A Guide to the Amphibians
and Reptiles of California

Yellow-bellied Sea Snake - Pelamis platurus

(Linnaeus, 1766)
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Yellow-bellied Sea Snake CA Range MapRange in California: Red

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Venomous and Potentially Dangerous!

Yellow-bellied Sea Snake Yellow-bellied Sea Snake Yellow-bellied Sea Snake
  Adult, Costa Rica © Dick Bartlett  
Yellow-bellied Sea Snake Yellow-bellied Sea Snake Yellow-bellied Sea Snake
Adult, Playa Ocotall, Guanacaste, Costa Rica. © William Flaxington Adult, Playa Ocotall, Guanacaste, Costa Rica. © William Flaxington Adult, Puerto Vallarta, Mexico
© Dr. Alan E. Leviton
Yellow-bellied Sea Snake Yellow-bellied Sea Snake Habitat  
A "xanthic" snake from Playa Zancudo, on the Pacific coast of Costa Rica.
© Karen Wyld
Habitat, Pacific Ocean  

Dangerously Venomous (Poisonous)

Venom yield is low, but still considered potentially dangerous to humans.
A bite by this snake can be very dangerous without immediate medical treatment. 

10 - 45 inches in length (25 - 114 cm.) Most snakes seen in the eastern Pacific are 18 - 25 inches long (46 - 64 cm.)

A marine serpent with a narrow elongated flattened triangular head with nostrils set high on the top.
The body is flattened and the tail even more so to facilitate swimming.
There are small fangs on the front of the upper jaw.
Color and Pattern
Dark brown or black with a bright yellow or pale yellow underside which extends up the sides.
Sometimes the underside is darker, sometimes a snake is all yellow or yellow with a narrow black stripe on the back.
The tail is marked with black spots or bars.

Life History and Behavior

Diurnal and primarily aquatic, living out its entire life cycle at sea.
Undulates the flattened tail and body side to side in order to swim and dive.
It is able to swim backwards and forwards, but is unable to move efficiently when washed on shore.
This snake is capable of spending up to three hours underwater without surfacing and studies estimate it spends up to 87 per cent of its life underwater, surfacing mainly when the seas are calm.
An alert snake, it may dive when approached, but often it shows no concern when confronted while it is floating at the surface and can be easliy captured with a net.
Not known to be very agressive, usually reluctant to strike, and often strikes without injecting venom.

In order to remove foreign items from its body such as algae, barnacles, or other growths aquired by a life at sea, this snake ties a knot in its body and runs the knot from one end of the body to the other, cleaning the skin in the process. This technique is also used when shedding skin.

Injects deadly venom through non-movable hollow fangs located at the front of the mouth to immobilize its prey.
Typically not very agressive towards humans, striking rarely, and often not injecting venom, but envenomation can be deadly.
Diet and Feeding
Eats small surface-dwelling fish and eels.
An ambush predator, it sits and waits quietly at the surface waiting for fish to swim by.
Probably breeds only in areas of water as warm as 68 degrees F (20 C) or warmer.
Large congregations of snakes have been found which were thought to be breeding congregations.
1 - 8 young are born in the ocean, or mangrove swamps or rocky tidal areas near shore, possibly throughout the year.

Geographical Range
Uncommon in California. Sight records include: San Clemente beach in Orange County, 1983; LA Bay, 1961; and the San Diego Area, 1985.

This snake is probably the most widely distributed snake in the world, inhabiting the Indian and Pacific Oceans, including the coasts of Africa, Asia, Australia, Mexico, including Baja California, and Central America.

Warm ocean waters. Usually seen within a few miles of the shore, but also occurs far out to sea. More common along drift lines with floating debris occuring where ocean currents converge creating quiet waters. These slicks attract fish providing an abundant food source for the snakes. In Central America, drift lines containing hundreds or more snakes are regularly observed.

Conservation Issues  (Conservation Status)
Family Hydrophiidae Sea Snakes Hydrophiidae Fitzinger, 1843
Genus Pelamis Yellow-bellied Sea Snakes Daudin, 1803

platurus Yellow-bellied Sea Snake (Linnaeus, 1766)
Original Description
Pelamis platurus - (Linnaeus, 1766) - Syst. Nat., 12th ed., p. 391

from Original Description Citations for the Reptiles and Amphibians of North America © Ellin Beltz

Meaning of the Scientific Name
Pelamis - Greek - tunny fish - presumably refers to the habitat or what Daudin thought they ate
- Greek - platys- flat and oura - tail - refers to the flattened tail.

from Scientific and Common Names of the Reptiles and Amphibians of North America - Explained © Ellin Beltz

Alternate Names

Related or Similar California Snakes

More Information and References
California Department of Fish and Wildlife

University of Michigan

Stebbins, Robert C., and McGinnis, Samuel M.  Field Guide to Amphibians and Reptiles of California: Revised Edition (California Natural History Guides) University of California Press, 2012.

Stebbins, Robert C. California Amphibians and Reptiles. The University of California Press, 1972.

Stebbins, Robert C. A Field Guide to Western Reptiles and Amphibians. 3rd Edition. Houghton Mifflin Company, 2003.

Behler, John L., and F. Wayne King. The Audubon Society Field Guide to North American Reptiles and Amphibians. Alfred A. Knopf, 1992.

Powell, Robert., Joseph T. Collins, and Errol D. Hooper Jr. A Key to Amphibians and Reptiles of the Continental United States and Canada. The University Press of Kansas, 1998.

Bartlett, R. D. & Patricia P. Bartlett. Guide and Reference to the Snakes of Western North America (North of Mexico) and Hawaii. University Press of Florida, 2009.

Bartlett, R. D. & Alan Tennant. Snakes of North America - Western Region. Gulf Publishing Co., 2000.

Brown, Philip R. A Field Guide to Snakes of California. Gulf Publishing Co., 1997.

Ernst, Carl H., Evelyn M. Ernst, & Robert M. Corker. Snakes of the United States and Canada. Smithsonian Institution Press, 2003.

Wright, Albert Hazen & Anna Allen Wright. Handbook of Snakes of the United States and Canada. Cornell University Press.

Ernst, Carl. H. Venomous Reptiles of North America. Smithsonian Institution Press, 1999.

Conservation Status

The following status listings come from the Special Animals List and the Endangered and Threatened Animals List which are published by the California Department of Fish and Wildlife.

This snake is not included on the Special Animals List, which indicates that there are no significant conservation concerns for it in California.
Status Listing
U.S. Endangered Species Act (ESA) None
California Endangered Species Act (CESA) None
California Department of Fish and Wildlife None
Bureau of Land Management None
USDA Forest Service None


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