Garter and ribbon snakes are all members of the North American genus Thamnophis. Although they are found as far north as SE Alaska and as far south as Central America, it is mainly the US and Canadian species and subspecies that are found in the pet trade. Mexican and Central American species are included here for the sake of completeness, although they are not often seen in captivity.
Thamnophis species can be characterised by slender bodies, heads that are slightly wider than the body, and three (usually) longitudinal stripes, one along the back and one along each side. They are normally found near water. However, there are so many species with a variation of colours that it can be confusing to the non-expert to try to identify exactly which snake is which. The following is a rough guide to the various Thamnophis snakes.
Conant and Collins offer the following advice for identification of the different species: check the position of the light lateral stripes, and whether they are encroached upon by the dark pattern. Accurate location is done by counting the scale rows upwards from the ventral scales (the flat scales on the underneath of the snake), about ¼ of the way back on the body. To quote: "'Stripe on rows 3 and 4", for example, means that the light lateral stripe is on the 3rd and 4th rows of scales above the ventrals".' All Ribbon Snakes have their lateral stripes on rows 3 and 4.
Within their normal range, Garter Snakes may also be confused with the water-dwelling Nerodia species, but can be easily distinguished from the latter by checking the anal plate. In Thamnophis, with the exception of the Mexican Garter Snake T. eques, the anal plate is single, whereas in Nerodia it is divided. Tropidoclonium lineatum, the Lined Snake, is also similar in appearance and habitat, but can be identified by its single anal plate and a double row of bold black half-moon shapes along the underside.
Garter snakes are often regarded as "beginner's snakes", but as is so often the case, this occasionally rather patronising description does not give any idea of the beauty of these animals, or the fact that there is so much variety within the genus that one could spend a lifetime observing them and making notes on them. They are indeed also suitable for beginners, but two points must be borne in mind. Firstly, although in nature they live near water, they do not like to live in wet conditions. In the wild they will indeed enter the water, but afterwards more often than not they will seek to dry off and raise their temperature by basking. Therefore an enclosure for garter snakes should be dry, with a bowl for the snake(s) to soak in if that particular species is known to prefer this. Secondly, most garters and ribbons do not usually prey on rodents in the wild. This is the usual food offered to captive snakes, but for most of these species a mouse-only diet would be somewhat unnatural. Instead, fish, earthworms and insects should be offered. See Perlowin for some suggestions. Many species also take frogs, newts and leeches, but most herp keepers would be reluctant to offer either of the first two of these and hard-pressed to find the last, although medical supply houses might be able to oblige. Conant and Collins state that captives usually learn to accept chopped fish, but that the entrails should be included.
Generally, Thamnophis species are docile (especially if captive-bred) and may be handled. However, some are feisty, especially in the wild, and may react by "musking" (emitting a foul-smelling odour from special glands). Also it should be noted that occasionally a person bitten by one of these snakes may have an allergic reaction to the saliva. See Perlowin for sensible suggestions on handling.
An interesting study from January 2009, published in Nature magazine, showed that garter snakes in the San Francisco Bay area (species unfortunately not given) had developed exceptional resistance to the toxins found in local newts, one of their prey species (again, species not given, but most probably a Taricha species, whose toxins are notoriously potent). The article went on to state that this could be explained by the snakes and newts evolving alongside one another since the end of the last ice age in 12,000 BC. A subsequent study showed that the basis for this immunity was a change in a particular sodium channel that prevents the newt toxin from binding to the cells of the snake. From my reading it is unclear whether this would apply to all Thamnophis or caudate species, so owners of these snakes would be ill-advised to attempt the experiment themselves.
NOTES: This is by no means a complete guide. In particular, details on different coloration and patterns are mostly absent, as are details of the location of many of the subspecies. Where "Garter Snake" is given as the common name, this is either because there is no common name for the species or we were unable to find one. This listing will be augmented as we come across further data. In the meantime please consult the Bibliography for good sources.
