Reprinted from the Journal of Wildlife Rehabilitation, Vol. 21 (3-4) by permission of the author and the International Wildlife Rehabilitation Council. All rights reserved.

*Special thanks go to: Mary D. Reynolds and Franklin Gould for giving the permission to publish the article on*

Author: Franklin D. Gould

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An Introduction to the Natural History of North American Garter Snakes with Basic Triage Practices. 


Garter Snakes (Thamnophis) are among the most successful and widely distributed snakes in the world. Highly adaptable, their range encompasses the areas between central Canada and Central America and California to Maine. As the public has become more knowledgeable about the environment they live in, they are now beginning to recognize the valuable role these often misunderstood and feared animals play in that environment. Thus, even snakes are becoming part of the yearly intake at many rehab centers. Snakes, like other reptiles, have distinct needs during rehabilitation that require specialized knowledge. The author attempts to provide a brief introduction to the Garter Snakes' natural history and a basic introduction to triage practices based on experience and current research. 

Keywords: Snakes, Triage, Trauma, Natural History, Reptile Rehabilitation 

I. Introduction

The following paper will discuss specifics relating to some species found commonly in the North America. Garter (and Ribbon) Snakes found in the US and Canada are non-venomous and thus do not pose a significant danger to most handlers. (The commonly named Garter snakes found in Africa are very different, belonging to the Elapsoidae and are highly dangerous due to their extremely toxic venom.)

II. Current Scientific Classification

Garter Snakes are currently classed as order Reptilia, sub-order Serpentes, family Colubridae, genus Thamnophis, and are divided into a variety of species (approximately thirty are discussed in The Garter Snakes ) (Rossman, Ford, Siegel 1996) by taxonomists. As with most reptile systematics, this is under near-continuous revision. Due to their broad distribution (leading to highly varied adaptive features and behavior), sexual dimorphism and various on-going debates, identification of the various species can be difficult. Approximately 16 of these species are native to North America (Collins - CNAAR 1998) and our focus will be on three of the more common varieties:

Thamnophis elegans elegans (Western Terrestrial Garter Snake)

Thamnophis radix (Plains Garter Snake)

Thamnophis sirtalis sirtalis (Common Garter Snake)

Even these three common species are distinguished by having a large number of highly variable subspecies with distinctive markings. This is compounded by the existence of color morphs within the subspecies. To make things worse, books written a few years apart will have different descriptions of these species based on the then-current taxonomy. Thankfully, from a rehabber's perspective, most garter snakes can be kept for a short term under generalized husbandry guidelines. The descriptions and taxonomy discussed below are primarily based on work published during or after 1996.

III. Identification

Identification of the Garter snakes is not always simple. The following guidelines may refer to scale counts and similar difficult ID techniques. Because of the need for this sort of complex identification, the typical rehabber may wish to consult a reptile expert in their area for a positive id. The distribution maps below are not exact in terms of range - they simply mark the states where these animals are commonly found.

Figure 4 T. elegans state distribution

Thamnophis elegans elegans (Western Terrestrial Garter Snake) (six subspecies) - Description: Length variable - 18" to 42". Variable color and markings. Dorsal scales usually limited to 19 -21 rows. The dorsal area is usually a uniform black, brown, red or gray. A side stripe is usually present in the second and third scale rows. The back stripe is generally well-marked. Typically two alternating rows of black spots between the stripes. The vertebral stripe is seldom more than three rows wide. The side stripes may be distinct or indistinct. Single anal plate. Scales generally keeled for 19 rows. Top of head - usually gray. Geographic distribution: New Mexico and Arizona to the south, California to the west, British Columbia, Alberta and SW Saskatchewan to the North, Montana, Wyoming, Colorado, New Mexico to the East. Some populations have been seen in South Dakota and Nebraska at the far western edges of those states.

Figure 5 T. radix state distribution

Thamnophis radix (Plains Garter Snake) (no subspecies) Description: Length variable - 20" to 40". Usually distinct bright yellow or orange vertebral stripe. Cream to yellow side stripes at the third or fourth scale rows. Double row of black spots between the side and back stripes. Frequently found with a light row of black spots just below the side stripe. Spots are sometimes obscured by a dark ground color. Supralabials ( upper lip) scales with black bars or wedges. Geographic distribution: Oklahoma panhandle. NE New Mexico and Northern Texas to the South, then through Nebraska, Missouri, Iowa and Illinois to the East, then up through Minnesota, SW Manitoba, S Saskatchewan and Alberta to the North, N Montana to the West, with some populations found on the eastern edges of Wyoming, and down into central Colorado.

