Ambystoma mavortium - Baird, 1850
Barred Tiger Salamander
Other English Common Names: Western Tiger Salamander, barred tiger salamander
Synonym(s): Ambystoma tigrinum mavortium Baird, 1850
Taxonomic Status: Accepted
Related ITIS Name(s): Ambystoma mavortium Baird, 1850 (TSN 668193)
French Common Names: salamandre tigrée de l'Ouest
Unique Identifier: ELEMENT_GLOBAL.2.100277
Element Code: AAAAA01142
Informal Taxonomy: Animals, Vertebrates - Amphibians - Salamanders
Kingdom Phylum Class Order Family Genus
Animalia Craniata Amphibia Caudata Ambystomatidae Ambystoma
Genus Size: D - Medium to large genus (21+ species)
Check this box to expand all report sections:
Concept Reference
Concept Reference: 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.
Concept Reference Code: B90COL01NAUS
Name Used in Concept Reference: Ambystoma tigrinum mavortium
Taxonomic Comments: This taxon is questionably distinct as a species separate from Ambystoma tigrinum (see taxonomy comments for Ambystoma tigrinum).
Conservation Status

NatureServe Status

Global Status: G5
Global Status Last Reviewed: 05Jun2015
Global Status Last Changed: 01Nov1996
Ranking Methodology Used: Ranked by inspection
Rounded Global Status: G5 - Secure
Nation: United States
National Status: N5 (05Nov1996)
Nation: Canada
National Status: N5 (05Jun2015)

U.S. & Canada State/Province Status
United States Arizona (S5), Colorado (S3S4), Minnesota (SNR), Navajo Nation (SNR), Oregon (SNR), Wyoming (S4)
Canada Alberta (S4), British Columbia (S2), Manitoba (S4S5), Saskatchewan (S5)

Other Statuses

Implied Status under the Committee on the Status of Endangered Wildlife in Canada (COSEWIC):PS: E,SC
Comments on COSEWIC: The Tiger Salamander (Ambystoma tigrinum) was originally assessed by COSEWIC in November 2001 as three separate populations: Great Lakes population (Extirpated), Prairie / Boreal population (Not at Risk), and Southern Mountain population (Endangered). In November 2012, Tiger Salamander was split into two separate species, Eastern Tiger Salamander (Ambystoma tigrinum) and Western Tiger Salamander (Ambystoma mavortium), each with two different populations that received separate designations. The Prairie / Boreal population of the Western Tiger Salamander was assessed as Special Concern.

NatureServe Global Conservation Status Factors

Range Extent Comments: Range extends from portions of southern Canada southward through much of the western United States and as far south as Puebla, Mexico. The ranges of A. mavortium and A. tigrinum meet in the Great Plains region, where their distributions meld. This species is absent from most of the Great Basin and most of the far western United States west of the Rocky Mountains. It has been introduced in many localities west of the Rocky Mountains. Elevational range extends to about 3,660 meters (12,000 feet).

Overall Threat Impact Comments: These salamanders occur throughout their historical range in the Rocky Mountains and Great Plains of Colorado and adjacent states. They remain easy to find and locally abundant in suitable habitat statewide. Ponds often contain up to several thousand larvae. Recent surveys found no evidence of significant declines in distribution or abundance (Corn, Stoltzberg, and Bury 1989; Hammerson 1989a, 1992; Corn, Jennings, and Muths 1997). In the Rocky Mountains, a local decline in numbers over several years, reported by Harte and Hoffman (1989), turned out to be a temporary fluctuation from which the population subsequently recovered (Wissinger and Whiteman 1992). Hovingh (1986) reported that tiger salamanders remain quite common in aquatic systems in glaciated portions of the Uinta Mountains in northeastern Utah. The widespread creation of small, fishless artificial bodies of water has provided much suitable habitat where previously there was little, and these salamanders have been quick to colonize it (Norris 1973; pers. obs.).

Many mountain lakes formerly inhabited by tiger salamanders now have few or none of these amphibians due to the stocking of trout, which easily consume and deplete the larval populations (e.g., Blair 1951; pers. obs.). Geraghty and Willey (1992) found that fish absence was the most important factor influencing tiger salamander presence in Gunnison County and vicinity, and Corn, Jennings, and Muths (1997) reported that trout and tiger salamanders rarely occur together in Rocky Mountain National Park. Trout and tiger salamanders do coexist in some lakes (Dartt 1879; Blair 1951), especially where vegetated shallows provide habitat not easily accessible to the fishes. Levi and Levi (1955) surmised that trout may conflict with paedomorphic salamanders but not with metamorphosing populations.

