Eastern rat snake

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Eastern ratsnake
Black Rat Snake Ontario.jpg
Adult eastern ratsnake
Murphys Point Provincial Park, Ontario
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Squamata
Suborder: Serpentes
Family: Colubridae
Genus: Pantherophis
Species:
P. quadrivittatus
Binomial name
Pantherophis quadrivittatus
(Holbrook, 1836) [2]
Synonyms

Pantherophis quadrivittatus, commonly called the eastern rat snake, is a species of non venomous snake in the family Colubridae. The species is endemic to North America. [10] [11]

Contents

Common names

Additional common names for P. quadrivittatus include black rat snake, pilot snake, pilot black snake, [11] chicken snake; and in Florida, yellow rat snake and Everglades rat snake. [12]

Geographic range

Eastern rat snake (subadult), Pantherophis quadrivittatus, in Maryland Eastern Ratsnake (Pantherophis alleghaniensis), residential, Montgomery County Maryland.jpg
Eastern rat snake (subadult), Pantherophis quadrivittatus, in Maryland

P. quadrivittatus is found in the United States east of the Apalachicola River in Florida, east of the Chattahoochee River in Georgia, east of the Appalachian Mountains, north to southeastern New York and western Vermont, eastern Pennsylvania, Maryland, South Carolina, North Carolina, Georgia, south to the Florida Keys. [10] [11] [12] [13] [14] In the Florida Panhandle, it readily hybridizes with the gray rat snake (Pantherophis spiloides). [12]

Description

Yellow rat snake, Pantherophis quadrivittatus ssp. quadrivittata, in Florida Pantherophis alleghaniensis ssp. quadrivittata 03.JPG
Yellow rat snake, Pantherophis quadrivittatus ssp. quadrivittata, in Florida

Adult eastern rat snakes commonly measure 90 to 183 cm (2 ft 11 in to 6 ft 0 in) in total length (including tail), with a few exceeding 200 cm (6 ft 7 in). [12] The longest recorded total length to date for an eastern rat snake is 228 cm (7 ft 6 in). [11] A sample of eastern rat snakes, including juvenile and adult snakes, weighed from 54 g (1.9 oz) to 1,274 g (2.809 lb). [15] A further adult weighed 833 g (1.836 lb). [16]

Adults are shiny black dorsally, with a cream or white chin and throat. White areas of skin can appear between scales. [17] The belly has an irregular black and white checkerboard pattern, becoming uniformly slate gray towards the tail. Juveniles have 28 to 40 [18] dark dorsal blotches on a grayish ground color. The ventral pattern in juveniles is the same as in adults. The eyes are round with a black pupil, and particularly in juveniles but not always present in adults, a distinct white margin. [11] [13]

In cross section, the bodies of rat snakes are not round, but instead resemble a loaf of bread. [19]

The dorsal scales are weakly keeled, and are arranged in 23 to 27 rows at midbody. [20]

Males and females have the same coloration. Males have proportionally longer tails (16–19% of total body length) compared to females (14–18% of total body length). [11]

Habitat

The eastern rat snake occurs in a variety of habitats. These include farmlands, hardwood forests, forested wetlands, thickets and fields adjacent to forests, isolated urban woodlots and backyards that support populations of prey species. The eastern rat snake does especially well in early successional and edge habitats. An arboreal species, it can get into human residences, where it may live in attics undetected. At the northern limits of its range, distribution appears to be restricted by the availability of suitable hibernating sites. In these climates, it requires southern exposures to receive maximal thermal benefit from the winter sun and to provide basking areas in early spring and late fall. [11] [13] In one study tracking habitat conditions, eastern rat snakes were found to exhibit site fidelity; returning to the same location for 12% of observations. [21] The three U.S populations located more northerly (Illinois at 378N, Kansas at 388, Maryland at 398) hibernate, with very rare appearances before April and after October. In most northern locations latitudinal and longitudinal effects are likely because of thermal restriction or modification of activity associated with winter temperatures at higher temperatures. [22] There are consequences of thermal constraints regarding ecological parameters such as causes of variation of seasonal mortality, population demography, limits to geographic distribution, and the expression or evolution of traits such as habitat selection, reproductive allocation, and mechanisms of physiological hibernation remain complex and incompletely understood. [22]

