The narrow-headed garter snake, ''Thamnophis rufipunctatus'', is a
species of
garter snake,
endemic to the southwestern
United States and adjacent northwestern
Mexico. Its
common names also include narrowhead garter snake and narrowhead watersnake.
Geographic range
It is found in
Arizona and
New Mexico, and in the Mexican states of
Sonora
Sonora (), officially Estado Libre y Soberano de Sonora ( en, Free and Sovereign State of Sonora), is one of the 31 states which, along with Mexico City, comprise the Administrative divisions of Mexico, Federal Entities of Mexico. The state is d ...
,
Chihuahua Chihuahua may refer to:
Places
*Chihuahua (state), a Mexican state
**Chihuahua (dog), a breed of dog named after the state
**Chihuahua cheese, a type of cheese originating in the state
**Chihuahua City, the capital city of the state
**Chihuahua Mun ...
and
Durango
Durango (), officially named Estado Libre y Soberano de Durango ( en, Free and Sovereign State of Durango; Tepehuán: ''Korian''; Nahuatl: ''Tepēhuahcān''), is one of the 31 states which make up the 32 Federal Entities of Mexico, situated in ...
.
Habitat and behavior
It is found near
river bank
Riverbank or river bank may refer to:
*Bank (geography), the bank of a river
Places
*Riverbank, California
*Riverbank, former name of Bryte, California
Enterprises and organizations
*Riverbank Academy, a special school in Coventry, England
* Ri ...
s or
streams
A stream is a continuous body of water, body of surface water Current (stream), flowing within the stream bed, bed and bank (geography), banks of a channel (geography), channel. Depending on its location or certain characteristics, a stream ...
. It is one of the most aquatic of all garter snakes.
[
]
Description
The snake is blue-grey to olive-grey, or greenish to brown, and it has brown, orange, or black spots on the back. The total length of adults is (about 81–112 cm). It has eight or 9 upper labial scaless, one of which enters the eye, two or three preocular scales, two to four postoculars, and one anterior temporal scale. The keeled dorsal scales are arranged in 21 rows at midbody. Ventrals number 152–177; the anal plate is entire; the subcaudals number 65–87, and are divided.
Diet
These snakes are piscivorous, meaning they primarily eat fish. Their diet includes dace, chubs, and both native and introduced trout. They might occasionally prey on salamanders.
Threatened species
The snake has declined in parts of its range, but the International Union for Conservation of Nature (IUCN) has classified it as of " Least concern" because of its wide range, presumably large population, and because the rate of decline is not high. However, its status in Mexico is poorly known; were it in a decline there, it might qualify for a category of higher risk.[
The decline is attributed to introduced species ( bullfrogs ''Lithobates catesbeianus'', fishes, crayfish), habitat loss and alteration, and sometimes, needless killing and excessive collecting.][
]
Subspecies
Sometimes three subspecies
In biological classification, subspecies is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (morphology), but that can successfully interbreed. Not all species ...
are recognized, including the nominate subspecies
In biological classification, subspecies is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (morphology), but that can successfully interbreed. Not all species ...
:
* ''T. r. nigronuchalis'' Thompson, 1957
* ''T. r. rufipunctatus'' (Cope, 1875)
* ''T. r. unilabialis'' W. Tanner, 1985
However, ''T. r. nigronuchalis'' is now commonly held as a full species, i.e., '' Thamnophis nigronuchalis'', whereas the status of ''T. r. unilabialis'' is more ambiguous; most recent molecular evidence suggests it is a full species as well (''Thamnophis unilabialis'').
References
{{Taxonbar, from=Q2714713
Thamnophis
Reptiles of Mexico
Reptiles of the United States
Reptiles described in 1875
Taxa named by Edward Drinker Cope
ESA threatened species
External Links
United States Fish and Wildlife Service Designation of Critical Habitat for the Narrow-Headed Gartersnake