Tropidoclonion lineatum

Geographic Range

Lined snakes are found in the Great Plains states, with their range snake extending from southeastern South Dakota to Texas. Disjoint populations also occur in New Mexico, eastern Colorado, southeast Iowa, and central Illinois. There are four recognized subspecies of lined snake. These include the central lined snake Tropidoclonion lineatum annectens , northern lined snake Tropidoclonion lineatum lineatum , Merten's lined snake Tropidoclonion lineatum mertensi , and the Texas lined snake Tropidoclonion lineatum texanum .

• Biogeographic Regions
• nearctic nearctic
  • native native

Habitat

Lined snakes are found in a variety of habitats, including open prairies, the edges of woodlands and sparsely wooded areas, vacant lots, and residential areas. They hibernate during winter months in the crevices of rocky outcroppings. Individuals have been found to hibernate at a depth of 6 to 8 inches.

• Habitat Regions
• temperate temperate
• terrestrial terrestrial

• Terrestrial Biomes
• savanna or grassland savanna or grassland
• forest forest

• Other Habitat Features
• suburban suburban

Physical Description

This species is a relatively small and slender. The head is small, barely wider than the body. Adults range in size from 22 to 38 cm (8.7 to 15 inches). A variety of body colorations are present, from olive- to gray-brown. Down the middle of the back, there is a light stripe that varies in color from white to orange. There are two additional stripes along the sides. The ventral belly scales are white, with two rows of black, half moon-shaped scales down the center.

Western ribbon snakes ( Thamnophis proximus proximus ) resemble lined snakes, and show significant overlap in their geographical distribution. However, ribbon snakes lack the double row of black half-moon scales on their belly. Lined snakes are distinguished from crayfish snake species (genus Regina ), whose color pattern also shows some resemblance, by having keeled dorsal scales and an undivided anal plate.

• Other Physical Features
• heterothermic heterothermic

• Sexual Dimorphism
• sexes alike

Development

Young are born fully formed, resembling smaller versions of adults. Like most snakes, they grow throughout their entire lives.

• Development - Life Cycle
• indeterminate growth indeterminate growth

Reproduction

Little is known regarding the specifics of mating systems in lined snakes. In related species of the genus Thamnophis , females become unattractive to sexually active males for at least 48 hours following copulation, due to the secretion and insertion of a mating plug by the previous male. This inhibition of courtship behavior minimizes the probability of multiple inseminations of his female mate. Extracts from female Thamnophis species act as pheremones, and will elicit courtship behavior from males, even when applied to other male individuals.

• Mating System
• polygynandrous (promiscuous) polygynandrous (promiscuous)

Female lined snakes reach sexual maturity at an age of 2 years. At this point, females may produce eggs which develop inside the body. Lined snakes breed in the fall, but fertilization is delayed until the spring, with birth occurring in August. The live young are independent at birth.

• Key Reproductive Features
• iteroparous iteroparous
• seasonal breeding seasonal breeding
• sexual sexual
• fertilization fertilization
• viviparous viviparous
• sperm-storing sperm-storing
• delayed fertilization delayed fertilization

As a viviparous species, a female lined snake provides nutrients and protection to her offspring as they develop inside her body. The young are born fully independent, and no post-birth parental investment occurs.

• Parental Investment
• female parental care female parental care
• pre-fertilization
  • provisioning
  • protecting
    • female
• pre-hatching/birth
  • provisioning
    • female
  • protecting
    • female

Lifespan/Longevity

There are several major factors that limit the lifespan of lined snakes. They are highly susceptible to mortality on busy roads, as well as from the loss of preferred habitat due to agricultural cultivation, livestock grazing, and residential or commercial development. Lifespan information for this species could not be found. Average lifespan in the closely related genus Thamnophis is between 3 to 10 years.

Behavior

Lined snakes are active from March to November. They overwinter in rock crevices and animal burrows that are located below the frost line. After hibernation, they emerge in March or April. They spend the most time at the surface during the cooler spring months (especially after heavy rains), spending more time in their dens during the hot summer months. These snakes are primarily nocturnal, although they may bask during the day in early spring and late fall when temperatures are not too high. They are often solitary, but it is not uncommon to find several snakes together. If these snakes are left undisturbed by humans they will make no effort to escape but if molested, they will thrash and exude musk. One case of cannibalism has been documented in captive individuals.

• Key Behaviors
• terricolous
• nocturnal nocturnal
• sedentary sedentary
• hibernation hibernation
• solitary solitary

Home Range

Information regarding the home range of lined snakes is not currently available. The summer home range of garter snakes ( Thamnophis ) averages 1,500 m^2, while the winter home range averages 3,400 m^2. However, this information came from populations in California, where lined snakes do not occur, and its applicability to this species is thus questionable. This is particularly true in the case of winter ranges, as this species hibernates during these months.