Behavior and ecology

The eastern rat snake is primarily active at night during the summer, and diurnal in the spring and fall. [23] It is a terrestrial burrower and an excellent climber, and it may enter water. It is found under rocks and boards, and in trees under bark and within knot holes and palm fronds. Eastern rat snakes have been found using water filled cavities in trees, with many using the cavities at the same time. Gravid females were also four times more likely to use the water cavities than non-gravid females or male ratsnakes. [24] Gravid females prefer edge habitat more extensively than males and non-gravid females, this is because of the need for gravid females to retain higher body temperature. [25] The snake is a constrictor, and adults eat mainly endotherms while young eat mainly ectotherms. The diet includes rodents, lizards, frogs, and birds and their eggs. [26] The snakes can also eat young chickens and chicks, hence the common name chicken snake.

Rat snakes are most vulnerable to predators as juveniles. Predators of P. quadrivittatus include hawks (Buteo spp.), great horned owls (Bubo virginianus), foxes, raccoons, and domestic cats. Adult eastern rat snakes have few known predators other than humans. When frightened, a rat snake will freeze. If harassed, it will produce a foul-smelling musk to deter predators. If provoked further, it may coil, shake its tail, and snap at its attacker. [27]

Eastern rat snakes hibernate during the winter underground or in deep crevices. They may congregate in the same dens with other species of snakes, such as copperheads (Agkistrodon contortrix), eastern racers (Coluber constrictor) and timber rattlesnakes (Crotalus horridus). In Northern climes, the snakes are active from late April to October and mate in May or June. It is active earlier in the South. [28]

Reproduction

Eastern rat snakes are oviparous and gaining nutrients for eggs is facilitated by the female maintaining her body temperature. [29] Eastern rat snakes reach sexual maturity in their fourth year. The snakes start to breed in May and June, earlier in the South. Males approach females to initiate breeding and may combat other males before breeding. About five weeks after mating, the female lays 5 to 27 eggs in hollow standing and fallen trees, compost and mulch heaps, sawdust piles, and decomposing logs. Incubation is about two months, and eggs hatch from July through September. Hatchlings are usually just over a foot long at birth, with the distinct gray and black pattern characteristic of juveniles. [23] [27] [28]

Juvenile eastern rat snake showing its grey base color with dark blotches. Juvenile ratsnake crop.jpg
Juvenile eastern rat snake showing its grey base color with dark blotches.

Eastern Rat snakes reach sexual maturity at 4 years old (about 3ft). [30]

Taxonomy

P. quadrivittatus has sometimes been considered a subspecies of P. obsoletus , to which it is closely related. [31]

Opportunistic yellow rat snake looking for prey atop live oak tree. Yellow Rat Snake 377.jpg
Opportunistic yellow rat snake looking for prey atop live oak tree.

This species has often been placed in the genus Elaphe , but recent phylogenetic analyses have resulted in its transfer to Pantherophis. [32] [33] [34]

Related Research Articles

<span class="mw-page-title-main">Rat snake</span> Common name for various snakes

Rat snakes are members – along with kingsnakes, milk snakes, vine snakes and indigo snakes – of the subfamily Colubrinae of the family Colubridae. They are medium to large constrictors and are found throughout much of the Northern Hemisphere. They feed primarily on rodents. Many species make attractive and docile pets and one, the corn snake, is one of the most popular reptile pets in the world. Like all snakes, they can be defensive when approached too closely, handled, or restrained. However, rat snake bites are not dangerous to humans. Like nearly all colubrids, rat snakes pose no threat to humans. Rat snakes were long believed to be completely nonvenomous, but recent studies have shown that some Old World species do possess small amounts of venom, though the amount is negligible relative to humans.

