Storeria dekayiBrown Snake

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Geographic Range

Storeria dekayi is an abundant snake that is widely distributed.

It is found in southern Canada, in the United States east of the Rocky Mountains, and in the northern portions of Mexico (Ditmars 1936).

Habitat

This is a snake that is still fairly abundant. The reason for this can be mostly attributed to its smaller size and broad habitat preferences. Brown snakes are typically found hiding among loose stones or flat rocks that are found in the wild and in large cities (Ditmars 1936). These snakes will spend most of their life under the ground, but during heavy rains they will sometimes go out into the open (Harding 1997). This usually occurs in October - November and during late March - April when they are moving to or from hibernation spots (Harding 1997). Sometimes these hibernation spots will be shared with other snakes such as garter snakes, red-bellied snakes, and smooth green snakes (Harding 1997). (Ditmars, 1936; Harding, 1997)

Physical Description

The brown snake is a fairly small snake that rarely exceeds 15 inches in length (Ditmars 1936). It has a stout body with large eyes and heavily keeled scales (Collins 1987). Storeria dekayi is typically found to be a grayish brown color with a lighter streak on its back that is bordered on each side with black dots. The belly of the brown snake is a pinkish white color. Typically there are 17 scale rows at midbody and the anal plate is divided (Harding 1997). Males and females generally look the same, but males tend to have longer tails (Harding 1997). There are several other subspecies of Storeria dekayi that look slightly different, but there is no textual evidence of any seasonal variation. Young brown snakes are small, about 3 1/2 inches long on average and are black or dark gray in color (Simon 1979). A distinguishing characteristic of the young is a light grayish white colored ring found around the neck. At this age they are sometimes confused with ring necked snakes, but are distinguished by their keeled scales (Ditmars 1936). (Collins, 1987; Ditmars, 1936; Simon, 1979)

  • Sexual Dimorphism
  • female larger
  • sexes shaped differently
  • Range length
    23.0 to 52.7 cm
    9.06 to 20.75 in

Reproduction

The brown snake is viviparous, and gives birth to 12 - 20 young (Ditmars 1936). This occurs during the later parts of the summer around late July to early August (Ditmars 1936). After the young are born there is no parental care involved, but sometimes young brown snakes will stay close with the parent (Harding 1997). Brown snakes reach sexual maturity by the end of their second summer, usually by this time they have doubled in

length (Harding 1997).

  • Breeding interval
    Brown Snakes breed once yearly.
  • Breeding season
    Brown Snakes give birth to their young in late summer.
  • Range number of offspring
    3.0 to 41.0
  • Average age at sexual or reproductive maturity (female)
    2.0 years
  • Average age at sexual or reproductive maturity (female)
    Sex: female
    730 days
    AnAge
  • Average age at sexual or reproductive maturity (male)
    2.0 years
  • Average age at sexual or reproductive maturity (male)
    Sex: male
    730 days
    AnAge

The young are nourished within their mother's body while they develop. Once the young are born there is no further parental care, but sometimes young Brown Snakes will stay near their mother.

Lifespan/Longevity

Little is known of Brown Snake lifespans in the wild, but a captive individual lived to be 7 years old. Wild Brown Snakes may approach this lifespan in the wild, though many young die before becoming mature.

  • Range lifespan
    Status: captivity
    7.0 (high) years
  • Average lifespan
    Status: captivity
    7 years
    AnAge

Behavior

Breeding in Storeria dekayi starts out with the male following a female that leaves a pheromone trail (Harding 1997). The brown snake (male) uses his tongue to identify a potential mate, making sure it is a female, the male then inserts a hemipenis into the female's cloaca after making various courting movements (Harding 1997). Brown snakes are typically harmless nonvenemous snakes. Some of their predators are large frogs and toads, larger snakes, crows, hawks, shrews, weasels, certain bird species, and domestic

cats and dogs (Harding 1997). When these snakes do feel threatened they will flatten their bodies out to appear larger and place their bodies in an aggressive posture, and they will even release a musky smelling fluid from the cloaca (Harding 1997).

Communication and Perception

Brown Snakes communicate with each other primarily through touch and smell. They use their forked tongues to collect chemicals from the air and insert these forks into a special organ in the roof of their mouth, which interprets these chemical signals. Because Brown Snakes hunt mostly underground and at night, they probably use almost exclusively their sense of smell to find prey. Snakes are also sensitive to vibrations and have reasonably good vision.

Food Habits

Brown snakes feed largely on earthworms, snails, and slugs, but will also eat small salamanders, soft-bodied grubs, and beetles. They have specialized teeth and jaws that allow them to pull snails out of their shells and eat them. (Ditmars, 1936; Harding, 1997)

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

Predation

Brown snakes are eaten by large frogs and toads, larger snakes, American crows, hawks, shrews, weasels, blue jays, and domestic cats. When these snakes feel threatened they flatten their bodies to appear larger and place their bodies in an aggressive posture. They will also smear their attacker with a foul-smelling musk that they exude from their cloaca.

Ecosystem Roles

Brown Snakes help to control populations of snails, slugs, and earthworms. They also serve as a valuable food supply for their predators.

Economic Importance for Humans: Positive

These little snakes may benefit humans by controlling slug damage in gardens (Harding 1997). No other known benefits have been found.

  • Positive Impacts
  • controls pest population

Conservation Status

This is a fairly common species, but it does face threats such as exposure to pollution and destruction of rural and urban habitats (Harding 1997). No known efforts are being made to ensure viable populations for the future.

Contributors

Leslie Seaholm (author), Michigan State University, James Harding (editor), Michigan State University.

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

carnivore

an animal that mainly eats meat

chaparral

Found in coastal areas between 30 and 40 degrees latitude, in areas with a Mediterranean climate. Vegetation is dominated by stands of dense, spiny shrubs with tough (hard or waxy) evergreen leaves. May be maintained by periodic fire. In South America it includes the scrub ecotone between forest and paramo.

female parental care

parental care is carried out by females

fertilization

union of egg and spermatozoan

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

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.

internal fertilization

fertilization takes place within the female's body

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.

molluscivore

eats mollusks, members of Phylum Mollusca

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

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.

polygynous

having more than one female as a mate at one time

scrub forest

scrub forests develop in areas that experience dry seasons.

seasonal breeding

breeding is confined to a particular season

sexual

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

solitary

lives alone

suburban

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

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.

urban

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

young precocial

young are relatively well-developed when born

References

Collins, J. 1987. Snakes Ecology and Evolutionary Biology. New York: Macmillan Publishing Company.

Ditmars, R. 1936. The Reptiles of North America. New York: Doubleday, Doran and Company, Inc..

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

Simon, H. 1979. Easy Classification Guide to North American Snakes. New York: Dodd, Mead, and Company.