Aspidoscelis tigris - (Baird and Girard, 1852)
Western Whiptail
Other English Common Names: Tiger Whiptail, western whiptail
Synonym(s): Cnemidophorus tigris Baird and Girard, 1852
Taxonomic Status: Accepted
Related ITIS Name(s): Cnemidophorus tigris Baird and Girard, 1852 (TSN 208940)
Unique Identifier: ELEMENT_GLOBAL.2.893088
Element Code: ARACJ02140
Informal Taxonomy: Animals, Vertebrates - Reptiles - Lizards
 
Kingdom Phylum Class Order Family Genus
Animalia Craniata Reptilia Squamata Teiidae Aspidoscelis
Genus Size: D - Medium to large genus (21+ species)
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Concept Reference
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Concept Reference: Crother, B. I. (editor). 2008. Scientific and standard English names of amphibians and reptiles of North America north of Mexico, with comments regarding confidence in our understanding. Sixth edition. Society for the Study of Amphibians and Reptiles Herpetological Circular 37:1-84. Online with updates at: http://www.ssarherps.org/pages/comm_names/Index.php
Concept Reference Code: B08CRO01NAUS
Name Used in Concept Reference: Aspidoscelis tigris
Taxonomic Comments: Reeder et al. (2002) examined phylogenetic relationships of the whiptail lizards of the genus Cnemidophorus based on a combined analysis of mitochondrial DNA, morphology, and allozymes. They determined that Cnemidophorus in the traditional sense is paraphyletic and thus in need of nomenclatural revision. Rather than subsume all cnemidophorine species (including Kentropyx) in a single large genus (Ameiva), they proposed a split that placed the North American "Cnemidophorus" clade in the monophyletic genus Aspidoscelis; under this arrangement, South American taxa remain in the genus Cnemidophorus.

Some authors regarded Aspidoscelis tigris marmorata as a distinct species (Hendricks and Dixon 1986). Molecular and morphological data from "hybrid" (secondary contact) zones in New Mexico indicate that random nonassortative mating prevails, with no selection agaianst hybrids; marmorata should be treated as a subspecies of A. tigris (Dessauer and Cole 1991). However, Crother et al. (2000) and de Queiroz and Reeder (in Crother 2008) interpreted this evidence differently and listed A. tigris and A. marmorata as "incompletely separated species." Stebbins (2003) maintained marmorata as a subspecies of A. tigris.

Annual hybridization between parthenogenetic A. tesselata and bisexual A. tigris marmorata occurs in several locations in New Mexico and Texas, but this interaction does not appear to be resulting in the production of a new triploid parthenogenetic species (all examined female hybrids were sterile) (Taylor et al. 2001).

See Taylor and Walker (1991) for morphological evidence for the conspecific relationship of subspecies aethiops and gracilis. See Taylor et al. (1994) for documentation of a broad zone of intergradation between subspecies tigris and gracilis in southwestern Arizona; despite the broad zone of intergradation, the authors concluded that these taxa warrant recognition as distinct subspecies because they are phenotypically distinctive across most of their ranges. See Taylor and Walker (Copeia 1996:140-148) for information on the proper relegation of the names C. t. gracilis, C. t. dickersoni, C. t. disparilis, and C. t. punctilinealis (the last is regarded as a provisional name for populations presently allocated to C. t. gracilis).

See Taylor and Buschman (1993) for information on geographic variation in morphology in subspecies septentrionalis.
Conservation Status
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NatureServe Status

Global Status: G5
Global Status Last Reviewed: 31Aug2005
Global Status Last Changed: 29Oct1996
Rounded Global Status: G5 - Secure
Nation: United States
National Status: N5 (05Oct1996)

