Pituophis melanoleucus

Geographic Range

Pituophis melanoleucus can be found in the eastern half of the United States. There are 5 subspecies recognized, including northern pine snakes found 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 are found in Florida, Alabama, Georgia, North Carolina, and southwestern South Carolina. Louisiana pine snakes are found in western Louisiana and eastern Texas. Black pine snakes are found in southwestern Alabama, southeastern Louisiana, and Mississippi. Finally, bullsnakes are found in western Indiana, Illinois, Wisconsin, southern Minnesota, parts of Canada and southwest to southern and western Texas and Mexico.

• Biogeographic Regions
• nearctic nearctic
  • native native

Habitat

Pine snakes are found at elevations up to 152.4 meters above sea level in a variety of habitats, including pine barrens, mixed scrub pine and oak woods, dry rocky mountain ridges, sand hills, and old fields. In New Jersey, disturbed habitats are used as much as 90% of the time by pine snakes. Males are generally found near logs and bark, while females are more frequently found under oak leaves.

• Habitat Regions
• temperate temperate
• terrestrial terrestrial

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

• Other Habitat Features
• agricultural agricultural

Physical Description

Pine snakes are the second-largest snake in northeastern North America, ranging in size from 91 to 254 cm in length and up to 5 cm in diameter. Pine snakes are powerful, nonvenomous constrictors. All members of the genus Pituophis have a cartilaginous keel in front of the glottis which amplifies hissing to mimic a rattlesnake. The head of the pine snake resembles that of a turtle, small in comparison to its body size, with a sharply pointed snout that protrudes over the lower jaw. Their skulls are different from those of western pine snakes , specifically in regard to nasal/premaxilla articulation, suggesting differences in digging behavior. The scales of pine snake are keeled in about 27 to 37 rows with a single anal plate. Unlike most other North American snakes, they have 4 instead of 2 prefrontal scales. Subspecies vary in appearance. Northern pine snakes are dull white to cream on the dorsum and intensely white on the sides with black body blotches anteriorly and brown blotches posteriorly. Bullsnakes range in color from yellow to tan with reddish-brown lateral spots. Florida pine snakes range in color from gray-brown to rusty-brown with faded, indistinct, blotched patterning. Black pine snakes are almost completely black or dark brown with a reddish snout. Juvenile pine snakes are dull in color and brighten after shedding their skin for the first time. Sexual dimorphism has not been reported in this species.

• Other Physical Features
• heterothermic heterothermic

• Sexual Dimorphism
• sexes alike

Development

Pine snakes are oviparous and have an incubation period of about 51 to 100 days. Hatchlings range in length from 30 to 58 cm. It is not known if pine snakes grow throughout their entire lives or not.

Reproduction

Pine snakes breed annually. Although information on the mating system of this species is known for only portions of its geographic range, research has shown that Florida pine snakes are polygynous. The home range of several females often overlaps that of a single male. There have been no recorded studies about the mating systems of other subspecies of pine snake. Studies show that the testes of male pine snakes are regressed in April and May and begin to appear in June. They go through spermiogenesis in late summer/early autumn. The sperm then pass to the epididymis and vas deferens where it is stored until the spring breeding season. During breeding, the male crawls over the female, holds onto her by grasping her head or neck in his mouth, and mates with her. Breeding may last from half an hour to over an hour.

• Mating System
• polygynous polygynous

Female pine snakes have an annual breeding cycle which extends from April through May. Detailed information regarding pine snakes is restricted to specific subspecies. Florida pine snakes may mate during the winter due to warmer weather throughout the rest of the year. Gestation usually lasts 28 to 39 days. Pine snakes are oviparous and lay eggs from May through July in underground burrows, underneath rocks or logs. Although some pine snakes are solitary and stick to their own nests, others are communal and share nests with conspecifics. Clutch size ranges from 3 to 24 eggs with an average of 8, and incubation lasts about 51 to 100 days with an average of 73. Louisiana pine snakes generally lay fewer, larger eggs. Young emerge in August or September. Hatchlings range in length from 30 to 58 cm and range in mass from 23 to 60 grams. Hatchling sex ratios generally favor males while adult females outnumber adult males. Pine snakes reach sexual maturity about 3 years after hatching. Males-male combat is common during the breeding season.

• Key Reproductive Features
• seasonal breeding seasonal breeding
• sexual sexual
• fertilization fertilization
• oviparous oviparous

Females lay their eggs in nests, which are sometimes communal. After the eggs are laid, there is no further parental care.

