Reptiles

Amphibians

Western Ratsnake (Pantherophis obsoletus)

Description

This species was previously known as the Black Ratsnake (Elaphe obsoleta obsoleta).

Adults of this species in Arkansas are large, muscular, constricting snakes. The dominating dorsal coloration is black. The chin and throat has a decidedly lighter coloration, usually a cream or white. The ventral coloration varies greatly from white to salmon to dark gray; a checkerboard pattern is typically present. Some amount of juvenile patterning may be retained well into adulthood, showing up as flecks of white, salmon, or yellow between the scales.

Juveniles of the species look decidedly different from the adults. Complete darkening may take 2-5 years. The juvenile patterning could best be described as "blotched". The background coloration can vary from light gray to brown to tan. The blotches are dark; either black, dark brown, or dark gray. These blotches may be bordered with a thin outline of cream.

This species was long considered the same species as the Gray Ratsnake, Western / Black Ratsnake, Yellow Ratsnake, and Everglades Ratsnake. Recent analysis has suggested the redefinition of this complex into three distinct lineages: Eastern Ratsnake (found east of the Apalachicola River and Appalachian Mountains), Gray Ratsnake (found between the Apalachicola River and the Mississippi River), and Western Ratsnake (found west of the Mississippi River).

The Western Ratsnake can be distinguished from the North American Racer, the other common "black snake" found in Arkansas, by the presence of a ridge (called a keel) on each body scale. The Western Ratsnake also has a larger head and therefore a more distinct neck than the North American Racer.

This species is known by several common names, including Black Ratsnake, Chicken Snake, Mountain Black Snake, or Pilot Snake. Often, it is simply Black Snake.


Habitats

This species can be found in a variety of habitats, especially where there is an abundance of mice and rats. Ideal habitat for this species can be found in and around barns, chicken houses, brush piles, old junk piles, and other similar structures. They can be found in both woodlands and open fields. A large portion of their time is likely spent high up in trees, either coiled in hollows or stretched out on branches.

This species, due to its larger size and need to actively forage, spends a good portion of time basking. The dark dorsal coloration facilitates absorbing heat from the sun quickly. Favorite "hot" spots are under loose pieces of tin and (to the detriment of the snakes) highway blacktop.


Habits and Life History

The snake appears to follow a pattern typical for many species in the state: hibernate through winter, breed in the spring, and lay eggs in the summer. Road kills of Ratsnakes in the early spring often provides the first evidence that snakes have emerged from hibernation. During this time, Ratsnakes are travelling to their summer foraging areas, searching for mates, and basking. Gravid females later in the summer will lay a number of eggs (up to 15 is not unusual).

One of the earliest species to emerge in the spring, the Ratsnake is also one of the last in the fall to seek a den site. It is thought that a single den site may be used year after year. The namesake "Pilot Ratsnake" comes from the erroneous belief that a Ratsnake will "pilot" other snakes, including venomous species, to their den site. Despite this misnomer, it is true that Ratsnakes may select the same hibernacula as other snakes due to the favorability of the temperature and structure provided. Ratsnakes may also hibernate singly in tree hollows, root structures, or animal burrows.


Prey and Hunting Techniques

This species eats a variety of warm-blooded prey, not just rats as the name implies. Any mammal or bird that is slow enough to catch and small enough to eat is fair game. Bird eggs are also a favorite.

While this species usually hunts by actively seeking after prey, it is also opportunistic and is certain to seize upon any suitable prey that wanders by it. A Ratsnake is a powerful constrictor that wraps its body around prey with lightning speed. Once a mouse or other rodent is clenched in a Ratsnake's coils, there is little question as to the outcome.


Temperament and Defense

The temperament of Ratsnakes varies by individual, though most tame with some handling.

As defense, a Ratsnake will employ the usual: pooping, releasing a foul-smelling musk, and biting. When defensive, they may tense their coils around a handler's hand and become reluctant to let go until positioned low to the ground so that they can "crawl out of their grip".


Conservation

Despite an apparent bad track record with regard to human encounters, this species remains abundant and common. Most human-attributable deaths are caused by vehicles. The species has a true affinity for blacktop, but its large size, coupled with high-speed traffic, and unfavorable attitudes makes for a deadly mix.