Figure 6 T. sirtalis state distribution

Thamnophis sirtalis sirtalis (Common Garter Snake) (eleven subspecies) Description: Length variable - 18" to 51". 19 or fewer dorsal scale rows, ground color generally brown or gray, but some western populations may have a red ground color. Back and side stripes generally well-defined. Side stripes generally confined to 2nd and 3rd dorsal scale rows. Single anal plate. Generally 7 supralabial scales. Often has two alternating rows of black spots between side and vertebral stripes. The spots are sometimes fused vertically, creating a 'barred' look. Sometimes spots are fused horizontally, creating thin black stripes. Geographic distribution: Broad distribution from New England and South Central Canada to Florida in the East, stretching West to the central plains states, including Oklahoma and eastern Texas. Found throughout Southern Canada and Central Alberta, along the coast of British Columbia and the Cassar Mountains. Southwards into Washington, Oregon Northern and Central California. Also found in Montana and the Dakotas.

Sexing Snakes:

Attempting to sex snakes can be an exercise in futility without the knowledge and practice of using sexing probes . However, the following general guidelines may prove helpful. Females generally have evenly tapering tails from the cloaca to the tail tip. Males generally have a longer tail and an area just behind the cloaca where a slight bulge may exist. Some males have an area just behind the cloaca where the sides appear to be parallel, after a slight taper at the cloaca itself.


Little is known of the longevity of wild snakes, though mortality estimates have been made, based on a number of field studies. The survival rate for many species living beyond two years old is approximately 35%. Some studies have shown these numbers to be larger, though; perhaps as high as 67% in some northern species. (Rossman, Ford, Seigel 1996) The longest lived garter snake in captivity was an Eastern or Common Garter Snake reported to have lived 14 years. (Slavens, 1998) Typical longevity in captivity appears to be about 6 - 10 years. Lifespan in the wild is undoubtedly little longer than that.

IV. Habitat

Garter snakes occupy a wide variety of habitats, ranging from prairie to mountain meadows. Their adaptability to a given habitat appears to depend more on access to water than particular foods, or even climates. The Thamnophis' overall North-South range, reaching from central Canada to central Mexico is a good indicator of their adaptability. In the field, different species appear to show different habitat preferences. Known preferred habitats are discussed below:

Thamnophis elegans elegans (Western Terrestrial Garter Snake)

Unlike many garters, T. e. elegans does not depend on permanent water. It can thrive in open grassland so long as there are shrubs present. It has been described as "a montane, terrestrial form" (Rossman, Ford, Seigel 1996). They also noted that animals found in Modoc and Lassen Counties in CA were an exception, being largely confined to the edges of lakes and streams.

Thamnophis radix (Plains Garter Snake)

T. radix is usually found in what is known as the 'wet prairie' areas of the US and Canada. It can typically be found in meadows and prairie-land near streams, ditches, ponds and marshes. When it is found near moving water, it seems to prefer sluggish, deep streams with few riffles. In many areas, it can found wherever farmsteads are abandoned or trash has been allowed to pile up. "Debris in grassy areas can attract large numbers of T. radix." (Rossman, Ford, Seigel 1996) The species is also sometimes found in aspen forest in Manitoba.

Thamnophis sirtalis sirtalis (Common Garter Snake)

Scientists have jokingly referred to its habitat as 'everywhere' and this is not far from the truth. T. sirtalis is probably the most widely distributed garter snake in North America. Rather than discuss all the possibilities, the following are simply some of the most common habitats: pond margins, seasonally flooded prairies, silt flats, woodland edges, trees in pastures, native prairies, meadows, fallow fields in bottomland, weedy upland fallow fields, disturbed or barren roads and yards.

V. Senses

Snake senses are different from any other reptile due their evolution and ecological niche. Snakes lack ears in a form that a typical person might recognize. There is some evidence that the snake's vestigial inner ear may be able to receive some airborne sounds at certain frequencies, but this is still under dispute. There is little doubt that snakes have a highly evolved tactile sense that allows them to sense vibrations and temperature variances very effectively. (Seigel and Collins, 1993)

They also possess a highly enhanced sense of taste created by combining taste and smell through an adaptation known as Jacobson's organ. This consists of two specially adapted sensory pits in the roof of the mouth. The normal use of this organ is demonstrated by the snake's tongue flicking in and out, tasting things that it touches with its tongue, or seemingly, sampling the air around it. The tongue is retracted into the mouth where it touches the sensory pits for analysis. Snakes also possess a limited sense of smell in the ordinary way. (Sweeney, 1992)

Garter snakes possess an excellent sense of sight in terms of the snake world, but it would be considered poor (even by human standards) in comparison to most other animals. It is thought that snake eyes are not as mobile as most other animals because of the lack of sensitivity in any particular area of the eye. Thus, the ability to focus a particular part of the eye is lacking. Snakes will typically move their heads to track any but the smallest movements. Their depth perception is poor compared to animals with forward-facing eyes.

It has been shown, in various studies, that snakes, deprived of a particular sense, can still function in a relatively normal fashion, but it would certainly limit their overall survival chances in the wild. The greatest single sensory loss would likely be their tongues. The loss of an eye might reduce their effectiveness somewhat but would unlikely be crippling. Since their tactile senses are spread throughout their bodies, it is unlikely that this would ever be incapacitating without the snake suffering death.

