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Canadian Herpetological Society Société d'Herpétologie du Canada |
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Eastern Red-backed Salamander
Plethodon cinereus
Family: Plethodontidae
COSEWIC status:- Not Assessed
- No Status
- Least Concern
Description
The Eastern Red-backed Salamander is slender-bodied and can reach 12.5 cm in total length, though most individuals are much smaller than this. Individuals have 17 to 20 (usually 18 or 19) costal groves on each side of the body. This salamander occurs in two different colour morphs, which vary in relative frequency across different populations. The red-back morph has a black or dark grey body with a broad red or brownish orange stripe down the back. The lead-back morph has a black or dark grey body and lacks the dorsal stripe. This species often has white flecking along the sides and the underside has black and white mottling.
Similar Species
The Eastern Red-backed Salamander can be confused with several other species of Plethodontid salamanders. The Four-toed Salamander has a constriction at the base of the tail, has four toes on the hind feet and has a bright white belly with black spots. The Northern Dusky Salamander and Alleghany Mountain Dusky Salamander both have a diagonal line running from the jaw to the eye and a laterally compressed tail. The Northern Two-Lined Salamander has two dark lines running down the back and a laterally compressed tail.
Distribution
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In Canada, the Eastern Red-backed Salamander occurs from the Great Lakes region in Ontario east through Quebec and all the Maritime provinces. They occur throughout the northeastern United States west to Minnesota and eastern Illinois and south to North Carolina.
Habitat
The Eastern Red-backed Salamander usually inhabits deciduous or mixed forests but may also be found in moist conifer forests. This species requires moist environments and is most common in mature forests with abundant woody debris and leaf litter. Individuals are typically absent or occur at low densities in forests with acidic soils and in hot, dry environments. This species is fully terrestrial and the eggs are deposited under logs, in rotting stumps or in other moist environments on the forest floor. Individuals overwinter below the frost line in mammal burrows, root hollows or other underground cavities.
Biology
Plethodontid salamanders, including the Eastern Red-backed Salamander, are also known as lungless salamanders because they do not have lungs; instead, they absorb oxygen directly through their skin. They must remain moist at all times so that oxygen and carbon dioxide can diffuse through the skin. Eastern Red-backed salamanders breed in the fall or spring and females lay an average of six to nine eggs in the late spring or early summer. The female guards the eggs until they hatch after six to eight weeks, usually in late August or September. There is no larval stage; the gills are absorbed around the time of hatching and the hatchlings are a miniature version of the terrestrial adults. Individuals reach sexual maturity in two years and females may only breed every second year at northern latitudes. The longevity of this species is unknown. Eastern Red-backed Salamanders are most active during wet weather and forage on the forest floor for insects, spiders, worms and other terrestrial invertebrates. Individuals communicate with each other though body posture and scent marking, and they establish and aggressively defend territories. When threatened, individuals may autotomize (drop) their tail, which creates a diversion while the salamander escapes. Although the tail will grow back over time, the individual will have lost much of the fat reserves on which it relies to survive the winter.
Threats
The Eastern Red-backed Salamander is widespread in Canada and remains abundant throughout most of its Canadian range. The primary threat to this species is the loss of mature forest, primarily through urbanization, clearing of land for agriculture and logging. 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. Earthworms, which are exotic to Canada, are also reducing the leaf litter in many forests and possibly causing declines in salamanders.