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A Guide to the Amphibians
and Reptiles of California


Yellow-bellied Sea Snake - Pelamis platura

(Linnaeus, 1766)

(= Pelamis platurus)    (= Hydrophis platura)
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Yellow-bellied Sea Snake CA Range MapRange in California: Red

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observation link






Venomous and Potentially Dangerous!

Yellow-bellied Sea Snake
Adult, Costa Rica © Dick Bartlett
Yellow-bellied Sea Snake Yellow-bellied Sea Snake Yellow-bellied Sea Snake
  Adult, Costa Rica © Dick Bartlett Adult, Puerto Vallarta, Mexico
© Dr. Alan E. Leviton
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 A "xanthic" snake from Playa Zancudo, on the Pacific coast of Costa Rica.
© Karen Wyld
  Yellow-bellied Sea Snake Habitat  
  Habitat, Pacific Ocean  
     
The Environmental organization Heal the Bay has published this Facebook Information asking
anybody who finds this snake in California to contact somebody and report it to iNaturalist.org.
   
Description

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. 

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

Appearance
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

Activity
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.

It is thought that sea snakes get all the water they need by drinking and filtering sea water using internal salt glands and excreting the salt, but a study of captive sea kraits near Taiwan done in 2008 by Harvey Lillywhite found that those sea snakes would only drink fresh water or heavily diluted sea water. The snakes would dehydrate if they only drank sea water. Sea snakes that live near land can drink freshwater that flows into the sea from creeks or springs. Sea snakes that live in the open ocean probably drink fresh water that sits on top of sea water during and after rains before they mix. The need for fresh water might explain the worldwide distribution of sea snakes which are most common in warm areas where there is abundant rainfall. (Science Daily, 11/9/08)

Breeding
Live-bearing.
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.

Habitat
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 occurring 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.

Geographical Range

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.


Pelamis platura found in California

Sea snakes are very rare in California. They probably range north into California waters mostly during El Niño years when ocean water temperatures rise several degrees above their average which allows marine animals normally found farther south to survive in California waters.  Ernst (1992) says about P. platurus: "On occasion they may be blown or drift to the extremes of their range in the eastern Pacific, and this is most likely how they rarely reach southern California."

(Climate and El Niño information shown below is from National Weather Service.)


I have found records of only four Yellow-bellied Sea Snakes that can be confirmed as found in California either by museum records or reputable sources:

1. San Clemente, Orange County, November 23, 1972 (LACM museum record)
(1972-1973 was a strong El Nino winter)
(This snake was documented in 1983, a year which has been mistakenly associated with the year the snake was found.)

2. Oxnard, Ventura County, October 15, 2015  The sea snake was found alive on a beach. After it died it was collected and will be deposited in the Natural History Museum of Los Angeles County.
(2015-2016 are shaping up to be a strong El Niño winter)
More information and pictures can be found in these news reports:
Ventura County Star
KTLA

3. A dead 27-inch long sea snake was found on December 12th at a Surfrider Foundation coastal cleanup event at Bolsa Chicka State Beach. The snake was collected and will be deposited in the Natural History Museum of Los Angeles County.
(2015-2016 are shaping up to be a strong El Niño winter)
More information and pictures can be found in these news reports:
KTLA   
LA Times 
Los Alamitos-Seal Beach Patch

4. A live sea snake was found at about 2:30 p.m. on Dog Beach in Coronado, San Diego County, on January 12th, 2016, making it the third one found during the 2015-2016 El Nino winter. The snake died shortly after capture. It has been described as being 20 inches in length. It will be put in the collection of the Scripps Institution of Oceanography.
LA Times
NBC San Diego


I cannot yet confirm the existence of another snake that is described as found in the San Diego area. This report might refer to the San Clemente report from 1972 which is not far north of San Diego.

References to a snake found on San Clemente Island appear to be in error and probably refer to the snake found on San Clemente beach in 1972.

There may be more sight records that have not been published or represented by a museum specimen.
If I find more confirmed sightings I will add them here.