Farmers who raise chickens may consider the Ratsnake to be a true pest (since nothing is tastier for a Ratsnake than baby chickens and chicken eggs).

The myth of Ratsnakes interbreeding with Copperheads to produce venomous hybrids is occasionally used as reason for killing these "disguised killers", however, such myths are completely untrue and unfounded.


State Distribution and Abundance

The Western Ratsnake occurs statewide and is arguably one of the most common large snakes found in the state.

Gallery

© Rex Lisman-1157 Jefferson Trip-August 2013 black snake, War Eagle Cavern, Arkansas Texas Ratsnake Texas Ratsnake Texas Ratsnake Texas Ratsnake Texas Ratsnake Texas Ratsnake Texas Ratsnake Texas Ratsnake Texas Ratsnake Texas Ratsnake Texas Ratsnake Texas Ratsnake Texas Ratsnake Texas Ratsnake Texas Ratsnake Texas Ratsnake © Rex Lisman-1160 Texas Ratsnake Arkansas River Snake Juvenile Texas Ratsnake Texas Ratsnake Texas Ratsnake Texas Ratsnake Texas Ratsnake Texas Ratsnake Texas Ratsnake Texas Ratsnake Texas Ratsnake Texas Ratsnake Texas Ratsnake Texas Ratsnake Treed snake Watching me DSC_0105 2010 AHS Spring Field Trip - Texas Ratsnake 2010 AHS Spring Field Trip - Texas Ratsnake 2010 AHS Spring Field Trip - Texas Ratsnake 2009 AHS Spring Field Trip 2009 AHS Spring Field Trip 2009 AHS Spring Field Trip 2009 AHS Spring Field Trip Scouting 2009 AHS Spring Field Trip Scouting 2009 AHS Spring Field Trip Scouting Lisman_070601_2249 Western Rat Snake Western Rat Snake Young Western Rat Snake Young Western Rat Snake Young Western Rat Snake Young Western Rat Snake Glenn Holding a Large Male Western (Black) Rat Snake Glenn Holding a Large Male Western (Black) Rat Snake Glenn Holding a Large Male Western (Black) Rat Snake Western Rat Snake Western Rat Snake Western Rat Snake Western Rat Snake Western Rat Snake Western Rat Snake Western Rat Snake Western Rat Snake Western Rat Snake Western Rat Snake Western Rat Snake Juvenile Western Rat Snake Juvenile Western Rat Snake Juvenile Western Rat Snake Juvenile Western Rat Snake Juvenile Western Rat Snake Juvenile Western Rat Snake Juvenile Western Rat Snake Western Rat Snake Western Rat Snake Western Rat Snake Western Rat Snake Western Rat Snake Western Rat Snake Western Rat Snake Western Rat Snake Western Rat Snake Western Rat Snake Western Rat Snake Western Rat Snake Western Rat Snake Western Rat Snake Western Rat Snake Western Rat Snake Western Rat Snake Western Rat Snake Western Rat Snake Western Rat Snake Western Rat Snake Western Rat Snake Western Rat Snake Western Rat Snake Western Rat Snake

Contributors

  • kaptainkory March 22, 2006, at 01:14 PM (Original Contributor)

Bibliography

  • Behler, J. L., and F. W. King. 1979 (1987). The Audubon Society Field Guide to North American Reptiles and Amphibians. 3rd ed. Alfred A. Knopf, New York. 743 pp.
  • Burbrink, F. T., R. Lawson, and J. B. Slowinski. 2000. MtDNA phylogeography of the North American rat snake (Elaphe obsoleta): a critique of the subspecies concept. Evolution 54:2107-2118.
  • Conant, R., and J. T. Collins. 1998. A Field Guide to Reptiles and Amphibians of Eastern and Central North America. 3rd ed., Expanded. Houghton Mifflin Co., Boston. 616 pp.
  • Irwin, K. J. 2004. Arkansas Snake Guide. Arkansas Game and Fish Commission Pocket Guide. 50 pp.
  • Trauth, S. E., H. W. Robison, and M. V. Plummer. 2004. Amphibians and Reptiles of Arkansas. University of Arkansas Press, Fayetteville. 421 pp.

Discussion

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Page last modified on December 27, 2013, at 06:48 PM