Comprehensive DescriptionRead full entry
Plethodon cinereus is a small terrestrial salamander that is widespread across a large part of eastern North America and which can be an extremely abundant inhabitant of forest floors. It is known as the Eastern Red-Backed salamander because many individuals exhibit a finely mottled grey coloration, trending towards black towards the dorsum, but with a striking dorsal stripe that is typically red. However, many other individuals, often from the same population will lack this stripe (lead-backed phase). Additionally, other color patterns can occur, such as yellowish or grey dorsal stripes, or red over the entire body (e.g. Tilley et al 1982). During the day these salamanders can be found in moist locations beneath objects such as rocks and logs, within rotting logs, under leaf litter, and within soil (e.g. Ransom 2012), with individuals often emerging to the surface and even climbing vegetation at night during appropriate weather (Jaegar 1978, 1980). Reproduction occurs with clutches of eggs being laid in cavities during the early summer, and the female remaining with her eggs until hatching perhaps two months later (see Tornick 2010). This species can be active throughout the year, although they tend to avoid dry conditions, and may be less active during the summer (see Grasser and Smith 2014).
Studies of behavior have found some notable phenomena. For example, both male and female P. cinereus can show territorial behavior during breeding and non-breeding seasons, that can include unusual (for amphibians) behavior such as joint territorial defense by socially monogamous pairs during the breeding season (e.g. see Kohn et al., 2013). This social monogamy is also associated with unusual behaviors such as punishment of cheating (Jaeger et al., 2002). Females subsequently defend and maintain their egg clutches, and can remain with young for some time after hatching (e.g. see Leiebgold and Cabe 2008; Tornick 2010).
This species has also been well studied ecologically. Under appropriate conditions P. cinereus can be a very large component of the vertebrate community in terms of the number of individuals and biomass (e.g. Hairston 1996). As such they have significant ecological roles such as predators of small arthropods, and as a food source for many other animals. However, in some locations populations have declined, due notably to forest removal (Alford and Richards 1999), and perhaps more subtle phenomena such as a reduction in leaf litter and invertebrate prey by exotic earthworms (Maerz et al 2009). Several studies have also looked at the role of environmental acidity on this species (e.g. Moore and Wyman 2010).
The skin of P. cinereus hosts bacteria that convey protection from chytrid fungal infections (Becker and Harris 2010).