Thamnophis butleriButler's Garter Snake

Geographic Range

Butler's garter snakes are found in the southern Great Lakes region and into Indiana and Illinois. There are isolated populations in southern Wisconsin and southern Ontario. Throughout its range, Butler's garter snakes are often found in isolated populations as their preferred habitats are increasingly fragmented by human habitat destruction. (Behler and King, 2000; Conant and Collins, 1998; Harding, 1997; Holman, et al., 1999)

Habitat

Butler's garter snakes prefer wet meadows and prairies. They are often found near marshy ponds and lake borders. These kinds of habitats sometimes occur in suburban and urban areas and relatively large concentrations of Butler's garter snakes can be found in those areas. Specific habitat preferences may help to reduce competition with their close relatives, eastern garter snakes and northern ribbon snakes. (Behler and King, 2000; Conant and Collins, 1998; Environment Canada, 2002; Harding, 1997; Holman, et al., 1999; "Adopt-A-Pond", 2002)

  • Aquatic Biomes
  • lakes and ponds
  • rivers and streams

Physical Description

Butler's garter snakes are small, stout garter snakes with three well-defined yellow or orange stripes that run along the length of their body on a background color of black, brown, or olive. They sometimes have two rows of dark spots running between their central stripe and the two side stripes. Their head is relatively narrow, not much wider than their body, and their scales are keeled (with a ridge along the length of the scale). Their belly color is pale green or yellow with black spots running along the edges. Adults reach a total length of from 38 to 73.7 cm. There are 19 scale rows total and the anal plate is single.

Male snakes are slightly smaller than females, and have slightly longer tails. Young Butler's garter snakes are born at from 12.5 to 18.5 cm.

Other garter snakes have somewhat longer and larger heads than do Butler's garter snakes. Other sympatric garter snake species can be distinguished from Butler's garter snakes by the position of the lateral (side) stripes relative to the dorsal scale rows. One must count the scale rows from the ventral scales to the dorsal scale row and note on which row of scales the stripes occur. In Butler's garter snakes, the stripe is found on the third scale row, and also runs partially onto the upper part of the second row of scales and the lower part of the fourth scale row. In contrast, eastern garter snakes have stripes confined to scale rows 2 and 3. Often, juveniles are more distinctly marked than adults. (Behler and King, 2000; Conant and Collins, 1998; Environment Canada, 2002; Holman, et al., 1999; "Adopt-A-Pond", 2002)

  • Sexual Dimorphism
  • female larger
  • sexes shaped differently
  • Range length
    38 to 73.7 cm
    14.96 to 29.02 in
  • Average length
    45 cm
    17.72 in

Reproduction

Butler's garter snakes breed each year as they emerge from winter hibernation sites. Rising air temperatures prompt males to begin courting females. Female Butler's garter snakes are capable of storing sperm from previous matings (perhaps occurring in the fall) and using that sperm in the spring. (Harding, 1997; Holman, et al., 1999)

Butler's garter snakes are ovoviviparous. Eggs are fertilized within the female's body and develop and hatch within her.

Butler's garter snakes mate at their hibernation sites in the spring, before they leave for their summer feeding areas. Females give birth in mid to late summer to from 4 to 20 live young. Larger females and those that are better nourished produce more young per litter. The young snakes grow rapidly and may become mature in their second or third spring. They continue to grow throughout their lives. (Behler and King, 2000; Conant and Collins, 1998; Environment Canada, 2002; Holman, et al., 1999; "Adopt-A-Pond", 2002)

  • Breeding interval
    Butler's garter snakes breed once yearly.
  • Breeding season
    Butler's garter snakes breed in the spring (March to April).
  • Range number of offspring
    4 to 20
  • Average number of offspring
    12
    AnAge
  • Average age at sexual or reproductive maturity (female)
    2-3 years
  • Average age at sexual or reproductive maturity (female)
    Sex: female
    730 days
    AnAge
  • Average age at sexual or reproductive maturity (male)
    2-3 years

Female Butler's garter snakes nurture their young inside their bodies until they are born. Once the young are born there is no further parental care. (Behler and King, 2000; Conant and Collins, 1998; Holman, et al., 1999)

  • Parental Investment
  • no parental involvement
  • pre-fertilization
    • protecting
      • female
  • pre-hatching/birth
    • provisioning
      • female
    • protecting
      • female

Lifespan/Longevity

The potential lifespan of Butler's garter snakes is unknown. The highest recorded lifespan in captivity is 14 years, average captive lifespans range from 6 to 10 years. Most wild individuals probably do not live as long as this due to predation and environmental stresses (Behler and King, 2000; Conant and Collins, 1998; Holman, et al., 1999)

  • Range lifespan
    Status: captivity
    14 (high) years
  • Typical lifespan
    Status: captivity
    6 to 10 years

Behavior

Butler's garter snakes are active generally from late March to October or November of each year. They are most often seen in spring and fall and may become nocturnal during the summer months. They retreat to underground hibernation sites during cold weather, often in rodent or crayfish burrows or in natural cavities or under rock piles. These are secretive snakes and they are mainly active underground. Butler's garter snakes are mostly solitary, though they congregate at hibernation sites. They may occupy hibernation sites with eastern garter snakes as well.