VI. Feeding, Movement, Normal Activities, Predators

Movement and normal activities are similar for all garter snakes. They can be classed into a number of broad categories - thermoregulating, foraging, mating, predator-defense, hibernation and shedding.

Most garters thermoregulate by warming themselves in the morning hours and then maintaining a preferred body temperature (or plateau phase) which typically ranges from 28 - 32 C during the day. Then, after the snake seeks shelter in the evening, body temperatures fall - the degree depending on the nature of the shelter. Body temperatures will also vary depending on micro-climate, season and local weather conditions. Geographic variation is also likely, based on preliminary evidence: southern examples of a given species have shown slightly higher preferred body temps than northern examples. Garter snakes are generally active over a broad temperature range : 10 - 36 C. Most garters will have difficulty digesting food at temperatures below 12 C. Some species do exhibit broader ranges than other - more typically northern species. T. sirtalis has been found hibernating at temperatures as low as .5 C. As an interesting aside, it has been noted that snakes found in summer exhibit a tendency toward a higher preferred body temperature than snakes caught in the spring or fall.

Foraging behaviors are typical of garter snakes, though not all snakes. Some snakes use an ambush technique instead. Garters have demonstrated the following foraging behaviors:

Peering - apparently seeking visual prey cues

Craning - where the snake will poise itself over water, tongue flicking, in search of chemical/olfactory prey cues.

Ambush - the snake holds its head a few centimeters above water, prepared to strike

Underwater crawling - the snake actively seeks prey at the bottom of a pond or stream.

Swimming - simply to get from place to place

Margin crawling - movement along a shore or stream verge, apparently simply to move from place to place.

Many garter snakes possess strong navigational abilities (T. sirtalis and t. radix for example), allowing them to move substantial distances from a point of origin and return to that point successfully. It has been demonstrated that these capabilities are based on a combination of both an internal 'clock' and the ability to use the sun as a compass. In these cases, even where snakes were released a substantial distance (5 km.) away from their origins, they were able to return there successfully. (Rossman, Ford, Seigel 1996) Not all garters possess these capabilities. T. ordinoides has been, for example, shown to have little true navigational ability. There is also strong evidence that pheromone trails act as orientation devices for some garters. In most cases, it is believed that females rather than males are the primary source of the pheromones. It has also been suggested that neonate garters use these trails to find foraging grounds away from over-wintering sites. These trails are also used to find a way back to dens by both males and neonates. Finally, males use pheromone trails to track females during mating season.

Mating behaviors are similar but not identical among the garter snakes. Male sexual cycles are generally 'disjunct' - that is, they are most actively producing sperm during the late summer and early fall, while they are most ready to mate in spring. Interestingly, there is strong evidence that hormonal cycles and courtship behavior are dissociated as well. Courtship tends to occur without reference to testosterone levels. Instead the male snakes appear to enter courtship behavior based on rising air temperatures at the end of hibernation. Most existing data points to a single early spring mating period, but there is increasing evidence that fall matings occur in several species as well. This is quite mysterious since the known courtship cues are related to increased air temperatures in the spring. There is some evidence that the simple presence of a receptive female may be enough to trigger courtship rituals in some species.

Female sexual cycles are a bit better understood, since it is relatively easy to spot a gravid female and note when she gives birth (all garter snakes are live-bearers). Females typically follow a pattern called 'pre-nuptial vitellogenisis', where the snake begins developing follicles in the fall and then enters a secondary period of egg production after mating in the spring. It appears that (much like the male) rising air temperatures after hibernation are the primary cue for the females to enter the receptive stage. While this pattern is generalized, there is considerable variation across species in the timing of these events. Young are born from late July to late September in some species, while others have delivered young as early as late May to as late as early October. Sperm storage appears to be common in most species of Garter. It has been observed that females can make use of the sperm from late fall matings in the following spring, whether they mate at that time or not. (Sweeney, 1992)

Clutch sizes appear to depend on both the species and food availability during gestation. Variations of as much as 100% were noted in some populations on an annual basis. These variances could be easily tied to rainfall and thus prey abundance. Most garter snakes appear to reproduce annually, though in some northern populations, a year or even two may be skipped.


Thamnophis elegans elegans (Western Terrestrial Garter Snake)

The preferred diet for T. e. elegans is quite broad, with invertebrates, fish, amphibian larvae, mammals and amphibians each making up more than 10% of their diets. These may be supplemented by small reptiles and birds as well. Preferred invertebrates include leeches, slugs, snails and earthworms. The species appears to define food preferences very simply - based on seasonal and micro-geographic availability (Rossman, Ford, Seigel 1996).

Thamnophis radix (Plains Garter Snake)

T. radix appears to have slightly more limited diet than T. e. elegans. It has strong preferences (greater than 10% of diet) for earthworms, leeches, amphibian larvae and amphibians. It will also fill in its diet with occasional small fish and mice. This may be related to its smaller size.

