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Lampropeltis triangulumScarlet kingsnake

By Todd Isberg

Geographic Range

Milk snakes, Lampropeltis triangulum, have a wider geographical range than most other species of snake. They can be found in the United States almost anywhere east of the Rocky mountains (Audubon 1979).

In Canada, they range from southcentral and southeastern Ontario to southwestern Quebec. They are also found in Mexico and Central America in any non-arid area (Williams 1994). (National Audubon Society Inc, 1979; Williams, 1994)

Habitat

Milk snakes can thrive in a variety of habitats. They are usually found around coniferous or deciduous forest edges, but they can also be found in tropical hardwood forests, open woodland, dry or wet prairies, savannahs, rocky hillsides, small streams or marshes, and agricultural or suburban areas. These snakes do not fear human proximity but are secretive, so are rarely observed (Vogt 1981). They can be found anywhere from sea level to 8000 feet (Audubon 1979). (National Audubon Society Inc, 1979; Vogt, 1981)

  • Aquatic Biomes
  • rivers and streams
  • Range elevation
    sea level to 2600 m
    to 8530.18 ft

Physical Description

Specimens of L. triangulum have been found in lengths ranging from 35 to 175 cm, with the neotropical populations achieving the greatest lengths. In the United States lengths are most often 60 to 130 cm.

L.triangulum is a very colorful snake. Its body may be gray or tan, having a light Y or V shaped patch on the neck. Black bordered "blotches", brown or rust colored down the sides of the body are common as are red, orange, yellow, or white "blotches" with colorful borders, depending on the subspecies. There are 25 different subspecies known throughout the snake's geographical range, all with slight color variations.

The neck has a light collar with colored, black bordered bands separated by light rings. There are no reported color differences between males and females.

L. triangulum has 19 to 23 rows of smooth scales and a single anal plate (Audubon 1979). (National Audubon Society Inc, 1979)

  • Sexual Dimorphism
  • sexes alike
  • Range length
    35 to 175 cm
    13.78 to 68.90 in

Reproduction

Milk snakes probably mate while still in their hibernacula. They mate in spring before emerging and dispersing to their summer ranges. Mating is probably indiscriminate.

Milk snakes lay elliptical eggs in rotting logs or humus in the spring or early summer (Audubon 1979). These eggs are laid in clutch sizes of 2 to 17, usually about 10 (Vogt 1981). Eggs hatch after an incubation period of 28 to 39 days with hatchlings measuring from 14 to 28 cm long upon hatching. The young are always brightly colored, though color dulls as maturity is reached. It takes 3 to 4 years to reach full maturity. (Canadian Amphibian & Reptile Conservation Network, March 1999; National Audubon Society Inc, 1979; Vogt, 1981)

  • Breeding interval
    Milk snakes breed once yearly.
  • Breeding season
    Breeding occurs in spring and early summer, from April through June.
  • Average number of offspring
    10
  • Range gestation period
    28 to 39 days
  • Average age at sexual or reproductive maturity (female)
    3 to 4 years
  • Average age at sexual or reproductive maturity (male)
    3 to 4 years

Milk snake females choose nest sites that are warm and humid. Once the eggs are laid there is no further parental care.

  • Parental Investment
  • no parental involvement

Lifespan/Longevity

Specific data on lifespan is not given, although it is known that one individual caught as an adult lived another 21 years in captivity. (Canadian Amphibian & Reptile Conservation Network, March 1999)

  • Range lifespan
    Status: captivity
    21 (high) years
  • Average lifespan
    Status: captivity
    22.6 years
    AnAge

Behavior

A solitary species, L. triangulum is rarely seen in the open during the day, but is often seen crossing roads at night. They usually hide under rotting logs or damp trash, but can be found still active at high temperatures, when other snakes seek refuge from the heat. A favorite hunting ground is around barns or other human locales, lying in wait to feed on the small rodents commonly found in such areas (Vogt 1981).