| QUICK INDEX | ||
| T. angustirostris, Longnose Garter Snake | T. atratus, Santa Cruz Garter Snake/Western Aquatic Garter Snake | T. bogerti, Bogert's Garter Snake |
| T. brachystoma, Short-Head Garter Snake | T. butleri, Butler's Garter Snake | T. chrysocephalus |
| T. conanti, Conant's Garter Snake | T. couchi, Western Aquatic Garter Snake | T. cyrtopsis, Blackneck Garter Snake |
| T. dubia | T. elegans, Terrestrial Garter Snake | T. eques, Mexican Garter Snake |
| T. exsul | T. fulvus | T. gigas, Giant Garter Snake |
| T. godmani | T. hammondi, Two-Striped Garter Snake | T. marcianus, Checkered Garter Snake |
| T. mendax | T. nigronuchalis, Black-Necked Garter Snake | T. ordinoides, Northwestern Garter Snake |
| T. proximus, Western Ribbon Snake | T. radix, Plains Garter Snake | T. rossmani, Rossman's Garter Snake |
| T. rufipunctatus, Narrowhead Garter Snake | T. sauritus, Eastern Ribbon Snake | T. scalaris |
| T. scaliger | T. sirtalis, Common Garter Snake | T. sumichrasti |
| T. valida | T. vicinus | |
| Scientific Name | Common Name | Distribution | Size | Notes |
| Thamnophis | ||||
| T. angustirostris | Longnose Garter Snake | Mexico | ?" | Status unclear: see JCVI reptile database entry for details. Sweeney says that the species is only known from specimens from Parras, Coahuila, in Mexico. |
| T. atratus | Santa Cruz Garter Snake Western Aquatic Garter Snake |
C. Californian coast | ?" | Formely considered by some to be subspecies of T. couchi. The dorsal stripe is orange, the overall colour dark grey to dark brown/black. Side stripes are very faint: between side and dorsal stripes there are often two rows of alternating black spots. Sweeney notes that although both the Santa Cruz Garter Snake and the Coast Garter Snake (T. couchi aquaticus) have light yellow throats, only the Santa Cruz Garter Snake has a bluish belly. Ventrolateral region is pale green (Mara). Scales across body: 19. Ventral scales: 140-169. Subcaudal scales: (approx) 80 male, 72 female. Brood size: 10-25, late summer.EMBL database entry has some data and photo links. |
| T. a. atratus | Santa Cruz Garter Snake | |||
| T. a. hydrophilus | Oregon Garter Snake | USA (SW Oregon, N Californian coast, Sacramento Valley) | ?" | Body colour is grey with indistinct black spots giving a blotching effect. Dorsal stripe is yellow but longitudinal side stripes are very faint or absent. Scales across body: 21-19. |
| T. bogerti | Mexico (Oaxaca) | Species defined in 2005: see JCVI database entry for details. | ||
| T. brachystoma | Shorthead Garter Snake | NW Pennsylvania, New York | 18" | Smallish garter snake with the head no longer than the width of the body. Background colour light grey-brown, darkening dorsally. The central dorsal stripe is a light green-yellow which fades towards the end of the tail. There are also longitudinal side stripes, often edged in black, running along the 2nd, 3rd and 4th scale rows. Though similar to the Eastern Garter Snake T. s. sirtalis, it does not have the double row of dorsal spots of that snake. Also its preferred habitat is meadows and damp grassland close to water, whereas that of T. sirtalis sirtalis is drier woodland (Sweeney). Scales across body: 17. Ventral scales: 132-146. Subcaudal scales: (approx) 68 male, 60 female. Brood size: up to 15, mid-Sept. |
| T. butleri | Butler's Garter Snake | NE Indiana, Ohio, Michigan, SE Wisconsin | 20" | Another rather small species of garter snake that could be confused with T. brachystoma, although T. butleri has a greater number of scale rows. Base colour is brown-black with three yellow longitudinal stripes: between these there may be rows of black spots. Preferred habitat is damp meadows, grasslands, or open areas near marshes and streams. Sweeney warns that this snake can be a fussy feeder when initially in captivity, often insisting on earthworms at first. Click here for EMBL entry and photo links. Scales across body: 19 (17 towards tail). Ventral scales: 130-147. Subcaudal scales: (approx) 64 male, 56 female. Upper labials: 7. Brood size: up to 16 (av. 8-10), late summer. |
| T. chrysocephalus | Garter Snake | Mexico (Guerrero, Oaxaca, Puebla and Vera Cruz) | ?" | Rarely seen species. |
| T. conanti | Conant's Garter Snake | Mexico | See JCVI reptile database entry for details: species only named in 2005. | |
| T. couchi | Western Aquatic Garter Snake | USA (Oregon, California) | 64" | The number of T. couchi subspecies has decreased in recent years as some have been elevated to full species status. The remainder vary somewhat in scalation, colouring and pattern. All however are mainly aquatic and diurnal, probably feeding mainly on fish and amphibians. Click here for the EMBL database entry and photo links. Upper labials: 8. Internasals are slightly pointed towards the front. Brood size: 10-25, late summer. |
