Arizona is a very dry state, with just 12.5 inches of rainfall per year, although around the Colorado River floodplain, the conditions may be slightly moister. Much of Arizona is composed of deserts, with four distinct areas: the Sonoran, Mohave, Chihuahuan, and Great Basin deserts. However, there are other habitats on offer, such as mountains, forests, tundra, and grasslands.
Somewhat surprisingly, there is just one species of salamander found in Arizona, the tiger salamander (Ambystoma tigrinum). However, there are multiple subspecies that differ slightly in their range and the niche they occupy. Tiger salamanders as a whole are widespread throughout North America and are one of the largest terrestrial salamanders in the world.
Arizona Salamanders
1) Sonoran tiger salamander (Ambystoma mavortium stebbinsi)
- Endemic to southeastern Arizona and northern Mexico
- Family: Ambystomatidae
- Order: Urodela
- Conservation status: Endangered
Sonoran tiger salamanders reach lengths of 33 cm (13 in) and are dark brown in color with yellow blotches covering the body and tail. The head is rounded, with small eyes and no parotid glands, and the body is of a stockier build than most salamanders. The diet of this species consists of insects, worms, and snails.
This species is confined to a very limited range in Arizona, only found in grasslands and woodlands in the San Rafael Valley in Santa Cruz and Cochise counties. They are also found in the furthermost northern regions of Sonora, Mexico. Sonoran tiger salamanders require access to standing water throughout the year, as it is essential for aspects of their life such as breeding and development.
Due to the destruction of habitat, populations are now confined to breeding in water tanks intended for cattle: conservation efforts are currently focusing on the maintenance of habitat and control of non-native predators. Some populations may also be susceptible to disease, such as the Ambystoma tigrinum virus, while others are undergoing hybridization with the closely related barred tiger salamander, resulting in alterations to the gene pool.
2) Arizona tiger salamander (Ambystoma mavortium nebulosum)
- Native to Arizona
- Family: Ambystomatidae
- Order: Urodela
- Conservation status: Unknown
Comparatively little is known about the Arizona tiger salamander. It is around the same size as the Sonoran tiger salamander, with typical lengths being somewhere between 7.6 – 16.5 cm (3 – 6.5 in). The dorsal region of this species is gray or gray-black, with mottled black patterns and yellow spots, while the ventral region is paler. Research has found that the color of the larvae of these salamanders differs depending on the substrate and water clarity of their habitat.
The range of Ambystoma mavortium nebulosum is predicted to cover portions of Arizona, Utah, Colorado, and New Mexico. This species has been found in high-elevation coniferous forests and grasslands, where it feeds on worms, snails, slugs, and insects. Arizona tiger salamander larvae are considered top predators in some areas, consuming crustaceans and aquatic insects. Some morphs are also cannibalistic – these individuals have broader heads and larger teeth than the others. The number of cannibalistic individuals that develop is heavily dependent on environmental factors.
3) Barred tiger salamander (Ambystoma mavortium mavortium)
- Native to western Canada and the western United States
- Family: Ambystomatidae
- Order: Urodela
- Conservation status: Least concern
Barred tiger salamanders are morphologically very similar to the other subspecies of Ambystoma mavortium, reaching maximum lengths of 33 – 36 cm (13 – 14 in) and displaying the characteristic small head and rounded snout. Coloration is also much the same, although it may vary depending on geographic location: typically dark gray or brown, with large yellow spots covering the back and tail.
This species is nocturnal and spends much of its time hiding in burrows. It can adapt to a broad range of habitats, including woodlands, grasslands, meadows, and even deserts, and consumes a diet of terrestrial insects and worms. As in the Arizona tiger salamander, some larvae are cannibalistic morphs.
Barred tiger salamanders have been introduced into southeastern Arizona because the larvae, which are often known as water dogs and have external gills, are used as fishing bait. They are a popular prey species for many species of snakes, birds, and fish, although their secretive lifestyle goes some way to protecting them from these threats.
An abundant species, barred tiger salamanders are not a conservation concern – however, they do present a threat to multiple other subspecies of Ambystoma mavortium, due to the likelihood of them hybridizing and impacting the gene pool.
4) Tarahumara salamander (Ambystoma rosaceum)
- Native to Mexico
- Family: Ambystoma
- Order: Urodela
- Conservation status: Least concern
Although the Tarahumara salamander is technically endemic to Mexico, it is found in some corners of Arizona, specifically in the Huachuca Mountains in the Coronado National Forest. With a maximum length of 16.4 cm (6.5 in), it has dark coloration with many small, yellow spots covering the body, tail, and legs, and a paler underbelly. This species shows sexual dimorphism: males have longer tails and shorter bodies than females.
In terms of habitat preferences, the Tarahumara salamander is quite adaptable and may be found in a variety of areas – although its preferred habitat is pine or oak forest. Not all individuals undergo metamorphosis, and some adults remain aquatic throughout their lives, feeding on freshwater snails and ostracods.
Although this species’ conservation status is classed as that of least concern, populations may still be threatened by loss of habitat, the introduction of non-native fish species, and agricultural processes. However, they can still reproduce in areas with livestock, by making use of their drinking ponds, in which they lay their eggs.
Tarahumara salamanders possess parotid glands and glands on the tail that secrete skin toxins, a function that is part of their antipredator response. Research into Ambystoma rosaceum is limited, but it’s likely that this species also postures with its head bent downwards to deter predators (this behavior is seen in other members of Ambystoma).
