Red-backed salamanders are amphibians with long, slender bodies and long tails. They have two color phases. In the "redback" phase they have a gray or black body with a straight-edged red or orange stripe down the back, extending from the neck to the tail. When they are in the "leadback" phase they lack the red stripe, and have a purely black or grey back instead. Their bellies are a mottled white and gray in both phases, creating a salt and pepper pattern. Red-backed salamanders have 16 to 19 grooves on their sides. They have no circular constriction at the base of their tails, and they have five toes on their hind feet and four toes on their front feet. Males and females look the same.
Red-backed salamanders are native to the Nearctic region only. They live in Eastern North America. Their range extends west to Missouri; south to North Carolina; and north from southern Quebec and the Maritime Provinces in Canada to Minnesota. They are most common in areas of appropriate habitat throughout the midwestern United States.
Red-backed salamanders are found in deciduous forests throughout their range. They live in fallen leaves as well as under rocks, logs, or in small burrows. Red-backed salamanders do not have lungs so they breathe through their skin instead. They must live in a wet environment to keep their skin damp enough to breathe. Another factor that effects these salamanders is soil pH. Like many other amphibians, salamanders can be hurt by high levels of acidity. Red-backed salamanders respond the same way to acidic surroundings as amphibian larvae do when exposed to acidic water, their sodium balance is disrupted. They are rarely found on soils with a pH of 3.7 or lower.
Red-backed salamanders lay eggs that develop directly into small salamanders. They do not have an aquatic larva stage, such as is found in other salamanders and most amphibians.
While there is little information on lifespan in red-backed salamanders, other salamanders in this family (Plethodontidae) can live for up to 32 years and the average lifespan is 10 years. There is no reason to expect that red-backed salamanders can't also reach these ages.
Red-backed salamanders are active during both day and night, depending on weather conditions. They are relatively solitary and defend small territories in which they feed.
Red-backed Salamanders protect their limited food supply by marking out territories. This behavior occurs most often when moisture levels are low and the salamanders have to hide under logs or rocks. Both males and females leave scent marks on the ground as well as leaving their droppings. Other salamanders can learn a lot from these clues. They learn each others territorial boundaries, the size and importance of the salamanders that live in the area, and their identity, including whether or not they are related. When finding food is very hard due to dry conditions, adults who have their own territories will sometimes allow young salamanders that are related to them to use their territories. Intruders are also warned away by seeing the size of the salamander and watching it give threatening displays.
Red-backed salamanders feed on a large variety of invertebrates. These include mites, spiders, insects, centipedes, millipedes, beetles, snails, ants, earthworms, flies, and larvae. They forage by thrusting out their tongue in a quick, forward motion to capture their prey. Their environment determines what kind of food is available and how they go about getting it. During and shortly after it rains is the best time for red-backed salamanders to emerge and forage for food because all the leaves and plants on the ground are wet. The salamanders wander throughout the leaves on the ground during the day and climb plants and trees at night to find food. When everything begins to dry off they can only look for food in the leaves on the ground, and as it gets even drier they can eventually only forage in areas under rocks or logs or in burrows that will stay wet for a long time. There is less food under logs and rocks and in burrows, and the supply is sometimes low. Red-backed salamanders can survive these times with little food because they are pulse feeders, which means they eat large amounts when conditions are good and store the extra nourishment as fat to live off of when conditions are bad.
Red-backed salamanders make up an important food source for a wide variety of snakes, birds, and mammals. They have the ability to drop all or part of their tail if under attack from a predator and can grow a new one afterwards. The tail that grows back is often lighter in color than the original tail.
Red-backed salamanders play an important biological role in both providing food for their predators as well as consuming large numbers of invertebrates.
Red-backed salamanders may help control pest populations where they occur in high numbers.
Red-backed salamanders are common throughout most their range. In the future, however, they could be effected by high levels of acid in the soil caused by human-induced factors like acid rain.
Craig Howard (author), University of Michigan-Ann Arbor.
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