The only time these snakes are found in groups is during hibernation. Right before and right after hibernation, they can be seen basking in the sun in large groups. (Vogt, 1981)

Communication and Perception

Not much is known about milk snake communication. They use sight, hearing, touch, and smell to perceive their environment. They may use chemical cues to detect sex during their spring mating.

Not much is known about milk snake communication. They use sight, hearing, touch, and smell to perceive their environment.

Food Habits

L. triangulum is carnivorous. Adults feed mainly on rodents such as voles, mice, and rats, but will also eat birds, bird eggs, lizards, snake eggs, or other snakes, including venomous species like coral snakes and rattlesnakes. Hatchlings seem to feed mainly on other young snakes. When prey is captured, it is contricted until it suffocates. It is then swallowed whole (Vogt 1981).

  • Primary Diet
  • carnivore
    • eats terrestrial vertebrates
  • Animal Foods
  • birds
  • mammals
  • reptiles
  • eggs

Predation

Milk snakes are prey for animals such as raccoons, foxes, skunks, and coyotes. When it feels threatened, the snake will vibrate its tail, sounding much like a rattlesnake. This habit may scare away some predators, but it can also get the Milk snake killed by frightened humans who mistake it for a venomous rattlesnake (Audubon 1979). Another adaptation this species has to avoid death by predator is its coloration. Many of the L. triangulum subspecies practice Batesian mimicry. Their color patterns look similar to either those of the venomous copperhead or the coral snake. Again, this adaptation can also mean death for the snake when encountering humans who can't tell the difference. (Canadian Amphibian & Reptile Conservation Network, March 1999; National Audubon Society Inc, 1979)

Ecosystem Roles

Milk snakes are important predators of small mammals, birds, and other snakes.

Economic Importance for Humans: Positive

Milk snakes have a close relationship with humans, as they are commonly found in farmland or urban areas. These snakes are beneficial to humans as they feed on rodents that concentrate around barns or trash (Vogt 1981).

  • Positive Impacts
  • controls pest population

Economic Importance for Humans: Negative

There are no negative affects of milk snakes on humans.

Conservation Status

Though milk snakes are often killed by humans who mistake them for venomous snakes, they are widespread and still considered abundant throughout most of their range. (Canadian Amphibian & Reptile Conservation Network, March 1999)

Other Comments

The milk snake got its name from an Old World folk tale. The tale tells that the snake sucks the milk of nursing mothers and cows until they are dry. Of course we know this to be impossible because the snake is harmless and a human mother or a cow would certainly not allow it. Also, the snake's belly could only hold a few tablespoons of milk (Vogt 1981).

Contributors

Todd Isberg (author), Pima Community College, Brad Fiero (editor), Pima Community College.

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.

aposematic

having coloration that serves a protective function for the animal, usually used to refer to animals with colors that warn predators of their toxicity. For example: animals with bright red or yellow coloration are often toxic or distasteful.

carnivore

an animal that mainly eats meat

chemical

uses smells or other chemicals to communicate

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

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.

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).

native range

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

nocturnal

active during the night

oviparous

reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.

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).

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.

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.

vibrations

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

visual

uses sight to communicate

References

Canadian Amphibian & Reptile Conservation Network, ,. March 1999. "Lampropeltis triangulum Milk Snake" (On-line). Accessed November 7, 1999 at http://cs715.cciw.ca/ecowatch/dapcan/reptiles/tour/glossary/milksnk2.htm.

National Audubon Society Inc, ,. 1979. National Audubon Society's Field Guide to North American Reptiles and Amphibians. New York: Alfred A. Knopf, Inc..

Roth, J., H. Smith. 1990. The milksnake, Lampropeltis triangulum, in northwest Colorado. Bulletin of the Chicago Herpetological Society: 6-7.

Vogt, R. 1981. Natural History of Amphibians and Reptiles of Wisconsin. Milwaukee, Wisconsin: Milwaukee Public Museum.

Williams, K. 1994. Reptilia:Squamata:Serpentes:Colubridae:Lampropeltis triangulum. Catalogue of American Amphibians and Reptiles: 594.

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