Worm snakes, belonging to the genus Carphophis, are small, secretive snakes found in the eastern and central United States. Often mistaken for earthworms due to their size and appearance, these fossorial creatures play a vital role in their ecosystems. This article delves into the diet and habitat preferences of worm snakes, with a particular focus on the eastern worm snake (Carphophis amoenus amoenus) and the western worm snake (Carphophis vermis).
General Description and Taxonomy
There are two recognized species of worm snakes: Carphophis amoenus and Carphophis vermis. Carphophis amoenus has two subspecies: Carphophis amoenus amoenus, the eastern worm snake, and Carphophis amoenus helenae, the midwestern worm snake. The eastern worm snake is found from Rhode Island, southwestern Massachusetts, and southeastern New York south to South Carolina, northern Georgia, and central Alabama. The two subspecies can be distinguished by the internasal and prefrontal scales, which are unfused in C. a. amoenus and fused in C. a. helanae.
Physical Characteristics
Worm snakes are small, slender snakes with smooth, glossy scales. They have a worm-like appearance, with a small, flattened head and tiny eyes. The tail is short and tipped with a hard point that aids in burrowing.
Eastern Worm Snake
The eastern worm snake (Carphophis amoenus amoenus) is typically brown to near black on its dorsal (upper) side, while its lower sides and belly are reddish-pink. Adults range from 7.5 to 15 inches (19-38 cm) in total length. The young are 3 to 5 inches (7.5 to 12.4 cm) in length.
Western Worm Snake
The western worm snake (Carphophis vermis) is uniformly black or very dark brown above and orange, red, or pink below. This ventral coloration extends to the first two to three rows of scales on the sides, creating the impression of stripes. Large adults can reach fifteen inches in snout to vent length, however, most individuals are smaller than that, usually about eight inches.
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Habitat and Distribution
Worm snakes are fossorial, meaning they spend most of their lives underground. They are typically found in moist habitats, usually in or near deciduous woodlands, but occasionally in gardens.
Eastern Worm Snake
The eastern worm snake's range extends from southwest Massachusetts, south to southern Alabama, west to Louisiana and north to Illinois. This species is common in the ecotone between woodlands and wetlands and may also be found in grasslands adjacent to woodlands. They prefer well-drained, sandy soils for burrowing and are typically found in moist habitats, usually in or near deciduous woodlands and occasionally in gardens. They can also be found in isolated wetlands in more xeric regions.
Western Worm Snake
Western wormsnakes live in wooded areas or rocky hillsides.
Diet and Feeding Habits
Worm snakes primarily feed on earthworms and other soft-bodied invertebrates. Their diet is restricted to elongated prey due to the small size of their mouths.
Eastern Worm Snake
The eastern worm snake's diet consists mainly of earthworms, but they may also consume soft-bodied insect larvae.
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Western Worm Snake
Western wormsnakes feed primarily on earthworms but may also eat other elongate invertebrates. Foods include earthworms, slugs, and some slender, soft-bodied insect larvae such as beetle grubs.
Behavior and Life Cycle
Worm snakes are secretive creatures that are rarely seen due to their fossorial lifestyle. They are most active in the late afternoon and early evening and generally remain inactive during extreme temperatures.
Activity and Movement
The annual activity period of the worm snake varies with latitude and elevation. Some have found them active in every month but February on the coastal plain of South Carolina. Farther north, the eastern worm snake is active from March-April to October-November. Few are active above ground in the summer, but a second, lesser period of activity occurs in the fall.
Reproduction
Courtship and mating probably occur in the spring; the sexes are most often found together between late April and June. Higher activity during September and October indicate possible fall breeding in Western North Carolina. Oviposition takes place between early June and mid-July. Eggs are laid in late June or early July, two to eight per clutch. Clutches are placed in depressions under rocks, in cavities in the rotting wood of logs and stumps, and in old sawdust piles. A female was nearby or with the eggs in 75% of the cases. The eggs are smooth and elongated, 16-25 mm (0.63-0.98 in) long by 7-8 mm (0.28-0.31 in) wide. Often, one end of an egg is wider than the other. Hatching occurs in August or early September.
Lifespan
Worm snakes generally have a lifespan of around 4 to 5 years, though this can vary depending on environmental conditions, predation and availability of resources.
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Conservation Status
In Massachusetts, eastern worm snakes are classified as threatened species; in New York, they are a species of special concern, meaning their populations are vulnerable to threats like habitat loss, fragmentation and environmental changes.
Threats
Predators of worm snakes include other snakes, thrushes, American robins, barn owls, and opossums. Occasionally, road traffic kills eastern worm snakes, and flooding of the lowlands and other natural disasters have been known to affect the population. Some die as a result of human habitat destruction and insecticide poisoning.
Conservation Efforts
Standardized survey protocols need to be developed and implemented at known and potential habitats in order to determine the character, quality, and full extent of the occupied habitat. Life history parameters of wormsnake populations need to be determined. To discourage snakes from entering buildings, make sure all cracks in the foundation are sealed. Basement windows should be closed tight or be covered with screens. If you wish to discourage snakes from your yard, remove the places where they can hide. Keep grass cut short, remove brush and rock piles, and keep shrubs trimmed up off the ground. The killing of this snake is strongly discouraged. Additionally, wild snakes should NEVER be collected as a pet.
Identifying Worm Snakes
Worm snakes can be distinguished from other small, unpatterned brownish snakes by their smooth scales, spine-tipped tail, and coloration.
Distinguishing from Similar Species
The eastern worm snake can be distinguished from the western worm snake by its less vibrant dorsal and ventral coloration and lack of ventral pigmentation on the third body scale row. Other small, unpatterned brownish snakes which may be confused with C. amoenus, such as earth snakes (genus Virginia) and red-bellied snakes (Storeria occipitomaculata), have keeled dorsal scales and lack the spine-tipped tail. The southeastern crown snake (Tantilla coronata) has 15 midbody scale rows, a dark head, and a dark collar.
The only species with which western worm snakes might be confused is the flat-headed snake. The flat-headed snake is much more common, is lighter in coloration on the dorsal surface, is much more streamlined in form, and the ventral pink coloration does not extend to the sides.
Interaction with Humans
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. When handled, C. amoenus may release a foul-smelling musk from their cloaca, defecate, attempt to burrow between the fingers, and probe the hand with the tail spine.