Aristophanes, the Athenian comic playwright, must have been a funny guy, since he is still remembered for the 40 plays that he produced in his lifetime. It is not his plays that amuse me, but his cynical wit when observing the natural world.
It was Aristophanes who stated that “you cannot teach a crab to walk straight.”
And why would you want these crawling crustaceans to change their mode of transportation? There is something entertaining and endearing about the sideways crab crawl.
Though I can’t say for certain why crabs don’t walk forward and backward, I expect that it is the result of the crab’s morphology. Crabs are decapods, meaning that they have 10 legs, more accurately called appendages, that allow them to move in their own special (side)ways.
Crabs would do well to be thoughtful about the distance that they cover sideways or otherwise, as a Haitian proverb warns that the crab that walks too far falls into the pot.
It is the blue crab that I want falling into my pot. So far, it seems to be a good year for Calinectes sapidus, the “beautiful swimmers” of our ponds and ocean. They are reported to be abundant in some of our great ponds, although the word on the pond is that there are many females.
This is important because you should never harvest mature females, in order to allow them to finish their breeding cycle. A harvestable crab is one that measures 5” from point to point on their shell or carapace.
There is no gender bending in crab country. Look to the claws to differentiate: females have red (think nail polish) on the tips of their claws, while the males do not. Or check the underside of the crawlers. Males, called “jimmies,” are distinguished by their apron, or abdomen, which is long and pointy (like the Washington Monument). Mature females are called “sooks.” Their apron is rounded and resembles the Capital Dome. Immature females are called “sallies,” and their aprons resemble the “great pyramid.”
It takes about two years and many molts, or shell shedding, for a blue crab to reach harvestable size. For a male, it is not uncommon that they have gone through 23 or more molts, while a female needs only about 20 to reach adulthood.
Those that become grown-ups are the lucky ones. The life cycle of crabs is full of twists and turns and “sea-soned” adventures.
A fertilized pregnant “sponge crab” can hold more than two million eggs under her apron. These eggs will take two weeks to ripen and then will hatch as 0.25mm larvae called zoeae.
These zoeae bear no resemblance to their parent crab. They are floating, planktonic filter feeders that will roam the waters for up to 49 days. The next stage is the megalops, which begins to have a crab-like appearance.
Blue crabs become juveniles next and are about 2.5 mm. They migrate to waters with lower salinity to grow and mature. In the following year and a half, blue crabs go through a few dozen molts before adulthood.
Danger lurks around every corner. A crab never knows who its next predator will be. Crabs not only eat almost anything, they actually eat each other. Aristophanes was right on when he said, “The wise learn many things from their foes,” especially when they are one and the same. More than 10 per cent of a blue crab’s diet is blue crabs. What the crab does know is that if it gets in trouble, it can get out. The crab’s secret weapon is autotomy.
Autotomy is simply self-sacrifice of a sort. In the case of the blue crab, it has reflex separation that will allow it to amputate its own claw or other appendate to escape a predator. Not to worry about the clawless crab, because it also has the power to regenerate its lost limb. Nor will it be lonely, since it has been estimated that one quarter of all crabs have missing or regenerating limbs.
Aristophanes, in his endearing way, might as well have been consoling the crabs for their lost limbs, or else referring to the crabs who had lost them before, when he penned the lines: “Your lost friends are not dead, but gone before, advanced a stage or two upon that road which you must travel in the steps they trod.”
Suzan Bellincampi is director of the Felix Neck Wildlife Sanctuary in Edgartown.