Monday, January 17, 2022

The secret life of the remarkable seahorse: It is the male which gives birth to the babies

They are tempting and attractive to keep as aquarium pets, but are delicate and notoriously difficult to look after.

Written by Ranjit Lal | New Delhi |
July 12, 2015 1:00:17 am
wildlife-main Seahorse (Source: Ranjit Lal)

He must have been born, along with perhaps hundreds of his siblings, some 50-odd years ago, in the shallows of the Bay of Bengal, not far off the coast of Madras. But the ocean is a hungry, moody place and the vast majority of his brothers and sisters would have become meals for predators or been swept away by the savage currents. This one was a survivor. Sucking up tiny plankton and crustaceans through a long tubular mouth, he grew from a filamentous fingernail to all of 8 cm tall. He etched out a tiny territory for himself in the shallows, anchoring himself by his prehensile tail to seagrass, so the currents wouldn’t bear him away, for as fish went, he was a dreadful swimmer. Any fish with such an upright stance probably would be. And he didn’t even have scales, like any normal self-respecting fish, but just skin stretched over bony plates. A long neck and horse-like face, with a tiny coronet on top and a friendly smile — say hello to the seahorse. (Actually, they remind me more of giraffes than horses).

He would have waited in his tiny kingdom till one day, a lady floated past. If she liked what she saw, she would have anchored herself beside him. And then over the next several days or so, they would have gone swimming and dancing together, side by side, tails entwined, perhaps even blushing as she assessed him as a potential life partner. When she finally made up her mind, their “courtship dance” would become more intense and serious, they’d swim down to the depths and turn to face each other, just the way young lovers do over a shared strawberry smoothie. He would have shown off his tummy pouch, and if she approved of it as a nursery, she would have proceeded to deposit her eggs in it, maybe just five, maybe as many as 2,500 (depending on her species) which he would have proudly fertilised in situ.

Here, the eggs would embed themselves in the pouch walls, surrounded by a spongy tissue, as he produced prolactin, the same hormone responsible for milk production in mammals. To her delight, (I presume) — she would have immediately slimmed down, and he, grown an instant paunch. And then they would have parted, but she would visit him every morning for the next nine to 45 days to ensure all was well until the eggs hatched. And then, one day after a labour that might have lasted two hours, the tiny replicas would have shimmied out of their father’s pouch into the big bad ocean, never to meet their parents — or each other — again. And the lady would be getting ready to give her gentleman yet another beer belly.

But then, sadly, a violent storm brewed up and, perhaps, the seahorse lost his grip on the sea grass, or was torn away with it by the powerful sinuous currents. Tossed up to the churning surface, he stood no chance as the mighty white-horses hurled him far onto the sands to die, gasping for oxygen. Where, days later, excited beachcombing children came across its skeleton and happily added it to their shell collection: here was one creature that even in its skeleton form wore a child-friendly smile and not a hideous rictus! More than 50 years later, I still have it, safely encased with other shells in a glass-topped box.

By all accounts, seahorses are remarkable fish. We don’t seem to be very certain about how many species there are. I’ve read accounts that say there are 33 species worldwide and others which put the figure at 105. One reason for the confusion could be the fact that seahorses can change colour and “add” appendages to their bodies to match their surroundings, and thus appear like different species.

They live in temperate and tropical waters, and along with pipefish, to which they are related, are the only species to swim (not very well) vertically. They have no stomachs and must eat constantly. Their eyes move independently of one another, and their prehensile tails curl around grass stalks and they may even hold your finger if you are sweet to them. The smallest is just 1.5 cm, the largest 35.5 cm. Most are believed to pair for life and it has been found that it is beneficial to the species’ survival if daddy has the babies. (It costs the female huge amounts in terms of energy to produce the large number of eggs she does).

Like so many other creatures, their population is on the decline worldwide because of over-angling and habitat destruction (they live in shallow waters, seagrass beds, estuaries, coral reefs and mangroves). One estimate suggested that about 20 million are taken every year. They are hugely popular in Chinese traditional medicine (what isn’t!), ostensibly curing everything from bed-wetting to heart problems, and, of course, are also considered to be aphrodisiacal (again, what isn’t!). India has banned the trade and export in seahorses and you can’t catch and keep wild ones. Hong Kong, Malaysia, Singapore and the UAE are the main importers of these delicate fish and also participate in the trinket and souvenir trade, converting these into key chains or even plating them with gold.

They are tempting and attractive to keep as aquarium pets, but are delicate and notoriously difficult to look after. You may only manage to handle captive bred specimens. It’s much better to learn scuba diving, or strap on a snorkel and meet them in their dazzling undersea gardens.

Their scientific “genus” name is Hippocampus: hippo is Greek for horse, and kampus means sea monster.

But when they curl their tails around your pinky finger and smile at you benignly, “monster” is the last word that comes to mind.

Ranjit Lal is an author, environmentalist and birdwatcher

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