MARINE ANIMALS THAT STING 



95 



Habits of Sea Snakes. Sea snakes are primarily inhabitants of 

 the tropical Pacific and Indian Oceans. With the exception of a 

 single freshwater species, Hydrophis semperi Garman, which is 

 found in the freshwater Lake Taal, Luzon, Philippine Islands, all 

 are marine. Sea snakes are characteristically residents of sheltered 

 coastal waters and are particularly fond of river mouths. However, 

 some species of sea snakes have been observed from 100-150 miles 

 from land. Pelamis platurus Linnaeus is the most widely distrib- 

 uted hydrophid species. Members of the genus Laticauda are said 

 to be semi-terrestrial, and never venture far from the tide to which 

 they return to feed. Sea snakes may sometimes appear swimming 

 together, or breaking at the surface, in large numbers. 



Fig. 59. Skull and fangs of the sea snake, Pelamis platurus. Note the venom 

 gland, which is located just below the eye, emptying into the two anterior fangs. 



With their compressed, oarlike tails, sea snakes are well adapted 

 for locomotion in their marine environment. Instead of the imbri- 

 cate position of the scales, such as is found in terrestrial snakes, 

 most of the scales of hydrophids are juxtaposed and hexagonal in 

 position, which further demonstrates an adaptation to an aquatic 

 existence. Swimming is accomplished by lateral undulatory move- 

 ments of the body. They have a remarkable ability to move back- 

 ward or forward in the water with equal rapidity, but are awkward 

 on land. Sea snakes are able to float on the surface of the ocean 

 for long periods of time. It is reported that sea snakes are able 

 to remain submerged for hours. 



Sea snakes capture their food underwater, which consists almost 

 entirely of fishes that are swallowed headfirst. A considerable por- 

 tion of time is spent feeding on, or near, the bottom around rocks, 

 in crevices where they capture eels and other small fishes, which 

 they promptly kill with a vigorous bite of their venomous jaws. 



Fig. 58. Top to bottom: Sea snake, Enhydrina schistosa (Daudin). Chittul 

 or Banded Sea Snake, Hydrophis caerulescens (Shaw). Sea Snake, Hydrophis 

 nigrocinctus Daudin. Yellow-bellied Sea Snake, Pelamis ]}latums (Linnaeus). 