U.S. & Canada State/Province Status
Due to latency between updates made in state, provincial or other NatureServe Network databases and when they appear on NatureServe Explorer, for state or provincial information you may wish to contact the data steward in your jurisdiction to obtain the most current data. Please refer to our Distribution Data Sources to find contact information for your jurisdiction.
United States Arizona (S5), California (SNR), Colorado (S4), Idaho (S4), Navajo Nation (S4), Nevada (S5), New Mexico (S2), Oregon (S4), Texas (S5), Utah (S5)

Other Statuses

IUCN Red List Category: LC - Least concern

NatureServe Global Conservation Status Factors

Range Extent: 200,000-2,500,000 square km (about 80,000-1,000,000 square miles)
Range Extent Comments: The range extends from Oregon and Idaho to southern Baja California, Sinaloa, and southern Coahuila; west to California, east to Colorado and Texas (Stebbins 2003). This includes the range of the marbled whiptail (Aspidoscelis tigris marmorata), which some list as a distinct (but "incompletely separated") species.

Subspecies marmoratus (regarded as a distinct species by some authorities): southern New Mexico and southern and western Texas south through eastern Chihuahua and southern Coahuila.

Number of Occurrences: > 300
Number of Occurrences Comments: This species is represented by hundreds of occurrences or subpopulations.

Population Size: >1,000,000 individuals
Population Size Comments: Total adult population size is unknown but probably exceeds 1,000,000. This is a common lizard in most of its range.

Number of Occurrences with Good Viability/Integrity: Very many (>125)

Overall Threat Impact: Low
Overall Threat Impact Comments: No major threats have been identified.

Short-term Trend: Relatively Stable (<=10% change)
Short-term Trend Comments: Extent of occurrence, area of occupancy, number of subpopulations, and population size are relatively stable.

Long-term Trend: Decline of <30% to increase of 25%

Intrinsic Vulnerability: Moderately vulnerable

Other NatureServe Conservation Status Information

Distribution
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Global Range: (200,000-2,500,000 square km (about 80,000-1,000,000 square miles)) The range extends from Oregon and Idaho to southern Baja California, Sinaloa, and southern Coahuila; west to California, east to Colorado and Texas (Stebbins 2003). This includes the range of the marbled whiptail (Aspidoscelis tigris marmorata), which some list as a distinct (but "incompletely separated") species.

Subspecies marmoratus (regarded as a distinct species by some authorities): southern New Mexico and southern and western Texas south through eastern Chihuahua and southern Coahuila.

U.S. States and Canadian Provinces

Due to latency between updates made in state, provincial or other NatureServe Network databases and when they appear on NatureServe Explorer, for state or provincial information you may wish to contact the data steward in your jurisdiction to obtain the most current data. Please refer to our Distribution Data Sources to find contact information for your jurisdiction.
Color legend for Distribution Map
Endemism: occurs (regularly, as a native taxon) in multiple nations

U.S. & Canada State/Province Distribution
United States AZ, CA, CO, ID, NM, NN, NV, OR, TX, UT

Range Map
No map available.