<span class="mw-page-title-main">Corn snake</span> Species of snake

The corn snake, sometimes called red rat snake, is a species of North American rat snake in the family Colubridae. The species subdues its small prey by constriction. It is found throughout the southeastern and central United States. Though superficially resembling the venomous copperhead and often killed as a result of this mistaken identity, the corn snake lacks functional venom and is harmless. The corn snake is beneficial to humans because it helps to control populations of wild rodent pests that damage crops and spread disease.

<i>Pantherophis obsoletus</i> Species of snake

Pantherophis obsoletus, also known commonly as the western rat snake, black rat snake, pilot black snake, or simply black snake, is a nonvenomous species of snake in the family Colubridae. The species is native to central North America. There are no subspecies that are recognized as being valid. Its color variations include the Texas rat snake. Along with other snakes of the eastern United States, like the eastern indigo snake and the eastern racer, it is called “black snake”.

<span class="mw-page-title-main">Gray ratsnake</span> Species of nonvenomous snake

The gray ratsnake or gray rat snake, also commonly known as the black ratsnake, central ratsnake, chicken snake, midland ratsnake, or pilot black snake, is a species of nonvenomous snake in the genus Pantherophis in the subfamily Colubrinae. The gray ratsnake is one of about ten species within the American ratsnake genus Pantherophis.

<i>Elaphe</i> Genus of rat snakes

Elaphe is a genus of snakes in the family Colubridae. Elaphe is one of the main genera of the rat snakes, which are found in many regions of the northern hemisphere. Elaphe species are medium to large constrictors by nature.

<i>Pantherophis</i> Genus of snakes

Pantherophis is a genus of nonvenomous colubrid snakes endemic to central and eastern regions of North America. It consists of the North American ratsnakes, the foxsnakes, and the cornsnakes. The genus, which contains 10 recognized species, first appeared in the fossil record in the Middle Miocene around 16.3 million years ago. They are a large terrestrial snake genus that lack subocular scales. Originally classified in the genus Elaphe, phylogenetic studies have found this taxon to be closely related to Pituophis. As with all snakes Pantherophis is an obligate faunivore with a diet that consists of small mammals, birds, reptiles and amphibians, and even insects. While many species conservation status is categorized as "least concern", many local populations in some species have declined where some places have them listed as federally protected. The corn snake is a popular pet reptile, due to the availability of captive-bred animals, their low maintenance and calm disposition, and the variety of color morphs. There are other species of Pantherophis that are in the pet trade, though are not as popular as the corn snake.

<span class="mw-page-title-main">Trinket snake</span> Species of snake

The trinket snake, also known commonly as the common trinket snake, is a species of nonvenomous constricting snake in the family Colubridae. The species is native to southern Central Asia.

<span class="mw-page-title-main">Mandarin rat snake</span> Species of snake

The mandarin rat snake is a species of nonvenomous colubrid snake endemic to Asia. It is closely related to Euprepiophis conspicillata, the Japanese forest rat snake. Mandarin rat snakes are one of the most popular rat snakes found in the pet trade.

<i>Pantherophis vulpinus</i> Species of snake

Pantherophis vulpinus, commonly known as the foxsnake or the eastern fox snake, is a species of nonvenomous rat snake in the family Colubridae. The species is native to North America.

<span class="mw-page-title-main">Eastern racer</span> Species of snake

The eastern racer, or North American racer, is a species of nonvenomous snake in the family Colubridae. The species is endemic to North America and Central America. Eleven subspecies, including the nominotypical subspecies, are recognized, which as a group are commonly referred to as the eastern racers. The species is monotypic in the genus Coluber.

