Blunt-nosed Leopard Lizard
FWS Focus

Overview

The blunt-nosed leopard lizard (Gambelia silus) is a relatively large lizard the Iguanidae family. It has a long, regenerative tail, long, powerful hind limbs, and a short, blunt snout. Adult males are slightly larger than females, ranging in size from 3.4 to 4.7 inches in length, excluding tail. Females are 3.4 to 4.4 inches long. Males weigh 1.3 to 1.5 ounces, females 0.8 to 1.2. Although blunt-nosed leopard lizards are darker than other leopard lizards, they exhibit tremendous variation in color and pattern on their backs. Their background color ranges from yellowish or light gray-brown to dark brown, depending on the surrounding soil color and vegetation. Their undersides are uniformly white. They have rows of dark spots across their backs, alternating with white, cream-colored or yellow bands.

Characteristics
Overview

The blunt-nosed leopard lizard is a relatively large lizard that is part of the iguana family. It has a long tail, powerful hind limbs and a short, blunt snout. They are yellowish to dark brown with rows of dark spots across their backs. The lizard was listed as endangered on March 11, 1967.

The blunt-nosed leopard lizard lives on the San Joaquin Valley floor and surrounding foothills in central California. Historically, it lived in arid lands throughout much of the San Joaquin Valley and adjacent foothills, ranging from Stanislaus County in the north to the Tehachapi Mountains in the south, as well as in the Carrizo Plain and Cuyama Valley. Widespread agricultural development of the San Joaquin Valley has reduced its habitat to 15 percent of its historic range. Today, small populations of the lizard are found on parcels of undeveloped land scattered from Merced County in the north to Santa Barbara and Ventura counties in the south.

USFWS. (U.S. Fish and Wildlife Service). 2010. Blunt-nosed leopard lizard (Gambelia sila) 5-Year Review, Summary and evaluation. U.S. Fish and Wildlife Service. Sacramento, California. 79 pp. February. Available online at: http://ecos.fws.gov/docs/five_year_review/doc3209.pdf. Date accessed: March 16, 2016. 2020.

Species Status Assessment for the Blunt-nosed leopard lizard (Gambelia sila) Version 1.0.  U.S. Fish and Wildlife Service. Sacramento, California. Available online at: https://ecos.fws.gov/ServCat/DownloadFile/173244

Scientific Name

Gambelia silus
Common Name
Blunt-nosed Leopard Lizard
FWS Category
Reptiles

Location in Taxonomic Tree

Identification Numbers

TSN:

Characteristics

Characteristic category

Habitat

Characteristics
Habitat

Blunt-nosed leopard lizards live in central California. They live in arid, open areas that have patchy or sparse vegetation, that is characterized by low, drought-tolerant shrubs. The lizards are found below 2,600 feet (800 meters) in elevation. Current distribution extends from Merced County in the north to Santa Barbara and Ventura counties in the south.

USFWS. (U.S. Fish and Wildlife Service). 2010. Blunt-nosed leopard lizard (Gambelia sila) 5-Year Review, Summary and evaluation. U.S. Fish and Wildlife Service. Sacramento, California. 79 pp. February. Available online at: http://ecos.fws.gov/docs/five_year_review/doc3209.pdf. Date accessed: March 16, 2016. 2020.

Species Status Assessment for the Blunt-nosed leopard lizard (Gambelia sila) Version 1.0.  U.S. Fish and Wildlife Service. Sacramento, California. Available online at: https://ecos.fws.gov/ServCat/DownloadFile/173244

Grassland

Ecosystem with large, flat areas of grasses.

Desert

Area of land that receives no more than 25 centimeters (10 inches) of precipitation a year.

Rural
Characteristic category

Food

Characteristics
Food

Blunt-nosed leopard lizards use both active foraging and a sit-and-wait strategy to feed. When using the sit-and-wait hunting strategy, the lizard waits for prey to wander near them, and then pounces to capture the prey. Insects make up 97 percent of their diet.