Butler's garter snakes, like all snakes, are ectothermic and must maintain their body temperature by choosing different microhabitats for periods of time. They may be seen sunning themselves on rocks or bare ground, especially when they are digesting. They seek shelter in order to cool body temperatures. ("Stimulus Control of Antipredator Behavior in Newborn and Juvenile Garter Snakes", 1989; Behler and King, 2000; Conant and Collins, 1998; Harding, 1997; Holman, et al., 1999)

These are docile and shy animals. They most readily flee when approached and are not easily provoked to bite. (Harding, 1997)

  • Range territory size
    30 to 270 m^2

Communication and Perception

All snakes have evolved special ways in which they perceive their environments. Their senses of taste and smell are combined by the use of a special organ, called the Jacobson's organ. This organ is composed of two specialized sensory pits located on the roof of the snakes' mouth. By flicking their tongues in and out rapidly, the snake transfers molecules from the air, as well as from things it may actually touch with its tongue, to the Jacobson's organ. This specialized sense is the way snakes gather and analyze most of the information from their environment. (Behler and King, 2000; Conant and Collins, 1998; Holman, et al., 1999)

Snakes are also highly tactile and sensitive to vibrations. Snakes have only an inner ear and they can probably detect low-frequency sounds. (Behler and King, 2000; Conant and Collins, 1998; Holman, et al., 1999; "Adopt-A-Pond", 2002)

Compared to other snakes, garter snakes have relatively good vision. However, vision is not the primary way that they perceive their environment. (Behler and King, 2000; Conant and Collins, 1998; Holman, et al., 1999)

Garter snakes primarily communicate with each other through pheromones, which act to stimulate reproduction. Touch may play a role as well.

Food Habits

Butler's garter snakes eat mostly earthworms. They will also eat leeches, small frogs, and salamanders. (Behler and King, 2000; Conant and Collins, 1998; Environment Canada, 2002; Harding, 1997; Holman, et al., 1999)

  • Animal Foods
  • amphibians
  • fish
  • mollusks
  • terrestrial worms

Predation

Butler's garter snakes are preyed upon by most predators throughout their range, including milk snakes, American crows, hawks, owls, raccoons, skunks, weasels, shrews, foxes, and domestic cats. They escape predation by attempting to escape. If harassed, though, they will exude a foul-smelling substance. If they are suddenly surprised they will thrash their bodies violently from side to side, perhaps to confuse predators and startle them in turn. (Harding, 1997)

  • Anti-predator Adaptations
  • cryptic

Ecosystem Roles

Butler's garter snakes help to control populations of earthworms, leeches, and slugs. They also act as important food sources for their predators where they are abundant. They are parasitized by certain species of trematodes. (Behler and King, 2000; Conant and Collins, 1998; Holman, et al., 1999)

Economic Importance for Humans: Positive

Butler's garter snakes occupy an important ecological niche within their geographic range. They help control the population of earthworms, leeches, and slugs which often makes them a friend to gardeners. (Behler and King, 2000; Conant and Collins, 1998; Environment Canada, 2002; Holman, et al., 1999; "Adopt-A-Pond", 2002)

  • Positive Impacts
  • controls pest population

Economic Importance for Humans: Negative

There are no known adverse affects of Butler's garter snakes on humans. (Behler and King, 2000; Conant and Collins, 1998; Holman, et al., 1999)

Conservation Status

Butler's garter snakes are much less common than their larger relatives, common garter snakes. They are easily disturbed by habitat destruction and other human modifications of their habitats. The wet meadow habitats that they prefer have been largely eliminated and are still being developed at a rapid pace. Large colonies may survive in small pockets of habitat, even in abandoned urban lots, but these colonies can be eliminated in one afternoon when the land is bulldozed. They are listed as endangered in Indiana. (Behler and King, 2000; Conant and Collins, 1998; Environment Canada, 2002; Holman, et al., 1999; "Adopt-A-Pond", 2002)

Other Comments

Butler's garter snakes were named after early Indiana naturalist Amos Butler. The scientific name comes from Greek 'thamn', meaning shrub or bush, and 'ophis,' meaning snake. (Conant and Collins, 1998; Holman, et al., 1999)

Contributors

Tanya Dewey (author), Animal Diversity Web.

Jennifer Loup (author), University of Michigan-Ann Arbor, Phil Myers (editor), Museum of Zoology, University of Michigan-Ann Arbor.

