CaliforniaHerps.com

A Guide to the Amphibians
and Reptiles of California


Western Red-tailed Skink -
Plestiodon gilberti rubricaudatus

(Taylor, 1935)

(= Eumeces gilberti rubricaudatus)
Click on a picture for a larger view



Gilbert's Skinks Range Map
Range in California: Red & adjacent Gray

Click the map for a guide
to the other subspecies



observation link





Gilbert's Skink Gilbert's Skink Gilbert's Skink Gilbert's Skink
Adult, Kern County Adult, Kern County Adult, Kern County
Gilbert's Skink Gilbert's Skink Gilbert's Skink Gilbert's Skink
Adult male, Kingston Mountains, San Bernardino County. © Keith Condon Adult, Kings County
© Patrick Briggs
Intergrade, Monterey County Adult, Kern County
Gilbert's Skink Gilbert's Skink Gilbert's Skink Gilbert's Skink
  Sub-adult, Kern County  
Gilbert's Skink Gilbert's Skink Gilbert's Skink Gilbert's Skink
A bitey Sub-adult, Kern County Breeding adult male, Kern County
© Ryan Sikola
Tail parts shortly after being released: part attached to lizard on left,
dropped part on right.
       
Juveniles
Gilbert's Skink Gilbert's Skink Gilbert's Skink Gilbert's Skink
Juvenile, Kern County Juvenile, Kern County
© Brad Alexander
Juvenile, Granite Mountains, San Bernardino County. © Keith Condon Juvenile, Kingston Mountains, San Bernardino County. © Keith Condon
Gilbert's Skink Gilbert's Skink Gilbert's Skink Gilbert's Skink
  Tiny juvenile missing its tail, Kern County   Sub-adult, coastal San Diego County
© Aaron Wells
Gilbert's Skink Gilbert's Skink Gilbert's Skink Gilbert's Skink
Sub-adult, Inyo County Sub-adult, Kern County, with tail, and after dropping its tail.
Gilbert's Skink Gilbert's Skink Gilbert's Skink  
  Juvenile, Kern County    
   
Identification
Gilbert Skink Tail Great Basin Collared Lizard Northern Brown Skink Skinks
Gilbert's Skinks usually have 8 supralabial scales.
Compare
with Western Skinks which usually have 7 supralabials.
Toothy Skinks, genus Plestiodon, have smooth shiny cycloid scales that are reinforced with bone. Plestiodon skiltonianus is shown here.
Note that the dark stripes on the sides of the tail on juvenile Gilbert's skinks do not extend far onto the tail as they do on the Western Skink.   Compare

More information about the differences between Gilbert's Skinks and Western Skinks.
Comparison of juvenile skinks:
Top: P. s. skiltonianus - Modoc County
Bottom: P. gilberti - Kings County
© Patrick Briggs
       
Habitat
Gilbert's Skink Habitat Gilbert's Skink Habitat Gilbert's Skink Habitat Gilbert's Skink Habitat
Creekside habitat, Kern County Habitat,Tehachapi Mountains,
Kern County
Desert riparian habitat, Inyo County
San Diego County coastal sage habitat
Gilbert's Skink Habitat Gilbert's Skink Habitat Gilbert's Skink Habitat Gilbert's Skink Habitat
Creekside habitat, 1,450 ft., Kern County Creekside habitat, Kern County Montane habitat, 5,800 ft.
San Bernardino County
Gilbert's Skink Habitat      
Habitat, Kern County      
       
Short Videos
Gilbert's Skink Gilbert's Skink Habitat Tail Gilbert's Skink San Diego Mountain Kingsnake
A sub-adult Western Red-tailed Skink shows the quick serpentine movement of a small skink. Skinks are masters at diving into grass and disappearing. This video opens with the skink wriggled into some grass roots to hide. A Western Red-tailed Skink dropped its tail to distract me from trying to catch it. The trick worked - I filmed the tail and its writhing distracting motion, some of which you can see here. A little juvenile Western Red-tailed Skink with no tail is discovered underneath a rock. This unfortunate Western Red-tailed Skink was found in the wild as it was being swallowed by a California Mountain Kingsnake in Kern County
© Ryan Sikola
     
Description
 
Size
2.5 - 4.5 inches long from snout to vent (6.3 - 11.4 cm).
Tail can be up to nearly 2 times the body length.

Appearance
A large skink with a heavy body, small head, thick neck, small legs, and a smooth, shiny body with cycloid scales.
The tongue is forked, and is frequently protruded.
The long tail is easily detached.
Color and Pattern
Adult coloring is a uniform olive or light brown with darker edging around the scales, and sometimes the appearance of faded light and dark stripes.
Striping fades with age.
Older adults may develop orange coloring.
Male / Female Differences
Males develop bright reddish-orange coloring on the head during the breeding season.
Females are smaller than males.
Young
Young look very much like adult P. s. skiltonianus, with distinct light and dark stripes (which fade with age) but with a pink tail. (Young in the Panamint and other desert mountains have a blue tail.) However, the dark stripe on the sides of young skinks usually extends only to near the base of the tail.

