Rat snakes are members – along with
kingsnake
Kingsnakes are Colubridae, colubrid New World members of the genus ''Lampropeltis'', which includes 26 species. Among these, about 45 subspecies are recognized. They are nonvenomous and ophiophagy, ophiophagous in diet.
Description
Kingsnakes ...
s,
milk snakes,
vine snakes and
indigo snakes – of the subfamily
Colubrinae
The Colubrinae are a subfamily of snakes within the family Colubridae. It includes numerous genus, genera, and although Taxonomy (biology), taxonomic sources often disagree on the exact number, the Reptile Database lists 717 species in 92 genera ...
of the family
Colubridae
Colubridae (, commonly known as colubrids , from , 'snake') is a family of snakes. With 249 genera, it is the largest snake family. The earliest fossil species of the family date back to the Late Eocene epoch, with earlier origins suspected. C ...
. They are medium to large
constrictors and are found throughout much of the
Northern Hemisphere
The Northern Hemisphere is the half of Earth that is north of the equator. For other planets in the Solar System, north is defined by humans as being in the same celestial sphere, celestial hemisphere relative to the invariable plane of the Solar ...
. They feed primarily on
rodent
Rodents (from Latin , 'to gnaw') are mammals of the Order (biology), order Rodentia ( ), which are characterized by a single pair of continuously growing incisors in each of the upper and Mandible, lower jaws. About 40% of all mammal specie ...
s. Many species make attractive and docile
pet
A pet, or companion animal, is an animal kept primarily for a person's company or entertainment rather than as a working animal, livestock, or a laboratory animal. Popular pets are often considered to have attractive/ cute appearances, inte ...
s and one, the
corn snake
The corn snake (''Pantherophis guttatus''), sometimes called red rat snake is a species of North American rat snake in the Family (biology), family Colubridae. The species subdues its small prey by constriction. It is found throughout the sout ...
, is one of the most popular
reptile pet
Herpetoculture is the keeping of live reptiles and amphibians in captivity (animal), captivity, whether as a hobby or as a commercial biological reproduction, breeding operation. "Herps" is an informal term for both reptiles and amphibians, shorte ...
s 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.
Previously, most rat snakes were assigned to the genus ''
Elaphe'', but many have been since renamed following
mitochondrial DNA
Mitochondrial DNA (mtDNA and mDNA) is the DNA located in the mitochondrion, mitochondria organelles in a eukaryotic cell that converts chemical energy from food into adenosine triphosphate (ATP). Mitochondrial DNA is a small portion of the D ...
analysis performed in 2002. For the purpose of this article, names will be harmonized with the
TIGR Database.
Species
Old World rat snakes

''
Coelognathus'' spp.
* Philippine rat snake, ''
C. erythrurus''
( A.M.C. Duméril, Bibron & A.H.A. Duméril, 1854)
* Black copper rat snake or yellow striped snake, ''
C. flavolineatus''
( Schlegel, 1837)
* Trinket snake, ''
C. helena''
( Daudin, 1803)
* Copperhead rat snake, ''
C. radiatus''
( F. Boie, 1827)
* Indonesian rat snake, ''
C. subradiatus''
(Schlegel, 1837)
''
Elaphe'' spp.
* Twin-spotted rat snake, ''
Elaphe bimaculata''
Schmidt
Schmidt may refer to:
* Schmidt (surname), including list of people and fictional characters with the surname
* Schmidt (singer) (born 1990), German pop and jazz singer
* Schmidt (lunar crater), a small lunar impact crater
* Schmidt (Martian c ...
, 1925
* King rat snake, ''
Elaphe carinata''
( Günther, 1864)
* Japanese rat snake, ''
E. climacophora''
( H. Boie, 1826)
* David's rat snake, ''
E. davidi''
( Sauvage, 1884)
* Dione rat snake, ''
E. dione''
(Pallas
Pallas may refer to:
Astronomy
* 2 Pallas asteroid
** Pallas family, a group of asteroids that includes 2 Pallas
* Pallas (crater), a crater on Earth's moon
Mythology
* Pallas (Giant), a son of Uranus and Gaia, killed and flayed by Athena
* Pa ...
