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Canadian Herpetological Society Société d'Herpétologie du Canada |
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Blue-spotted Salamander
Ambystoma laterale
Family: Ambystomatidae
COSEWIC status:- Not at Risk
- No Status
- Least Concern
Description
Blue-spotted Salamanders are heavy-bodied and can reach 14 cm in total length. Adults are dark grey to black with varying amounts of blue flecks and spots, which are concentrated along the sides. The belly ranges from dark grey to black with blue flecks. Terrestrial juveniles are light grey to brown with smaller, more diffuse blue spots. This species has 12–14 costal groves. Aquatic larvae have feathery gills behind the head, legs (both front and back) and a tail fin. The larvae are generally grey-brown with light-coloured mottling, a yellow lateral stripe and black mottling on the tail fin.
Similar Species
Small-mouthed Salamanders have a short snout, small toes and grey mottling and in Canada they only occur on Pelee Island. Jefferson Salamanders are brown or grey and have longer limbs and a broad snout. Ambystoma unisexuals can overlap in body form and colouration making identification almost impossible without genetic tests. Aquatic larvae of Ambystomatidae salamanders are difficult to distinguish from one another.
Distribution
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In Canada, Blue-spotted Salamanders range from southern Manitoba to New Brunswick and Nova Scotia. In the United States, this species ranges from western Minnesota, Iowa, and Indiana to the Gulf of Saint Lawrence, New England and New Jersey.
Habitat
Blue-spotted Salamanders are usually found in deciduous and mixed forests, typically within close proximity to breeding habitats. Leaf litter and cover objects, such as logs and rocks, are important microhabitats where the salamanders forage and seek shelter. Individuals are sometimes found beneath wood piles and other debris in back yards. This species breeds in vernal pools (temporary woodland ponds) or fish-free permanent wetlands. Blue-spotted Salamanders overwinter underground below the frost line in mammal burrows, root cavities and other underground crevices.
Biology
Blue-spotted Salamanders migrate to breeding wetlands on rainy nights in early spring, often moving over snow banks and the icy edges of thawing ponds. Adults can migrate several hundred metres between overwintering and breeding sites. Each female will lay up to 500 eggs as small gelatinous masses of 2–12 eggs, which she attaches to submerged sticks or other vegetation. The eggs hatch into aquatic larvae after about one month, and the larvae transform into terrestrial juveniles by the end of summer. Individuals reach sexual maturity in two years and may only breed every few years. There is little information on the longevity of this species, but individuals may live more than 20 years based on studies on other Ambystomatid salamanders. 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. Adults and juveniles eat insects, spiders, worms and other terrestrial invertebrates, while larvae prey on immature aquatic insects and microcrustaceans.
Threats
The Blue-spotted Salamander is relatively abundant throughout its Canadian range and threats to most populations are minimal. The extensive conversion of natural habitat to agricultural and urban land uses has destroyed and fragmented much of this species’ habitat throughout the southern portion of its range in Canada, especially in Ontario. Ongoing habitat destruction, primarily from urbanization, cottage development and road construction, continues to cause localized population declines. Road mortality can be a significant threat to this species 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. Climate change and introduced pathogens pose potentially serious future threats to Canadian salamanders.