed before realizing its full commercial potential, but it did manage to leave a legacy of the Caribbean King Crab.

A common denominator for all clinging crabs is the blunted tips of the claws that fit together like small rows of teeth. These claws are typically used to scrape algae and other bits off the rocks and reefs where they are found.

DROWNING YOUR SORROWS . . .

This is not an option for members of the Swimming Crab (Portunidae) family whose lives depend on their ability swim. These crabs come readily equipped with paddles on their last pair of legs enabling them to swim for their lives if need be. Unlike the other crabs who are limited to one mode of transport, swimming crabs can crawl and swim, and are quite capable of lengthy trips from onshore estuarine habitats to offshore open ocean grounds.

Of the swimming crabs, the most famous are the Blue Crabs, prized for their delectable meat. A strong and somewhat stable commercial fishery from Cape Cod to Florida, they are unfortunately not as common in the Caribbean. In particular, they are not readily found in islands like the TCI that have a paucity of fresh and brackish water rivers and run-off for nutrient loading. In other words, the clean, clear waters found here are less productive.

A few other types of swimming crabs found in this region include the Ocellated Swimming Crab that is easily distinguished by the two red-ocellated eyespots on its carapace. The Sargassum Swimming Crab is colored to blend in with the floating rafts of sargassum where it lives. Blotched Swimming Crabs are varying shades of brown with some blotches and mottling to blend with the bottoms of harbors and bays where they are commonly found. Redhair Swimming Crabs are smaller (1 to 1 1/2 inches) and have red blotches on their reddish to yellowish brown carapace. These crabs inhabit shallow areas of sand and can often be found washed up in the surf.

All of these crabs are voracious carnivores and can do real damage to small fish, clams and any other mollusk they come across. Swimming crabs have strong, sharply pointed pinchers for this purpose. They can also inflict a great deal of pain to human fingers and toes if given the chance. (I’ve even seen a number of swimming crabs clipped to the noses of unassuming and overly curious dogs.)

FEELING FRAGILE?

Try being a Porcelain Crab, with a tiny body that for most, is less than an inch long. This family of crabs is more closely related to Hermit crabs (Section Anomura) than the rest of their brachyuran relatives. There are several species you may happen upon here.
Porcelain crabs do look somewhat fragile with their flattened carapaces and bodies, but make up for this with enlarged claws which appear about half the size of their entire bodies. The Green Porcelain crab is mottled shades of green and the Red Porcelain crab is a deep red, with the Banded Porcelain crab banded red with shades of yellow to brown.

The Spotted Porcelain Crab is the most colorful of the group, being red to orange with large white and violet spots ringed in red. This little wee crab is commonly associated with Giant Hermits, Stareye Hermits, Red Hermits (with matching coloration) and Queen Conchs. When disturbed, it will withdraw into the host’s protective shell.

shame-faced-crabSHAME ON YOU!

Whatever dastardly deed the Box Crabs’ ancestors committed, we may never know, but now the poor souls are forever covering their faces in shame. So much so that Box Crabs’ alias is the Shamefaced Crab. There are three species of Box Crabs commonly found in this area: the Rough Box Crab, the Ocellated Box Crab and the Flame Box Crab. All of the Box Crabs have a “pinched in” area located on the top of their carapace, but their most distinguishing feature is that the crab appears to be hiding its face with its claws. The claws fit perfectly against the shell, making a compact box of a crab.

The Rough Box Crab varies from pale yellow, pink, red, orange and brown in color, but often becomes encrusted, hiding the true colors of its shells. The Ocellated Box Crab has a network of dark brown to reddish brown to lavender lines on its carapace. The Flame Box Crab is similar in coloration but the pattern on this species fades towards the rear becoming a series of non-intersecting lines.

All three types of Box Crabs inhabit sandy bottoms with the latter two also liking to live in areas of mixed sand and rubble. Not only are they shame-faced, but shy, often burying themselves up to their eyeballs in sand to hide from passersby.

TALK ABOUT A BAD HAIR DAY!
What do you do when your doo just won’t do? The Sponge and Decorator Crabs have it all worked out. Just plop a piece of colorful sponge, bits of algae, some seaweed, or maybe a few hydroids on top to cover up the mess. These clever crabs even have built-in bobby pins to aid all their hairdressing needs.

The Sponge Crabs are the real stylists. They literally cut and shape their fancy sponge “caps” before hooking them on with two pairs of their short, upturned rear legs. These crabs range in size from one to three inches.

The Decorator Crabs are not as savvy in the styling salons, but are true pioneers in camouflage coordination. Their secret seems to be in utilizing a variety of locally made materials, such as sponges, hydroids, anemones, zoanthids, tunicates and both leafy and hairy algae. They go all out too, and cover not only their carapaces, but snouts and legs, securing the debris on built-in tiny hooks. A lot of fuss for a 1/2 to 3/4-inch long crab.

ALL WASHED UP
Crabs of the Genus Percnon seem to be perpetually in peril as they dash around the splash zones of rocky intertidal areas. Here in the TCI, they are commonly seen along the ironshore, where the surf pounds the rocky ledges. Most of the ones I’ve seen are black/brown with some bright red markings.

These may or may not be the same species as the Nimble Spray Crab, Percnon gibbessi, that is commonly found on the reefs. Also known as the Urchin Crab, this clever creature often hides beneath the protective spines of the Long-spined Urchins.

LIKE A FISH OUT OF WATER
There are species of crabs that are literally like fish out of water, from when their ancestors invaded terra firma many thousands of years ago. (Talk about having to dry out for a while!)