| T. c. couchi | Sierra Garter Snake | USA (Sierra Nevadas, California & Nevada) | 64" | Body colour is dull yellow chequered with darker blotches. Narrow black dorsal stripe fades towards posterior. Any longitudinal side stripes are normally a rather indistinct yellow. Scales across body: 21-19. Preoculars are often divided. |
| T. c. aquaticus | Coast Garter Snake | USA (San Francisco Bay area inland to Sacramento Valley) | 64" | This subspecies is now no longer recognised as such but rather as an intergrade between T. a. atratus and T. a. hydrophilus (see Stebbins). Body colour is olive to dark brown dorsally, ventral surfaces varies from yellow to light blue-green with darker blotches: throat is light yellow. Wide yellow dorsal stripe is quite distinctive. Longitudinal side stripes are normally also yellow but less clear. Scales across body: 19. Ventral scales: 142-167. Subcaudal scales: (approx) 85 male, 74 female. |
| T. cyrtopsis | Blackneck Garter Snake | SW USA, Mexico, Costa Rica, poss. Honduras | 44" | The T. cyrtopsis species are collectively known as Blackneck Garter Snakes. Overall colour is dull grey to brown, with an orange dorsal stripe that fades to yellow towards the tail and is slightly broader at the neck. The side stripes are usually grey: two alternate rows of black spots run between the dorsal and side stripes. A distinguishing feature is the black collar on the neck, which is divided by the dorsal stripe but otherwise unbroken. According to Sweeney these garter snakes prefer more arid regions to their congenerics, favouring fir and pine forests, or sparse areas around desert flats not too far from water. He also notes that their main prey is amphibians. Scales across body: 19. Ventral scales: 162-167. Brood size: Up to 25, July-August. Click here for the EMBL database entry and links. |
| T. c. cyrtopsis | Western Blackneck Garter Snake | USA (Texas) | The alternating black spots in the area of the neck are particularly well-defined in this species (Sweeney). | |
| T. c. ocellatus | Eastern Blackneck Garter Snake | USA (SE Utah, S Colorado), N Mexico | This subspecies has single large black less clearly defined spots in the area of the neck instead of the usual clear-defined double rows (Sweeney). | |
| T. c. collaris | Blackneck Garter Snake | USA, Mexico | No further data currently available. | |
| T. c. postremus | Blackneck Garter Snake | |||
| T. c. pulchrilatus | Blackneck Garter Snake | |||
| T. dubia | Garter Snake | Venezuela | ?" | |
| T. elegans | Terrestrial Garter Snake | W USA (Washington, Oregon, Arizona), SW Canada, Mexico (Baja California Norte) | 43" | T. elegans is known as the Terrestrial Garter Snake, although all of its subspecies, including the nominate form, have different common names. One distinguishing mark is that the internasals are not pointed in front. All the subspecies are diurnal, preferring moist habitats and being opportunistic feeders (Sweeney). Scales across body: 19/21. Ventral scales: 167 (average). Subcaudal scales: (approx/average) 57. Brood size: Up to 19, July-September. Click here for the EMBL database entry and links. |
| T. e. elegans | Mountain Garter Snake | W USA (W. Nevada, Sierra Nevada, coastal California, W. Oregon) | Dull overall colour with distinct light orange dorsal stripe and dull grey side stripes. Ventral surface is grey. Its habitat in California and Oregon is generally mountainous (Sweeney). Scales across body: 21. | |
| T. e. arizonae | Arizona Garter Snake | W USA (Arizona, New Mexico) | Based on a proposal by Tanner and Lowe (1989) on coloration changes in some areas within the Little Colorada River Basin. Other authorities do not regard this as definitive for the moment. SOURCE: | |
| T. e. errans | Mexican Wandering Garter Snake | Mexico (N Baja California, Chihuahua) | Dorsal stripe is quite narrow with side stripes slightly wider: distinctive black collar larger than that found in T. e. vagrans. The habitat of this subspecies is pine oak forest. In NW Chihuahua it intergrades with T. e. vagrans. Webb gives details as follows: Scalation: 7 supralabials. Dorsal scalation: dorsal scale rows 19-19-17. Coloration: pale vertebral stripe distinct along body and tail and usually confined to vertebral row; pale lateral stripe on 2nd and 3rd rows anteriorly and only slightly paler than 1st dorsal row; black collar usually not separated middorsally by pale midvertebral stripe; immaculate belly with pale orange wash in both sexes; tongue entirely black. Can be distinguished in life from T. cyrtopsis pulchrilatus by having olive dorsolateral area (black in T. c. pulchrilatus) and having dorsal row scarcely darker than pale lateral stripe (dorsal row is blackish brown in T. c. pulchrilatus). Also all subspecies of T. cyrtopsis have red tongue with black tip and yellow venter. Webb notes that these latter two coloration characteristics are difficult if not impossible to determine in preserved material. [SOURCE: Webb 1976] | |
| T. e. hueyi | Mountain Garter Snake | |||