<span class="mw-page-title-main">Texas rat snake</span> Subspecies of snake

The Texas rat snake is a subspecies of the black rat snake, a nonvenomous colubrid. It is found in the United States, primarily within the state of Texas, but its range extends into Louisiana, Arkansas and Oklahoma. It intergrades with other subspecies of Elaphe obsoleta, so exact range boundaries are impossible to distinguish. The epithet lindheimeri is to honor the German-American naturalist Ferdinand Jacob Lindheimer, who collected the first specimen in New Braunfels, Texas.

<i>Pantherophis emoryi</i> Species of snake

Pantherophis emoryi, commonly known as the Great Plains rat snake, is a species of nonvenomous rat snake in the family Colubridae. The species is native to the central part of the United States, from Missouri to Nebraska, to Colorado, south to Texas, and into northern Mexico.

<i>Pantherophis bairdi</i> Species of snake

Pantherophis bairdi is a species of harmless snake in the family Colubridae. The species is native to the southwestern United States and adjacent northeastern Mexico. No subspecies are recognized as being valid.

<i>Euprepiophis conspicillata</i> Species of snake

Euprepiophis conspicillata, commonly known as the Japanese forest rat snake, is a species of nonvenomous colubrid snake endemic to Japan. Its Japanese common name, jimuguri, roughly translates to "the burrower". It is closely related to Euprepiophis mandarinus, the Mandarin rat snake.

<span class="mw-page-title-main">Japanese striped snake</span> Species of snake

Elaphe quadrivirgata, commonly known as the Japanese four-lined ratsnake or the Japanese striped snake, is a species of non-venomous colubrid snake native to Japan.

<span class="mw-page-title-main">Slowinski's corn snake</span> Subspecies of snake

Slowinski's corn snake is a subspecies of nonvenomous snake in the family Colubridae. The subspecies is indigenous to Louisiana, eastern Texas, and Arkansas.

<span class="mw-page-title-main">Four-lined snake</span> Species of snake

Elaphe quatuorlineata is a member of the family Colubridae. The four-lined snake is a non-venomous species and one of the largest of the European snakes.

<span class="mw-page-title-main">Steppe rat snake</span> Species of snake

Elaphe dione, commonly known as Dione's rat snake, the steppe rat snake, or the steppes rat snake, is a species of snake in the family Colubridae. The species is native to Asia and Eastern Europe. There are no subspecies that are recognized as being valid. A large specimen from Putyatin Island measured up to 90 cm (3.0 ft) in length.

<i>Elaphe moellendorffi</i> Species of snake

Elaphe moellendorffi, commonly called the flower snake or Moellendorf's [sic] rat snake, is a species of snake in the family Colubridae. The species is endemic to southeastern Asia.

<span class="mw-page-title-main">Northern black racer</span> Subspecies of snake

The northern black racer is a subspecies of the eastern racer, a nonvenomous snake in the family Colubridae. Their geographic range extends from southern Maine to northern Georgia and westward to central Kentucky and eastern Ohio. Their occupancy is dependent on the availability of large patches of open habitats.