In this neck of the woods we commonly call them land crabs, which refers to the members of the family Gecarcinidae. The family includes Cardisoma, which lives in the fields and woods in southern Florida and the West Indies and also Gecarcinus, which inhabits grasslands and forests along the coasts of Florida, tropical America and throughout the West Indies.

Although terrestrial, the land crabs are nevertheless coastal in distribution, for the females must return to the sea to release their spawn. To be able to live on land, the crab’s gills have had to become more like lungs. Land crab gills occupy cavities that have become so highly vascularized with fine blood vessels that the cavities can take up oxygen from the air. They must keep their gill cavities moist, but can do so by taking up droplets of dew from plants or moisture from sand.

Land crabs live in deep burrows, sometimes in the dune areas, intervening flats and upper lagoon shore-type areas. They are most often seen at night, when they emerge to feed. This is also a good to time to catch them if you hunger for land crab fare. A burlap sack, stick and torch are the tools of the trade, but speed and skill are the key components for harvest success.

WELL FIDDLE DEE DEE
Even Scarlett O’Hara would have to show some sympathy for the lowly Fiddler Crabs that abound in the muddy marshes of the deep south (and up to Cape Cod) as well as along our sand and mud shores. The poor little (one-inch) Fiddlers are rather drab in appearance, usually a chocolate to grey coloration with some purples and/or reds speckled through. They would never stand out at a crab cotillion, but in fact are quite gregarious and burrow very close to one another.

This makes it easy for the males and females to get together. Males are easily distinguished by their claws, of which one is greatly enlarged. The females have two tiny claws. The males are actually quite courtly and have an elaborate ritual of claw waving and rapping to attract the females to their burrows (their way of saying “Hey Babe, wanna come to my place?”).

If you are out walking along an intertidal shoreline, look for dozens of small holes with balls of soil at the entrances. The fiddlers make their burrows by excavating the sand/mud to the surface in small balls attached to their legs. At low tide, fiddlers come out to eat the detritus along the shoreline and retreat to their burrows as the tide comes in.

LIFE’S A BEACH AND THEN YOU DIE
Another amphibious sort is the Ghost Crab, who spends his entire existence haunting the beaches of the world. Rarely seen during the day, they race up and down the beaches at night in a sideways fashion, constantly changing directions as they go. Late-night beach lovers are often startled by the crabs’ sudden appearance and equally astounded at the speed with which they can vanish in the blink of an eye.

Their coloration is also cause for their ghostly name. They are white to nearly opaque to blend in with their sandy surrounds. On average, their carapace is about two inches from side to side, but I have been startled by some monsters that were at least five inches long.

Ghost Crabs are not as gregarious as the Fiddlers; they like their burrows spaced far apart and build them in a J-shape down to the water table. Like the Fiddlers, they can exist on land as long as they keep their gills wet, so the subterranean shelter includes a small dipping pool. Both types of crabs have reduced gills capable of extracting oxygen from the air, much like their land crab cousins.

Most active at night, Ghost Crabs can be seen scavenging at the surf line for detritus and bivalves while taking a dip to wet their gills. For this reason, it is important to leave the weed lines along the beaches intact, if we hope to keep our Ghost Crabs around.

DON’T BE A HERMIT
Talk about the ultimate embarrassment! The poor Hermit Crabs really have it rough. The top half of their bodies are armored like the rest of the crab world, but their rears are totally exposed soft skin. To cover this seemingly embarrassing predicament, they cloak themselves with a shell, but even it, of course, is a hand-me-down from some poor deceased snail.

hermit-crabTo add insult to injury, the hermit crabs’ lives are still complicated by the molt thing, so as they grow they must constantly seek larger shells to fit their expanding form. (Their predicament adds a whole new meaning to “shop ’til you drop.”)

Apparently modest as well, when hermit crabs do find a new outfit, they are extremely speedy changers. They will park their shell as close to the aperture of the new one as possible and switch in an instant, so that no one has the chance to view (or take a chunk out of) their exposed hind end. They would rather die (and probably would) if they were forced to leave their shell before finding a new one.

Opportunistic in all regards, hermit crabs spend the rest of their time scavenging for dead animals and debris. There are several types of hermit crabs and they can be found on both land and in the sea. Sizes range from the Giant Hermit Crab (5 to 8 inches), often seen living in adult conch shells, to the tiny Red-reef, Orangeclaw, Red-striped or Polkadotted Hermits (1/2 to 1 inch) that are found in any appropriately sized shell.

CHANGES IN LATITUDES, CHANGES IN ATTITUDES
So whether you are a regular here in these fair isles or just passing through these latitudes, crab a lil attitude — adjustment that is. When you’re feeling a bit crabby, think of the poor cantankerous crabs and all the deserving reasons they have for being the way they are. Picture yourself in one of their seemingly ridiculous predicaments, and see if that can’t put a smile on your face. We will all be the better for it . . . well, except for the crabs.

Marsha Pardee is a marine ecologist who has lived and worked in the Turks & Caicos Islands for the past 11 years. The views and opinions expressed in this article are those of the author and not of the crabs. The author asks that the readers please forgive any insults, comments and/or comparisons to members of the opposite sex. The author also wishes to thank the readers for putting up with her cranky attitude — she’s just been feeling a little crabby lately . . . but is working on an attitude adjustment while counting her blessings and being thankful she is not a crab.



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Marta Morton, owner/operator of Harbour Club Villas (www.harbourclubvillas.com) took this photo of the native Turks & Caicos rock iguana on Bay Cay. This endemic animal is being threatened by the invasive green iguana. See article on page 36.

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