Communication and Perception

Snakes perceive their environment through a number of sensory channels, primarily relying upon sight, ground vibrations, taste, and smell. Female snakes release pheromones that elicit male courtship behavior. Males secrete a mating plug that is produced from their renal sex segment, and is able to be sensed by other males, inhibiting their courtship behaviors and minimizing the probability of multiple inseminations of mated females.

• Communication Channels
• visual visual
• chemical chemical

• Other Communication Modes
• pheromones pheromones

• Perception Channels
• visual visual
• tactile tactile
• vibrations vibrations
• chemical chemical

Food Habits

Lined snakes mainly feed on earthworms ( Lumbricus terrestris ). They usually forage at night or after a rainstorm, when earthworms are most active. Their secondary diet has also been recorded to include sow bugs ( Oniscus asellus ), snails ( Helix aspersa ), slugs, and soft-bodied insects.

• Primary Diet
• carnivore carnivore
  • vermivore

• Animal Foods
• terrestrial non-insect arthropods
• mollusks
• terrestrial worms

Predation

Lined snakes are preyed upon by carnivorous mammals and a variety of birds. This species possesses cryptic coloration as an anti-predator adaptation and is also very secretive, hiding under various surfaces, which further helps to reduce predation.

• Anti-predator Adaptations
• cryptic cryptic

Ecosystem Roles

Lined snakes are both predators and prey in their ecosystems.

Economic Importance for Humans: Positive

Lined snakes have little economic importance to humans, although similar species (i.e. garter snakes) are popular in the pet trade.

• Positive Impacts
• pet trade pet trade

Economic Importance for Humans: Negative

Lined snakes have been forced out of their preferred habitat in some areas, being pushed into residential and commercial areas. While they could possibly bite, they are non-venomous and the bite would have no lasting affect on a human, barring any allergies to the snake's saliva.

• Negative Impacts
• injures humans
  • bites or stings

Conservation Status

Although they are susceptible to mortality on busy roads and face habitat loss in some areas, populations of this species throughout its range appear to be stable, and it is not currently listed as threatened or endangered by any regulatory body.

Additional Links

Encyclopedia of Life

BioKIDS Critter Catalog

Contributors

Keri O'Keefe (author), Minnesota State University, Mankato, Robert Sorensen (editor), Minnesota State University, Mankato, Jeremy Wright (editor), University of Michigan-Ann Arbor, Catherine Kent (editor), Special Projects.

References

Conant, R., J. Collins. 1991. A Field Guide to Reptiles and Amphibians of Eastern and Central North America. Third Edition, Expanded . New York, NY: Houghton Mifflin Company.

Force, E. 1931. Habits and Birth of Young of the Lined Snake, Tropidoclonion lineatum. Copeia , 2: 51-53.

Garstka, W. 1981. Female sex pheromone in the skin and circulation of garter snake. Science , 214: 681-683.

Kaplan, M. 2009. "HerpCare Collection" (On-line). Garter Snakes: an overview of their natural history and care in captivity. Accessed April 26, 2011 at http://www.anapsid.org/gartcare.html .

LeClere, J. 2011. "Amphibians and Reptiles of Minnesota" (On-line). Lined Snake-Tropidoclonion lineatum. Accessed April 04, 2011 at http://www.herpnet.net/Minnesota-Herpetology/ .

MacRae, M. 2008. "Canadian Wildlife Federation" (On-line). Common Garter Snake. Accessed April 26, 2011 at http://www.wildaboutgardening.org/en/gardening-for-wildlife/search?page=2 .

Ramsey, L. 1953. The Lined Snake, Tropidoclonion lineatum. Herpetologica , 9: 7-24.

Ross, P. 1978. Stimuli Influencing Mating Behavior in the Garter Snake, Thamnophis radix. Behavioral Ecology and Sociobiology , 4: 133-142.

Smith, H. 1965. Two New Colubrid Snakes from the United States and Mexico. Journal of the Ohio Herpetological Soceity , 5: 1-4.

Zeiner, D. 1990. Life history accounts for species in the California Wildlife habitat relationships. California's Wildlife , 1: 1-3.

2011. "MN Department of Natural Resources" (On-line). Tropidoclonion lineatum. Accessed April 03, 2011 at http://www.dnr.state.mn.us/index.html .

United States Geological Survey. 2006. "Northern Prairie Wildlife Research Center" (On-line). Fragile legacy: Endangered, Threatened, and Rare Animals of South Dakota. Accessed April 03, 2011 at http://www.npwrc.usgs.gov/resource/ .

Illinois Natural History Survey. Tropidoclonion lineatum -- Lined Snake. 2009. Urbana-Champaign: University of Illinois. 2009. Accessed April 03, 2011 at http://www.inhs.illinois.edu/animals_plants/herps/species/tr_lineatu.html .