U.S. Distribution by County Help
State County Name (FIPS Code)
CA Los Angeles (06037), Orange (06059), Riverside (06065), San Bernardino (06071), San Diego (06073), Ventura (06111)
ID Ada (16001)*, Canyon (16027), Elmore (16039), Gem (16045)*, Gooding (16047), Jerome (16053)*, Owyhee (16073), Payette (16075)*, Power (16077)*, Twin Falls (16083)*, Washington (16087)*
* Extirpated/possibly extirpated
U.S. Distribution by Watershed Help
Watershed Region Help Watershed Name (Watershed Code)
17 Lake Walcott (17040209)+*, Upper Snake-Rock (17040212)+, C. J. Idaho (17050101)+, Bruneau (17050102)+*, Middle Snake-Succor (17050103)+, Lower Boise (17050114)+*, Payette (17050122)+*, Brownlee Reservoir (17050201)+*
18 Ventura (18070101)+, Santa Clara (18070102)+, Calleguas (18070103)+, Santa Monica Bay (18070104)+, Los Angeles (18070105)+, San Gabriel (18070106)+, San Jacinto (18070202)+, Santa Ana (18070203)+, Newport Bay (18070204)+, Aliso-San Onofre (18070301)+, Santa Margarita (18070302)+, San Luis Rey-Escondido (18070303)+, San Diego (18070304)+, Cottonwood-Tijuana (18070305)+, Whitewater River (18100201)+, Carrizo Creek (18100202)+, San Felipe Creek (18100203)+
+ Natural heritage record(s) exist for this watershed
* Extirpated/possibly extirpated
Ecology & Life History
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General Description: These lizards have a long and slender body, small granular scales on the back, and larger rectangular scales on the belly. Belly scales are unmarked or have black marks on the front edge of some scales. The upper side often has light stripes; the dark fields between the light stripes are interrupted by light areas, or the dark fields are broken into separate bars or spots, or the pattern may be more or less marbled. The scales along the front edge of the fold of skin across the throat are not conspicuously enlarged. The throat may be pinkish or orangish in adults. Maximum size is about 5 inches (12.7 cm) snout-vent length. Hatchlings are orange-yellow with dark brown-black spots, stripes, or marbling; the tail is bright blue. Source: Hammerson (1999).
Reproduction Comments: At the northern end of the range, mating occurs in the first half of June, egg laying occurs in late June and July, individual females produce one clutch per year, and hatchlings appear by mid-August. In Colorado, courtship and mating occur from late May to mid-June, eggs are laid in mid- to late June, and eggs hatch in early August. At the southern end of the range in Mexico, egg laying occurs as early as early May, hatchlings first appear as early as mid-June, and individual females may produce two clutches each year. Clutch size averages between 2 and 4(Nussbaum et al. 1983; Fitch 1970; Taylor et al., Copeia 1994:1047-1050). Individuals become sexually mature in 20-23 months in Idaho and Colorado (see Hammerson 1999), probably at the end of the first year in the far south (Hendricks and Dixon 1984).
Ecology Comments: Home range size in Colorado averaged 1,335 sq m in males and 1,010 sq m in females (McCoy 1965). Home ranges overlap and are not defended. In general, other lizards of the same or other species are ignored. Much larger home ranges occur in California (e.g., about 10,000 sq m in adult males and about 3,200 sq m in adult females; Anderson 1993). Jorgensen and Tanner (1963) found intermediate sizes of 2,900 sq m in males, 5,200 sq m in females, and 2,200 sq m in juveniles in Nevada. Some of this variation results from methodological differences and may not reflect biological differences.

Population density in Colorado was about 17/ha (McCoy 1965).

Non-Migrant: Y
Locally Migrant: N
Long Distance Migrant: N
Palustrine Habitat(s): Riparian
Terrestrial Habitat(s): Desert, Grassland/herbaceous, Shrubland/chaparral, Woodland - Conifer, Woodland - Hardwood, Woodland - Mixed
Special Habitat Factors: Burrowing in or using soil, Fallen log/debris
Habitat Comments: Habitat includes deserts and semiarid shrublands, usually in areas with sparse vegetation; also woodland, open dry forest, and riparian growth. Soil may be firm, sandy, or rocky. Lizards seek shelter in underground burrows (dug by rodent or lizard) or under surface objects. Eggs are laid in soil/underground.
Adult Food Habits: Invertivore
Immature Food Habits: Invertivore
Food Comments: Eats insects, spiders, scorpions, and lizards (Stebbins 1985). Storm-petrel eggs and hatchlings included in diet in spring and summer on Isla Partida, Gulf of California (Maya and Malone 1989).

These whiptails forage widely and intensively, probing into leaf litter, digging out buried prey, and sometimes climbing into plants to obtain prey (primarily arthropods). Much flicking of the tongue suggests that odors help reveal potential prey.