Glossary

Nearctic

living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

World Map

acoustic

uses sound to communicate

agricultural

living in landscapes dominated by human agriculture.

carnivore

an animal that mainly eats meat

chemical

uses smells or other chemicals to communicate

crepuscular

active at dawn and dusk

cryptic

having markings, coloration, shapes, or other features that cause an animal to be camouflaged in its natural environment; being difficult to see or otherwise detect.

diurnal
  1. active during the day, 2. lasting for one day.
heterothermic

having a body temperature that fluctuates with that of the immediate environment; having no mechanism or a poorly developed mechanism for regulating internal body temperature.

hibernation

the state that some animals enter during winter in which normal physiological processes are significantly reduced, thus lowering the animal's energy requirements. The act or condition of passing winter in a torpid or resting state, typically involving the abandonment of homoiothermy in mammals.

infrared/heat

(as keyword in perception channel section) This animal has a special ability to detect heat from other organisms in its environment.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

marsh

marshes are wetland areas often dominated by grasses and reeds.

natatorial

specialized for swimming

nocturnal

active during the night

ovoviviparous

reproduction in which eggs develop within the maternal body without additional nourishment from the parent and hatch within the parent or immediately after laying.

pheromones

chemicals released into air or water that are detected by and responded to by other animals of the same species

polygynandrous

the kind of polygamy in which a female pairs with several males, each of which also pairs with several different females.

riparian

Referring to something living or located adjacent to a waterbody (usually, but not always, a river or stream).

scent marks

communicates by producing scents from special gland(s) and placing them on a surface whether others can smell or taste them

scrub forest

scrub forests develop in areas that experience dry seasons.

seasonal breeding

breeding is confined to a particular season

sedentary

remains in the same area

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

solitary

lives alone

sperm-storing

mature spermatozoa are stored by females following copulation. Male sperm storage also occurs, as sperm are retained in the male epididymes (in mammals) for a period that can, in some cases, extend over several weeks or more, but here we use the term to refer only to sperm storage by females.

suburban

living in residential areas on the outskirts of large cities or towns.

swamp

a wetland area that may be permanently or intermittently covered in water, often dominated by woody vegetation.

tactile

uses touch to communicate

temperate

that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).

terrestrial

Living on the ground.

tropical savanna and grassland

A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.

savanna

A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.

temperate grassland

A terrestrial biome found in temperate latitudes (>23.5? N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.

urban

living in cities and large towns, landscapes dominated by human structures and activity.

vibrations

movements of a hard surface that are produced by animals as signals to others

visual

uses sight to communicate

References

Toronto Zoo. 2002. "Adopt-A-Pond" (On-line ). Toronto Zoo. Accessed 03/21/02 at www.torontozoo.com/adoptapond/guide/butlergartersnake.html.

The Center for Reptile Conservation and Management. "Butler's Garter Snake: Thamnophis butleri" (On-line ). Indiana University Purdue University Fort Wayne. Accessed 03/21/02 at herpcenter.ipfw.edu/outreach/accounts/reptiles/snakes/Butlers_Garter_Snake.htm.

American Psychological Association. 1989. Stimulus Control of Antipredator Behavior in Newborn and Juvenile Garter Snakes. Journal of Comparative Psychology, 103/3: 233-242.

Behler, J., F. King. 2000. National Audubon Society: Field Guide to Reptiles and Amphibians. New York: Alfred A. Knopf Inc..

Brattstrom, B. 1965. Body Temperatures of Reptiles. American Midland Naturalist, 73/2: 376-422.

Carpenter, C, 1951. Comparative Ecology of the Common Garter Snake (Thamnophis s. sirtalis), the Ribbon Snake (Thamnophis s. sauritus), and Butler's Garter Snake (Thamnophis butleri) in Mixed Populations. Dissertation..

Carpenter, C, 1953. A Study of Hibernacula and Hibernating Associations of Snakes and Amphibians in Michigan. Ecology, 34/1: 74-80.

Carpenter, C, 1956. Body Temperature of Three Species of Thamnophis. Ecology, 37/4: 732-735.

Conant, R., J. Collins. 1998. Reptiles and Amphibians: Eastern/Central North America. New York: Houghton Mifflin Company.

Environment Canada, 2002. "Species at Risk: Butler's Gartersnake" (On-line). Environment Canada. Accessed March 21, 2002 at http://www.speciesatrisk.gc.ca/species/search/SearchDetail_e.cfm?SpeciesID=588#note.

Gould, F. An Introduction to the Natural History of North American Garter Snakes with Basic Triage Practices.. Journal of Wildlife Rehabilitation, Vol. 21 (3-4). Accessed 03/15/02 at http://www.thamnophis.com.

Harding, J. 1997. Amphibians and Reptiles of the Great Lakes Region. Ann Arbor, Michigan: The University of Michigan Press.

Holman, J., J. Harding, M. Hensley, G. Dudderar. 1999. Michigan Snakes. East Lansing, MI: Michigan State University Extension/MSU Museum.

Jayne, B, , Bennet, A. 1990. Selection of Locomotor Performance Capacity in a Natural Population of Garter Snakes. Evolution, 44/5: 1204-1229.

Shine, Richard, 1991. Intersexual Dietary Divergence and the Evolution of Sexual Dimorphism in Snakes. American Naturalist, 138/1: 103-122.