CaliforniaHerps.com

A Guide to the Amphibians
and Reptiles of California


Shasta Alligator Lizard - Elgaria coerulea shastensis

(Fitch, 1934)
Click on a picture for a larger view



Northern Alligator Lizards California Range Map
Range in California: Blue & Gray

Click the map for a guide
to the other subspecies


observation link





Shasta Alligator Lizard Shasta Alligator Lizard Shasta Alligator Lizard
Adult, Humboldt County Adult, Humboldt County Adult, Humboldt County
Shasta Alligator Lizard Shasta Alligator Lizard Shasta Alligator Lizard
Adult, Humboldt County Underside of adult, Humboldt County
Shasta Alligator Lizard Shasta Alligator Lizard Shasta Alligator Lizard
Gravid adult female, Siskiyou County
Shasta Alligator Lizard Shasta Alligator Lizard Shasta Alligator Lizard
  Adult Humboldt County  
Shasta Alligator Lizard Shasta Alligator Lizard Shasta Alligator Lizard
Adult, Mendocino County © James Morry Adult male with a nice blue-gray head, Shasta County © Steve Berry
Shasta Alligator Lizard Shasta Alligator Lizard Shasta Alligator Lizard
Adult male, Colusa County  © James R. Buskirk Adult male in intergrade zone with the San Francisco Alligator Lizard in Mendocino County. © Allen Vinson
   
Shasta Alligator Lizard Alligator lizard with ticks Great Basin Collared Lizard
This adult was found eating a huge Jerusalem Cricket in Mendocino County just north of the Sonoma County line in the intergrade area. © Jason McKinney It is common to find blood-engorged ticks attached to alligator lizards, especially around and behind the ears, as you can see on this adult from Humboldt County.

Western Alligator Lizards, genus Elgaria, have large rectangular keeled scales on the back that are reinforced with bone.
(Elgaria multicarinata multicarinata is shown here).
     
Atypical Color or Pattern
Shasta Alligator Lizards Shasta Alligator Lizard  
Dark (melanistic) adult with normal-colored adult, Humboldt County.
© Joe Eastham
Underside of melanistic adult, Humboldt County. © Joe Eastham  
Shasta Alligator Lizard Shasta Alligator Lizard Shasta Alligator Lizard
Adult, Siskiyou County. This one lacks the yellow coloring and looks like it might be a mix of E. c. shastensis and E. c. principis.
     
Breeding Behavior
Shasta Alligator Lizards Shasta Alligator Lizard  
Breeding male and female, Humboldt County.   © Kelly Mathson Adult male and female, Colusa County
© James R. Buskirk
 
     
Juveniles
Shasta Alligator Lizard Shasta Alligator Lizard Shasta Alligator Lizard
Neonates, one day old, Siskiyou County Juvenile, Siskiyou County
Shasta Alligator Lizard Shasta Alligator Lizard  
Juvenile, Humboldt County  
   
Habitat
Shasta Alligator Lizard Habitat Shasta Alligator Lizard Habitat Shasta Alligator Lizard Habitat
Habitat, Siskiyou County Habitat, Siskiyou County Habitat, Siskiyou County
Shasta Alligator Lizard Habitat Shasta Alligator Lizard Habitat Shasta Alligator Lizard Habitat
Habitat, logged evergreen forest Humboldt County Habitat beach grassland,
Humboldt County
Habitat, evergreen forest, Siskiyou County. (The gravid adult female shown above was found on the road at this spot.)
  Shasta Alligator Lizard Habitat  
  Habitat, Colusa County
© James R. Buskirk
 
     
Short Videos
Shasta Alligator Lizard Shasta Alligator Lizard alligator lizard detached tail
An adult Shasta Alligator Lizard in Humboldt County. Juvenile Alligator Lizards look and move like a little skink. Here, a tiny recently-born Shasta Alligator Lizard races around on sandy ground then ducks back into the piece of driftwood it was hiding under.

This video shows how an alligator lizard's tail thrashes around after it has been dropped to distract a predator. The tail moved for about 4-5 minutes, which has been cut down here to about a minute, showing several different speeds until it is just barely moving.
   
Description
 
Size
Elgaria coerulea ranges from 2 3/4 - 5 7/8 inches in snout to vent length (7 - 13.6 cm) (Stebbins)

Appearance
Alligator lizards, genus Elgaria, are members of the family Anguidae, a family of lizards found in the Americas, Europe, Asia, and Africa.
Large bony scales, a large head on an elongated body and powerful jaws probably give the lizards their common name.
They are characterized by a slim body with short limbs and long tail.
The tail can reach twice the length of its body if it has never been broken off and regenerated.
Scales are keeled on the back, sides, and legs, with 16 rows of scales across the back at the middle of the body.
The temporals are not keeled.

A band of small granular scales separates the larger bone-reinforced scales on the back and on the belly, creating a fold along each side. These folds allow the body to expand to hold food, eggs, or live young. The fold contracts when the extra capacity is not needed.

The eyes are dark around the pupils.
(Compare with the light eyes of a similar species - the Southern Alligator Lizard - Elgaria multicarinata.)
The head is usually mottled with dark color.
The head of a male is broader than a female's with a more triangular shape.

