Pelamis platuraYellowbelly Sea Snake, Pelagic Sea Snake

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Geographic Range

Indian and Pacific oceans around eastern Africa, Madagascar, Arabia, and India. Throughout coastal southeastern Asia, Indonesia, Japan, Australia, New Zealand, and the Pacific Islands. Extending to the western coast of the Americas from Equador and the Galapagos Islands north to Baja California and the Gulf of California.

Habitat

These snakes are restricted to tropical and subtropical waters. They are usually found within a few kilometers of the coast and prefer shallow inshore waters. Normally these snakes live in waters with temperatures between 11.7 and 36 degrees Celsius.

Physical Description

The maximum length of this sea snake is 113 cm.

Reproduction

This snake reproduces sexually in water, usually near the surface. It breeds in water with a temperature greater than 20 degrees Celsius. This species is ovoviviparous, and gestation is thought to be 5 to 6 months. One to 10 young are born per litter, each 220-260 mm long at birth. Adult males grow to greater than 600 mm.

Lifespan/Longevity

Behavior

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.

Food Habits

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.

Economic Importance for Humans: Negative

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.

Conservation Status

These snakes are not currently listed as endangered or threatened.

Other Comments

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.

Contributors

Jennifer Liptow (author), University of Michigan-Ann Arbor.

Glossary

Pacific Ocean

body of water between the southern ocean (above 60 degrees south latitude), Australia, Asia, and the western hemisphere. This is the world's largest ocean, covering about 28% of the world's surface.

World Map

coastal

the nearshore aquatic habitats near a coast, or shoreline.

native range

the area in which the animal is naturally found, the region in which it is endemic.

oceanic islands

islands that are not part of continental shelf areas, they are not, and have never been, connected to a continental land mass, most typically these are volcanic islands.

References

Ernst, Carl H. 1980. Venomous Reptiles of North America. Smithsonian Institution Press, Washington, pages 41-45.

Pope, Clifford H. 1937. Snakes Alive and How They Live. Viking Press, New York, pages 81-82.