| T. e. terrestris | Coast Garter Snake | USA (SW Oregon, California) | Distinguished by wide yellow dorsal stripe and red and orange flecks on the lower sides. | |
| T. e. vagrans | Wandering Garter Snake | USA (SW Manitoba, SW Dakota, W. Oklahoma, W. Washington, Oregon, California), Canada (British Columbia) | Most widespread subspecies. Rather dull in coloration, being overall brown with indistinct dull grey dorsal and side stripes. Between side and dorsal stripes are two rows of somewhat haphazard black markings (Sweeney). The head is somewhat more distinctive, being light brown with darker markings behind the eyes and at the base of the neck. Scales across body: 21 (usually: Sweeney implies that this may sometimes differ). | |
| T. e. vascotanneri | Upper Basin Garter Snake | W USA (Utah) | Based on a proposal by Tanner and Lowe (1989) on coloration changes in some areas within the Upper Colorada River Basin. Other authorities do not regard this as definitive for the moment. SOURCE: | |
| T. eques | Mexican Garter Snake | Mexico, USA (New Mexico, Arizona) | 40" | The Mexican Garter Snake is unusual in a couple of ways. Firstly, it is the only Thamnophis species to have a divided anal plate. Secondly, the pale yellow side stripes run down the 3rd and 4th scale rows rather than the usual 2nd and 3rd arrangement. The dorsal stripe is also pale yellow. The side stripes fade towards the end of the body. Between the dorsal and side stripes there are small but indistinct alternating black spots, plus two large black spots on the top of the neck which create the effect of a black collar, similar to that of T. cyrtopis. However, T. eques can be distinguished as it has less than 162 ventral scales. Overall coloration is green-brown: the ventral surface may be pale green, grey or blue, but usually has dark spots. This is a mainly diurnal and aquatic snake that hunts along the edges of bodies of water that it inhabits: it preys mainly on frogs but will take other water-based items such as fish or leechs (Sweeney). Brood size: Up to 25, June-August. |
| T. e. eques | Common Mexican Garter Snake | Mexico | Nominate subspecies: see notes above. | |
| T. e. megalops | Northern Mexican Garter Snake | Mexico, USA (New Mexico, Arizona) | The only subspecies to be found within the borders of the USA, and hence sometimes available. The main variation from the nominate subspecies is that this snake is more of an olive-brown colour. Sweeney considers this an attractive snake. | |
| T. e. virgatenuis | Durango Mexican Garter Snake | Mexico (Durango) | Very similar to nominate subspecies. | |
| T. exsul | Garter Snake | Mexico | ?" | |
| T. fulvus | Garter Snake | SE Mexico, Guatemala, Honduras, El Salvador | ?" | Until recently was a subspecies of T. cyrtopsis. It differs from the subspecies of the latter by its brownish-coloured head and reduced number of ventral scales, while it can be distinguished from T. eques, the Mexican Garter Snake, by its single anal plate. Ventral scales: 132-154. |
| T. gigas | Giant Garter Snake | USA (California) | 48"+ | Formerly considered a subspecies of T. couchi. Overall colour is dull olive-brown (Sweeney): dorsal and side stripes are a lighter yellow-olive but faint. Between the side and dorsal stripes are two alternating rows of black blotches. The head appears comparatively elongated. Scales across body: 21-23. Ventral scales: 165-170. |
| T. godmani | Garter Snake | Mexico | ?" | Upgraded in 1994 from subspecies of T. scalaris. |
| T. hammondi | Two-Striped Garter Snake | S California, USA, and Baja California, Mexico | 36" | T. hammondi derives its common name from the absence of a dorsal stripe. The overall colour may be grey, brown or olive-green (Mara) with rows of dorsal spots on the back and side stripes as normal. The belly can vary in pattern and colour, between yellow-orange and salmon pink possibly with light spotting (Mara). Click here for EMBL entry and links. |
| T. marcianus marcianus | Northern Checkered Garter Snake | USA (SE California, S Arizona, SW & E New Mexico, E Texas, SW Kansas) | 43" | The T. marcianus snakes are all collectively known as Checkered Garter Snakes. The nominate subspecies T. m. marcianus has the common name of Marcy's Checkered Garter Snake. Scales across body: 21. Upper labial scales: 8. Ventral scales: 155 max. Subcaudal scales: 74 (males), 72 (females). Brood size: Up to 18, June-August (dependent upon range and climate (Sweeney)). Click here for the EMBL entry and photo links. |
| T. m. praeocularis | Southern Chequered Garter Snake | Mexico, Belize, Honduras and Costa Rica and poss. Guatemala and El Salvador | Sweeny notes that this snake is recorded as inhabiting wetter, sub-tropical forest type areas. The major differences between this and the nominate subspecies is that a third row of black spots may be visible under the side stripes and that the ventral scales average 155-160, slightly higher than in T. m. marcianus. | |
