I was surprised to read in an answer to one of the Last Word鈥檚 previous questions that sea snakes don鈥檛 live in the Atlantic Ocean. While snorkelling on the north coast of Cuba last September, both my partner and I repeatedly saw what I can only describe as a sea snake 鈥� it was thin, about 1 metre long with dark and pale markings. It was swimming among thin sea grass about 3 metres down. The locals didn鈥檛 seem at all surprised that we鈥檇 seen one, and told us with much mirth that it was poisonous. What did we see? Was it just a land snake that fancied a swim?
鈥� There has never been a verified sighting of a sea snake in the Caribbean. Although Caribbean waters are warm enough for sea snakes, getting there from the Pacific Ocean is a problem. The water is too cold for a sea snake to go around the southern tip of South America and while the possibility of one passing through the Panama canal has been suggested, the volume of fresh water in the locks of the canal would kill it. There was an excellent article in New 杏吧原创, 鈥�The sea snakes are coming鈥� (10 November 1990, p 29), that discussed this very topic.
鈥淭here is no verifiable evidence of a sea snake in the Caribbean although the waters are warm enough鈥�
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Additionally, the description of the animal observed by the reader does not match that of the species of sea snake found on the Pacific side of the canal, the yellow-bellied sea snake (Pelamis platurus), which is black with no markings visible from above and bright orange/yellow on its underside.
After doing some sleuthing regarding this topic, it seems very likely that the reader saw a species of snake eel. Tourists in the Caribbean often report sea-snake sightings that turn out to be snake eels. These animals are very common in the Caribbean and are frequently referred to as sea snakes by locals, who believe them to be venomous. Viewed from a few metres above, or even closer, a snake eel is very easily mistaken for a true snake.
鈥淭ourists in the Caribbean often report sea-snake sightings, but they turn out to be snake eels鈥�
Sara Ruane, Department of Biology, College of Staten Island, New York, US
鈥� When snorkelling in Tobago I, too, came across what looked like a sea snake. I consulted the book Reef Fish Identification: Florida, Caribbean, Bahamas by Paul Humann and Ned DeLoach (New World Publications, 2007) and, feeling quite relieved, discovered the existence of snake eels. I saw a , Myrichthys breviceps, which is dark grey with pale spots and about a metre long. It can be found in a variety of habitats, including shallow grass beds, at depths between 1.3 and 13 metres. I also encountered one in Bonaire in the Netherlands Antilles. Perhaps this is what your correspondent saw in Cuba.
Anne Perrett, St Andrews, Fife, UK
鈥� This is a simple case of mistaken identity. What your reader saw was most likely a member of the family Ophichthidae, which are not snakes but fish, specifically eels. They are commonly called snake eels because they are often mistaken for sea snakes.
Snake eels are more widespread because, unlike sea snakes, they are able to tolerate cool water. As a result, snake eels have managed to spread into the Atlantic Ocean, the Red Sea and other water bodies that sea snakes can鈥檛 reach. For example, the Red Sea is an ideal habitat for sea snakes but has a large upwelling of cool water near its opening to the Indian Ocean. This barrier has prevented sea snakes from entering, but not snake eels.
Snake eels are not venomous. The locals were probably well aware that you had seen a snake eel, hence their mirth at leading you on about its poisonous nature.
Alan Clague, Liverpool, UK