Thamnophis sirtalis sirtalis (Common Garter Snake)

T. S. sirtalis appears to fall somewhere in between the above species in terms of it s preferences. The largest components of it's diet are leeches, slugs, earthworms, amphibian larvae, amphibians and small mammals. It will , on occasion, add small birds and fish to its main diet.

In all cases, it should be noted that prey items will vary based on the size of the animals. Nearly all species will eat earthworms while young, though as many become larger they may broaden their diets to include all the above noted prey items. Individual snakes will also very their diet based on prey availability in their particular micro-habitats. Generally speaking, larger animals will eat larger prey items.

Predators and Defense. Adult garter snakes are subject to predation by a large number of other species. The most common are hawks, raccoons, minks, foxes, badgers, and other snakes (particularly racers, king snakes and coral snakes). While they are young they are also popular food items with shrews, jays, crows, fish, frogs and certain smaller snakes. The most popular defensive tactic for Thamnophis is simple flight. This may be combined with the voiding of strong-smelling cloacal secretions. If pursued to exhaustion they may either ball up and wave their tails, attempting to confuse a predator, or they may hiss and strike. The latter is primarily a bluffing behavior, since they seldom bite. (Rossman, Ford, Seigel 1996) Defense tactics have been shown to vary between species, with some snakes such as Butler's Garter seldom becoming aggressive, even under extreme circumstances, while others, such as T. melanogaster rely heavily on aggressive striking behaviors to ward off attacks. Most garters will respond defensively to a model of a mammalian eye, when pushed to extreme, striking repeatedly at it.

Skin Shedding

All snakes shed their skin on a regular basis and the general success of the snake in shedding it's skin can be used as one measure of it's health. Snakes shed their skins in a single piece if they are healthy and in an environment that is healthy for them. Shedding frequency will very with age. Younger snakes may shed as often as monthly, in order to keep up with their rapid growth. Older snakes may shed as little as once every three to six months. It is generally fairly easy to tell if a snake is ready to shed. They will generally become somewhat irritable and you will notice a dulling of the snakes skin. Soon after this is noted, the snakes eyes will become milky or 'blue' looking. This frequently referred to as going 'blue' by many keepers, as in "My snake is blue". Just before the actual shed takes place, the eyes will clear. The actual process of shedding starts with the animal rubbing it's lips on rough surface. Once loosened, the snake will rub the top of it's head carefully to pull away the skin over the eyecaps (spectacles). Then the lower jaw is started. If no tears or breaks occur during this process, the snake will then simply 'roll' the rest of it's skin off much as a sock can be rolled of your foot. In a perfect shed, the snake skin is a continuous and unbroken 'inside-out' version of the snake, lacking only the colors. Since snake skin is made of keratin, like our fingernails, the skin actually feels very similar.

Common problems with shed include retained spectacles, retained shed fragments, and nasal blockage due to retained shed. The first is easily observed as roughened dry skin over the eye itself. Shed fragments appear as dry patchy areas usually with bits of skin sticking up around the edges. If the nares are blocked by retained shed, you can sometimes hear breathing sounds, somewhat like an adenoidal child. These can all be indications of poor health and/or keeping conditions. In the wild, snakes seldom have shed problems, unless they have been wounded. In that case, the skin around and over the wound sometimes is retained while it heals - developing a scab-like appearance.

VII. Reproduction Particulars

Thamnophis elegans elegans (Western Terrestrial Garter Snake)

Typically reaches sexual maturity at about 2 years of age and a length of about 400 mm. Clutch sizes typically 6 -13.

Thamnophis radix (Plains Garter Snake)

Sexual maturity data is lacking at this time, but likely to be in the 20 -26 month range. Clutch sizes 9 - 29.

Thamnophis sirtalis sirtalis (Common Garter Snake)

Sexual maturity typically reached at about 24 months for females, 20 months for males. Length for females 420 -570 mm, males 360 -380 mm. Clutch sizes 7 - 32.

VIII. Hibernation

All garter snakes hibernate to some extent, T. sirtalis up to 7 months out of the year at the northern end of its range.. Two critical burrow features for successful hibernation are variable depth (to allow for thermoregulation as temperatures fall) and access to water. Habitat destruction can be a critical issue, since it appears that many dens are 'traditional' and used for many generations, particularly in the northern ranges of these animals. Since many places may appear suitable as dens, not all snakes entering a particular den will survive the winter. These sites may lack adequate water or may not allow the snake to den deep enough to survive in extreme conditions. This may also explain some of the great aggregations of garter snakes found in some locales.

IX. Conservation and Legal Issues

As with most animals, habitat destruction has proven to be the worst enemy of the Garter snake. Over-collection by commercial interests has had an impact on some species as well. However, the general fecundity and adaptability of the garter snakes has managed to stave off disaster so far. This may not hold true for all species in the long term. Many of the snakes living at the extreme northern edge of the ranges have a tendency to produce smaller clutches with larger individual sizes than their southern cousins. They are also more likely to skip years in breeding cycles. Thus, the impact of losing an animal in those ssp. is generally greater than in their southern cousins. Further, due to the variability of clutch sizes due to prey availability, destruction of habitat or over-collection may have a far greater impact on a ssp. during harsh weather conditions. This can be particularly true if those conditions are prolonged. In general, the garter snakes are doing well at this point, though this may not last if we persist in ignoring their needs for undisturbed habitat.