| T. m. bovalli | Garter Snake | Nicaragua, Costa Rica | Regarded by some (including Sweeney) as a full species. | |
| T. melanogaster | Black-Bellied Garter Snake | Mexico | ?" | Click here for a citation of some academic work on the species. The JCVI database entry also has some details. |
| T. m. melanogaster | ||||
| T. m. canescens | ||||
| T. m. chihuahuaensis | ||||
| T. m. linearis | ||||
| T. mendax | Tamaulipan Mountain Garter Snake | Mexico (Tamilaupas) | ?" | |
| T. nigronuchalis | Black-Necked Garter Snake | Mexico | ?" | I have only found this species noted in Sweeney, who merely states that possibly subspecies were under review. The JCVI Thamnophis page does not record it, though that does not necessarily make it invalid. |
| T. ordinoides | Northwestern Garter Snake | British Colombia (Canada), W Washington, W Oregon, NW California (USA) | 38" | The main distinguishing feature of T. ordinoides is the deep red-orange colour of the dorsal and side stripes. The overall colour varies from green-brown to black, and depending on the darkness of the body there may be two rows of black spots present between the stripes. The ventral surface is pale yellow with occasional orange blotching. Preferred habitat is meadows and grasslands, especially if in proximity to a stream. Normal diet apparently consists of creatures caught in the vicinity of freshwater bodies, viz. leeches, earthworms and smaller fishes and amphibians. It may be this non-mammalian diet which accounts for the rarity of T. ordinoides in captivity. Scales across body: 17. Upper labial scales: 7. Ventral scales: 140-160 average. Subcaudal scales: 74 (males), 68 (females). Brood size: Up to 15, late June-August (Sweeney). |
| T. proximus | Western Ribbon Snake | Central USA (Indiana, S Wisconsin, E Nebraska south to S Louisiana and NE Texas) | Max 48" | The T. proximus species and subspecies are collectively known as Western Ribbon Snakes. They are one of the slenderest Thamnophis species. Many of the subspecies were defined by Rossman in the sixties. Mara notes that one distinguishing feature of the T. proximus species is the labial scales which are much lighter than the rest of the head. Sweeney also notes the two fused spots on the top of the head. Body colour is a plain black, with the light cream yellow or orange stripes, the dorsal stripe usually being slightly darker. All the Western Ribbon snakes are diurnal but seem to avoid the hottest parts of the day when foraging (Sweeney): favoured locations are covered areas near water such as reeds by ponds, etc. Main prey item is amphibians but fish, leeches, slugs and earthworms are also taken (Sweeney). Scales across body: 19. Upper labial scales: 8: the eye is situated over the 4th and 5th. Brood size: Up to 27, July-September (Sweeney). |
| T. p. proximus | Western Ribbon Snake | |||
| T. p. alpinus | Ribbon Snake | Mexico, Guatemala, Belize, El Salvador, Honduras, Nicaragua, Costa Rica | Distinguished from T. p. rutiloris by the parietal spots on the head which are chevron-shaped, unlike those of T. p. rutiloris (Sweeney). | |
| T. p. diabolicus | Arid Land Ribbon Snake | USA (SE Colorado, Kansas, W Texas), Mexico | Differs mainly from the nominate subspecies by a lighter olive-grey to brown uper body and a narrow dark stripe bordering the ventral scales. | |
| T. p. orarius | Gulf Coast Ribbon Snake | S coastal USA (S Missisippi to S Texas) | Differs mainly from the nominate subspecies by a lighter olive-grey to brown uper body and from T. p. diabolicus by a wider, bright gold dorsal stripe and the absence of any stripe bordering the ventral scales. | |
| T. p. rubrilineatus | Red-Lined Ribbon Snake, Redstripe Ribbon Snake | USA (Texas) | 20-30"/51-76cm, max 48"/122cm | Dorsal stripe is a very distinctive ochre red. The body colour is olive-brown and there may be a narrow dark stripe bordering the ventral scales. Its distribution in Texas is fairly limited, which suggests that captive breeding of this attractive subspecies should be a priority. |
| T. p. rutiloris | Ribbon Snake | Mexico, Guatemala, Belize, El Salvador, Honduras, Nicaragua, Costa Rica | Moderately common in Mexico, Guatemala and Belize, being active by day and night. Normally terrestrial but may be found on vegetation on water surface. Feeds on frogs, tadpoles and small fish. Similar to T. p. alpinus. Coloration: dorsal coloration is brownish-/olive green with a light tan dorsal stripe and yellow-orange side stripes. Ventrally light yellow-green or yellow-orange; there may be also a dark line bordering the ventral scales. Chin and throat usually immaculate white. [SOURCES: Lee, Sweeney] | |
