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bullsnake

Pituophis melanoleucus

What do they look like?

Pine snakes are the second-largest snakes in northeastern North America. They are 91 to 254 cm long and up to 5 cm in across. They are powerful constrictors, so they wrap themselves around their prey to kill it. They don't have poisonous venom. Like their close relatives, they have a skin flap in their throat which makes their hisses loud like a rattlesnake. Their heads are small compared to their bodies and shaped like heads of turtles. They look a lot like western pine snakes, but their skulls have different shapes. The five subspecies look a little bit different from each other. Northern pine snakes are dull white to cream on their back, bright white on the sides. They have big black splotches on their front and brown ones on their back. Bullsnakes are yellow to tan and have reddish-brown spots along their length. Florida pine snakes are gray or rusty brown, and don't have clear patterns. Black pine snakes are almost all black or dark brown, and their noses are reddish. Young pine snakes are not very brightly colored until they shed their skin for the first time. (Cochran and Goin, 1970; Conant and Collins, 1991; Ditmars, 1931; Ditmars, 1939; Ernst and Barbour, 1989; Ernst and Ernst, 2003; Greene, 1997; Wright and Wright, 1957)

  • Sexual Dimorphism
  • sexes alike
  • Range length
    91 to 254 cm
    35.83 to 100.00 in

Where do they live?

Pine snakes live in the eastern half of the United States. There are 5 subspecies, and each of them lives in a different region. Northern pine snakes live in southern New Jersey, the coastal plains of North Carolina and South Carolina, the mountains of western Virginia and eastern West Virginia, Maryland, New York, southern Kentucky, Tennessee, Alabama and Georgia. Florida pine snakes live in Florida, Alabama, Georgia, North Carolina, and southwestern South Carolina. Louisiana pine snakes are found in western Louisiana and eastern Texas. Black pine snakes live in southwestern Alabama, southeastern Louisiana, and Mississippi. Bullsnakes are found in western Indiana, Illinois, Wisconsin, southern Minnesota, parts of Canada, and down to southwestern Texas and Mexico. (Ernst and Barbour, 1989; Ernst and Ernst, 2003; Wright and Wright, 1957)

What kind of habitat do they need?

Pine snakes live in dry pine forests and similar habitats. They are found in dry forests of pine trees or pine shrubs, oak forests, dry places on mountain ridges, sandy hills, and old fields. In New Jersey, about 90% of their habitats are disturbed. Males are generally found near logs and bark, while females are more frequently found under oak leaves. They live up to 152.4 meters in elevation. (Ernst and Ernst, 2003)

  • Range elevation
    0 to 152.4 m
    0.00 to 500.00 ft

How do they grow?

Pine snakes lay eggs that take 51 to 100 days to hatch. At birth, baby snakes are 30 to 58 cm long. Scientists don't know if pine snakes grow throughout their entire lives or not. (Cochran and Goin, 1970; Ernst and Barbour, 1989; Ernst and Ernst, 2003; Greene, 1997; Wright and Wright, 1957)

How do they reproduce?

Pine snakes breed once a year in the spring. The home area of several females often overlaps that of a single male. Male Florida pine snakes mate with more than one female. (Ernst and Barbour, 1989; Ernst and Ernst, 2003; Greene, 1997; Seigel and Collins, 1993)

Pine snakes generally breed once a year from April to May, but Florida pine snakes may mate during the winter because of the heat during the rest of the year. Some pine snakes nest by themselves, but others share nests with one another. Males are more likely to fight each other during the breeding season. The eggs develop inside the mother for 28 to 39 days before she lays them. They lay eggs in May through July in underground burrows or underneath rocks or logs. They have 3 to 24 eggs at a time, but usually about 8. The eggs take 51 to 100 days to hatch, and usually about 73. Louisiana pine snakes generally lay fewer eggs, but they are larger. Young pine snakes hatch in August or September. They are 30 to 58 cm long and weigh 23 to 60 grams. Usually more males are born, but more females survive to be adults. Pine snakes are able to have their own young about 3 years after they hatch. (Cochran and Goin, 1970; Conant and Collins, 1991; Ernst and Barbour, 1989; Ernst and Ernst, 2003; Greene, 1997; Wright and Wright, 1957)

  • How often does reproduction occur?
    Pine snakes breed once yearly.
  • Breeding season
    Pine snakes usually breed from April to May.
  • Range number of offspring
    3 to 24
  • Average number of offspring
    8
  • Range gestation period
    28 to 39 days
  • Average gestation period
    35 days
  • Average age at sexual or reproductive maturity (female)
    3 years
  • Average age at sexual or reproductive maturity (male)
    3 years

Neither one of the parents invest time or effort into caring for the young after the females lay the eggs.