X. Rehabilitation Notes

Several concerns should be addressed prior to attempting the rehabilitation of these animals. The first is access to an experienced veterinarian. While many vets will treat reptiles, fewer have the experience necessary to do so successfully. Few veterinarians should be offended by a request for their qualifications in this area of expertise.

A second area is your own knowledge. Reading about reptile care, both in general and regarding the specific species you are likely to encounter, is very important. Reptiles are likely to be the most 'alien' creatures you will encounter as a rehabber. They have few or no facial expressions and are seldom vocal - thus they are exceptionally difficult to triage. Pain is very real for them, but it seldom shows in ways that are obvious to humans. A recognition of what constitutes 'normal' behavior for a reptile is essential if you are to successfully treat illness or injury.

Assuming you have made the effort to address the issues above, the next area of focus is the keeping environment. Without an appropriate vivarium setup, the best trauma care in the world will likely fail. Snakes, like all reptiles, are ectotherms - requiring external heat sources to maintain and manage their own temperatures. When we, as rehabbers, isolate and contain them, we are taking responsibility for this maintenance. They also select 'micro-habitats' based on issues such as humidity and light that are nearly as important as temperature. If we cannot provide an appropriate setup for their care, we should not try to rehabilitate them.

Two setups are required for the proper care of injured snakes. The first is a 'hospital' setup, used during the early stages of treatment for trauma and illness. The second is used for maintenance if long-term convalescence is required. All animals should be quarantined from each other during rehabilitation.

Garter Snake Keeping Issues:

These goals can be met through the design of an appropriate vivarium for keeping.

Minimum 'Hospital' setup:

10 or 20L Gallon Aquarium

non-tippable, appropriately sized water dish (see below)

Un-printed newsprint or plain paper towels for substrate.

Overhead heat source or under-tank heater (UTH)


Fine-mesh screen top

Cage Clips

The aquarium should be set up in a quiet, low-traffic area. Install heating unit and adjust heat. The sides of the aquarium may be covered with cardboard or cloth to provide a sense of security for the snake. Overhead heat sources can be adjusted either through the use of a rheostat or by simply varying the height of the lamp from the cage. UTHs can be controlled by rheostat or by varying the cage height above the UTH through the use of shims under the edge of the aquarium. While undergoing antibiotic treatment, the animal can be maintained at temperatures of 80 - 85 F to improve response to the drug. A non-tippable bowl large enough for the snake to soak in can be placed over the UTH or under the heat lamp if surgery has not been required. (This insures that the water will evaporate and raise humidity.) Otherwise, use a smaller bowl to prevent the animal from soaking and possibly infecting the wound. If you choose to use a UTH, be sure to measure the temperature at the cage bottom, not in the air above it. The screen top must be used with appropriate clips to prevent injury to the snake from outside sources, as well as to prevent escape. Garters are extremely prone to escape due their slender builds and athletic abilities. Fine mesh is preferred to limit rostral scale damage. It also provides a convenient method for mounting an overhead heat lamp. Temperature settings should be established before a reptile is placed in the tank.. Snakes should be housed separately - never together, due to the possibility of aggression, particularly during feeding.

Feeding should not be attempted unless okayed by your vet. Snakes are capable of going for a substantial period of time without feeding so long as they have access to water and have adequate body weight to begin with. Feeding can be accomplished with this species either by placing the feeder animal in an appropriate container (for example, fish in a small transparent dish) in the cage or by forceps. Food animals should be appropriately sized - they should never be larger than the garter snakes diameter. Fish filet (sprinkled with an appropriate vitamin supplement such as Rep-Cal Repti-Vite) can be cut into strips thinner than the snakes head and approximately ½ to 1 and ½ " long (depending on snake size). These can offered by forceps. The snake should be allowed to feed based on the appropriate MEC for it's weight. If a snake is suffering from spinal injuries - attempt to feed by forceps or by stunning the prey prior to feeding. This will prevent over-activity during the healing process.

Maintenance Setup:

The following is a generic maintenance setup likely to prove successful with most garter snake species. If your animal is from the extreme north or south, some variation may be necessary.