References

  1. ↑ Hammerson GA (2007). "Pantherophis obsoletus ". The IUCN Red List of Threatened Species 2007: e.T63864A12715740. https://dx.doi.org/10.2305/IUCN.UK.2007.RLTS.T63864A12715740.en. Downloaded on 30 July 2016.
  2. 1 2 Holbrook, John E. (1836). Coluber alleghaniensis (plate XX) (PDF). North American Herpetology; or, A Description of the Reptiles Inhabiting the United States. Vol. 1 (1st ed.). Philadelphia, PA: J. Dobson. pp. 111–112.
  3. ↑ Baird SF, Girard C (1853). Catalogue of North American Reptiles in the Museum of the Smithsonian Institution. Part I.—Serpents. Washington, District of Columbia: Smithsonian Institution. xvi + 172 pp. (Scotophis alleghaniensis, new combination, p. 73).
  4. ↑ Hallowell E (1856). "Notice of a collection of reptiles from Kansas and Nebraska, presented to the Academy of Natural Sciences by Dr. Hammond". U.S.A. Proc. Acad. Nat. Sci. 8: 238–253. (Elaphis alleghaniensis, new combination, p. 243).
  5. ↑ Garman S (1892). The Discoboli. Cyclopteridæ, Liparopsidæ, and Liparididæ. Cambridge, MA: Museum of Comparative Zoology at Harvard College. ISBN   978-1-176-12022-8.
  6. ↑ Boulenger GA (1894). Catalogue of the Snakes in the British Museum (Natural History). Volume II., Containing the Conclusion of the Colubridæ Aglyphæ. London: Trustees of the British Museum (Natural History). (Taylor and Francis, printers). xi + 382 pp. + Plates I-XX. (Coluber obsoletus, pp. 50-51).
  7. ↑ Stejneger L, Barbour T (1917). A Check List of North American Amphibians and Reptiles. Cambridge, Massachusetts: Harvard University Press. 125 pp. (Elaphe obsoleta, p. 83).
  8. ↑ Burbrink FT (2001). "Systematics of the eastern ratsnake complex (Elaphe obsoleta)". Herpetological Monographs. 15: 1–53. doi:10.2307/1467037. JSTOR   1467037.
  9. ↑ Collins, Joseph T.; Taggart, Travis W. (2008). "An alternative classification of the New World Rat Snakes (genus Pantherophis[Reptilia: Squamata: Colubridae])" (PDF). Journal of Kansas Herpetology. 26: 16–18.
  10. 1 2 3 "Pantherophis alleghaniensis " (PDF). The Reptile Database. Zoological Museum Hamburg. Retrieved 2015-07-08.
  11. 1 2 3 4 5 6 7 "Eastern Ratsnake: Pantherophis alleghaniensis " (PDF). Massachusetts Division of Fisheries & Wildlife. Westborough, MA. Retrieved 2015-07-08.
  12. 1 2 3 4 "Pantherophis alleghaniensis ". Florida Museum of Natural History. Gainesville, FL. Retrieved 2015-07-09.
  13. 1 2 3 "Field Guide to Maryland's Snakes (Order Squamata): Eastern Ratsnake". Maryland Department of Natural Resources. Annapolis, MD. Retrieved 2015-07-08.
  14. ↑ Powell R, Conant R, Collins JT (2016). Peterson Field Guide to Reptiles and Amphibians of Eastern and Central North America, Fourth Edition. Boston and New York: Houghton Mifflin Harcourt. xiv + 494 pp. ISBN   978-0-544-12997-9. (Pantherophis alleghaniensis, pp. 384-385 + Plate 36 + Figures 161, 180).
  15. ↑ Penning DA, Moon BR (2017). '"The king of snakes: performance and morphology of intraguild predators (Lampropeltis) and their prey (Pantherophis)". Journal of Experimental Biology220 (6): 1154-1161.
  16. ↑ Veilleux J, Dombrowski DS, Allender MC, Lewbart G (2020). "Diagnosis, treatment and post‐release monitoring of an eastern black rat snake (Pantherophis alleghaniensis) with ophidiomycosis and traumatic injuries". Veterinary Record Case Reports8 (2): e000954.
