The four-toed salamander averages three to four inches in length. It has four toes on each hind foot, and four toes on each front foot (most salamanders have five toes on each hind foot). A constriction at the base of the tail allows the salamander to break free of the tail. The tail will regenerate but will not grow as long as it was previously. A distinct impressed line is present in the middle of the back from the tail to the top of the head. The belly is white with black blotches. The body is yellow-brown or red-brown.
The four-toed salamander lives in association with sphagnum, particularly around peatlands. The adult four-toed salamander is terrestrial while the larva is aquatic. The adult may drop its tail when disturbed. Breeding occurs in late summer and fall, but eggs are not deposited until spring. The female deposits about 30 eggs in a cluster near water. Several females may deposit eggs in the same nest. The female stays with the eggs until they hatch, about one to two months. Newly hatched larvae wriggle to reach the water. Transformation to the land-based adult occurs about six weeks after hatching. The four-toed salamander eats insects and other small invertebrates.