The above setup may be used with some variations for longer term care. A temperature gradient of 72 F(22 C) to 86 F(30 C) should be provided to allow for thermoregulation. The heat source should be placed at one side of the enclosure to create a proper gradient. It should not heat more than one-third of the enclosure directly. If the room temperature is maintained in the mid-70's then it is only necessary to provide a basking spot. Several commercial products may be used successfully as substrates -, unused newsprint or paper towels, for example. Carefresh and small animal aspen bedding are both readily available at many pet stores. Never use an aromatic wood chip, such as cedar. Two hide areas should be provided for the snake at opposite ends of the vivarium - rocks or small branches will lend a sense of security. Drapes can be removed during this phase of convalescence, enabling you to monitor the animal for improvements in behavior. A rock or branch placed under the basking light or over the UTH will be used regularly by a healing snake. Ill or underweight snakes should never be hibernated. You may generally prevent hibernation by maintaining a summer light and heat schedule throughout the winter. This may require the application of UVB light with some animals.

Assuming you have the basic components noted above, you are prepared to perform basic triage and provide appropriate care during convalescence. The following material is presented primarily for the inexperienced reptile rehabber. It is not all-inclusive and should act only as a guideline. Veterinary care is indicated in a number of instances where more experienced reptile rehabbers might treat on their own. If you have access to culturing, cytology and similar diagnostic tools, you may wish to perform some tests yourself. However, it should be noted that what constitutes normal bacteria and/or parasites for reptiles may not be normal for other species you may work with. Salmonella, for example, is a fairly normal resident as are a good many Gram-negative bacteria. Often, the only indication of these as a disease-causing agent is a specific knowledge of appropriate counts. Thus, interpretation is best left to an appropriately trained and experienced veterinarian or technician.


The following signs indicate the need for immediate transport to a veterinarian.

  1. Blood in mouth or nares accompanied by facial fractures or head trauma. Attempt to clear blood from nares and mouth with a sterile cotton swab or ball.
  2. Object obstructing breathing. Remove with forceps.
  3. Signs of major blood loss. Apply pressure with a sterile gauze pad or tie off. Begin fluid replacement.
  4. Crushing wounds to the body. (Cover with sterile gauze moistened with saline.)
  5. Unconsciousness accompanying any of the above.
Handling Safety Precautions:

It is appropriate to assume that all reptiles are reservoirs for Salmonella and similar zoonoses. It is good practice to wash your hands thoroughly both before and after handling any reptile. If available, standard surgical gloves are appropriate. If you treat more than one reptile, this practice is even more important due to the possibility of cross-infection. Standard procedures for the sterilization of any instruments used is mandatory. Disposable equipment should be used where possible.

All snakes are carnivorous animals and thus may be somewhat defensive during handling. Bites are not common but may occur. These are seldom more than a nuisance in the species under discussion. A typical snake bite from a snake of this size seldom hurts more than a light pinch. Small puncture wounds may result, that should be examined thoroughly for broken teeth or tooth fragments. Simple debriding with soap and water, followed by application of a topical antibiotic will usually prove sufficient. On rare occasions, septicemia may result (usually from Gram-negative bacteria) and this should be followed up immediately with a visit to your physician. Snake bites from a non-venomous species are unlikely to cause problems except in the extremely rare circumstance that the victim proves to be allergic to snake saliva. There is, however, one known instance of a person dying as a result of a hyper-allergic reaction to garter snake saliva. (Steve Grenard - Personal Commentary)

Basic Exam

First, try to gather as much background information regarding the animal as possible - interview the person who found the animal as well as anyone who transported it. Next, weigh and measure the snake. Examine the snakes behavior: look for star-gazing, circling, thrashing, body rotation, head-scraping, and lack of movement or muscle tone in a particular area of the body. Turn the snake on it's back. Is it able right itself without difficulty? (This particular exam should be done without restraint on a surface that allows some traction for the animal - i.e. - not stainless steel.) You may find that examinations are considerably easier if two people are available - one to restrain and one to manipulate. Begin the examination by looking over the eyes of the snake. Make sure the snake's body is fully supported during this operation. Look for swelling, discharge, redness, and foreign bodies that might be present. Next, examine the nares for discharge or blockage. Then move on to the mouth. Look for hemorrhaging, a generalized yellow appearance, necrosis, swellings or caseous material. Also note any signs of 'stringy' mucous. Watch to see if the snake wheezes or keeps it's mouth open for breathing when not held. The mouth may be opened by gently inserting a moistened cotton swab at the side and pushing back toward the joint - do not use the end of the swab other than to enter the mouth - use the length of the swab. Overly rough handling can cause mouth damage by itself.

The next step is to review general skin condition. Examine all skin closely for the following: retained dry skin, edema, abscesses, redness under the scales, jaundice, perforations and other signs of trauma. Run your hand down the body lightly and firmly - there should be no lumps or palpable masses. Look carefully for the presence of mites and ticks. Mites will generally appear as small, mobile red or black dust specks. Finally, examine the cloaca for trauma, discharge or other signs of infection. If you have access to a laboratory, you may wish to take samples of urine, feces and/or oral and cloacal swabs. X-rays should be taken if spinal fractures or head swelling appear to be present.

