The western wormsnake is a small two-toned snake that lives in wooded areas or rocky hillsides. Its dorsal (upperside) color is purple brown to black; the ventral side (underside) is unmarked with a salmon-pink color extending up the sides. The head is flattened to aid in burrowing. The tail terminates in a harmless spike that also aids in maneuvering through soil. The western wormsnake has smooth scales and a divided anal plate (the anal plate is the last belly scale of a snake, which covers the anal opening). Wormsnakes have a pair of enlarged teeth at the rear of their mouth that are presumed to help with swallowing earthworms and other prey.
Males have longer tails than females, and they normally have keels or ridges on the dorsal scales above the anal plate.
Newly hatched western wormsnakes are only 3½ to 4 inches long; they have a purplish-black dorsum, and the ventral surface is orange red to pink.
Similar species: This small snake is Missouri's only snake that has the clearly contrasting purplish brown above and salmon pink on the belly and lower sides, and is otherwise unpatterned (no stripes, spots, rings, bands, or blotches).
Adult total length: 7½ to 11 inches; occasionally to 15½ inches. Adult males are smaller than females.
Statewide, except for the extreme southeastern corner of the state.
Habitat and Conservation
Western wormsnakes are small, secretive, and seldom seen. They rarely venture out in the open. Instead, they spend most of their time in burrows underground, under thick leaf litter, or beneath large rocks or logs.
The western wormsnake is considered a forest or forest-edge species. They are most often encountered on rocky, forested hillsides and on rocky, open glades, especially in the spring and fall. Within these larger habitats, they require slightly moist places, so they live in thick leaf litter and under rocks or rotting logs on the forest floor. Specimens have been found in deep leaf litter that had accumulated in shaded, steep-sided forest ravines. Even old trash embedded in the soil can harbor western wormsnakes.
In Missouri, they are active between March and October. However, they become inactive during hot, dry summers and burrow down into the soil to estivate. These small snakes are not known to bask in the sun on the surface. Instead, western wormsnakes burrow under rocks exposed to the sun and become warm when the rock is heated by the morning sun.
Individuals mainly overwinter in small rodent burrows, in crevices among large rocks, or under rotting logs and stumps. A few western wormsnakes have been documented overwintering in a cave in Jefferson County.
Foods include earthworms, slugs, and some slender, soft-bodied insect larvae such as beetle grubs. Western wormsnakes have also been reported eating young prairie ring-necked snakes.
Breeding occurs in the spring and possibly also in fall. Eggs are laid in a burrow under a rock or inside a rotting stump or log during June and early July. These burrows may be about 8 inches below the surface. About 1–6 eggs are laid, though the largest females may produce up to about 12 in a clutch. There is probably only one clutch per season. Hatching normally occurs between the middle of August and the middle of September.
Males become sexually mature at age 2, females at age 3. The females have been known to live for up to 10 years.
This common, harmless, burrowing snake has never been known to bite. When handled, a wormsnake is difficult to hold because of its smooth scales. Also, it attempts to escape by trying to work its head through one’s fingers. It will also press its sharp but harmless tail against the skin: poke, poke, poke.
As predators, wormsnakes help to keep worm and insect populations in check.
Animals that burrow into the soil create openings for water and surface nutrients to penetrate into the ground. This contributes to soil health, benefiting plants, animals, and the entire natural community.
Being small and relatively defenseless, wormsnakes are preyed upon by larger predators, which helps explain their secretive habits. Their natural predators include kingsnakes and milksnakes, and predatory mammals such as moles and shrews.
Opossums have been reported to prey on western wormsnakes. It's worth nothing that although the remains of wormsnakes have been found in the stomachs of many opossums (particularly in springtime), opossums are known to consume dead wildlife on roads and highways. It's possible that in many of these cases, the opossums had been eating the snakes as road carrion, and not capturing them alive.