USFWS. (U.S. Fish and Wildlife Service). 2010. Blunt-nosed leopard lizard (Gambelia sila) 5-Year Review, Summary and evaluation. U.S. Fish and Wildlife Service. Sacramento, California. 79 pp. February. Available online at: http://ecos.fws.gov/docs/five_year_review/doc3209.pdf. Date accessed: March 16, 2016. 2020.

Species Status Assessment for the Blunt-nosed leopard lizard (Gambelia sila) Version 1.0.  U.S. Fish and Wildlife Service. Sacramento, California. Available online at: https://ecos.fws.gov/ServCat/DownloadFile/173244

Characteristic category

Behavior

Characteristics
Behavior

Blunt-nosed leopard lizards are active during the day in the spring, summer and fall months. Adult activity decreases during the hot summer months of July and August, just as the hatchlings emerge from the burrows. At that point, adults generally retreat into their burrows for the winter. Hatchlings stay out until October or November, before going into burrows. Adults are capable of remaining below ground for two winters when poor environmental conditions, such as drought, are present. Younger lizards may not have enough fat reserves to stay below ground for more than one season.

Threats to the species:

  • Habitat loss and degradation from urbanization, agriculture expansion, solar power development, and oil and gas exploration
  • Non-native plants and grasses
  • Vehicle-related mortality from automobile traffic and off-road vehicles
  • Above- or below-average precipitation
  • Pesticide use
  • Climate change

USFWS. (U.S. Fish and Wildlife Service). 2010. Blunt-nosed leopard lizard (Gambelia sila) 5-Year Review, Summary and evaluation. U.S. Fish and Wildlife Service. Sacramento, California. 79 pp. February. Available online at: http://ecos.fws.gov/docs/five_year_review/doc3209.pdf. Date accessed: March 16, 2016. 2020.

Species Status Assessment for the Blunt-nosed leopard lizard (Gambelia sila) Version 1.0.  U.S. Fish and Wildlife Service. Sacramento, California. Available online at: https://ecos.fws.gov/ServCat/DownloadFile/173244

Characteristic category

Physical Characteristics

Characteristics
Size & Shape

The blunt-nosed leopard lizard is a relatively large lizard in the iguana family. It has a long, regenerative tail and powerful hind limbs. It also has a short, blunt snout. Adult males are slightly larger than females.

MeasurementsLength:

  • Males range in size from 3.4 to 4.7 inches (8.7 to 12.0 centimeters), excluding tail
  • Females are 3.4 to 4.6 inches (8.6 to 11.6 centimeters), excluding tail

USFWS. (U.S. Fish and Wildlife Service). 2010. Blunt-nosed leopard lizard (Gambelia sila) 5-Year Review, Summary and evaluation. U.S. Fish and Wildlife Service. Sacramento, California. 79 pp. February. Available online at: http://ecos.fws.gov/docs/five_year_review/doc3209.pdf. Date accessed: March 16, 2016. 2020.

Species Status Assessment for the Blunt-nosed leopard lizard (Gambelia sila) Version 1.0.  U.S. Fish and Wildlife Service. Sacramento, California. Available online at: https://ecos.fws.gov/ServCat/DownloadFile/173244

Weight

Males weigh 1.1 to 2.1 ounces (31.8 to 60.0 grams) and females weigh 0.7 to 1.0 ounces (20.6 to 37 grams).

USFWS. (U.S. Fish and Wildlife Service). 2010. Blunt-nosed leopard lizard (Gambelia sila) 5-Year Review, Summary and evaluation. U.S. Fish and Wildlife Service. Sacramento, California. 79 pp. February. Available online at: http://ecos.fws.gov/docs/five_year_review/doc3209.pdf. Date accessed: March 16, 2016. 2020.

Species Status Assessment for the Blunt-nosed leopard lizard (Gambelia sila) Version 1.0.  U.S. Fish and Wildlife Service. Sacramento, California. Available online at: https://ecos.fws.gov/ServCat/DownloadFile/173244

Color & Pattern

Blunt-nosed leopard lizards exhibit tremendous variation in color and pattern on their backs. Their background color ranges from yellowish or light gray-brown to dark brown, with their undersides uniformly white to yellow. They have rows of dark spots across their backs, alternating with white, cream-colored or yellow bands. During breeding season, males and females develop reddish-orange patches on their sides.

