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Monday, January 25, 2021

How moreish crabs can teach table manners

Since the omnivores are themselves on the menu of many, several species have become endangered

Written by Ranjit Lal | New Delhi | December 13, 2020 6:28:50 am
Get off my back: Speckled swimming crabs

Where did it go, Bambi? Where did it go, girl?” Poised on the beach, our bamboozled Boxer would stare at the sand, her brow furrowed in a worried frown. The ghost (or sand) crab that had caught her eye would skedaddle sideways and Bambi would pounce, but then, poof! it was gone again. This time with a disdainful wriggle as it lowered itself beneath the sand: now Bambi would dig frantically, but to no avail. The crab was gone!

I loved watching her try and catch crabs on the beach — and I admired these nondescript-looking crabs, exactly the shade of the sand, for their sheer disdain and their marvelously delicate table manners. Very fastidiously, they would pick up a tidbit from the sand with their pincers and put it in their mouths — like any well-bred socialite dining with the hoity-toity.

Most crabs seem to have good table manners — in spite of looking antediluvian (some have come down over 450 million years). Close to 7,000 species around the world (some say 10,000) are found living in fresh and salt water, on land, up in trees and in paddy fields. The tiny pea crab is a few millimetres long, while the mighty Japanese spider crab has a leg span of four metres. Brown, black, scarlet, blue, green, etc., their most prominent feature is their shell (or ‘shield’ as the biologists call it) and those whopping front pincers. Not particularly friendly with one another (especially dudes interested in the same girl), those pincers help them fight each other.
They communicate by wafting pheromones (perfume equivalent), waving pincers, sound, vibration and sight. The famous fiddler crab has one massively enlarged (sometimes gaudy) front claw, used exclusively to beckon the girls. Some spider-crab species decorate their shells with seaweed and sponges — effective cover and a wonderful camouflage for ambush. Others use anemones for protection, which live off the leftovers of the crabs’ meals. When nothing suitable is in sight, they even use tin cans and other fatally undesirable objects.

Not all crabs carry their homes on their backs: the hermit crabs occupy shells vacated by snails, often it’s a challenge to find one just the right size (and probably with all mod-cons!) A hermit crab finds a prospective home, a little too large for it, and waits by this empty shell for eight hours, while other hermits trundle up to examine the premises. Whoever fits into it, stays, vacating his old residence, which our friend-in-waiting will now take possession of. And, thus, the cycle continues as others move on to the next best fit. But at other times, a boorish group will gang up to forcibly evict a poor victim from its shell and fight amongst each other for possession. Sounds familiar, doesn’t it?

Many species of crabs are terrestrial and most have to migrate long distances to the ocean to release their larvae. Thousands die en route while crossing roads. Their larvae — tiny transparent, legless creatures called zoea — are taken by the currents and float with plankton. A tough childhood, they have to moult several times — each making them vulnerable to predation. Even as adults, they moult several times. Hormones soften their shells and the crabs crack them by ingesting a lot of water and swelling up, and take advantage of the fissure line along their backs. If they get stuck while getting out, they die. Smaller than the males, with their abdominal flap broader and rounded, females can only mate just after they’ve moulted. But they can store sperm in their bodies for a while (if the dude a girl made out with turns out to be a good-for-nothing, she may dump his seeds!)

Crabs are omnivores, delicately picking off algae, mollusks, crustaceans, worms and, sometimes, even fish. They are themselves, buttery delectable, on the menu of many — fish, bird, animal, and, of course, humans. Several species have become endangered — in Sri Lanka, all except one of its 50 freshwater crab species are endemic and critically endangered. Horseshoe crabs are endangered in the West (used by pharmaceutical and cosmetic companies for their famous “blue” blood), while in India, they are discarded as “by-catch” in the nets.
Every classy restaurant will have crabs on its menu, though there’s controversy over how they are killed and cooked: usually they’re just dunked alive in boiling water. While some scientists claim that they don’t feel pain, others have counter-claimed that some do react to electric shocks.

It’s long been said that you can keep a bunch of crabs in an open bucket and none will escape because the others will pull it down, which is exactly why we’ve not excelled as a people: the moment anyone tries to reach the top, s/he is pulled down by the rest!

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