Once complete notes are taken, review the following list of common presenting symptoms. They are presented in the order of the exam protocol. Do not attempt to treat prior to a complete review.
Symptoms  Likely cause  Indicated Treatment 
Inflamed, swollen  Conjunctivitis, may be secondary to respiratory infection. (Also check for foreign bodies.)  Apply triple antibiotic ointment 3 -4 times per day. 
Pupil non-responsive to light  possible blindness, brain damage, trauma  Requires veterinary review. 
White or opaque eyes, eye-caps  This may be normal - due to the snake being in a pre-shed state. Otherwise, conjunctivitis with pus retained under spectacle May also be caused by blindness: this is seldom seen in more than one eye at a time. May be caused, in captivity, by multiple retained eyecaps.  Apply triple antibiotic ointment 3 -4 times per day. 
Sunken eyes  Probable moderate to severe dehydration  see Folds in Skin below 
spot hemorrhaging, viscous secretions, excessive drooling, yellowish pus  Stomatitis (Mouth Rot)  

This is generally an indicator of a more serious underlying condition, seldom a disease in itself. 

Requires veterinary review. Treatment involves debridement of the affected areas followed by flushing with a mild Betadine solution. Insure that the animal does not ingest any of the Betadine. 
Bubbling, discharge  Upper respiratory tract infection  If bacterial, it is likely to be colored. Colorless discharge may indicate a virus. Both may be present. Transport to vet. 
Neuro-motor symptoms:  ; may be caused by brain damage, viruses, liver impairment, Vit. B1 deficiency, encephalitis, IBD, poisoning.  Requires veterinary evaluation. 
Circling, thrashing, rolling  usually caused by brain damage, sometimes extreme pain  Requires veterinary evaluation. 
Lack of tactile response, lack of muscle tone  usually caused by a spinal injury.  Requires veterinary evaluation. 
Paralysis Severed spinal cord, viral or bacterial infection, parasites, toxins  Requires immediate veterinary evaluation. 
Tremors see star-gazing 
Wheezing, open-mouth breathing, distended throat.  Lower respiratory tract infection (If accompanied by cyanosis and/or concurrent illness it may indicate an acute pneumonia) Also check for physical obstruction. Be careful not to confuse this with normal defensive hissing. The latter will disappear when the animal is not threatened.  Likely to be pneumonia or severe bronchitis. Requires veterinary treatment. If acute - transport immediately to veterinarian. 
Simple Wounds  trauma Depending on severity, deride, flush with Betadine, treat with triple antibiotic ointment. If massive, or obvious severe local infection seek veterinary intervention. 
Wound with small white larvae  Myiasis - complications: location of the larvae are an indicator of possible underlying damage - review carefully for trauma issues  Pluck larvae with tweezers. Treat same as wounds above. Repeat as needed. (Treatment may be required for some days due to hatching fly eggs.) 
Localized Body Swelling  May be an indicator of internal injury. Steatitis. Cellulitis. May also be caused by pregnancy or malignancy.  If the swelling is regular and slightly mobile, it is likely a pregnant snake. If the swelling is hard and offset to one side, malignancy is possible. Swellings around obvious trauma sites can indicate severe internal injuries. 
Lumps, bumps under skin  Likely to indicate an abscess - see abscesses below  Requires veterinary evaluation. 
Visible ribs or visible spine  Probable starvation, tumor, parasites, systemic infection  Rehydrate gradually. Tubefeed small amounts of Ensure (2% body weight q24) after animal is rehydrated and demonstrates weight gain. Then tubefeed small amounts (2% of body weight q24) of slurried Hills a/d after animal is rehydrated and demonstrates weight gain. Review with vet for differential diagnosis. 
Folds, wrinkles in skin where the animal coils  probable dehydration - check for skin tone by pinching.  Mild to moderate: snake will drink -  

Rehydrate via soaking and making water available. 

Moderate to severe - sq or ic fluids - 15 -25 ml/kg q24 divided dose 

Severe - sq or ic fluids, 25 - 40 ml/kg q24 divided dose 

Scale loss - abscesses at injection site.  Drug reaction  If within two or three drug injections, assume an allergic reaction. Discontinue treatment and review case with veterinarian for alternate drug therapies. Treatment involves keeping in a sterile cage with daily sterilization of water dish. Change a plain paper substrate daily. Flush affected areas with dilute Betadine and dry. Apply triple antibiotic ointment daily. 
Ticks Manual removal can be risky due to possible infection from mouth parts embedded in skin. MacArthur reports some success with dilute Amitraz (2 ml/l) (MacArthur, 1996) 
Mites red or black 'specks' moving around the eyes or at scale edges.  Provent-a-Mite has proven very successful when used exactly as directed. 
Blisters on ventral area  'Blister disease' - generally found only in captive snakes.  Too wet a keeping environment. Move to a dry 'hospital cage' setup and treat with triple antibiotic ointment 2 -3 times daily. 
Red flush under skin  Septicemia, Peritonitis 

(frequently accompanied by vomiting, lethargy, yellow mucous membranes) 