, 1773)
* Japanese four-lined rat snake, ''
E. quadrivirgata''
(H. Boie, 1826)
* Four-lined snake, ''
E. quatuorlineata''
( Lacépède, 1789)
* Red-backed rat snake, ''
E. rufodorsata''
(Cantor
A cantor or chanter is a person who leads people in singing or sometimes in prayer. Cantor as a profession generally refers to those leading a Jewish congregation, although it also applies to the lead singer or choir director in Christian contexts. ...
, 1842)
* Eastern four-lined snake, ''
E. sauromates''
(Pallas, 1811)
* Russian rat snake, ''
E. schrenckii''
Strauch
Strauch, a German word meaning ''bush'' or ''shrub
A shrub or bush is a small to medium-sized perennial woody plant. Unlike herbaceous plants, shrubs have persistent woody stems above the ground. Shrubs can be either deciduous or evergreen. ...
, 1873
''
Euprepiophis'' spp.
* Japanese forest rat snake, ''
E. conspicillatus''
(H. Boie, 1826)
* Mandarin rat snake, ''
E. mandarinus''
(Cantor, 1842)
''
Gonyosoma'' spp.
* Green trinket snake, ''
G. frenatum''
(Gray
Grey (more frequent in British English) or gray (more frequent in American English) is an intermediate color between black and white. It is a neutral or achromatic color, meaning that it has no chroma. It is the color of a cloud-covered s ...
, 1853)
* Celebes black-tailed rat snake, ''
G. jansenii''
( Bleeker, 1858)
* Red-tailed green rat snake, ''
G. oxycephalum''
(F. Boie, 1827)
''
Oreocryptophis'' spp.
* Mountain rat snake, ''
O. porphyracea''
(Cantor, 1839)
''
Orthriophis'' spp.
* Cantor's rat snake, ''
O. cantoris''
( Boulenger, 1894)
* Hodgson's rat snake, ''
O. hodgsoni''
(Günther, 1860)
* 100 flower rat snake, ''
O. moellendorffi''
( Boettger, 1886)
* Beauty snake, ''
O. taeniurus''
(Cope
A cope ( ("rain coat") or ("cape")) is a liturgical long mantle or cloak, open at the front and fastened at the breast with a band or clasp. It may be of any liturgical colour.
A cope may be worn by any rank of the Catholic or Anglican clerg ...
, 1861)
''
Ptyas
''Ptyas'' is a genus of colubrid snakes. This genus is one of several colubrid genera colloquially called " rat snakes" or "ratsnakes".
The generic name derives from Ancient Greek πτυάς, meaning " spitter", which referred to a kind of snak ...
'' spp.
* Keeled rat snake, ''
P. carinata''
(Günther, 1858)
* ''
P. dhumnades''
(Cantor, 1842)
* Sulawesi black racer, ''
P. dipsas''
(Schlegel, 1837)
* White-bellied rat snake, ''
P. fusca''
(Günther, 1858)
* Chinese rat snake, ''
P. korros''
(Schlegel, 1837)
* ''
P. luzonensis''
(Günther, 1873)
* Oriental rat snake, ''
P. mucosa''
(Linnaeus
Carl Linnaeus (23 May 1707 – 10 January 1778), also known after ennoblement in 1761 as Carl von Linné,#Blunt, Blunt (2004), p. 171. was a Swedish biologist and physician who formalised binomial nomenclature, the modern system of naming o ...
, 1758)
* Green rat snake, ''
P. nigromarginata''
( Blyth, 1854)
''
Rhadinophis'' spp.
* Green bush snake, ''
R. prasinus''
(Blyth, 1854)
''
Rhynchophis'' spp.
*
Rhinoceros ratsnake, ''
R. boulengeri''
Mocquard, 1897
''
Zamenis'' spp.
* Transcaucasian rat snake, ''
Z. hohenackeri''
(Strauch, 1873)
* Italian Aesculapian snake, ''
Z. lineatus''
(Camerano
Camerano is a ''comune'' (municipality) in the Province of Ancona in the Italy, Italian region Marche, located about southeast of Ancona.
Camerano borders the following municipalities: Ancona, Castelfidardo, Osimo, Sirolo.
Camerano is most notab ...
, 1891)
* Aesculapian snake, ''
Z. longissimus''
( Laurenti, 1768)
* Persian rat snake, ''
Z. persicus''
( F. Werner, 1913)
* Ladder snake, ''
Z. scalaris''
( Schinz, 1822)
* Leopard snake, ''
Z. situla''
(Linnaeus, 1758)
New World rat snakes

''
Bogertophis'' spp.