Usually there are dark lines running lengthwise on the underside which run between the scales, along their edges. (Compare with the underside lines on Elgaria multicarinata which run through the middle of the scales.)
Color and Pattern
Color is brown, grey, olive, or brown, above, with heavy dark blotches or irregular crossbands edged with white spots. Body color may be yellowish with the head slate gray in some areas. Underside can be bright yellow on some males.
Usually the dark bands on the back are so irregular that they cannot be counted.
Young
Young usually lack the dark barring and can have a plain copper or brownish band on the back.

Life History and Behavior

Activity
Active during the day. Inactive during cold periods in winter.
Moves with a snake-like undulating motion.
A good swimmer, sometimes diving into the water to escape by swimming away.
Alligator lizards are generally secretive, tending to hide in brush or under rocks, although they are often seen foraging out in the open or on roads in the morning and evening.
Defense
The tail of an alligator lizard is easily broken off, as it is with many lizards.
The tail will grow back, although generally not as perfectly as the original.
A lizard may detach its tail deliberately as a defensive tactic.
When first detached, the tail will writhe around for several minutes, long enough to distract a hungry predator from the lizard.
Other defensive tactics used by alligator lizards are smearing the contents of the cloaca on the enemy and biting.
Males sometimes also extrude the hemipenes when threatened.
Diet and Feeding
Eats a variety of small invertebrates, including slugs, snails, and worms. Will also eat small lizards and small mammals. Occasionally feed on bird eggs and young birds. (Stebbins)
Breeding
Young are born live and fully-formed sometime between June and September.

During the spring breeding season, a male lizard grabs on to the head of a female with his mouth until she is ready to let him mate with her. They can remain attached this way for many hours, almost oblivious to their surroundings. Besides keeping her from running off to mate with another male, this probably shows her how strong and suitable a mate he is.

Geographical Range
The subspecies Elgaria coerulea shastensis ranges from a zone of intergradation with E. c. coerulea in northern Sonoma County, north to northern Humboldt County, and east around the central valley into the Northern Sierra Nevada mountains. Isolated populations occur in the Warner Mountains. Also occurs in southern Oregon, with isolated populations occurring in southeastern Oregon and northwestern Nevada.

The species Elgaria coerulea ranges from Southern British Columbia south chiefly west of the Cascades and Coast Ranges to northern Monterey County, east into northern Idaho and northwestern Montana, with isolated populations occurring in southeastern Oregon, northwestern Nevada and the Warner Mountains in California, and south through the Sierra Nevada Mountains to Kern County.

Full Species Range Map
Elevational Range
Stebbins (2003) shows the elevational range of the species Elgaria coerulea as sea level to around 10,500 ft. (3,200 m.) but only the subspecies E. c. palmeri can be found that high up. The other subspecies range much lower.

Habitat
Woodland, forests, grassland, coastal chaparral. Commonly found hiding under rocks, logs, bark, boards, trash, or other surface cover. Prefers wetter and cooler habitats than E. multicarinata, but generally found near sunny clearings.

Notes on Taxonomy
Formerly placed in the genus Gerrhonotus, with the Latin name Gerrholotus coeruleas shastensis.


Alternate and Previous Names (Synonyms)

Elgaria coerulea shastensis - Shasta Alligator Lizard (Stebbins 2003)
Gerrhonotus coeruleus shastensis - Shasta Alligator Lizard (Smith 1946, Stebbins 1966, 1985)

Conservation Issues  (Conservation Status)
None
Taxonomy
Family Anguidae Alligator Lizards & Allies Gray, 1825
Genus Elgaria Western Alligator Lizards Gray, 1838
Species coerulea Northern Alligator Lizard Wiegmann, 1828
Subspecies

shastensis Shasta Alligator Lizard (Fitch, 1934)
Original Description
Elgaria coerulea - (Wiegmann, 1828) - Isis von Oken, Vol. 21, p. 380
Elgaria coerulea shastensis - (Fitch, 1934) - Copeia, p. 6

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

Meaning of the Scientific Name
Elgaria - obscure - possibly named for an "Elgar" or a pun on "alligator."
coerulea
- Latin - dark colored, dark blue - referring to the dorsal color of the type specimen
shastensis - belonging to the Shasta Mountains - type locality is Shasta County, CA 1932

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

Related or Similar California Lizards
E. c. coerulea - San Francisco Alligator Lizard
E. c. palmeri - Sierra Alligator Lizard
E. c. principis - Northwestern Alligator Lizard
E. m. multicarinata - California Alligator Lizard
E. m. scincicauda - Oregon Alligator Lizard
E. m. webbii - San Diego Alligator Lizard
E. panamintina - Panamint Alligator Lizard

More Information and References
California Department of Fish and Wildlife

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 Turtles and Lizards of Western North America (North of Mexico) and Hawaii. University Press of Florida, 2009.

Jones, Lawrence, Rob Lovich, editors. Lizards of the American Southwest: A Photographic Field Guide. Rio Nuevo Publishers, 2009.

Smith, Hobart M. Handbook of Lizards, Lizards of the United States and of Canada. Cornell University Press, 1946.

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 animal 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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