Although red-backed salamanders (Plethodon cinereus) exhibit color polymorphism, the color variation that is most common in eastern Massachusetts is true to their name. Here you will likely find individuals with a red, or at least reddish, colored dorsal band running down their midline from the head to the tail (the alternative color variation is sometimes referred to as the “lead-backed” form and is darker in coloration, lacking most or all of the distinctive red pigmentation). The sides of their bodies are dark gray or black, becoming lighter and mottled toward the belly. These fairly slender salamanders are approximately 3 inches long, and have small, short legs. In the red-backed form, these salamanders may avoid predation by mimicking the terrestrial red eft stage of the red-spotted newt, which is toxic. This likely explains the difference in predator response between the two color morphs: the lead-backed phase tends to run away, while the red-backed phase is more likely to remain immobile, relying on its coloration to deter predators.

 

Red-backed salamanders can be found beneath old logs, bark, moss, leaf mold, and stones in moist evergreen, mixed, and deciduous forests, where they feed on insects, such as ants, termites and mites in the leaf litter. In fact, that’s exactly how I found the ones pictured here – I turned over a couple old logs while walking through the Herb Hadfield Conservation Area in Westport on Sunday. In the early spring, small groups (2 to 7 individuals) can be found together under rocks and logs. Mating occurs in the spring and eggs are laid in June and July. As is the case for all members of the genus Plethodon, red-backed salamanders lay their eggs in terrestrial cavities where they will be guarded by the female until they hatch 6 to 9 weeks later.

 

Red-backed salamanders are extremely common throughout their range, and in some locations represent the highest biomass of vertebrates (exceeding that of all the birds and mammals in an area). Its range extends from Quebec to Minnesota, south to Missouri and North Carolina.