* Baja California rat snake, ''
B. rosaliae''
(Mocquard, 1899)
* Trans-Pecos rat snake, ''
B. subocularis''
(Brown
Brown is a color. It can be considered a composite color, but it is mainly a darker shade of orange. In the CMYK color model used in printing and painting, brown is usually made by combining the colors Orange (colour), orange and black.
In the ...
, 1901)
''
Pantherophis
''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 fox snake, foxsnakes, and the cornsnakes. The genus, which contains 10 recognize ...
'' spp.
* Eastern rat snake, ''
P. alleghaniensis''
( Holbrook, 1836)
* Baird's rat snake, ''
P. bairdi''
(Yarrow
''Achillea millefolium'', commonly known as yarrow () or common yarrow, is a flowering plant in the family Asteraceae. Growing to tall, it is characterized by small whitish flowers, a tall stem of fernlike leaves, and a pungent odor.
The plan ...
, 1880)
* Great Plains rat snake, ''
P. emoryi''
( Baird & Girard, 1853)
* Eastern fox snake, ''
P. gloydi''
( Conant, 1940)
* Corn snake, ''
P. guttatus''
(Linnaeus, 1766)
* Black rat snake, ''
P. obsoletus''
( Say, 1823)
* Western fox snake, ''
P. ramspotti''
(Crother, White, Savage, Eckstut, Graham & Gardner, 2011)
* Gray rat snake, ''
P. spiloides''
(A.M.C. Duméril, Bibron & A.H.A. Duméril, 1854)
* Eastern fox snake, ''
P. vulpinus''
(Baird & Girard, 1853)
''
Pseudelaphe'' spp.
* Mexican rat snake, ''
P. flavirufa''
(Cope, 1867)
''
Senticolis'' spp.
* Green rat snake, ''
S. triaspis''
(Cope, 1866)
''
Spilotes
''Spilotes'' is a genus of snakes in the Family (biology), family Colubridae. The genus is Endemism, endemic to the New World.
Geographic range
Species in the genus ''Spilotes'' are found in Mexico, Central America, and South America..
Species
...
'' spp.
* Chicken snake or yellow rat snake, ''
S. pullatus''
(Linnaeus, 1758)
''
Nota bene
( ; plural: ) is the Latin language, Latin phrase meaning ''note well''.
In manuscripts, ''nota bene'' is abbreviated in upper-case as NB and N.B., and in lower-case as n.b. and nb; the editorial usages of ''nota bene'' and ''notate bene'' fi ...
'': In the above species lists, an authority's name in parentheses indicates that the
species
A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...
was originally described in a different
genus
Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...
. An authority's name not in parentheses indicates that the species is still assigned to the original genus in which it was described.
Taxonomy
In recent years, some taxonomic controversy has occurred over the genus of North American rat snakes. Based on mitochondrial DNA, Utiger et al. (2002) showed that North American rat snakes of the genus ''Elaphe'', along with closely related genera such as ''Pituophis'' and ''Lampropeltis'', form a monophyletic group separate from Old World members of the genus. They therefore suggested the resurrection of the available name ''Pantherophis''
Fitzinger for all North American taxa (north of Mexico).
[''Elaphe obsoleta''](_blank)
a
The Center for North American Herpetology
Accessed 20 June 2008. Crother et al. (2008) accepted the taxonomic change to ''Pantherophis''.
[Crother BI, et al. (2008) Scientific and Standard English Names of Amphibians and Reptiles of North America North of Mexico: 6th edition. Herp. Rev. 37, pp. 58–59. or se]
pp. 64 ff in the 7th edition
Venom
Like nearly all
colubrids, rat snakes pose no threat to humans. Although rat snakes were long believed to be completely nonvenomous, recent studies have shown that some Old World species do possess small amounts of venom, though the amount is negligible relative to humans.
Rat snakes usually hunt and kill mice and other small animals by grasping with their teeth to prevent escape, wrapping their body around that of the prey, and suffocating the prey by constriction.
In captivity
Rat snakes are commonly kept as pets by reptile enthusiasts. The
corn snake
The corn snake (''Pantherophis guttatus''), sometimes called red rat snake is a species of North American rat snake in the Family (biology), family Colubridae. The species subdues its small prey by constriction. It is found throughout the sout ...