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

How long do they live?

Scientists don't know the average lifespan of pine snakes. The oldest snake in captivity was 22 years, 5 months, and 1 day old. (Ernst and Barbour, 1989; Ernst and Ernst, 2003; Wright and Wright, 1957)

  • Range lifespan
    Status: captivity
    4.5 to 22.5 years

How do they behave?

Pine snakes are usually active during the day, but some subspecies may be active at night. They are usually active from late March or April until late October or early November. In the winter, they hibernate in underground burrows and sometimes go partly asleep in the summer. Some subspecies warm up by resting in the morning sun. They use their pointed noses to burrow underground if it's too warm or cold, to hide from predators, find prey, or build their nests. They usually stay on the ground, but sometimes climb into low bushes or trees. Males sometimes fight each other in the breeding season. If they feel threatened, they make a hissing noise that sounds like a rattlesnake. When they are ready to wrap around their prey, they strike in a sweeping motion to look vicious. They intimidate predators by making a noise called a bellow, which is a loud and deep sound like a bull would make. (Ditmars, 1931; Ditmars, 1939; Ernst and Barbour, 1989; Ernst and Ernst, 2003; Knight, 1986; Young, et al., 1995)

  • Range territory size
    0.11 to 0.92 km^2
  • Average territory size
    0.50 km^2

Home Range

Scientists only know about the size of the areas where pine snakes live for some subspecies. Florida pine snakes normally live in an area or 0.50 sq km. Females have smaller ranges that overlap with each other, and males have larger ranges that don't overlap. This probably means that pine male pine snakes mate with multiple females. (Ernst and Ernst, 2003; Seigel and Collins, 1993)

How do they communicate with each other?

Scientists don't know much about how pine snakes communicate or sense the world. Juvenile pine snakes recognize each other by smell, and adults may recognize females the same way. (Ernst and Ernst, 2003)

What do they eat?

Pine snakes find food mainly by olfaction. Prey are captured in the snake's mouth and constricted in its coils. Typical prey includes mice (Peromyscus leucopus, Peromyscus maniculatus), hispid cotton rats, moles, red squirrels, southeastern pocket gophers, eastern cottontails, meadow voles, lizards, eastern worm snakes and eggs. Eggs are partially swallowed and broken by the snake's muscular neck. Liquid contents of eggs are swallowed while the shell is either swallowed or spit out. Captive pine snakes eat domestic mice, rats, and bird eggs. (Ernst and Barbour, 1989; Ernst and Ernst, 2003; Wright and Wright, 1957)

Pine snakes find food mostly by smelling it. They catch prey in their mouth and then wrap themselves around it to kill. Foods they commonly eat are white-footed mice, deer mice, hispid cotton rats, moles, red squirrels, southeastern pocket gophers, eastern cottontails, meadow voles, lizards, eastern worm snakes and eggs. When they eat eggs, they partially swallow them and break them with their muscular necks. They swallow the egg but might spit out the shell. In captivity, pine snakes eat domestic mice, rats, and bird eggs. (Ernst and Barbour, 1989; Ernst and Ernst, 2003)

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

What eats them and how do they avoid being eaten?

Common predators of pine snakes are short-tailed shrews, raccoons, striped skunks, red foxes, domestic dogs and cats. Their eggs are often eaten by scarlet snakes. When threatened, pine snakes hiss or make a loud, deep sound called a bellow. They also move their tails back and forth like rattlesankes. These noises intimidate predators. Very young pine snakes avoid places where they smell predators or hide from predators under branches of pine trees. (Burger, et al., 1992; Ernst and Barbour, 1989; Ernst and Ernst, 2003; Greene, 1997)

  • These animal colors help protect them
  • mimic

What roles do they have in the ecosystem?

