Eastern rat snake

The generic name Pantherophis, meaning "panther-like snake", is from {{langx|grc|πάνθηρ}}: pánthēr, "panther" and {{langx|grc|ὄφις}}: óphis, "snake".

The specific name name quadrivittatus, meaning "four-banded", is from {{langx|la|vitta}} meaning "band" in reference to the four dark stripes running the length of the snake's body.

Additional common names for Pantherophis quadrivittatus include black rat snake, pilot snake, pilot black snake, {{cite web

| url= http://www.mass.gov/eea/docs/dfg/nhesp/species-and-conservation/nhfacts/pantherophis-alleghaniensis.pdf

| title=Eastern Ratsnake: Pantherophis alleghaniensis

| author=

| website=Massachusetts Division of Fisheries & Wildlife

| location=Westborough, MA

| access-date=2015-07-08}} chicken snake; and in Florida, yellow rat snake and Everglades rat snake. {{cite web

| url=http://www.flmnh.ufl.edu/herpetology/fl-snakes/list/pantherophis-alleghaniensis

| title=Pantherophis alleghaniensis

| author=

| website=Florida Museum of Natural History

| location=Gainesville, FL

| access-date=2015-07-09}}

Pantherophis quadrivittatus is found in the United States east of the Apalachicola River in Florida, east of the Piedmont in Maryland, South Carolina, North Carolina, Georgia, and south to the Florida Keys. In the Florida Panhandle, it readily hybridizes with the gray rat snake (Pantherophis alleghaniensis).

File:Pantherophis alleghaniensis ssp. quadrivittata 03.JPG

Adult eastern rat snakes commonly measure {{cvt|90|to|183|cm|ftin|abbr=on}} in total length (including tail), with a few exceeding {{cvt|200|cm|ftin|abbr=on}}. The longest recorded total length to date for an eastern rat snake is {{cvt|228|cm|ftin|abbr=on}}. A sample of eastern rat snakes, including juvenile and adult snakes, weighed from {{cvt|54|to|1274|g|lb|abbr=on}}.{{cite journal|author=Penning DA|author2= Moon BR |year=2017|title=The king of snakes: performance and morphology of intraguild predators (Lampropeltis) and their prey (Pantherophis)|journal=Journal of Experimental Biology|volume=220|issue=6|pages= 1154–1161|doi= 10.1242/jeb.147082 |pmid= 28298469 |bibcode= 2017JExpB.220.1154P }} A further adult weighed {{cvt|833|g|lb}}.{{cite journal|author=Veilleux J|author2= Dombrowski DS |author3= Allender MC|author4= Lewbart G |year=2020|title=Diagnosis, treatment and post-release monitoring of an eastern black rat snake (Pantherophis alleghaniensis) with ophidiomycosis and traumatic injuries |journal=Veterinary Record Case Reports|volume=8|issue=2|page=e000954|doi= 10.1136/vetreccr-2019-000954 }}

Adults in the north of its range are shiny black dorsally, with a cream or white chin and throat. White areas of skin can appear between scales. The belly has an irregular black-and-white checkerboard pattern, becoming uniformly slate gray towards the tail. Juveniles have 28 to 40{{Cite web |title=Black Ratsnake |url=https://www.marshall.edu/herp/Snakes/Black_Ratsnake.htm |access-date=2023-04-22 |website=www.marshall.edu}} 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, with particularly in juveniles, but not always present in adults, a distinct white margin.{{cite web |author= |title=Field Guide to Maryland's Snakes (Order Squamata): Eastern Ratsnake |url=http://dnr2.maryland.gov/wildlife/Pages/plants_wildlife/herps/Squamata.aspx?SnakeName=Eastern+Ratsnake |access-date=2015-07-08 |website=Maryland Department of Natural Resources |location=Annapolis, MD}}

In the Florida Peninsula, adult rat snakes can be yellow, orange, tan, or gray, with four dark, longitudinal stripes.{{Cite web |title=Eastern Ratsnake |url=https://www.floridamuseum.ufl.edu/florida-snake-id/snake/eastern-ratsnake/ |access-date=2025-02-24 |website=Florida Snake ID Guide |language=en-US}}

In cross section, the bodies of rat snakes are not round, but instead resemble a loaf of bread.{{Cite web |title=Black Ratsnake |url=https://www.marshall.edu/herp/Snakes/Black_Ratsnake.htm |access-date=2023-04-22 |website=www.marshall.edu}}

The dorsal scales are weakly keeled, and are arranged in 23 to 27 rows at midbody.{{cite web|title=Pantherophis alleghaniensis |website= Pennsylvania Herp Identification |url=http://www.paherps.com/herps/snakes/rat_snake}}

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).

The eastern rat snake occurs in a variety of habitats, including 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.