Adult Phenology: Diurnal, Hibernates/aestivates
Immature Phenology: Diurnal, Hibernates/aestivates
Phenology Comments: Activity occurs in warm daylight hours. Adults are active mainly April-September in the north. Juveniles have a longer activity season and may be active earlier in spring and later in summer and (in the southern part of the range) on warm days in winter. In Texas, juveniles emerge in spring prior to adults; adults inactive by early September (Hendricks and Dixon 1984).
Length: 31 centimeters
Economic Attributes Not yet assessed
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Management Summary Not yet assessed
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Population/Occurrence Delineation
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Group Name: Teiid Lizards (Whiptails and Others)

Use Class: Not applicable
Minimum Criteria for an Occurrence: Occurrences are based on evidence of historical presence, or current and likely recurring presence, at a given location. Such evidence minimally includes collection or reliable observation and documentation of one or more individuals (including eggs) in or near appropriate habitat where the species is presumed to be established and breeding.
Separation Barriers: Busy highway or highway with obstructions such that lizards rarely if ever cross successfully; major river, lake, pond, or deep marsh; densely urbanized area dominated by buildings and pavement (but note that some rural residential areas are suitable habitat for some species).
Separation Distance for Unsuitable Habitat: 1 km
Separation Distance for Suitable Habitat: 5 km
Separation Justification: Teiids have home ranges that are generally less (often much less) than 1 ha but sometimes move hundreds of meters from one location to another (Fitch 1958, Jorgensen and Tanner 1963, McCoy 1965, Knopf 1966, Lewis and Saliva 1987, Anderson 1993, Eifler and Eifler 1998). Little is known about dispersal distances, but these lizards clearly are capable of making extensive movements.

The separation distance for unsuitable habitat reflects the nominal minimum value. The separation distance for suitable habitat takes into consideration the small home range sizes of these lizards, their tendency to occur throughout patches of suitable habitat, and the likely low probability that two locations separated by less than several kilometers of suitable habitat would represent different populations.

Inferred Minimum Extent of Habitat Use (when actual extent is unknown): .2 km
Date: 21Sep2004
Author: Hammerson, G.
Population/Occurrence Viability
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U.S. Invasive Species Impact Rank (I-Rank) Not yet assessed
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Authors/Contributors
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NatureServe Conservation Status Factors Edition Date: 28Jan2010
NatureServe Conservation Status Factors Author: Hammerson, G.
Element Ecology & Life History Edition Date: 28Jan2010
Element Ecology & Life History Author(s): Hammerson, G.

Zoological data developed by NatureServe and its network of natural heritage programs (see Local Programs) and other contributors and cooperators (see Sources).

References
Help
  • Allen, C. R., S. Demarais, and R. S. Lutz. 1994. Red imported fire ant impact on wildlife: an overview. The Texas Journal of Science 46(1):51-59.

  • Anderson, R. A. 1993. An analysis of foraging in the lizard, Cnemidophorus tigris. Pages 83-116 in J. W. Wright and L. J. Vitt, editors. Biology of whiptail lizards (genus Cnemidophorus). Oklahoma Museum of Natural History, Norman, Oklahoma.

  • Anderson, R. A. 1994. Functional and population responses of the lizard CNEMIDOPHORUS TIGRIS to environmental fluctuations. American Zoologist 34:409-421.

  • Collins, J. T. 1990. Standard common and current scientific names for North American amphibians and reptiles. 3rd ed. Society for the Study of Amphibians and Reptiles. Herpetological Circular No. 19. 41 pp.

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  • Crother, B. I. (editor). 2012. Scientific and standard English names of amphibians and reptiles of North America north of Mexico, with comments regarding confidence in our understanding. 7th edition. SSAR Herpetological Circular 39:1-92.

  • DIXON, JAMES R. 1987. AMPHIBIANS AND REPTILES OF TEXAS, WITH KEYS, TAXONOMIC SYNOPSES, BIBLIOGRAPHY, AND DISTRIBUTION MAPS. TEXAS A& M UNIV. PRESS, COLLEGE STATION. xii + 434 pp.