USFWS. (U.S. Fish and Wildlife Service). 2010. Blunt-nosed leopard lizard (Gambelia sila) 5-Year Review, Summary and evaluation. U.S. Fish and Wildlife Service. Sacramento, California. 79 pp. February. Available online at: http://ecos.fws.gov/docs/five_year_review/doc3209.pdf. Date accessed: March 16, 2016. 2020.

Species Status Assessment for the Blunt-nosed leopard lizard (Gambelia sila) Version 1.0.  U.S. Fish and Wildlife Service. Sacramento, California. Available online at: https://ecos.fws.gov/ServCat/DownloadFile/173244

Physical Characteristics

Blunt-nosed leopard lizards are active during the day in the spring, summer and fall months. Adult activity decreases during the hot summer months of July and August, just as the hatchlings emerge from the burrows. At that point, adults generally retreat into their burrows for the winter. Hatchlings stay out until October or November, before going into burrows. Adults are capable of remaining below ground for two winters when poor environmental conditions, such as drought, are present. Younger lizards may not have enough fat reserves to stay below ground for more than one season.

Threats to the species:

  • Habitat loss and degradation from urbanization, agriculture expansion, solar power development and oil and gas exploration
  • Non-native plants and grasses
  • Vehicle-related mortality from automobile traffic and off-road vehicles
  • Above or below-average precipitation
  • Pesticide use
  • Climate change
Characteristic category

Lifecycle

Characteristics
Reproduction

Females generally lay eggs once a year, with one to six eggs per clutch. Some females may lay more than one clutch per season under favorable environmental conditions.

USFWS. (U.S. Fish and Wildlife Service). 2010. Blunt-nosed leopard lizard (Gambelia sila) 5-Year Review, Summary and evaluation. U.S. Fish and Wildlife Service. Sacramento, California. 79 pp. February. Available online at: http://ecos.fws.gov/docs/five_year_review/doc3209.pdf. Date accessed: March 16, 2016. 2020.

Species Status Assessment for the Blunt-nosed leopard lizard (Gambelia sila) Version 1.0.  U.S. Fish and Wildlife Service. Sacramento, California. Available online at: https://ecos.fws.gov/ServCat/DownloadFile/173244

Lifespan

The blunt-nosed leopard lizard may live up to eight or nine years, but few adults are seen across more than two years.

USFWS. (U.S. Fish and Wildlife Service). 2010. Blunt-nosed leopard lizard (Gambelia sila) 5-Year Review, Summary and evaluation. U.S. Fish and Wildlife Service. Sacramento, California. 79 pp. February. Available online at: http://ecos.fws.gov/docs/five_year_review/doc3209.pdf. Date accessed: March 16, 2016. 2020.

Species Status Assessment for the Blunt-nosed leopard lizard (Gambelia sila) Version 1.0.  U.S. Fish and Wildlife Service. Sacramento, California. Available online at: https://ecos.fws.gov/ServCat/DownloadFile/173244

Characteristic category

Similar Species

Characteristics
Similar Species
  • Long-nosed leopard lizard

Geography

Characteristics
Range

Small populations of the lizard are found on parcels of undeveloped land scattered from Merced County in the north to Santa Barbara and Ventura counties in the south.

USFWS. (U.S. Fish and Wildlife Service). 2010. Blunt-nosed leopard lizard (Gambelia sila) 5-Year Review, Summary and evaluation. U.S. Fish and Wildlife Service. Sacramento, California. 79 pp. February. Available online at: http://ecos.fws.gov/docs/five_year_review/doc3209.pdf. Date accessed: March 16, 2016. 2020.

Species Status Assessment for the Blunt-nosed leopard lizard (Gambelia sila) Version 1.0.  U.S. Fish and Wildlife Service. Sacramento, California. Available online at: https://ecos.fws.gov/ServCat/DownloadFile/173244

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