The eastern rat snake is primarily active at night during the summer, and diurnal in the spring and fall.{{cite book |last1=Behler |first1=John L. |author-link=John L. Behler |last2=King |first2=F. Wayne |author2-link=species:Frederic Wayne King|year=1979 |title=National Audubon Society Field Guide to North American Reptiles and Amphibians |series=Audubon Society Field Guide Series |publisher=Knopf Doubleday Publishing Group |location=New York, NY |isbn=978-0-394-50824-5 |url-access=registration |url=https://archive.org/details/audubonsocietyfi00behl }} 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 knotholes 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.{{Cite journal |last1=Cerreta |first1=Anthony J. |last2=Cannizzo |first2=Sarah A. |last3=Smith |first3=Dustin C. |last4=Minter |first4=Larry J. |date=2020-02-14 |title=Venous hematology, biochemistry, and blood gas analysis of free-ranging Eastern Copperheads (Agkistrodon contortrix) and Eastern Ratsnakes (Pantherophis alleghaniensis) |journal=PLOS ONE |volume=15 |issue=2 |pages=e0229102 |doi=10.1371/journal.pone.0229102 |pmid=32059022 |issn=1932-6203|pmc=7021292 |doi-access=free |bibcode=2020PLoSO..1529102C }} 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.{{cite journal |last1=Blouin-Demers |first1=G. |last2=Weatherhead |first2=P.J. |title=HABITAT USE BY BLACK RAT SNAKES ( ELAPHE OBSOLETA OBSOLETA ) IN FRAGMENTED FORESTS |journal=Ecology |date=2001 |volume=82 |issue=10 |page=2882-2896|doi=10.1890/0012-9658(2001)082[2882:HUBBRS]2.0.CO;2 }} 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.{{cite web| url = http://explorer.natureserve.org/servlet/NatureServe?searchName=Pantherophis+alleghaniensis | website = Nature Serve | title =Pantherophis alleghaniensis | series = Nature Server Explorer: An Online Encyclopedia of Life | access-date = 2015-07-10| author = }} 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.{{cite web| url = http://www.marylandzoo.org/animals-conservation/reptiles/black-rat-snake/ | title =Black Rat Snake | location=Baltimore, MD | website = The Maryland Zoo | access-date = 2015-07-10| author = }}

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. They are active earlier in the south.{{cite web| url = http://www.virginiaherpetologicalsociety.com/reptiles/snakes/eastern-ratsnake/blackrat_snake.php | title =Eastern Ratsnake (Pantherophis alleghaniensis) | access-date = 2015-07-10| website = Virginia Herpetological Society | author = }}

Eastern rat snakes are oviparous, and gaining nutrients for eggs is facilitated by the female maintaining her body temperature. They reach sexual maturity in their fourth year.{{cite journal |last1=Fitch |first1=H.S. |title=Natural History of the Black Rat Snake (Elaphe o. obsoleta) in Kansas |journal=Copeia |date=1963 |volume=1963 |issue=4 |pages=649–658 |doi=10.2307/1440967 |jstor=1440967 }} The snakes start to breed in May and June, earlier in the south. Males approach females to initiate breeding, and may fight other males before breeding. About five weeks after mating, the female lays five 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.

File:Juvenile ratsnake crop.jpg

Pantherophis quadrivittatus has sometimes been considered a subspecies of P. obsoletus, to which it is closely related.{{cite web |title=Pantherophis |url=http://www.ssarherps.org/pages/comm_names/Pantherophis_main.php |url-status=dead |archive-url=https://web.archive.org/web/20111030054421/http://www.ssarherps.org/pages/comm_names/Pantherophis_main.php |archive-date=2011-10-30|website=SSARHerps}}

File:Yellow Rat Snake 377.jpg tree]]

This species has often been placed in the genus Elaphe, but recent phylogenetic analyses have resulted in its transfer to Pantherophis.{{cite journal|author=Utiger U |author2=Helfenberger N |author3=Schätti B |author4=Schmidt C |author5=Ruf M |author6=Ziswiler V |year=2002|title=Molecular Systematics and Phylogeny of Old and New World ratsnakes, Elaphe Auct., and related genera (Reptilia, Squamata, Colubridae)|url=http://vipersgarden.at/PDF_files/PDf-352.pdf|journal= Russian Journal of Herpetology |volume=9|issue=2|pages= 105–124}}{{cite journal|vauthors=Burbrink FT, Lawson R |year=2007|title=How and when did Old World ratsnakes disperse into the New World?|journal= Molecular Phylogenetics and Evolution|volume= 43|pages= 173–189|doi=10.1016/j.ympev.2006.09.009|pmid=17113316|issue=1|bibcode=2007MolPE..43..173B }}{{cite journal|author=Pyron RA |author2=Burbrink FT |year=2009|title=Neogene diversification and taxonomic stability in the snake tribe Lampropeltini (Serpentes: Colubridae)|journal= Molecular Phylogenetics and Evolution |volume=52|pages= 524–529|doi=10.1016/j.ympev.2009.02.008|pmid=19236930|issue=2|bibcode=2009MolPE..52..524P }}

Previously, the eastern rat snake was assigned the binomial Pantherophis alleghaniensis and was thought to occupy the entire eastern seaboard north to Massachusetts. In 2021, genetic analysis found that the holotype for P. allegheniensis belongs to the species then known as Pantherophis spiloides, commonly called the central or gray rat snake. This species is now known to occupy a range between the Mississippi River in the west and the Piedmont in the east, north to New England. Due to the principle of priority, P. spiloides was reassigned to P. alleghaniensis. Therefore, the eastern rat snake, the species distributed east and south of the Piedmont and on the Florida Peninsula, was reassigned to what had been the junior synonym Pantherophis quadrivittatus.

{{Reflist|30em}}

• Holbrook JE (1836). North American Herpetology; or, A Description of the Reptiles Inhabiting the United States. Vol. I. Philadelphia: J. Dobson. 120 pp. (Coluber quadrivittatus, new species, 113–114 + Plate XXI).

{{Commons}}

• {{NRDB species|genus=Pantherophis|species=quadrivittatus|date=29 November|year=2008}}

{{Taxonbar|from=Q3362474}}

Alleghaniensis

Category:Reptiles of the United States

Category:Reptiles of Canada

Category:Reptiles of Ontario

Category:Taxa named by John Edwards Holbrook

Category:Reptiles described in 1836