Eastern red-backed salamander
General Description
Plethodontidae is the family that the eastern red-backed salamanders are classified in, as they are lungless. Oxygen dissolves into the moisture on their skin and then the oxygen is absorbed into the skin. It is vital for them to maintain their moisture, without it they cannot breathe. It should also be noted that one should not physically handle a salamander for long period of time as they can lose that moisture.
These salamanders come in two different color phases, the first being the lead-back, and the other being the red-back. The red-backed phase is the usual coloring of reddish orange along the back. Lead-backs have a dark grey to black coloring over their body and are much less commonly found. Adults will reach about 2-5 inches in length.
Geographic Distribution & Habitat
The Eastern red-backed salamander can be found all the way south to North Carolina, westward to Ohio and northward into New England through Nova Scotia. There are a variety of forest types where they can be found, ranging from deciduous to coniferous. The species of this species prefers moist soils, and will usually avoid dry, sandy soils and floodplains. During the cooler months, namely October to March, they tend to move underground. [1] The Eastern red-backed salamander is more likely to be found in areas containing neutral or basic soils rather than areas containing high acidity. Like most salamanders, they are typically found hidden under logs, leaf litter, and rocks during the day as they are most active at night. [3]
Ecology
Their importance in the soil ecosystem is particularly important in the context of the fungi community. Fungi contribute to the nutrient cycling of forests, and without them the organic matter would not decompose as rapidly. Invertebrates including mites, beetles, centipedes, and snails take advantage of fungus as a source of nutrition. The eastern red-backed salamander maintains a balance as a result of feeding on the insects and thus controlling their populations [2]. The Eastern red-backed salamander not only indirectly influences the total amount of fungus in the habitat, but also its diversity.
According to the study conducted by Jaeger et al. (2002), one square kilometer can be home to more than three million eastern red-backed salamanders. The populations of their species are estimated to outnumber all birds and mammals in the specific regions, making them the most populous vertebrates in the north-eastern forests [2]. They are most commonly preyed upon by larger salamanders, birds, snakes, and mammals [1]. To escape said predators, they can detach their tail, which wiggles in a way that serves as a distraction, allowing them to flee. Once escaping the predator, the salamander will then regrow a new tail over time [1]. The eastern red-backed salamander responds well to habitat disturbance as long as the key components are maintained (e.g., leaf litter, fallen logs, and rocks) [1].
Reproduction & Growth
Mating season for eastern red-backs begins in sometime between October through December. Males will follow the pheromone trails left by the females. The courtship initiates with the male rubbing his head on the female's snout. After the rubbing has ceased the male then deposits the spermatophore and the female retrieves it with her cloaca.
A very large amount of energy is required for the females to produce their eggs, so it is thought that they only breed once every other year. She lays her eggs sometime in the summer, they prefer a nesting site underground or in moist log. Most amphibians will leave their eggs after they have been laid but the female salamander remains with them until hatching occurs. Since dehydration of eggs can occur easily she will wrap herself around them to ensure they stay moist, she will only eat when opportunity presents itself. [2]. After two months of careful monitoring by the mother, the hatchlings emerge in August or September. Once hatched, these young remain with their mother for a few weeks before going out on their own as their is no aquatic larval stage for this species [2] Maturity is reached in approximately two years and females usually lay their first clutch at three years old.
References
[1] Harding, J. & Mifsud, D. "Amphibians & Reptiles of the Great Lakes Region". University of Michigan Press, 2017. pg 91-95
[2] Clark,E. "Essential ubiquity: "How one tiny salamander species has a huge impact" Mongabay Series: Salamanders, 21 December 2018
[3] AmphibiaWeb. 2021. <https://amphibiaweb.org> University of California, Berkeley, CA, USA.
[4] Eastern red-backed salamander photographed by Larry Clarfeld on April 26th, 2018 from iNaturalist
[5] Robert G. Jaeger, Jennifer R. Gillette, Robert C. Cooper, Sexual coercion in a territorial salamander: males punish socially polyandrous female partners, Animal Behavior, Volume 63, Issue 5, 2002, Pages 871-877, doi:10.1006/anbe.2001.1977.
[6] Female eastern red-backed salamander guarding her eggs, photograph from https://www.amphibianfact.com/red-backed-salamander.asp
[7] Distribution map from Harding, J. & Mifsud, D. "Amphibians & Reptiles of the Great Lakes Region". University of Michigan Press, 2017. pg 92