Sea snakes of several different species belong to a group related to the cobras but aquatic rather than land dwelling. They are only moderately large, rarely exceeding 6 feet long, often with peculiarly small heads for their body. The body is compressed as an adaptation for swimming and the snakes are so thoroughly aquatic that they are either clumsy or helpless when brought ashore. Only genus Laticauda has the typical broad ventral scales of snakes, and it is often considered the least advanced of the sea snakes. Nevertheless, similar to cetaceans, their lungs still require them to surface occasionally to breathe.

Sea snakes are venomous. They have short hollow fangs near the front of the upper jaw, and the poison acts on the nervous system like that of the related cobras.

Sea snakes are confined to the tropical oceans, chiefly the Indian ocean and the western Pacific ocean. The yellow-bellied sea snake, Pelamydrus platurus, extends to the eastern Pacific. The olive sea snake, Aipysurus laevis, tends to live in reefs.

Systematics

• Aipysurus -group
  • Aipysurus
  • Amydocephalus
• Hydrophis -group
  • Acalyptophis
  • Astrotia
  • Enhydrina
  • Ephalophis
  • Hydrelaps
  • Hydrophis
  • Kerilia
  • Kolpophis
  • Lapemis
  • Parahydrophis
  • Pelamis
  • Thalassophina
  • Thalassophis
• Laticauda -group
  • Laticauda

Literature

• Rasmussen AR (1997): Systematics of sea snakes; a critical review, Symp. Zool. Soc. London 70, 15-30
• Smith MA (1996): Monograph of the sea snakes (Hydrophiidae), British Museum of Natural History, London
• Voris HK (1977): A phylogeny of the sea snakes (Hydrophiidae), Fieldiana Zool. 70, 79-169