  17. ↑ "Black Ratsnake". www.marshall.edu. Retrieved 2023-04-22.
  18. ↑ "Black Ratsnake". www.marshall.edu. Retrieved 2023-04-22.
  19. ↑ "Black Ratsnake". www.marshall.edu. Retrieved 2023-04-22.
  20. ↑ Pantherophis alleghaniensis at Pennsylvania Herp Identification. http://www.paherps.com/herps/snakes/rat_snake.
  21. ↑ Howze, Jennifer M.; Sash, Kimberly J.; Carroll, John P.; Smith, Lora L. (2019-01-15). "A regional scale assessment of habitat selection and home range of the eastern rat snake in pine-dominated forests". Forest Ecology and Management. 432: 225–230. doi: 10.1016/j.foreco.2018.09.018 . ISSN   0378-1127.
  22. 1 2 Ferguson GW (2020). "Seasonal Activity and Population Fluctuations of a Free-Ranging Population of the Rat Snake Pantherophis obsoletus Inhabiting the Dallas Zoo, Texas". The Southwestern Naturalist. 64 (3–4, Southwestern Association of Naturalists, 2020): 173–79. doi:10.1894/0038-4909-64.3-4.173. S2CID   228881070.
  23. 1 2 Behler, John L.; King, F. Wayne (1979). National Audubon Society Field Guide to North American Reptiles and Amphibians . Audubon Society Field Guide Series. New York, NY: Knopf Doubleday Publishing Group. ISBN   978-0-394-50824-5.
  24. ↑ Cerreta, Anthony J.; Cannizzo, Sarah A.; Smith, Dustin C.; Minter, Larry J. (2020-02-14). "Venous hematology, biochemistry, and blood gas analysis of free-ranging Eastern Copperheads (Agkistrodon contortrix) and Eastern Ratsnakes (Pantherophis alleghaniensis)". PLOS ONE. 15 (2): e0229102. Bibcode:2020PLoSO..1529102C. doi: 10.1371/journal.pone.0229102 . ISSN   1932-6203. PMC   7021292 . PMID   32059022.
  25. ↑ Blouin-Demers, G.; Weatherhead, P.J. (2001). "HABITAT USE BY BLACK RAT SNAKES (ELAPHE OBSOLETA OBSOLETA) IN FRAGMENTED FORESTS". Ecology. 82 (10): 2882-2896. doi:10.1890/0012-9658(2001)082[2882:HUBBRS]2.0.CO;2.
  26. ↑ "Pantherophis alleghaniensis ". Nature Serve. Nature Server Explorer: An Online Encyclopedia of Life. Retrieved 2015-07-10.
  27. 1 2 "Black Rat Snake". The Maryland Zoo. Baltimore, MD. Retrieved 2015-07-10.
  28. 1 2 "Eastern Ratsnake (Pantherophis alleghaniensis)". Virginia Herpetological Society. Retrieved 2015-07-10.
  29. ↑ Blouin-Demers, G.; Weatherhead, P.J. (2001). "HABITAT USE BY BLACK RAT SNAKES (ELAPHE OBSOLETA OBSOLETA) IN FRAGMENTED FORESTS". Ecology. 82 (10): 2882-2896. doi:10.1890/0012-9658(2001)082[2882:HUBBRS]2.0.CO;2.
  30. ↑ Fitch, H.S. (1963). "Natural History of the Black Rat Snake (Elaphe o. obsoleta) in Kansas". Copeia. 1963 (4): 649–658. doi:10.2307/1440967. JSTOR   1440967.
  31. ↑ Pantherophis Archived 2011-10-30 at the Wayback Machine . SSARHerps.
  32. ↑ Utiger U; Helfenberger N; Schätti B; Schmidt C; Ruf M; Ziswiler V (2002). "Molecular Systematics and Phylogeny of Old and New World ratsnakes, Elaphe Auct., and related genera (Reptilia, Squamata, Colubridae)" (PDF). Russian Journal of Herpetology. 9 (2): 105–124.
  33. ↑ Burbrink FT, Lawson R (2007). "How and when did Old World ratsnakes disperse into the New World?". Molecular Phylogenetics and Evolution. 43 (1): 173–189. doi:10.1016/j.ympev.2006.09.009. PMID   17113316.
  34. ↑ Pyron RA; Burbrink FT (2009). "Neogene diversification and taxonomic stability in the snake tribe Lampropeltini (Serpentes: Colubridae)". Molecular Phylogenetics and Evolution. 52 (2): 524–529. doi:10.1016/j.ympev.2009.02.008. PMID   19236930.

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