References in Literature

"On 23 November 1972, a live adult P. platurus was discovered stranded on the beach at San Clemente, Orange County (lat 33*25'). Andrew J. Reich, a lifeguard, took custody of the snake and placed it in a salt water aquarium where it survived for 12 hours. The specimen was frozen shortly after death and borrowed 6 days later by Pickwell for examination and preservation. It was returned to the collector, who ultimately deposited it in the herpetological collections of the Natural History Museum of Los Angeles County (LACM 109657). This is the first sea snake collected in the continental United States.
The specimen is a female with a shout-vent length of 660 mm, tail length of 79 mm, tricolor pattern, dark venter, narrow lateral yellow stripe, eggs present in oviduct, substantial fat deposits, and no ectoparasites.
Mean sea surface temperature at San Clemente for 23 November 19172 was 16.1 degrees C, and for the month of November 15.5 degrees C, with a range of daily means of 15.6 to 17.8 degrees C."

Pickwell, G. V., R. L. Bezy, and J. E. Fitch. 1983. Northern occurances of the sea snake, Pelamis platurus, in the eastern Pacific, with a record of predation on the species. California Fish and Game 69:172-177.



Carl H. Ernst, in Venomous Reptiles of North America, 1992 writes this about Pelamis in Callifornia (p.42):
"It is the only sea snake to have reached the Hawaiian Islands, and waifs have been collected at San Clemente, Orange County, California (*Pickwell et al. 1983) and Los Angeles Bay (Shaw, 1961) and seen in the San Diego area (Stebbins, 1985). See Hecht et al. (1974)** for a detailed discussion of the distribution of Pelamis. He says later (p.44) that "...Pickwell et al. (1983) found a dying Pelamis on a southern California beach after the water temperature had dropped to 16 degrees C. [60.8 degrees F.] ... The optimal temperature range for Pelamis seems to be 28-32 degrees C." [82.4-89.6 degrees F.]

-- The 1961 record is not from California, it is a 1960 observation from Bahia de Los Angeles (Bay of LA) in Baja California.

** Hecht, M. K., C. Kropach, and B. M. Hecht. 1974. Distribution of the yellow-bellied sea snake Pelamis platurus, and its significance in relation to the fossil record. Herpetologica 30:387-396.



Online news articles about the Oxnard snake found in 10/15 mention that a sea snake was found in the early 1980's, citing Heal The Bay, or some say a snake was found in 1983. These are probably referencing the Pickwell record shown above, which is actually a specimen from 1972 that was written about in 1983.

In his 1985 and 2003 field guides, Stebbins writes that this species "Occasionally reaches the San Diego area of s. Calif. and has been reported off the coast as far north as San Clemente, Orange Co."

In their 2012 California field guide, Stebbins and McGinnis write about the range of this species only that: "It has been reported off the southern California coast as far north as San Clemente in Orange County."

Lemm, 2006, Field Guide to Amphibians and Reptiles of the San Diego Region, in describing this species, writes "Stragglers have been found as far north as San Clemente Island on the California coast. this species appears to enter California's waters during El Niño events, when San Diego's water temperatures increase."

Full Species Range Map
Notes on Taxonomy
Alternate and Previous Names (Synonyms)

Formerly called Pelamis platurus, the species name was changed to the feminine platura to match the feminine Pelamis.
Also called Hydrophis platurus (Linnaeus, 1766)
Yellowbelly Sea Snake
Pelagic Sea Snaike

Conservation Issues  (Conservation Status)
None
Taxonomy
Family Hydrophiidae Sea Snakes Hydrophiidae Fitzinger, 1843
Genus Pelamis Yellow-bellied Sea Snakes Daudin, 1803
Species

platura 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
platura
- 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

Related or Similar California Snakes
None

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, 1957.

Ernst, Carl. H. Venomous Reptiles of North America. Smithsonian Institution Press, 1992.


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.
Organization
Status Listing
NatureServe Global Ranking
NatureServe State Ranking
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
IUCN

 

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