Requires veterinary intervention. Supportive therapy includes fluid therapy, increased temps and immediate systemic antibiotic treatment 
Abscesses, present as lumps that break up the normal outline of the skin. Frequently caused by partially healed wounds.  Multiple possible bacterial agents such as Pseudomonas, Aeromonas, Citrobacter, Serratia, Klebsiella  Generally requires veterinary intervention. The abscess must be lanced, then curetted. Supportive therapy may require fluids, daily flushing and wound packing. Systemic antibiotics may be required, depending on severity. 
Burns trauma Debride with dilute Betadine or hydrogen peroxide. Dry. Treat with Triple Antibiotic cream, Silvadene or Gentamicin applied topically. 
Masses under skin  If found in the rear third - possibly a gestating female. Possible constipation. Possible tumor. If in the center or front third, possible tumor.  Try soaking in warm water (80 - 85 F) to see if constipation is an issue. This may several soaks over a period of two days. If unresolved, review with vet. 
Mass protruding from cloaca  If red, may be prolapsed organ. If any areas are blackened - this may indicate gangrene. Possible sperm plug (usually tan or brown in color)  Saturate sterile bandage in sterile saline. Wrap gently around mass and transport to vet immediately. 
Swelling, redness, or discharge from cloaca.  Cloacitis , systemic infection. 

Complications: cloacal calculus, egg retention, parasite infestation 

Requires veterinary intervention. Cultures and physical exam required to determine cause. 
Bloody or mucous-laden stools  parasite infestation or enteritis  Requires fecal exam and/or culture. 
Diarrhea  Temps too low. Parasites.. bacterial infection.  Review with veterinarian. 
Vomiting Stress. Obstruction. Tumor.  If this occurs more than once, review with your veterinarian. Avoid handling snake 24 -48 hours after feeding. 
Dirty vent  possible infection or endoparasites  Requires veterinary intervention. Cultures and physical exam required to determine cause 
Shock - may be indicated by lack of responsiveness, pale mucosa, low blood pressure, muscle weakness, elevated heart rate  May be caused by fluid loss from a number of possible causes - wound seepage, vomiting, diarrhea, bleeding, or toxic shock.  Raise temperatures to mid 80's, administer fluids, consider the use of corticosteroids such as dexamethasone. A generalized dose for dex is .1 mg/kg IM. 

The drugs noted above are the most common, readily available and least expensive brands or type available in America. Others that are perfectly suitable substitutes are available and should be used as recommended by your veterinarian. Provent-A-Mite is a trademark of Pro Products. Carefresh is a trademark of Absorption Corp.

Transport Protocol:

At a minimum, the rehabber should keep a several small cardboard boxes or 'Critter Carrier' - type enclosures and several cotton bags available at all times. Small to medium-sized styrofoam coolers are also very good for transport, especially in the depths of winter (or summer) when temperature variations between indoors and outdoors are at their worst. Coolers should have a series of tiny holes punched through the wall near the top, using a tool such as an icepick - do not make the holes larger than necessary. The animal should never be shifted through a substantial temperature change. Snakes should always be bagged in a cotton bag with tightly sewn seams before transport. The top of the bag should be twisted tightly and then tied off. I use heavy rubber bands, though twine will work fine. The bag should then be placed in a cooler or box. A hot water bottle may be placed under the cloth in the carrier to provide warmth; well - insulated ice packs may be used to keep the animal cool. Make sure the temp range is between 65 - 80 if a long transport is required. In emergencies, I have bagged an animal and then transported inside clothing near the body.


Euthanasia in reptiles is an on-going debate at this time. There are a number of possible non-veterinary methods, most of which have significant drawbacks for the rehabber and/or animal. Decapitation is not suitable since there is evidence that some level of consciousness may be maintained for as long as one hour after administration. It may be used in an emergency situation, if the animal is immediately pithed. (This is not a preferred method.) Freezing, while accepted in the past, may or may not be effective. Temperature requirements for successful freezing are extreme, substantially below those available to the average rehabber. Inhalant use is risky as well, particularly to the administrator, due to the lengthy period of time and large amounts of agent required for successful usage of inhalants.

My current preferred method is the administration of a suitable barbituate (i.e. Pentobarbitone), administered IV or intracardiac. Dosage should be administered to excess, no less than 200 mg/kg. Ketamine IM, at a high dose, may be administered for immobilization to aid in subsequent injection of the euthanasia agent. (MacArthur, 1996) This procedure must be performed by a veterinarian due to the restricted class of drugs required.

X . Glossary

Betadine - trade name for Povidine-Iodine

Caseous - paste-like

Cloaca - a chamber where the urinary, genital and digestive systems empty.

Dorsal - the upper half of the snake.

Ectothermic - characterizes animals that regulate their temperature by external sources, for example, solar radiation or sun-warmed rocks.

Nares - paired nasal openings

Rostral - nose tip

Scale rows - are always counted from the ventral scales up to the spine on the diagonal.

Supralabial - above the mouth

Ventral - the lower half of the snake.

Vivarium - an enclosure designed to mimic the natural conditions an animal lives in.