| T. radix radix | Eastern Plains Garter Snake | S Canada, USA (Wisconsin, Iowa, Missouri, Illinois, Indiana NW towards Canada) | ?" | The T. radix species are known collectively as Plains Garter Snakes. This snake is known for large litters, with a record of about 90 young being produced. Both subspecies are similar in colour. Overall colour varies from grey-brown to red-orange (Sweeney): a bright yellow dorsal stripe is almost always present. The side stripes are a much paler grey and run along the 3rd and sometimes 4th scale row (Sweeney). There are two rows of distinct black spots between dorsal and side stripes and a third row beneath the side stripes. A distinguishing feature of the species is vertical black stripes on the labial scales. Habitat tends to be open damp grasslands, wet meadows, drainage ditches or the open vicinity of lakes and marshes (Sweeney). Diet is the usual semi-aquatic fare (amphibians, leeches and earthworms) but interestingly also reportedly small mammals and even carrion. T. radix is diurnal. Details for T. r. radix: Scales across body: 21 (19 across neck region (Sweeney)). Ventral scales: < 155 average. <B>Subcaudal scales: 75 (males), 65 (females). Brood size (both subspecies): 20-30, July-September (Sweeney). Click here |
| T. r. haydeni | Western Plains Garter Snake | USA (W Iowa, Montana, North Dakota, South Dakota, Nebraska, Kansas, E Wyoming, E Colorado, NE New Mexico, Oklahoma, N Texas, Minnesota, Arkansas) | Scales across body: 21. Ventral scales: > 155 average. Subcaudal scales: 75 (males), 65 (females). | |
| T. rossmani | Rossman's Garter Snake | Mexico (Nayarit) | First described in 2000: see JCVI database entry. | |
| T. rufipunctatus | Narrowhead Garter Snake | USA (E Arizona to SW New Mexico), NW Mexico | ?" | This Thamnophis species more closely resembles the Nerodia water snakes due to its drab base colouring (dull green or gray) and its eyes, which are set high up on its head. The head itself is more elongated than in most other Thamnophis species. The deviancy of this snake from the Thamnophis norm is reinforced by its colouring: the overall body colour is a dull light brown, with usually no stripes present: instead rather indistinct dark brown blotches run along the body which may join up on the back to form saddles. If side stripes are present they normally run along scale rows 2-3. T. rufipunctatus is very aquatic and normally inhabits streams in woodland or forest. It hunts mainly fish and aquatic invertebrates and normally only leaves the water to bask. Sweeney warns that of all the Thamnophis species this one seems to adapt least well to captivity: this may be due to its aquatic habitat and/or its extreme nervousness. Scales across body: 21-23. Upper labial scales: 8 |
| T. sauritus | Eastern Ribbon Snake | Eastern USA, SE Canada, Bahamas | 26-34" | The four T. sauritus snakes are collectively known as Eastern Ribbon Snakes. Distinction among them seems to be mainly by distribution and colour. So far the only reference to these snakes living in the Bahamas that I have found is on the EMBL database. Habitat is invariably near water, whether grassland, marsh or lake, and these snakes can often be found basking on rocks or bushes overhanging the water (Sweeney). They are adept swimmers, diving into water if feeling threatened. Diet is mainly amphibians and fish with some invertebrates (Sweeney). Scales across body: 19. Brood size (all subspecies): up to 26, July-August (Sweeney). Click here for the EMBL entry on this species. |
| T. s. sauritus | Eastern Ribbon Snake | USA (S Indiana, S&E Pennsylvania, SE New York State, S New Hampshire, Florida, Louisiana & S Carolina) | Overall colour is red-brown to black, sometimes fading below the side stripes: dorsal stripe is yellow-orange, side stripes a paler yellow. Faint dark spots can sometimes be made out above the side lines. | |
| T. s. nitae | Bluestripe Ribbon Snake | USA (Gulf coast of Florida from Withlacoochee River to Wakulla County) | Overall colour is dark-brown to black. Less well-defined dorsal stripe is lighter brown, narrow side stripes a bright blue: these meet the chin which is the same colour. | |
| T. s. sackerii | Peninsula Ribbon Snake | USA (Florida, S Carolina, SE Georgia) | Overall colour is brown with a tan dorsal stripe and side stripes of light brown. Range is mostly sympatric with that of T. s. nitae. | |
| T. s. septentrionalis | Northern Ribbon Snake | USA (Michigan, S Indiana, S Maine, New Hampshire & Pennsylvania coastal areas), Canada (S Ontario) | Overall colour is dark-brown to black. Striping is very similar to that of T. s. sauritus except that the dorsal stripe is usually darker. | |
| T. scalaris | Longtail Alpine Garter Snake | Mexico | ?" | Both these species were until 1994 considered to be Tropidonotus instead: see the JCVI Thamnophis listing for details. |
| T. scaliger | Shorttail Alpine Garter Snake | Mexico | ?" | |