Pine snakes are important predators of animals which damage farms, like small mammals such as mice and rats, squirrels, and gophers. (Ditmars, 1939)

Do they cause problems?

Pine snakes will bite in self-defense if they feel threatened. Their bites hurt, but they're not poisonous. (Ditmars, 1939; Ernst and Barbour, 1989)

  • Ways that these animals might be a problem for humans
  • injures humans
    • bites or stings

How do they interact with us?

Pine snakes eat rodents, so they may limit the numbers of animals that cause damage to farms. Young pine snakes are one of the most popular snakes to own as a pet. (Burger, et al., 1992; Ernst and Barbour, 1989; Greene, 1997)

  • Ways that people benefit from these animals:
  • pet trade
  • controls pest population

Are they endangered?

Pine snakes are not endangered as a species, but more than one of the subspecies in protected in certain areas. Black pine snakes are protected in Alabama and Mississippi. Common pine snakes are a species of "special concern" in North Carolina and are threatened in Kentucky, New Jersey and Tennessee. Florida pine snakes are protected in Alabama and South Carolina, and are a species of "special concern" in Florida. Their biggest threat is habitat destruction, but they have protected habitats in some locations. (Ernst and Ernst, 2003)

Some more information...

Pine snakes are part of the largest family of snakes in the world. ("Snake", 1987)

Contributors

Lynn Rasmussen (author), Northern Michigan University, Mary Martin (editor), Northern Michigan University, John Berini (editor), Animal Diversity Web Staff, Catherine Kent (editor), Special Projects.

References

1987. Snake. Pp. 436-438 in S-Sn, Vol. 17, 15 Edition. Chicago, London, Sydney, Toronto: World Book, Inc..

Burger, J. 2007. The behavioral response of emerging pine snakes (Pituophis melanoleucus) to people: implications for survival and protection. Urban Ecosystems, 10: 193-201.

Burger, J., R. Zappalorti, J. Dowdell, T. Georgiadis, J. Hill, M. Gochfeld. 1992. Subterranean Predation on Pine Snakes (Pituophis melanoleucus). Journal of Herpetology, 26: 259-263.

Cochran, D., C. Goin. 1970. The New Field Book of Reptiles and Amphibians. New York: G.P. Putnam's Sons.

Conant, R., J. Collins. 1991. A Field Guide to Reptiles and Amphibians - Eastern and Central North America. Boston: Houghton Mifflin Company.

Ditmars, R. 1939. A Field Book of North American Snakes. Garden City, NY: Doubleday & Company, Inc..

Ditmars, R. 1931. Snakes of the World. New York: The Macmillan Company.

Ernst, C., R. Barbour. 1989. Snakes of Eastern North America. Fairfax, VA: George Mason University Press.

Ernst, C., E. Ernst. 2003. Snakes of the United States and Canada. Washington and London: Smithsonian Institute.

Greene, H. 1997. Snakes: The Evolution of Mystery in Nature. Berkeley and Los Angeles, CA: University of California Press.

Knight, J. 1986. Variation in Snout Morphology in the North American Snake Pituophis melanoleucus (Serpentes: Colubridae). Journal of Herpetology, 20: 77-79.

Seigel, R., J. Collins. 1993. Snakes -Ecology and Behavior. New York: McGraw-Hill, Inc..

Wright, A., A. Wright. 1957. Handbook of Snakes. Ithaca, NY: Comstock Publishing Associates.

Young, B., S. Sheft, W. Yost. 1995. Sound Production in Pituophis melanoleucus (Serpentes: Colubridae) With the First Description of a Vocal Cord in Snakes. The Journal of Experimental Zoology, 273: 472-481.

 
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Rasmussen, L. 2012. "Pituophis melanoleucus" (On-line), Animal Diversity Web. Accessed July 22, 2014 at http://www.biokids.umich.edu/accounts/Pituophis_melanoleucus/

BioKIDS is sponsored in part by the Interagency Education Research Initiative. It is a partnership of the University of Michigan School of Education, University of Michigan Museum of Zoology, and the Detroit Public Schools. This material is based upon work supported by the National Science Foundation under Grant DRL-0628151.
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