In Indian mythology, Vishnu, the Lord of preservation, is said to have been supported by a giant sea snake called Shesha that rests on the cosmic ocean upon which the entire world is balanced. Snake Vasuki was wielded as a rope to churn milk from the ocean. Our myths, legends and stories have always integrated sea snakes and serpents into their storylines. Whether these stories have portrayed them as holy, higher entities or as ruthless monsters, they have familiarized the idea of sea snakes in us since our childhood. Out of the 3000 species of sea snakes found across the globe, India is endemic to 26 species according to a report catalogued by Chennai’s National Centre for Sustainable Coastal Management (NCSM).
Herpetologist Nirmal Kulkarni says that all snakes can swim. “In fact, all snakes are good swimmers and have to drink water in order to survive. Water snakes are a common grouping of snakes that are found in the vicinity of water bodies.” But land snakes and sea snakes are distinctly different from each other in their physiology, adaptations and behaviour. Sea snakes, which are largely venomous creatures that fall in the Elapidae or cobra family, have a flatter body than land snakes and own rudder-shaped tails that facilitate them in sifting through their marine ecosystem. Eyes and nostrils are situated at the top of their heads for most sea snakes. As air-breathing creatures, these features aid them in breathing with only the tip of their head peeking above the surface of the water. Although some of these slithering monsters could grow as long as 2.7 metres, most adults attain a length of 1–1.5 metres during their lifetime.
Sea snakes are categorized into two basic kinds. True sea snakes, which are labelled under the genus Hydrophis, are the ones that live their whole life exclusively in the sea. The other variety called sea kraits is segregated into the genus Laticauda and consists of snakes that favour plodding in estuaries, mangrove swamps, coral reefs and mud flats rather than in the nearby water body itself. 52 of the total sea snake species are identified as true sea snakes.
Sea snakes are predominantly found in the tropical and sub-tropical coastal regions of the Indian and Pacific oceans. The hook-nosed sea snake (Hydrophis schistosa) is the most prevalently found species in India. They are distributed across a range of deep and shallow waters. Also known as Beaked sea snakes, these are lethally venomous creatures who rely on their toxins to catch their prey instantaneously in the aquatic ecosystem. They possess a beak-like or hook-like rostral scale that protrudes above their mouth. They are usually known to prefer sea catfishes, eel-tailed catfishes and pufferfishes. Annulated sea snake (H. cyanocinctus), which has unique triangular stripes over a cream coloured body, and the many-toothed Malacca sea snake (H. caerulescens) are two other types in the Hydrophis genus or true sea snakes that are native to India.
The Rainbow Water Snakes (Enhydris enhydris) are largely freshwater snakes that pervade settings like marshlands, ponds, rice paddies etc. Two long, pale stripes run down the length of its body and intersect on the crown.
In the other category of Sea Kraits in the Laticuda genus, India is home to Banded Sea Krait (Laticauda colubrina) and Blue Lipped Sea Krait (Laticuda laticaudata). The Banded Sea Krait also referred to as yellow lipped sea krait, are nocturnal species that contain alternating markings of black with blue, white or grey rings. They also have a prominent yellow snout, thus the name Yellow lipped sea krait. These snakes crawl up into limestone caves and rock crevices to lay their eggs. The Blue Lipped Sea Krait or Blue-ringed sea krait is the reptile replica of the blue-black version of “Is the dress blue-and-black or gold-and-white?” It is found in abundance on the coasts of the Bay of Bengal.
Some other sea snakes that traverse the oceans of the Indian Ocean are Annandale’s Sea Snake (Kolpophis annadalia) and Shaw’s Sea Snake (Lapemis curtus). From Genus Rhabdops, species like Rhabdops olivaceus and the Rhabdops aquaticus populate the streams of West Bengal.
However, the continuity of these sea snakes is threatened by climate change, excessive fishing and increased human intervention. Sea snakes are found as bycatch in fishing nets and are often killed or left to die by the fishermen. Although these snakes are protected under schedule IV of the Indian Wildlife (Protection) Act, 1972, they are of no economic value to the fishermen, and that lands as a huge disadvantage to the sea snake population. A significant incident of Mass bycatch would be the one in Goa where 81 hook-nosed sea snakes were found dead over an expanse of beach shore as small as 30 meters. Tragically, the same woe repeated itself only a couple days ago with 69 dead hook-nosed sea snakes. We could prevent such incidents by directing more incentives to sea snake monitoring and research, more funds into constructing safer fishing gear etc.
- Distribution of Sea Snakes in the Indian Coastal Waters by P. Kannan and M. Rajagopalan
- Sea snakes – britannica.com
- Threatened and undocumented sea snakes of India – Mongabay news