Ribbonsnakes and Gartersnakes | Herps of Texas

Thamnophis cyrtopsis

Mon, 01 Jan 0001 00:00:00 +0000

Scientific name. Thamnophis cyrtopsis

Common Name. Black-necked Gartersnake

General information. In these warmer habitats, Thamnophis cyrtopsis is nocturnal or crepuscular, becoming diurnal in the spring, or during the fall as the day length shortens. Amphibians and fish make up the majority of the diet of these non-venomous snakes. Thamnophis cyrtopsis is also quick to make use of its scent glands if disturbed, but generally will not bite unless seriously molested. Thamnophis cyrtopsis is known for flattening its body in an attempt to look larger.

Protected status. The Black-necked Gartersnake is not a protected species in Texas and can be legally collected with a hunting license.

Diagnostic features. Undivided anal plate Keeled dorsal scales in 19 rows near midbody

Coloration. Called the “black-necked gartersnake” for black blotches found behind jaws; a yellow vertebral stripe separates these neck blotches. Vertebral stripe may be a shade of orange near the head. Two additional white lateral stripes are positioned over the second and third dorsal scale rows. Dorsal ground color is generally olive; head color is gray. Two rows of alternating blotches are found between the lateral and vertebral stripes. Series of alternating spots is found along the first dorsal scale row. Belly is greenish white and without pigmentation. There are two recognized subspecies of Thamnophis cyrtopsis with their distinction based on slight pattern differences.

General distribution. Thamnophis cyrtopsis is present in the southwestern U.S., found in Arizona, Utah, Colorado, New Mexico, and Texas. Large populations are also present throughout much of northern Mexico, as far south as San Luis Potosi.

Texas distribution. In Texas, Thamnophis cyrtopsis is restricted to the wetter portions of the Trans-Pecos and Edwards Plateau.

Habitat. The habitats of the black-necked gartersnake range from the dry deserts to forested mountains, yet some form of water can almost always be found nearby. Even in around desert springs, miles from any other water source, Thamnophis cyrtopsis can be present in surprising high numbers.

Reproduction. Thamnophis cyrtopsis is viviparous, as are the rest of the garter snakes. As many as 25 young may be born in a single litter, measuring between 20-25.5 cm (8-10 in), making their first appearance in the late summer.

Size. Adult Thamnophis cyrtopsis may grow to 40.5-71 cm [16-28 in] in length.

Map. Orange counties indicate new county records since previous Herps of Texas update in 1998; all other colored counties reflect known distribution prior to 1998 for species and/or subspecies. Map is based on museum voucher specimens.

Thamnophis marcianus

Mon, 01 Jan 0001 00:00:00 +0000

Scientific name. Thamnophis marcianus

Common Name. Checkered Gartersnake

General information. A non-venomous snake, Thamnophis marcianus will often bite would-be captors, leaving only superficial bite marks. Another important defensive mechanism of the checkered garter snake is the habit of defecating foul-smelling liquids upon aggressors. The checkered gartersnake feeds on fish, various amphibians and earthworms. Some individuals have been seen eating carrion from the roadway.

Protected status. The Checkered Gartersnake is not a protected species in Texas and can be legally collected with a hunting license.

Diagnostic features. Anal plate undivided Keeled dorsal scales in rows of no more than 21 near midbody.

Coloration. Dark checkerboard pattern found running entire length of body. Checkerboard blotches are on an olive background and even overlap a light colored middorsal stripe. Two additional two white or yellow lateral stripes are found along the second and third dorsal scale rows (near the head, this stripe is found only on the third scale row). Dorsal surface below lateral stripe may be a lighter shade of green or grey, lighter than the upper dorsal surface. Two yellow or white crescents present directly behind the corner of the mouth, with a large black blotch placed behind each crescent. Belly is mostly without dark markings, except for blotches along the lateral edges of the ventrals.

General distribution. Thamnophis marcianus is found portions of six southwestern U.S. states: California, Arizona, New Mexico, Oklahoma, Kansas, and Texas; Thamnophis marcianus also has an extensive range through portions of northern and east-central Mexico.

Texas distribution. The single subspecies of Thamnophis marcianus present in Texas, T. m. marcianus, occurs across much of the state, being more prevalent in the southern portions of the state, but entirely absent in the eastern quarter of the state

Habitat. Found in a variety of habitats, Thamnophis marcianus is usually not far from a water source, whether it be a pond, stream or irrigation canal, though the nearby water source is not always visible above ground.

Reproduction. As garter snakes are viviparous, young Checkered Gartersnakes are born live throughout the summer months. As many as 18 neonates may be born at one time, with most measuring around 20 cm (8 in).

Size. Thamnophis marcianus adults rarely measure more than 61 cm (24 in) in length, though the record size is over 107 cm (42.5 in).

Thamnophis proximus

Mon, 01 Jan 0001 00:00:00 +0000

Scientific name. Thamnophis proximus

Common Name. Western Ribbonsnake

General information. Foods consumed by ribbonsnakes are primarily amphibians, with tadpoles eaten when available and frogs and toads taken year round. Fish and lizards are also known as potential prey items. Active at dusk and dawn during the spring and fall seasons, T. proximus is can be entirely nocturnal in hot habitats during the summer months. Although it is listed as a non-venomous snake, the saliva of T. proximus has been reported to have toxic properties, though few human envenomations have been reported. It is not thought to be dangerous to humans, and will not bite unless provoked.