  • Dessauer, H. C., C. J. Cole, and C. R. Townsend. 2000. Hybridization among western whiptail lizards (CNEMIDOPHORUS TIGRIS) in southwestern New Mexico: populations genetics, morphology, and ecology in three contact zones. Bulletin of the American Museum of Natural History 246:1-148.

  • Dessauer, H. C., and C. J. Cole. 1991. Genetics of whiptail lizards (Reptilia: Teiidae: CNEMIDOPHORUS) in a hybrid zone in southwestern New Mexico. Copeia 1991:622-637.

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  • Hammerson, G. A. 1982. Amphibians and Reptiles in Colorado. Colorado Division of Wildlife, Denver. vii + 131 pp.

  • Hammerson, G. A. 1982b. Amphibians and reptiles in Colorado. Colorado Division of Wildlife, Denver. vii + 131 pp.

  • Hendricks, F. S., and J. R. Dixon. 1984. Population structure of CNEMIDOPHORUS TIGRIS (Reptilia: Teiidae) east of the Continental Divide. Southwest. Nat. 29:137-140.

  • Hendricks, F. S., and J. R. Dixon. 1986. Systematics and biogeography of CNEMIDOPHORUS MARMORATUS (Sauria: Teiidae). Texas J. Sci. 38:327-402.

  • JORGENSEN, ERIC E. AND STEPHEN DEMARAIS. 1998. HERPETOFAUNA ASSOCIATED WITH ARROYOS AND UPLANDS IN FOOTHILLS OF THE CHIHUAHUAN DESERT. SOUTHWEST. NAT. 43:441-448.

  • Jorgensen, C. D., and W. W. Tanner. 1963. The application of density probability function to determine the home ranges of Uta stansburiana stansburiana and Cnemidophorus tigris tigris. Herpetologica 19:105-115.

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  • McCoy, C. J. 1965. Life history and ecology of Cnemidophorus tigris septentrionalis. Ph.D. thesis, University of Colorado, Boulder.

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  • Reeder, T. W., C. J. Cole, and H. C. Dessauer. 2002. Phylogenetic relationships of whiptail lizards of the genus Cnemidophorus (Squamata: Teiidae): a test of monophyly, reevaluation of karyotypic evolution, and review of hybrid origins. American Museum Novitates (3365):1-61.

  • Reeder, T. W., C. J. Cole, and H. C. Dessauer. 2002. Phylogenetic relationships of whiptail lizards of the genus Cnemidophorus (Squamata: Teiidae): a test of monophyly, reevaluation of karyotypic evolution, and review of hybrid origins. American Museum Novitates 3365: 1-61.

  • Schwinn, M. A., and L. Minden. 1980. Utah reptile and amphibian latilong distribution. Publ. No. 80-1. Utah Division of Wildlife Resources, Salt Lake City, Utah.

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  • Taylor, H. L., C. J. Cole, L. M. Hardy, H. C. Dessauer, C. R. Townsend, J. M. Walker, and J. E. Cordes. 2001. Natural hybridization between the teiid lizards Cnemidophorus tesselatus (parthenogenetic) and C. tigris marmoratus (bisexual): assessment of evolutionary alternatives. American Museum Novitates 3345:1-65.

  • Taylor, H. L., and D. Buschman. 1993. A multivariate analysis of geographic variation in the teiid lizard CNEMIDOPHORUS TIGRIS SEPTENTRIONALIS. Herpetologica 49:42-51.

  • Taylor, H. L., and J. M. Walker. 1991. Morphological evidence for the conspecific relationship of the teiid lizards, CNEMIDOPHORUS TIGRIS AETHIOPS and C. TIGRIS GRACILIS. Copeia 1991:800-809.

  • Taylor, H. L., et al. 1994. Subspecific relationships in the lizard CNEMIDOPHORUS TIGRIS in southwestern Arizona. J. Herpetol. 28:247-253.

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