Some have suggested that breeding-pond acidification related to atmospheric pollution may cause periodic failure of tiger salamander reproduction in the mountains of Colorado (Harte and Hoffman 1989, 1994). Low pH, even if not fatal to salamander larvae, may result in reduced growth rates and ultimately could diminish salamander populations through decreased survival or feeding success (Kiesecker 1996). However, recent water chemistry data, together with information on acid tolerances of salamander larvae, suggest that eggs and embryos in the wild do not experience harmful levels of acidification (Corn, Stoltzenburg, and Bury 1989; Corn and Vertucci 1992; Wissinger and Whiteman 1992; Vertucci and Corn 1994).

Under certain conditions, larval populations may be vulnerable to bacterial infections associated with livestock grazing. In the mountains of Utah, Worthylake and Hovingh (1989) observed recurrent mass mortality of larvae associated a bacterial infection and suggested that increased nitrogen levels due in part to sheep grazing may have been involved. Bryant (1995) observed a mass mortality event in the summer of 1993 that appeared to be associated with an opportunistically pathogenic bacterium. In Arizona, similar die-offs, apparently associated with bacterial pathogens, have been reported (Pfennig, Loeb, and Collins 1991). Cannibal morphs seemed particularly vulnerable, probably due to their feeding on diseased larvae. Again, fecal contamination of ponds by introduced livestock was suggested as a possible cause of the fatal outbreaks. In contrast to these reports, larvae sometimes do thrive in large numbers in manure-laden ponds in Colorado (Hammerson 1999). Nevertheless, die-offs of larvae, apparently associated with pathogenic bacteria, have been observed in Colorado (Hammerson 1999).

Infection by chytrid fungus, which has been associated with amphibian declines in several areas, has been observed in southern Arizona. Observations and experiments with salamanders and frogs indicated that chytridiomycosis does not always lead to mortality, individuals within a species vary in susceptibility to infection, animals appear to recover from the infection, and syntopic salamanders and frogs may act as reciprocal pathogen reservoirs for chytrid infections (Davidson et al. 2003).

Populations in the southeastern United States have been detrimentally affected by deforestation and loss of wetland habitats (Petranka 1998). Similarly, populations in the Great Plains have declined in the extensively cultivated portions of the Great Plains.

Long-term Trend:  
Long-term Trend Comments: Quantitative information is not available for most areas, but the long-term trend in most areas likely is of relative stability in population attributes. Significant declines likely have occurred mostly in the extensively cultivated regions of the Great Plains and in the southeastern United States where intensive deforestation and drainage of wetlands have occurred.

Other NatureServe Conservation Status Information

Global Range: Range extends from portions of southern Canada southward through much of the western United States and as far south as Puebla, Mexico. The ranges of A. mavortium and A. tigrinum meet in the Great Plains region, where their distributions meld. This species is absent from most of the Great Basin and most of the far western United States west of the Rocky Mountains. It has been introduced in many localities west of the Rocky Mountains. Elevational range extends to about 3,660 meters (12,000 feet).

U.S. States and Canadian Provinces
Color legend for Distribution Map
Endemism: occurs (regularly, as a native taxon) in multiple nations

U.S. & Canada State/Province Distribution
United States AZ, CO, MN, NN, OR, WY
Canada AB, BC, MB, SK

Range Map
No map available.

