Range extends from southeastern Utah, southern Colorado, Kansas, and central and southern Missouri south through Arizona, New Mexico, western and central Texas, Oklahoma, and Arkansas to Sonora and north-central mainland Mexico (Zacatecas and San Luis Potosi) (McGuire 1996, Stebbins 2003). Records for Louisiana may not represent natural occurrences (Dundee and Rossman 1989, McGuire 1996).

Crotaphytus insularis is native to the western states of the U.S. (Jones, 1997).

Biogeographic Regions: nearctic (Native )

occurs (regularly, as a native taxon) in multiple nations

United States

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

Global Range: (200,000 to >2,500,000 square km (about 80,000 to >1,000,000 square miles)) Range extends from southeastern Utah, southern Colorado, Kansas, and central and southern Missouri south through Arizona, New Mexico, western and central Texas, Oklahoma, and Arkansas to Sonora and north-central mainland Mexico (Zacatecas and San Luis Potosi) (McGuire 1996, Stebbins 2003). Records for Louisiana may not represent natural occurrences (Dundee and Rossman 1989, McGuire 1996).

Continent: Middle-America North-America
Distribution: USA (Arizona, Nevada, SE Utah, S Colorado, New Mexico, Texas, Oklahoma, Kansas, Missouri, Illinois, Arkansas),  Mexico (Baja California, Sonora, Chihuahua, N Durango, Coahuila, N Zacatecas, Nuevo Leon)  auriceps: Utah;
Type locality: "3 1/2 mi. NNE Dewey, west side of the Colorado River, Grand County, Utah". (syn with Crotaphytus collaris baileyi fide Montanucci, Axtell, and Dessauer, Herpetologica, 31: 338)   baileyi: New Mexico, Utah  fuscus: New Mexico;
Type locality: "6.5 mi. N and 1.5 mi. W of Chihuahua City, Chihuahua, Mexico".

Length: 8-14 inches including tail.

Colors and markings are diverse in Crotaphytus insularis. They are sexually dimorphic. Males tend to be green to tan colored with patterns of dorsal spots and bars to a speckled pattern across the dorsum. Male C. insularis can also exhibit vivid yellow and orange head coloration. Female C. insularis tend to be less colorful except during breeding season when they exhibit bright orange side spots or bars. Both male and female C. insularis possess two prominent collar-like black bands at their neck, hence their name (Jones, 1997).

Length: 36 cm

Differs from all other species of Crotaphytus by the absence of dark brown or black pigmentation in the gular fold of adult males (McGuire 1996, which see for further information).

Habitat and Ecology

Systems

• Terrestrial

C. insularis inhabit rocky areas with sparse vegetation. Boulder strewn hillsides and rocky outcroppings are common in their living areas. Collared lizards dig under boulders to sleep and lay their eggs (Jones, 1997).

Habitat Type: Terrestrial

Comments: The habitat consists of rocky areas with sparse vegetation and encompasses open woodlands, bunchgrass areas, canyons, gullies, slopes, and mesa tops (Degenhardt et al. 1996, McGuire 1996, Bartlett and Bartlett 1999, Hammerson 1999, Johnson 2000, Stebbins 2003, Trauth et al. 2004). When inactive, these lizards hide under rocks or in crevices. Eggs are laid under large rocks or in burrows (Collins 1982).

Non-Migrant: Yes. At least some populations of this species do not make significant seasonal migrations. Juvenile dispersal is not considered a migration.

Locally Migrant: No. No populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).

Locally Migrant: No. No populations of this species make annual migrations of over 200 km.

In Kansas, males maintained home ranges averaging about 0.4 ha and spent most of their time in just a small portion of this area (Yedlin and Ferguson 1973). In Oklahoma, 14 adult males had home range areas averaging 1,865 sq m (core = 441 sq m) (Stone and Baird 2002).

Crotaphytus insularis is mainly insectivorous and carnivorous. Occasionally their diet may consist of plant matter. C. insularis does vary its diet depending on what is abundant. Food can range from grasshoppers to smaller lizards (Jones, 1997).

Comments: Eats insects, lizards, and occasionally plant material (Stebbins 1985).

Note: For many non-migratory species, occurrences are roughly equivalent to populations.

Estimated Number of Occurrences: > 300

Comments: McGuire (1996) mapped hundreds of collection sites across the broad range in the United States and Mexico.

100,000 to >1,000,000 individuals

Comments: Total adult population size is uncertain but clearly exceeds 100,000.

In Oklahoma, density was 6.4 dominant males per ha; including subordinate males, density was 17.2 males per ha (Stone and Baird 2002).

Comments: Active March or April to October in north; lizards active in fall are mostly hatchlings (Hammerson 1999). The active season lasts several weeks longer in south than it does in the north.

Crotaphytus insularis courts and mates on the ground in spring to early summer. An average clutch size is 4-6 eggs and 1-2 clutches are produced per year. Eggs are deposited in underground burrows underneath rocks or loose sand (BISON-M, 1997). The incubation period for the eggs is generally 53-94 days. Adult C. insularis exhibit no parental care (Jones, 1997).

Eggs laying occurs in June-July in Kansas, mainly May-June in west-central Texas. Clutch size usually is 4-11. IReproductive females produce a single clutch annually in the northern part of the range, often 2 clutches in the south. Young-of-year first appear in early August in Missouri (Copeia 1992:968-990) and Colorado (Hammerson 1999). Individuals become sexually mature in their 1st or 2nd year (1st year in areas with long growing season). In Oklahoma, males established all-purpose territories (and presumably became reproductively active) when they were two years old (Stome and Baird 2002).

IUCN Red List of Threatened Species: least concern

United States

Rounded National Status Rank: N5 - Secure

Rounded Global Status Rank: G5 - Secure

Intrinsic Vulnerability: Moderately vulnerable

Population

Population Trend

Global Short Term Trend: Relatively stable (=10% change)

Comments: Extent of occurrence, area of occupancy, and abundance all appear to be relatively stable.

Global Long Term Trend: Increase of 10-25% to decline of 30%

Major Threats

Comments: No major threats have been identified.

Conservation Actions

Global Protection: Very many (>40) occurrences appropriately protected and managed

Comments: Many populations exist in protected areas.

Comments: This species formerly included several closely related Crotaphytus species that are now recognized as distinct species. A phylogenetic analysis by McGuire (1996) concluded that C. collaris is monotypic; none of the nominal subspecies represent independent lineages, with the exception of nebrius, which McGuire recognized as a distinct species (C. nebrius). See Montanucci (1983) for information on hybridization with C. bicinctores in Arizona.