Body compressed, posteriorly more than twice the diameter of the neck; body scales juxtaposed, sub-quadrangular in shape, in 49-67 rows around thickest part of body; ventral scales, 264-406, very small and, if distinct, divided by a longitudinal groove, but usually indistinguishable from adjacent body scales; head narrow, snout elongate, head shields entire, nostrils superior, nasal shields in contact with one another; pre-frontal in contact with second upper labial; 1-2 pre- and 2-3 post-oculars; 2-3 small anterior temporals; 7-8 upper labials, 4-5 below eye but separated from border by sub-ocular; color variable but most often distinctly bi-colored, black above, yellow or brown below, the dorsal and ventral colors sharply demarcated from one another; ventrally there may be a series of black spots or bars on the yellow or brown background, or the yellow may extend dorsally so that there is only a narrow mid-dorsal black stripe, or a series of black crossbars. Total length males 720 mm, females 880 mm; tail length males 80 mm, females 90 mm.
These snakes breed in warm waters and they are ovoviviparous with a gestation period of about 6 months. They are helpless on land and they sometimes form large aggregations of thousands in surface waters. The snake has a neurotoxic venom that is used against its fish prey. No human fatalities are known. It occurs on both sides of the Pacific and is the only sea snake to have reached the Hawaiian Islands
Indian Ocean, Pacific Ocean (Japan), South China Sea northward to the coastal regions of Zhejiang and Taiwan, Persian Gulf (Oman etc.) to Bay of Bengal, India, Pakistan, Maldives, Malaysia, coasts of Malay Peninsula and Indo-Australian Archipelago to New Guinea, Gulf of Thailand and Philippines, Andaman Islands, Nicobar Islands, Korea, Russia (S Primorskij Territory; Only one dead specimen was found in Russia: on the coast of the Sea of Japan, near Vladivostok city), Madagascar, Tanzania, Australia (New South Wales, North Territory, Queensland, Tasmania, Victoria, West Australia), New Zealand, Solomon Islands.
New Caledonia, Mexico, Guatemala, Honduras, El Salvador, Nicaragua, Costa Rica, Panama, Colombia, Ecuador, Galapagos Islands, Peru.
These snakes feed during the day and spend nights on the ocean bottom, occassionally rising to the surface to breath. They can dive to maximum depths of 6.8 m in the dry season, and 15.1 m during the wet season. Sea snakes can stay underwater between 1.5 and 3.5 hours. They are capable of cutaneous breathing, removing oxygen from the water and releasing carbon dioxide. The yellow-bellied sea snake has a salt gland under its tongue, which secretes salt taken in from the water. It swims on the surface by sideward undulations aided by the laterally compressed tail, which acts as a paddle. It can move quickly, but usually it floats by ocean currents. These snakes are poorly suited for land and are relatively helpless when washed ashore. These fairly mild-mannered creatures can occur in huge aggregations with varying male to female ratios, and numbering in the thousands.
This snake is a carnivore. It forages during the day, hunting by ambushing its prey. It is venomous snake, and it chews poison into fish and then swallows them.
These are venomous snakes and could pose a threat to humans. Their venom is neurotoxic; however, it is in fairly low yield and is no great threat. No human fatalities have been reported.
This is the only sea snake that occurs on both sides of the Pacific. It is also the only sea snake to have reached the Hawaiin Islands.