I was surprised to read in an answer to one of the Last Word's previous questions that sea snakes don't 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 - 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't seem at all surprised that we'd 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?

Darren Darby, London, UK

(The photograph shows a yellow-bellied sea snake, and was taken in an aquarium (Image: David Burgess/Wikimedia Commons))