Protected status. The Western Ribbonsnake is not a protected species in Texas and can be legally collected with a hunting license.

Diagnostic features. Keeled dorsal scales in 19 rows at midbody Undivided anal plate.

Coloration. Sharply defined longitudinal stripes: a vertebral stripe and two lateral, light colored stripes placed on the third and fourth scale rows Absence of checkerboard blotches seen in many other species of Thamnophis Absence of pigmentation outlining white supralabials. Body shape is particularly slender when compared to other species of Thamnophis. Elongated tail is much longer than other congeners There are four recognized subspecies of T. proximus found in Texas, all of whose definitions differ in the coloration of their stripes as well as their background color. Adding to the confusion, these four subspecies all readily interbreed, and consequently distinct boundaries for the ranges of the subspecies are impossible to define with intergradation seen between all four taxa.

General distribution. Thamnophis proximus is seen throughout many of the south central United States, and ranges well through Mexico, along the Atlantic versant, reaching as far south as Costa Rica.

Texas distribution. The range of the four subspecies of Thamnophis proximus covers the majority of Texas, only being absent from portions of the western Trans-Pecos and Panhandle.

Habitat. The range of the four subspecies of Thamnophis proximus is widespread over Texas. Western Ribbonsnake are found in a wide variety of habitats including Chihuahuan desert, coastal marshes, south Texas thornscrub, and north Texas woodlands. The unifying factor of all these habitats is the nearby availability of water, whether in the form of ponds, streams, or swamps

Reproduction. Thamnophis proximus is viviparous, as are all Thamnophis, giving birth to live young in July and August. Litter sizes can be as great as 25 snakes, with each neonate measuring between 23-30.5 cm (9-12 in).

Size. Thamnophis proximus is one of the largest gartersnakes in Texas with adults measuring between 51-76 cm (20-30 in) in length, with exceptional individuals measuring over 91.5 cm (36 in).

Thamnophis radix

Mon, 01 Jan 0001 00:00:00 +0000

Scientific name. Thamnophis radix

Common Name. Plains Gartersnake

General information. Thamnophis radix is a non-venomous snake, and will not bite unless provoked and handled. It feeds on frogs, insects, earthworms and mice. The snakes themselves are often prey for hawks. In certain areas of its range, T. radix is the most common snake, yet in Texas, it is infrequently encountered.

Protected status. The Plains Gartersnake is not a protected species in Texas and can be legally collected with a hunting license.

Diagnostic features. Keeled dorsal scales, in a maximum 21 rows near midbody Undivided anal plate.

Coloration. Pattern of dark dorsal blotches, distributed in a checkerboard manner Series of three dorsal stripes that run the length of the body; one of these stripes is found middorsally and is not obscured by any of the black dorsal blotches. The lateral stripes are placed on the third and fourth dorsal scale rows, with blotches present above and below the lateral stripe. Brown or green background color, with a row of dark blotches along each side of the belly. White labial scales are outlined with dark pigment.

General distribution. Thamnophis radix is found throughout much of the midwestern U.S., as well as portions of northern Canada.

Texas distribution. Texas is at the southern limits of the distribution of Thamnophis radix; a single subspecies, T. r. haydeni, is found only in the extreme northern portions of the Panhandle.

Habitat. Thamnophis radix lives in the lowland prairies and associated habitats near and around water.

Reproduction. Breeding takes place in the fall, with the young Thamnophis radix born the following summer. When born, as many as 60 young snakes (an unsubstantiated record lists 92) may emerge from their mother during the late summer months. The neonate snakes are no more than 19 cm (7.5 in) in length.

Size. Adult lengths of Thamnophis radix average 38-71 cm (15-28 in).

Thamnophis sirtalis

Mon, 01 Jan 0001 00:00:00 +0000

Scientific name. Thamnophis sirtalis

Common Name. Common Gartersnake

General information. The generalistic feeder (and non-venomous) Thamnophis sirtalis eats whatever appropriately sized prey it can find. Adults primarily eat amphibians, fish and insects, with juvenile T. sirtalis eating a greater proportion of earthworms and insects than do adults. Birds, mammals, and mollusks are also taken as prey items.

Protected status. The Common Gartersnake is not a protected species in Texas and can be legally collected with a hunting license.

Diagnostic features. Keeled dorsal scales in 19 rows near midbody Undivided anal plate

Coloration. White supralabials outlined with black pigment There are four subspecies in Texas, united together by having varying amounts of red or orange pigmentation found between or on the dorsal scales.

General distribution. Thamnophis sirtalis is found across much of the U.S. and southern Canada, with additional populations extending into parts of northern Mexico.

Texas distribution. In Texas, all four subspecies of Thamnophis sirtalis are uncommonly encountered, with populations scattered along the upper Gulf Coast, central and north-central Texas, the Red River Valley, and the eastern edges of the Panhandle. Thamnophis s. dorsalis is historically known only from the El Paso area in far west Texas, though individuals have not been found in years.

Habitat. Found primarily in lowland habitats in Texas, Thamnophis sirtalis lives in areas with standing or running water, but can also be seen in open or edge habitats.

Reproduction. During the summer and fall, females Thamnophis sirtalis give live birth to an average of 26 young snakes, each of whom measure between 13-23 cm (5-9 in).

Size. Adult Thamnophis sirtalis measure between 46-71 cm (18-28 in) in length.