Click for more images

Blotched Tiger Salamander

Ambystoma mavortium melanostictum

Family: Ambystomatidae

The Blotched Tiger Salamander is a subspecies of the Western Tiger Salamander (Ambystoma mavortium).

COSEWIC status:
  • Endangered
SARA status:
  • Endangered
IUCN status:
  • Least Concern

Description

The Blotched Tiger Salamander is one of the largest terrestrial salamanders in North America and can grow to over 30 cm in total length, although most individuals are smaller than this. Blotched Tiger Salamanders are very heavy-bodied with broad heads, small eyes, 12–14 (usually 13) costal groves and a laterally compressed tail (especially in males). Young individuals have light yellow or cream-coloured blotches or bars on a dark background but this colouration switches as individuals age, with the light colour becoming the background and the dark colours being reduced to bars and blotches. The belly is dark grey. Neotenic individuals (see biology) tend to attain larger sizes than terrestrial adults. Aquatic larvae are generally olive to greenish yellow with legs (both front and back), a tail fin and feathery gills that are longer than the head.

Similar Species

Blotched Tiger Salamanders are most easily confused with the Eastern Tiger Salamander and the Gray Tiger Salamander. The Gray and Blotched Tiger Salamanders are both sub-species of the Western Tiger Salamander and are very difficult to differentiate based on appearance. For the most part, the ranges of these two subspecies do not overlap and they are best identified based on their location. The Eastern Tiger Salamander has smaller light spots (rather than bars and blotches) on a dark background.

Distribution

In Canada, the Blotched Tiger Salamander occurs in southwestern Saskatchewan, southern Alberta and the southern mountain region of British Columbia. In the United States, this subspecies has a large distribution ranging from Canada south to Arizona, New Mexico and Texas.

Habitat

Blotched Tiger Salamanders breed in permanent or semi-permanent lakes, ponds or wetlands that are fish-free. They inhabit a variety of terrestrial habitats within close proximity to these breeding sites, including forest, parkland, grassland, sub-alpine meadows and semi-desert. Loose or sandy soil that the salamanders can burrow into, cover objects (rocks, woody debris) and small mammal burrows are important microhabitat features that provide shelter. Individuals overwinter underground below the frost line in burrows they excavate or in mammal burrows.

Biology

Blotched Tiger Salamanders migrate to breeding wetlands on rainy nights in the early spring just after the ice cover recedes from the breeding habitats. After breeding, females attach eggs singly or in small clusters to submerged sticks or other vegetation at least 30 cm below the surface of the water. The number of eggs that each female lays depends on geographic location and female body size, but can range from 100 to 5000. The eggs hatch into aquatic larvae after two to three weeks, and the larvae transform into terrestrial juveniles in late summer. Some individuals retain larval features as adults and remain aquatic their entire life (neoteny). Males usually reach sexual maturity in two years, while females may not reach maturity until they are three to five years old. Females may only breed every two years. Tiger Salamanders are long-lived, and individuals may live over 25 years. After the breeding season, adults spend most of their time in underground burrows and cavities, making them difficult to find during the summer and fall. Tiger Salamanders are opportunistic predators and eat a wide variety of insects, spiders, worms and other terrestrial invertebrates, as well as small vertebrates such as mice. Larvae prey on aquatic invertebrates, larval frogs and salamander larvae, including other Tiger Salamander larvae.

Threats

Habitat loss and fragmentation, particularly the destruction of wetlands, is a threat to this species throughout its Canadian range. This species’ habitat is vanishing at alarming rates in the mountain valleys in B.C. as land is converted to urban areas, orchards and vineyards. Road mortality can be a significant threat to Ambystoma salamanders when roads bisect spring migration routes. Pollution, such as herbicides, agricultural effluent and road salt can be detrimental to salamanders since toxins are easily absorbed though their skin. The introduction of predatory sport fish into breeding habitats can quickly decimate local populations. Climate change and introduced pathogens pose potentially serious threats to Canadian salamande

Additional Information About This Species In Canada