, one of the most popular pet reptiles, is a rat snake. New World species are generally thought to be more docile in captivity than Old World rat snakes.
Effects of climate change on rat snakes
Positive impacts
All snakes are
ectotherm
An ectotherm (), more commonly referred to as a "cold-blooded animal", is an animal in which internal physiological sources of heat, such as blood, are of relatively small or of quite negligible importance in controlling body temperature.Dav ...
species, meaning they depend on the temperature of the environment to maintain
homeostasis
In biology, homeostasis (British English, British also homoeostasis; ) is the state of steady internal physics, physical and chemistry, chemical conditions maintained by organism, living systems. This is the condition of optimal functioning fo ...
. Although it is predicted that the current rate of
climate change
Present-day climate change includes both global warming—the ongoing increase in Global surface temperature, global average temperature—and its wider effects on Earth's climate system. Climate variability and change, Climate change in ...
will be too rapid for many reptiles and amphibian species to adapt or to evolve, studies have suggested that a warmer climate may actually be beneficial to rat snake species. Global warming also poses less threats to rat snakes in temperate zones than in tropical zones as rat snake species in temperate zones can tolerate broader ranges of temperature.
Global climate change will increase both day and night time temperatures. This will make the night time environment more thermally suitable for rat snakes to hunt, thereby making them more active at night.
Increasing night time activity allows rat snakes to catch larger prey such as
bird
Birds are a group of warm-blooded vertebrates constituting the class (biology), class Aves (), characterised by feathers, toothless beaked jaws, the Oviparity, laying of Eggshell, hard-shelled eggs, a high Metabolism, metabolic rate, a fou ...
s, since female birds usually incubate their eggs in the nest at night and have decreased ability to detect rat snakes due to poor visibility conditions. Global warming may also lead to changes in
predation
Predation is a biological interaction in which one organism, the predator, kills and eats another organism, its prey. It is one of a family of common List of feeding behaviours, feeding behaviours that includes parasitism and micropredation ...
. Rat snakes are prey species to predators like
hawk
Hawks are birds of prey of the family Accipitridae. They are very widely distributed and are found on all continents, except Antarctica.
The subfamily Accipitrinae includes goshawks, sparrowhawks, sharp-shinned hawks, and others. This ...
s. While rat snakes are being hunted during the day, being more active at night due to warmer temperatures may allow rat snakes to be less vulnerable to predation from hawks.
A warming climate also enhances food digestion in rat snakes thereby making them more efficient, which enables rat snake individuals to grow larger in size and allowing them to consume more prey.
In comparison to rat snake species at relatively colder regions, rat snake species at lower latitudes tend to be larger in size due to warmer climate conditions. As the global climate warms, the average body size of rat snakes at higher latitudes will become larger, which will allow the species to catch more prey and thus increase their overall reproductive success.
Negative impacts
Eastern rat snake species in
North America
North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...
are experiencing negative shifts in their
behaviour
Behavior (American English) or behaviour (British English) is the range of actions of Individual, individuals, organisms, systems or Artificial intelligence, artificial entities in some environment. These systems can include other systems or or ...
due to Global Warming and increasing temperatures. These shifts differ between the large distribution of rat snakes that range from
Ontario
Ontario is the southernmost Provinces and territories of Canada, province of Canada. Located in Central Canada, Ontario is the Population of Canada by province and territory, country's most populous province. As of the 2021 Canadian census, it ...
to
Texas
Texas ( , ; or ) is the most populous U.S. state, state in the South Central United States, South Central region of the United States. It borders Louisiana to the east, Arkansas to the northeast, Oklahoma to the north, New Mexico to the we ...
.
The increasing Global Warming can negatively impact this species and can be responsible for population declines in some areas.
Rat snake populations from their northern range, such as Ontario, are experiencing a shift in
hibernation
Hibernation is a state of minimal activity and metabolic reduction entered by some animal species. Hibernation is a seasonal heterothermy characterized by low body-temperature, slow breathing and heart-rate, and low metabolic rate. It is mos ...
emergence.
The populations in these regions typically emerge from hibernation in late April.
However, the increasing variability in temperature may cause rat snakes to emerge on a warm sunny day in the months of February or March.
Climate change has caused winters that can have weather turn back very quickly from sunny periods with high temperatures to snow and below freezing temperatures. The early emergence of these rat snakes will begin to expose them to these fatal conditions if a snake cannot return to its
hibernaculum in time.