| T. sirtalis | Common Garter Snake | Virtually the entire continental USA except Alaska: S Canada, Mexico & Bahamas | 16-43" | The T. sirtalis species complex is collectively known as the Common Garter Snake. These snakes range right across North America and are often the most frequently encountered reptiles (Sweeney). They are also very catholic in their habitats, even venturing into urban areas: the only requirement seems to be that the habitat is moist. Apart from the usual fish, amphibians, earthworms and leeches, Common Garter Snakes also take slugs and other molluscs and even the occasional mouse or young bird (Sweeney). Scales across body: 19. Upper labial scales: normally 7. Ventral scales: 138-168 Subcaudal scales: (average) 84 (males), 58 (females). Brood size (all subspecies): 20-30 but occasionally as many as 85, June-August (Sweeney). Click here for the EMBL link and photos. |
| T. s. sirtalis | Eastern (Common) Garter Snake | USA & Canada (S Ontario, E Minnesota, Iowa to S Missouri, Arkansas; E Texas to Atlantic, S Newfoundland to S Florida) | 18-26"/45½-66cm; max 48¾"(123cm); young 5-9"/12½-23cm at birth | Distribution is very widespread. Coloration: overall dark brown, black, green or olive: 3 yellowish stripes are normally present but are missing in some individuals, or may be brownish, greenish or bluish. Often double rows of spots of a variable colour (green-blue to brown, Sweeney) between the stripes or even intruding on the stripes. Some individuals, especially in the western areas, may have red or organce interstitial spaces; melanistic individuals are also known, especially near Lake Erie. Ventrally greenish or yellowish, with 2 rows of indistinct black spots partially hidden by overlapping ventrals. [SOURCES: Conant & Collins, Sweeney]. |
| T. s. annectens | Texas Garter Snake | USA (Oklahoma-Texas border into Texas: isolated pop'n in S Texas, SW Kansas and Oklahoma) | 18-25"/45¾-63½cm; max 42¾"/108cm | Wide dorsal stripe is orange. Lateral stripes run along 3rd scale row but on anterior third of body also touch 2nd and 4th rows. |
| T. s. concinnus | Red-Spotted Garter Snake | USA (NW Oregon, SW Washington) | ?" | Overall colour is nearly black with bright yellow-grey dorsal stripe. Side stripes run along 3rd scale row but also touch 2nd and 4th rows. This subspecies is easily distinguished by the single row of red spots either side of the dorsal stripe and the red on the top of the head. |
| T. s. dorsalis | New Mexican Garter Snake | USA (Rio Grande, S Colorado, New Mexico, W Texas) | 18-28"/45¾-71cm; max 51½"/131cm | Similar in appearance to T. s. concinnus or T. s. parietalis but the red spots along the sides are reduced to being markings between the scales rather than on the scales (Sweeney); furthermore in some individuals the red is reduced, the stripes very prominent and the overall appearance greenish. Lateral stripes on rows 2 and 3. Ventrally bluish or brownish, immaculate or with lateral dark spots. Young may be rusty orange. |
| T. s. fitchi | Valley Garter Snake | USA (N & coastal California, NW Nevada, SW & E Oregon, Idaho, Utah, W Montana, Washington, SE Alaska), Canada (British Columbia) | ?" | Dark grey to brown with well-defined dorsal stripe and black area on top of the head. In its Californian habitat it is not found in areas populated by T. s. infernalis (Californian Red-Sided Garter). |
| T. s. infernalis | California Red-Sided Garter Snake | USA (California coastal region from Humboldt County to Diego County) | ?" | Dark grey to brown with well-defined dorsal stripe and black area on top of the head. In its Californian habitat it is not found in areas populated by T. s. infernalis (Californian Red-Sided Garter). |
| T. s. lowei | Garter Snake | ? | ?" | No data found. |
| T. s. pallidulus | Maritime Garter Snake | Canada (maritime provinces, esp. Quebec), USA (New England to NE Massachusetts) | 36"/91¾cm max | Similar in appearance to T. s. sirtalis but differs as follows. Coloration: dorsolateral coloration overall brown, yellowish-olive or olive-grey with alternating rows of brown or black spots in a checkered pattern; grey, tan or yellow dorsal stripe is either lacking or faintly present on anterior part of body, the spotting being much more pronounced; ventrally whitish anteriorly, becoming dusky grey posteriorly. |
| T. s. parietalis | Red-Sided Garter Snake | Canada (SE British Columbia, Alberta, S Manitoba, SW Sasketchwan), USA (Great Plains as far as Oklahoma-Texas border) | 16-26"/41-66cm; max 48¾"/124cm | Well-defined back stripe with rather indistinct side stripes. Distinguishing feature is the clearly marked red bars between the stripes that give it a chequered appearance. Top of head is usually olive-brown. |
| T. s. pickeringii | Puget Sound Garter Snake | Canada (Vancouver Island, coastal SW British Columbia), USA (W Washington) | ?" | Similar to T. s. parietalis (Red-Sided Garter Snake) but is darker in overall colouration and lacks the red markings. Dorsal stripe is also narrower and the top of the head is usually darkly coloured. |
