Book Review | The superheroes of the shore continue to surprise and allure

What do you get where sand and sea water, wind and sunlight all come together? A coast, you might say. But this book says it’s magic!
Like any other zone on earth, coasts bear their own unique range of life forms. Being a meeting point between the elements, they boast of an unusual diversity of life forms. Much of India’s 7,500 kilometres of coastline is in temperate zones that tend to be kinder to life more extreme zones: it offers a wider and stranger variety of life than most.
Coasts consist of three distinct areas: the sea, which is all water; land, above the high tide mark; and, finally, the intertidal zone, which is water at high tide and land at low. Each has its own set of colourful characters, the most colourful of which live between the tides. For all the kindness of nature, survival tends to be tough. So life forms here have evolved their own little bits of magic: the superpowers in the title.

The first of these superpowers is disguise, the ability to disappear by merging into your surroundings. It shows up in many ways, such as the ability to change colours. Others involve artifice: a spiky sea urchin adorns itself with a leaf, and its brother with shells, and both disappear into their own different backgrounds. The decorator crab, a master of disguise, uses its pincers to cut bits of sponges and to pick up shells and other debris. It then “sticks” them onto   patches of hooked “hairs” — like Velcro — on its shell. Small octopi — some only a foot long — that appear sometimes even on Mumbai’s Juhu beach, are so weird that there’s controversial — read questionable — research that indicates they’re of alien origin!

The coast, most of all, is a place that encourages creation. Sea slugs and sea snails and other resident creatures lay their eggs in the intertidal zone, where, in the fullness of time, they hatch. But there are other creatures, like squid, who are not residents, but turn up to lay their eggs in a place where some of the litter have a good chance of survival. And there are still others, turtles, for instance, who travel far to find a quiet beach where they can bury their eggs and leave them with some hope of hatching.

Sex, the precursor to egg-laying, is another story. The party goes on, methods and variety unimaginable. Some hermaphrodite flatworms, for instance fight for male privilege: bearing and laying eggs is a burden best avoided. And there are different kinds of hermaphroditism: one in which an animal can have both male and female organs simultaneously, the other in which an animal can only be male or female at one time! As you read this chapter, you can’t help thinking that an intertidal kama sutra would be bigger than the Encyclopaedia Britannica!

Other superpowers include a variety of weapons that belong to the assassin, some built on stealth, others on force. There are spears and poisons, guns and bludgeons, teeth and claws. The intertidal zone is a ground where battle lines shift as the sun goes and the tide comes in, and again when the sun arrives and the water departs. These shifting battlegrounds are without villains, for the killers take what they need and no more. There are cone snails with complex million-year-old toxins that immobilise prey. There are mantis shrimps — named after the praying mantis — of two kinds, one armed with spears, going after softer prey, the other with bludgeons or hammers to beat their prey — or even attackers — into submission. There’s even a shrimp with a gun of sorts, the pistol shrimp that shoots jets of water that create bubbles that pop and stun their prey!

Interspersed with chapters on the superpowers are smaller chapters on the intertidal environment itself, with simple things to look for and listen for when you happen to be on the beach, where the waves pound the sand in the intertidal zone, where all good things happen.

There are niggles, mostly from uneven editing. A clumsy bit from page 77: “The venom of a cone snail has at least 500 different components in the venom [italics mine], perhaps more now.” Another from the same page: “The arsenals of the creatures in the intertidal zone are incredible to fathom [italics mine].”

There’s also the question of how the book is organised. There’s a section on unusual weaponry — harpoons, toxins, and bludgeons — and a whole separate chapter on stings, entitled, “Defence Against the Dark Arts”. But stings are both offensive and defensive, as is most of the weaponry nature has given animals, and could perhaps be considered as part of the earlier chapter.

But these are only niggles. With these gone, it would have been a splendid book. Even with them, if you have the faintest interest in life forms other than human, or if, like me, you’re a beach freak, this is a read you shouldn’t miss.

Superpowers on the Shore
By Sejal Mehta
Penguin Viking
pp. 203, Rs.499