Therefore, the fluctuations in temperature affect the
thermoregulation
Thermoregulation is the ability of an organism to keep its body temperature within certain boundaries, even when the surrounding temperature is very different. A thermoconforming organism, by contrast, simply adopts the surrounding temperature ...
that rat snakes need for bodily functions like digestion and movement.
The unpredictability of the weather is causing more rat snakes in their northern range to get caught in these cold snaps and freeze to death.
Increasing temperatures due to climate change have increased the
nocturnal
Nocturnality is a ethology, behavior in some non-human animals characterized by being active during the night and sleeping during the day. The common adjective is "nocturnal", versus diurnality, diurnal meaning the opposite.
Nocturnal creatur ...
activity of rat snakes, especially in warmer climates such as Texas.
This has allowed them to alter their predation habits and feed more on nesting birds and other accessible prey. However, their increased nocturnal activity puts them at risk to a new range of nocturnal predators. Rat snakes may not be used to the presence of nocturnal predators such as
raccoon
The raccoon ( or , ''Procyon lotor''), sometimes called the North American, northern or common raccoon (also spelled racoon) to distinguish it from Procyonina, other species of raccoon, is a mammal native to North America. It is the largest ...
s and
owl
Owls are birds from the order Strigiformes (), which includes over 200 species of mostly solitary and nocturnal birds of prey typified by an upright stance, a large, broad head, binocular vision, binaural hearing, sharp talons, and feathers a ...
s and may be more vulnerable as prey. Until rat snakes are able to adapt to their relatively new predators, populations may be at risk due to heavy predation.
Life history alterations in Ontario gray rat snakes
As rat snakes are ectothermic species, they require sunlight and heat to maintain their body temperatures. Across their range in North America each species of rat snake has different ideal body temperatures. In Ontario, the average ideal body temperature of a rat snake is 28.1 degrees Celsius with free ranging gravid females tending to require a bit higher in order to meet their thermoregulatory requirements for
gestation
Gestation is the period of development during the carrying of an embryo, and later fetus, inside viviparous animals (the embryo develops within the parent). It is typical for mammals, but also occurs for some non-mammals. Mammals during pregn ...
.
With ambient air temperatures over the course of their entire active season (from May to September) almost never reaching the required 28.1 °C, rat snakes in Ontario resort to basking
habitat
In ecology, habitat refers to the array of resources, biotic factors that are present in an area, such as to support the survival and reproduction of a particular species. A species' habitat can be seen as the physical manifestation of its ...
s where conditions allow temperatures to rise above normal and up to 43 degrees Celsius at the hottest times of day and year.
These habitats include areas such as rock
outcrop
An outcrop or rocky outcrop is a visible exposure of bedrock or ancient superficial deposits on the surface of the Earth and other terrestrial planets.
Features
Outcrops do not cover the majority of the Earth's land surface because in most p ...
s, bare ground, or edge habitat where they can bask on tree branches fully exposed to the sun. However, with climate change and an associated increase in ambient air temperature by 3 °C, the amount of required time spent by snakes in these habitats will decrease. This will result in alterations in the amount and time of activity of rat snakes in the province. They will have the potential to be generally more active during both the day and night as it will be easier for them to maintain their ideal body temperature. Habitat choices may also shift with increased temperatures. More time could be spent in areas such as forests or barns where the temperatures are currently too low for the snakes to spend most of their time.
There will be less of a need to expose themselves in their open basking habitats, causing decreases in predator vulnerability as well as increases in thermoregulatory ability and foraging time. In addition, rat snakes in Ontario have a slower growth and maturation rates due to the cooler climate and shorter active seasons compared to other species of rat snakes further South in North America. This means that Ontario's rat snakes are more vulnerable to population declines. But, with an increase in temperature and an increase in the duration of the active season from climate change, it is possible that the growth and maturation rates of these snakes will increase.
See also
*
Black rat snake
*
Beauty rat snake
*
Gray rat snake
*
Texas rat snake
* ''
Ptyas mucosa
''Ptyas'' is a genus of colubrid snakes. This genus is one of several colubrid genera colloquially called " rat snakes" or "ratsnakes".
The generic name derives from Ancient Greek πτυάς, meaning " spitter", which referred to a kind of sn ...
''
References
{{Authority control
*
Colubrids
Snake common names