| T. s. semifasciatus | Chicago Garter Snake | USA (Illinois, SE Wisconsin, NW Indiana) | 18-26"/45½-66cm, max 35½"/90½cm | Similar to T. s. sirtalis (Eastern Common Garter Snake) but on front of body has black vertical bars, formed by fusion of black spots above and below light stripe, crossing the side stripes in the neck region. One or more black lines may cross vertebral stripe in neck region. |
| T. s. similis | Bluestripe Garter Snake | NW coastal region of Florida | 20-26"/51-66cm; max 39¼"/99¾cm | Attractive garter snake with sky-blue side stripes and blue-green or dull yellow narrow dorsal stripe: overall coloration is dark brown. Occurs with T. sauritus nitae, the Bluestripe Ribbon Snake, which it closely resembles: the two can be distinguished by the Garter Snake having its lateral stripes on rows 2 and 3, the Ribbon Snake on rows 3 and 4. Found in the coastal lowlands including marshes and pine flatwoods. |
| T. s. tetrataenia | San Francisco Garter Snake | California (San Mateo County) | ?" | Very beautiful snake with two red dorsal stripes outlined in black on a cyan background. The top of the head is light red and the underside of the head a green-blue. Unfortunately the San Francisco Garter Snake is endangered and therefore may not be collected or kept captive without a permit. It should go without saying that this species should really only be kept at this time by serious herpetoculturists who are willing to dedicate the time to captive breeding. See Melissa Kaplan's page on this subspecies. |
| T. sumichrasti | Sumichart's Garter Snake | Mexico | ?" | Sweeney noted that the putative several subspecies for this species were under review. Evidently these have been invalidated: see JCVI database entry. |
| T. validus | Garter Snake | Mexico (Baja California Sur) | 23-38"/58-94cm | |
| T. v. celaeno | ||||
| T. v. isabellae | ||||
| T. v. thamnophisoides | ||||
| T. vicinus | Garter Snake | Mexico | ?" | Now considered to be the subspecies T. cyrtopsis collaris: see JCVI database entry for details. |
The information above was culled from a number of sources. The Thamnophis-specific books are as follows:
The General Care and Maintenance of Garter Snakes & Water Snakes, David Perlowin, Herpetocultural Library Series 200, Advanced Vivarium Systems Inc, 1994. As in most of the books in this series, gives very useful information. Covers mainly Thamnophis but also Nerodia and gives an introductory paragraph on the similar Asian genus Amphiesma.
Garter & Ribbon Snakes, W P Mara, TFH 1994. Good introduction, albeit a slim one: the basics of husbandry are covered, as well as the most popular Thamnophis species, and there are many useful photographs. The identification of species does go into useful details such as the distinguishing factors of the number of ventral scales, scale rows, etc.
Garter Snakes: Their Natural History and Care in Captivity, Roger Sweeney, Blandford, 1992. A somewhat thick and more expensive but nevertheless excellent book that covers all aspects of Garter & Ribbon Snakes, including anatomy, senses and natural history, plus terrarium construction, feeding and other aspects of snake husbandry, and finally a good section on the various Thamnophis species and subspecies. As with Mara's book a useful section on snake identification is included. Unusually for a Garter Snake book the author is British. Recommended if you can get hold of it, although a few details of the taxonomy of the lesser-known species may now have changed.
A Field Guide to Reptiles and Amphibians of Eastern and Central North America, R Conant and J T Collins, Peterson Field Guides, Houghton Mifflin, Boston/New York 1998.
A Field Guide to Western Reptiles and Amphibians, R Stebbins, Peterson Field Guides, Houghton Mifflin, Boston/New York 2003.
Amphibians and Reptiles of Baja California, Grismer, L Lee Grismer, University of California Press, 2002. Impressive guide to the herpetofauna of the region.
"A Review of the Garter Snake Thamnophis elegans in Mexico", Robert G Webb, Natural History Museum of Los Angeles County Contributions in Science, Number 284, September 15 1976.
www.Thamnophis.com is a very comprehensive German-English site run by Jürgen Chlebowy, "the Garterphile". The site hosts a group of articles on Garter & Ribbon Snakes, as well as a chat forum and classifieds page. Well worth visiting if you wish to know more about these snakes.
Melissa Kaplan has a good page on the natural history and care of garter snakes.
Alan Francis has a good Garter Snake page, including some excellent photographs.
Reptile Trust also provide a concise and useful care sheet.
European Garter Snake Association: I have not seen this site advertised elsewhere and there is little information given, but there are a couple of addresses and an E-mail link, so please visit this site and enquire if you are interested in finding out more.
Martin Hallmen has a good page on the visual sense of Thamnophis snakes.
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