U.S. Distribution by County Help
State County Name (FIPS Code)
AZ Cochise (04003), Santa Cruz (04023)
OR Malheur (41045)
WY Albany (56001), Big Horn (56003), Carbon (56007), Fremont (56013), Goshen (56015), Hot Springs (56017), Johnson (56019), Laramie (56021), Natrona (56025), Park (56029), Sublette (56035), Sweetwater (56037), Teton (56039), Uinta (56041), Weston (56045)
* Extirpated/possibly extirpated
U.S. Distribution by Watershed Help
Watershed Region Help Watershed Name (Watershed Code)
10 Upper Wind (10080001)+, Upper Bighorn (10080007)+, Greybull (10080009)+, Big Horn Lake (10080010)+, Shoshone (10080014)+, South Fork Powder (10090203)+, Clear (10090206)+, Upper Cheyenne (10120103)+, Beaver (10120107)+, Upper North Platte (10180002)+, Pathfinder-Seminoe Reservoirs (10180003)+, Medicine Bow (10180004)+, Little Medicine Bow (10180005)+, Sweetwater (10180006)+, Upper Laramie (10180010)+, Horse (10180012)+, Crow (10190009)+, Upper Lodgepole (10190015)+*
14 Upper Green (14040101)+, New Fork (14040102)+, Bitter (14040105)+, Blacks Fork (14040107)+, Great Divide closed basin (14040200)+, Little Snake (14050003)+
15 Upper San Pedro (15050202)+, Upper Santa Cruz (15050301)+
17 Gros Ventre (17040102)+, Middle Owyhee (17050107)+, Jordan (17050108)+
+ Natural heritage record(s) exist for this watershed
* Extirpated/possibly extirpated
Ecology & Life History
General Description: Tiger salamanders have smooth, somewhat slippery skin and a long tail. Each front foot has four toes. Maximum total length (TL) is about 13.6 inches (34.6 cm). The color pattern is highly variable, ranging from black with yellowish bars or spots to pale or dark with dark spots or mottling. Metamorphosed adults are stocky, have 11-14 vertical grooves on each side of the body, a broad head, small eyes, tubercles on the bottom of the feet. Mature male: large dark papillae posterior to bulbous vent during breeding season; tail relatively long. Larvae: hatchlings about 9-14 mm long, initially lack limbs; front limbs develop first, and hind limbs develop after larvae reach about 25 mm total length; large larvae (usually less than 13 cm TL but up to 35 cm TL) have three conspicuous pairs of gills and four gill slits on each side of neck; tail fin extends forward to about shoulder region; variable coloration. Eggs: laid singly or in short rows or small clusters; egg 2-4 mm in diameter, brown on upper surface, surrounded by jelly covering of thin dense inner coats and a thick soft outer coat, the whole unit being less than 10 mm in diameter; after laying, inner capsule surrounding egg liquefies, allowing egg to rotate. Source: Hammerson (1999).
Reproduction Comments: In general, breeding occurs in spring in the north and at high elevations, in winter in the southern U.S., in late winter/spring and/or summer in the Southwest. Egg deposition may occur in early to mid-March in the Lower Columbia Basin (Leonard and Darda, 1995, Herpetological Review 26:29-30). In Arizona, within a single pond, opportunistic summer breeding may occur after the usual late winter/early spring breeding period (e.g., when dried ponds refill after summer rains) (Allison et al. 1994). Individual female deposit up to 1,000 eggs singly or in small clusters. Eggs hatch in about 2-5 weeks, depending on the temperature. Larvae metamorphose in their first or second summer, or they may not metamorphose at all (become sexually mature as gilled larvae). Breeding aggregations may include a few or up to several hundred adults.
Habitat Type: Freshwater
Non-Migrant: N
Locally Migrant: Y
Long Distance Migrant: N
Mobility and Migration Comments: Most populations migrate seasonally up to several hundred meters between uplands and aquatic breeding sites. Timing of migrations and breeding is extremely variable throughout the range.
Riverine Habitat(s): CREEK, Pool, SPRING/SPRING BROOK
Lacustrine Habitat(s): Shallow water
Terrestrial Habitat(s): Alpine, Bare rock/talus/scree, Desert, Forest/Woodland, Grassland/herbaceous, Sand/dune, Savanna, Shrubland/chaparral, Suburban/orchard
Special Habitat Factors: Benthic, Burrowing in or using soil, Fallen log/debris
Habitat Comments: Tiger salamanders inhabit almost any terrestrial habitat as long as it includes the required aquatic breeding habitat, such as a lake, reservoir, permanent and ephemeral pond, or stream pool. They range from warm lowlands to high mountains and spend much of their lives in rodent burrows.
Adult Food Habits: Carnivore, Invertivore
Immature Food Habits: Carnivore, Invertivore, Planktivore
Adult Phenology: Circadian, Hibernates/aestivates
Immature Phenology: Circadian, Hibernates/aestivates
Phenology Comments: As in most other land-dwelling amphibians, most terrestrial activity occurs during and after rains; freezing weather and drought inhibit activity.
Economic Attributes Not yet assessed
Management Summary Not yet assessed
Population/Occurrence Delineation
Group Name: Ambystomatid Salamanders

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 larvae or eggs) in or near appropriate habitat where the species is presumed to be established and breeding.
Separation Barriers: Heavily traveled road, especially at night during salamander breeding season, such that salamanders almost never successfully traverse the road; road with a barrier that is impermeable to salamanders; wide, fast rivers; areas of intensive development dominated by buildings and pavement.
Separation Distance for Unsuitable Habitat: 1 km
Separation Distance for Suitable Habitat: 3 km
Separation Justification: BARRIERS/UNSUITABLE HABITAT: Rivers may or may not be effective barriers, depending on stream width and hydrodynamics; identification of streams as barriers is a subjective determination. Bodies of water dominated by predatory fishes have been described as barriers but probably should be regarded as unsuitable habitat. For A. barbouri, a stream-pool breeder, predatory fishes appeared to act as a barrier to larval dispersal and gene flow for populations separated by as little as 500-1000 m (Storfer 1999). Highly disturbed land, such as the cleared and bedded soils of some silvicultural site preparation, may serve as an impediment to movement of A. cingulatum (Means et al. 1996), although Ashton (1998) noted the species' use of pine plantations, pastures, and three-year-old clearcuts. Such areas should be treated as unsuitable habitat rather than barriers.