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

Lifespan/Longevity

There is no information available regarding the average lifespan of wild pine snakes. In captivity, the oldest known pine snake lived to be 22 years, 5 months, and 1 day old. At the San Diego Zoo, a captive born female pine snake lived to be 20 years, 9 months, and 2 day old. One pine snake reportedly lived only 4 years, 6 months in captivity.

Behavior

Pine snakes are generally diurnal, but a few subspecies may be active during the night. In general, they are active from late March or April until late October or early November. They hibernate in underground burrows during the winter months and sometimes aestivate during the summer. Some subspecies are known to bask in the morning sun in order to raise their body temperature. Pine snakes have a pointed snout and enlarged rostral scale which are designed for burrowing underground to escape uncomfortable temperatures or predators, to find prey, and to build their nests. Pine snakes are usually found on the ground, but may climb into low bushes or trees. Males of several subspecies are known to engage in combat during breeding season. When threatened, eastern pine snakes use a cartilaginous keel in front of the glottis to amplify a hissing sound and vibrates its tail to resemble a rattlesnake. When attaching, they use a sweeping strike to make appear more vicious. Eastern pine snakes can make a hissing sound or a bellow (i.e., a loud, deep sound like a bull) in order to intimidate potential predators.

• Key Behaviors
• terricolous
• fossorial fossorial
• diurnal diurnal
• crepuscular crepuscular
• sedentary sedentary
• hibernation hibernation
• aestivation

Home Range

Information regarding regarding home range in pine snakes is limited to certain subspecies. Studies show that the Florida pine snakes have an average home range of 0.50 km^2. Two radio tracked females had ranges of 0.11 km^2 and 0.12 km^2. Three radio tracked males had a range of approximately 0.23 to 0.92 km^2. Males have non-overlapping ranges while female home ranges frequently overlap. Several females occupy the home range of a single male, suggesting that pine snakes are polygynous.

Communication and Perception

Little information is known about communication and perception in Pituophis melanoleucus . Juveniles recognize conspecifics via olfaction. It is possible that adult males recognize females in a similar manner.

• Communication Channels
• visual visual
• acoustic acoustic

• Other Communication Modes
• mimicry mimicry
• vibrations vibrations

• Perception Channels
• visual visual
• acoustic acoustic
• chemical chemical

Food Habits

• Primary Diet
• carnivore carnivore
  • eats terrestrial vertebrates
  • eats eggs

• Animal Foods
• birds
• mammals
• reptiles
• eggs

Predation

Pine snakes are preyed upon by short-tailed shrews , raccoons , striped skunks , red foxes , domestic dogs and cats . Pine snake eggs are commonly eaten by scarlet snakes . When threatened, pine snakes make a hissing sound or a bellow (i.e., a loud, deep sound) to intimidate its predators and vibrates its tail to resemble a rattlesnake. They also use a sweeping strike in an effort to appear more vicious. Evidence suggests that hatchlings avoid scent trails made by potential predators and are able to avoid predators such as hawks and owls by finding cover under pine boughs and other debris.

• Anti-predator Adaptations
• mimic

Ecosystem Roles

Pine snakes are important predators of small mammals such as mice and rats , ground squirrels , and gophers , which are destructive agricultural pests. Parasites of this species are unknown.

Economic Importance for Humans: Positive

Pine snakes prey on many species of rodents and may help control the abundance of agricultural pests throughout their geographic range. Hatchlings are sometimes captured and either sold or kept as pets. They are among the most popular snakes kept as pets.

• Positive Impacts
• pet trade pet trade
• controls pest population

Economic Importance for Humans: Negative

When threatened, the pine snake can inflict a painful bite. Pine snakes are non-venomous and only bite in self-defense. There are no other known adverse effects of pine snakes on humans.

• Negative Impacts
• injures humans
  • bites or stings

Conservation Status

As a collective species, Pituophis melanoleucus is classified as "least concern" on the IUCN's Red List of Threatened Species. However, several subspecies are currently protected throughout parts of their geographic ranges. For example, black pine snakes are protected in Alabama and Mississippi. Common pine snakes are considered 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. The single greatest threat to this species is habitat destruction; however, it occurs in protected habitat at various locations throughout its geographic range.

Other Comments

Pituophis melanoleucus belongs to the family Colubridae , the largest family of snakes in the world.

Additional Links

Encyclopedia of Life

BioKIDS Critter Catalog

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

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

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..

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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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