Western Tiger Salamander

Subspecies in Arizona: •Barred Tiger Salamander (A. m. mavortium) – non-native, introduced widely; dorsal pattern consists of bars or spots; ventral light markings often present. •Arizona Tiger Salamander (A. m. nebulosum) – native to the Mogollon Rim and Colorado Plateau; typically darker with yellow to olive blotches. •Sonoran Tiger Salamander (A. m. stebbinsi) – native, endangered; restricted to San Rafael Valley and adjacent Huachuca and Patagonia mountains; dark background with reticulated or spotted pattern. Western Tiger Salamanders occur throughout much of Arizona, excluding the driest southwestern and western deserts. Native populations are generally found above 1,524 m (5,000 ft), while many low-elevation populations are introductions. The Sonoran subspecies is limited to the San Rafael Valley and nearby mountains. Populations also occur in neighboring areas of New Mexico and northern Mexico. Breeds in ponds, cattle tanks, lakes, ciénegas, backwaters, and temporary pools. Terrestrial adults occupy upland habitats adjacent to breeding waters, including grasslands, forests, chaparral, and desert scrub. Adults are often found under logs, rocks, or burrows of other animals. Larvae and paedomorphs remain in aquatic habitats until metamorphosis or adulthood. Terrestrial adults spend much of their time underground or under surface objects, emerging during humid or rainy weather, particularly at night. Larvae, paedomorphs, and neotenes are aquatic. Populations exhibit complex life histories, allowing persistence despite fluctuating wetland conditions. Cannibalistic morphs may feed on other salamanders. Terrestrial adults feed on invertebrates and occasionally small vertebrates such as tadpoles, lizards, small snakes, and mice. Larvae consume a variety of aquatic invertebrates; cannibalistic morphs preferentially feed on conspecifics. Breeding occurs primarily in winter and spring, and occasionally in late summer. Adults return to natal ponds to breed, laying 200–2,000 eggs individually or in small clusters attached to vegetation or substrate. Eggs hatch in 2–7 weeks depending on temperature. Larvae metamorphose in as little as 2 months, though some overwinter, and paedomorphs may remain aquatic for extended periods. The Sonoran Tiger Salamander (A. m. stebbinsi) is federally listed as Endangered. Threats include habitat loss, introduced non-native salamanders, predation by fish, hybridization, and iridovirus outbreaks. The species is also a known carrier of chytridiomycosis and iridovirus, which can be lethal to other amphibians. Barred Tiger Salamanders are non-native and have been widely introduced, complicating conservation of native populations. Western Tiger Salamanders exhibit remarkable plasticity in life history, with terrestrial and aquatic forms, and cannibalistic morphs. They are Arizona’s only salamanders and play important ecological roles in both upland and aquatic ecosystems.