MOVEMENTS: Palis's (1997b) suggested use of 3.2 km between breeding sites to distinguish breeding populations of A. cingulatum was based on Ashton's (1992) finding that individuals may move as much as 1.6 km from their breeding ponds. Ambystoma californiense sometimes migrates up to 2 km between breeding ponds and terrestrial habitat (see USFWS 2004). Funk and Dunlap (1999) found that A. macrodactylum managed to recolonize lakes after trout extirpation despite evidence of low levels of interpopulation dispersal. Based on a review of several Ambystoma species (e.g., Semlitsch 1981, Douglas and Monroe 1981, Kleeberger and Werner 1983, Madison 1997), Semlitsch (1998) concluded that a radius of less than 200 meters around a breeding pond would likely encompass the terrestrial habitat used by more than 95 percent of adults. Faccio's (2003) study of radio-tagged A. maculatum and A. jeffersonianum in Vermont supports this conclusion. In New York, all movements of A. tigrinum occurred in areas within 300 m of the nearest breeding pond (Madison and Farrand 1998). However, most studies of these salamanders had small sample sizes and/or were not designed to detect long-distance movements, so migration distance may be somewhat underestimated.

In summary, ambystomatid salamanders generally stay within a few hundred meters of their breeding pool. Due to high breeding site fidelity and limitation of breeding to pool basins, populations using different breeding sites exhibit little or no interbreeding among adults. Thus one might argue that each pool constitutes a separate occurrence or that the separation distance for suitable habitat should be the nominal minimum of 1 km. However, little is known about how frequently first-time (or experienced) breeders use non-natal pools (pools from which they did not originate) or how far they may move to such sites. Frequent colonization of new and remote habitats by at least some species suggests that dispersal movements sometimes may be longer than typical adult migration distances. It seems unlikely that locations separated by a gap of less than a few kilometers of suitable habitat would represent independent occurrences over the long term.

Inferred Minimum Extent of Habitat Use (when actual extent is unknown): .3 km
Inferred Minimum Extent Justification: Inferred extent distance pertains to breeding sites (with the center of the circle in the center of the breeding site). Most ambystomatids stay within a few hundred meters of their breeding pool (see separation justification section).
Date: 10Sep2004
Author: Hammerson, G.
Population/Occurrence Viability
U.S. Invasive Species Impact Rank (I-Rank) Not yet assessed
Element Ecology & Life History Edition Date: 25Jan2010
Element Ecology & Life History Author(s): Hammerson, G.

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Citation for data on website including State Distribution, Watershed, and Reptile Range maps:
NatureServe. 2017. NatureServe Explorer: An online encyclopedia of life [web application]. Version 7.1. NatureServe, Arlington, Virginia. Available (Accessed:

Citation for Bird Range Maps of North America:
Ridgely, R.S., T.F. Allnutt, T. Brooks, D.K. McNicol, D.W. Mehlman, B.E. Young, and J.R. Zook. 2003. Digital Distribution Maps of the Birds of the Western Hemisphere, version 1.0. NatureServe, Arlington, Virginia, USA.

Acknowledgement Statement for Bird Range Maps of North America:
"Data provided by NatureServe in collaboration with Robert Ridgely, James Zook, The Nature Conservancy - Migratory Bird Program, Conservation International - CABS, World Wildlife Fund - US, and Environment Canada - WILDSPACE."

Citation for Mammal Range Maps of North America:
Patterson, B.D., G. Ceballos, W. Sechrest, M.F. Tognelli, T. Brooks, L. Luna, P. Ortega, I. Salazar, and B.E. Young. 2003. Digital Distribution Maps of the Mammals of the Western Hemisphere, version 1.0. NatureServe, Arlington, Virginia, USA.

Acknowledgement Statement for Mammal Range Maps of North America:
"Data provided by NatureServe in collaboration with Bruce Patterson, Wes Sechrest, Marcelo Tognelli, Gerardo Ceballos, The Nature Conservancy-Migratory Bird Program, Conservation International-CABS, World Wildlife Fund-US, and Environment Canada-WILDSPACE."

Citation for Amphibian Range Maps of the Western Hemisphere:
IUCN, Conservation International, and NatureServe. 2004. Global Amphibian Assessment. IUCN, Conservation International, and NatureServe, Washington, DC and Arlington, Virginia, USA.

Acknowledgement Statement for Amphibian Range Maps of the Western Hemisphere:
"Data developed as part of the Global Amphibian Assessment and provided by IUCN-World Conservation Union, Conservation International and NatureServe."

NOTE: Full metadata for the Bird Range Maps of North America is available at:

Full metadata for the Mammal Range Maps of North America is available at:

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