Identifying Skinks in California - Differences between Western Skinks and Gilbert's Skinks
 
Life History and Behavior

Activity
Rarely found moving about on the ground in the open, however, they are active in the daytime and will occasionally be seen moving in grass, among rocks, or in leaf litter.
Often found under surface objects.
Diet and Feeding
Eats a variety of small invertebrates.
Breeding
Females lay 3 - 9 eggs in summer.

Geographical Range
Found from the foothills and middle elevations of the southern Sierra Nevada Mountains and South Coast ranges, south along the Transverse and Peninsular ranges into Baja California.
Isolated populations east of the Sierra Nevadas, including Deep Springs and Saline Valleys, and in several desert mountain ranges, including the Kingston, Clark, and Providence Mountains.

The species Plestiodon gilberti ranges from the northern Sierra Nevada foothills from south of the Yuba River through the southern Sierra Nevada, and south through the Sacramento and San Joaquin Valleys, the coast ranges, and the southern interior and mountains, into northern Baja California. Also found in isolated regions east of the Sierras along the Nevada border and into Nevada, and in the southern tip of Nevada into western Arizona.

Full Species Range Map
Elevational Range
From sea level to 7,300 ft. (2.220 m).

Habitat
Prefers areas where moisture is present nearby, including grassland, chaparral, woodlands, and pine forests.

Notes on Taxonomy
Brandley et al. (2005 Syst. Biol. 54:373-390) replaced Eumeces with Plestiodon.

The Society for the Study of Amphibians and Reptiles adopted the use of Plestiodon in the sixth edition of their Scientific and Standard English Names of Amphibians and Reptiles of North America north of Mexico list.

"Richmond and Reeder (2002, Evolution 56: 1498-1513) presented evidence that populations previously referred to Eumeces gilberti represent three lineages that separately evolved large body size and the loss of stripes in late ontogenetic stages. Although they considered those three lineages to merit species recognition, they did not propose specific taxonomic changes in that paper. We have placed the name "gilberti" in quotation marks to indicate that it refers to a group composed of several species." *

* Herpetological Review 2003, 34(3), 196-203.


"Richmond and Reeder (2002, Evolution 56: 1498-1513) present mitochondrial DNA evidence that populations previously referred to Plestiodon gilberti represent three lineages that separately evolved large body size and the loss of stripes in late ontogenetic stages. Although they considered those three lineages to merit species recognition, they did not propose specific taxonomic changes, and subsequently Richmond and Jockusch (2007, Proc. Roy. Soc. Lond. B 274: 1701-1708) and Richmond et al. (2011, Am. Nat. 178: 320-332) have treated them as a single species based on extensive introgressive hybridization between two of the forms and the lack of prezygotic isolation between members of all pairs of them. The results of Richmond and Reeder (op. cit.) contradict the recognition of P. g. arizonensis, which is not differentiated from P. g. rubricaudatus and therefore has been eliminated from this list, and indicate the existence of an unnamed and at least partially separate lineage within P. g. rubricaudatus (their Inyo clade)." **

** Comments under P. gilberti in the Society for the Study of Amphibians and Reptiles Herpetological Circular No. 39, 2012.

Arizona populations of this subspecies were formerly E. g. arizonensis - Arizona Skink


Alternate and Previous Names (Synonyms)

Arizona populations of this subspecies were formerly E. g. arizonensis - Arizona Skink

Eumeces gilberti rubricaudatus - Western Red-tailed Skink (Smith 1946, Stebbins 1966 & 1985 & 2003)

Conservation Issues  (Conservation Status)
None
Taxonomy
Family Scincidae Skinks Gray, 1825
Genus Plestiodon (formerly Eumeces) Toothy Skinks Duméril and Bibron, 1839
Species gilberti Gilbert's Skink (Van Denburgh, 1896)
Subspecies

rubricaudatus Western Red-tailed Skink (Taylor, 1935)
Original Description
Eumeces gilberti - Van Denburgh, 1896 - Proc. California Acad. Sci., Ser. 2, Vol. 6, p. 350
Eumeces gilberti rubricaudatus - Taylor, 1936 - Sci. Bull. Univ. Kansas, Vol. 23, p. 446, figs. 72-73, pl. 39

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

Meaning of the Scientific Name
(Eumeces - Greek - eu- good or nice and mekos length or height)
Plestiodon = ?

gilberti
- honors Gilbert, Charles H.
rubricaudatus - Latin - rubra - red, ruddy and caudatus- bearing a tail (bearing a red tail)

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

Related or Similar California Lizards
P. g. cancellosus - Variegated Skink
P. g. gilberti - Greater Brown Skink
P. g. placerensis - Northern Brown Skink
P. s. interparietalis - Coronado Skink
P. s. skiltonianus - Skilton's Skink

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.

Lemm, Jeffrey. Field Guide to Amphibians and Reptiles of the San Diego Region (California Natural History Guides). University of California Press, 2006.

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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