Common garter snake
Thamnophis sirtalis
Photo: Thamnophis sirtalis sirtalis Wooster · Wilson44691 · Public domain · Changes and credits
These guides provide general husbandry information and do not replace veterinary assessment. If your animal shows symptoms or its condition worsens, contact a veterinarian experienced with exotic animals.
- Warm zone
- Basking surface: 29–32 °C
- Cool zone
- Cool air: 24–27 °C
These notices cover the cited provisions, not every possible national or local rule. Check additional requirements with the competent authority.
Description
Thamnophis sirtalis is a slender North American snake often recognised by longitudinal stripes. Colours and patterns vary between populations and subspecies. It inhabits meadows, woodland and watersides, searching for amphibians, earthworms and other prey; it is often active by day and gives birth to live young.
Behaviour
Observe the individual’s behaviour and limit handling.
Housing together
Thamnophis sirtalis can be kept singly or with similarly sized conspecifics in enlarged housing. Offer food to each separately under observation, preventing two snakes from taking the same prey item. Do not combine neonates and adults; separate bitten animals or those losing weight or excluded from hides. A mixed-sex group may breed.
Enclosure and climate
This sheet covers Thamnophis sirtalis. Retain a large terrestrial area with hides, low branches and litter; add a bathing container the snake can leave easily. Dry spills rather than keeping the whole enclosure wet. Active maintenance conditions are not a brumation protocol for every population.
Night: 18–24 °C.
Setup
Test the bathing container in the empty enclosure: it must be removable without dismantling branches and leave usable land space.
Warm area, cool area and hides
If heating is specified, place it at one end and distribute hides between that area and the cool side. Choose openings and internal space suitable for the body; after adding bedding, check that entrances remain clear. Set the dish on a stable base and leave routes between retreats; use low supports only where suitable for the species.
Testing and access
Connect specified heat sources to compatible thermostats and guard against contact. Secure probes according to device instructions; measure air at resting sites and heated surfaces separately with independent instruments. In housing with water, also check water temperature and quality: one zone’s thermostat does not control the others.
With the complete enclosure running, record day and night readings and compare them with the sheet. Test doors, cable openings and cleaning access, keeping vents clear. Change one variable at a time and recheck after each adjustment.
Lighting and UVB
Ferguson zone not assigned with sufficient precision to this taxon.
At the exposed position aim for approximately UVI 2–3, measured at the back or head. The animal must choose its exposure and reach UVI 0 retreats. This local target differs from the Ferguson ecological band and should not be maintained everywhere throughout the day.
UVB is recommended at an intensity appropriate to the species, with the option to withdraw from the light. Evidence of its necessity varies between animals: assess exposure alongside diet and species identification.
UVA is recommended as part of daytime lighting, including when UVB has not been shown to be indispensable. Check the UVB source’s spectrum, as it may already emit UVA: a second lamp is not automatically necessary.
Linear UVB tube with reflector. Indicative UVB percentage stated on the lamp: 2–7%; final selection depends on UVI achieved at the actual distance.
For maintenance, a cycle of approximately 12 hours of light and 12 hours of darkness can serve as an initial reference. Use a timer to switch lights off at night, and keep retreats available so the animal can withdraw from light during the day. Adapt day length to species and origin, following the specific guidance for seasonal care and breeding.
Light in the animal’s daily life
The published ecological assignment is for T. s. tetrataenia and is not extended to all populations. The practical peak is listed at species level; retain hides and screening vegetation.
An example layout in the enclosure
To make the layout concrete, take housing measuring 120 × 60 × 60 cm, using the first dimensional configuration in the sheet. This is a mounting example: retain the conditions and any alternatives attached to the stated minimum.
In a wooden enclosure with internal lighting, imagine the tube 55 cm above the floor and the back or head at 25 cm. The geometric distance is therefore 30 cm. The branch or platform lies below animal height, according to body size. Place lighting over one side, with a route to fully screened retreats.
In a glass enclosure with a mesh roof, retain the same animal height and imagine the tube 5 cm above the mesh: distance becomes 40 cm. Mesh attenuates UV variably; ordinary glass roofs block UVB. Increasing the percentage alone is insufficient: measure beneath the mesh and adjust height, output or layout as needed.
These distances describe the example, not a safe clearance for every lamp. Select the source and adjust mounting until approximately UVI 2–3 is measured at animal height in the exposed position. Also respect the minimum clearance specified for the model used. Recheck with furnishings, guards and mesh installed, including the highest reachable points and animal growth.
Choosing and checking lighting
First define the patch that should illuminate the whole body and the route to a screened retreat. For a broad patch, select a linear tube with reflector; consider a compact only if its useful patch covers the body and leaves an accessible gradient. Check model, output, reflector and mounting distance, then compare measured UVI with the species target. Label UVB percentage alone cannot determine distance and intensity.
The decisive check uses a UVI meter facing the source at animal height. Check the centre and edges of the exposed patch, the highest supports and retreats, which must allow withdrawal from UV. Repeat after moving equipment, changing lamps and plant growth. Without a meter, use the manufacturer’s instructions and measurements for the exact configuration, including safety clearances.
When UVB or UVA are absent
When UVB is absent, an appropriate whole-prey diet can provide vitamin D3; do not automatically add supplements to prey. Dietary provision does not recreate every effect of light, so retain plans for controlled UVB exposure.
UVA contributes to environmental perception and behaviour and cannot be replaced by vitamins or calcium. A reptile UVB source normally also emits UVA: check its declared spectrum. If the existing lighting lacks it, complete the installation with a suitable source; an ordinary white LED does not guarantee UVA and a UVA-only lamp does not provide UVB.
Humidity and ventilation
35–60% in terrestrial-area air, with a local humid hide and bathing water separate from the substrate. Keep terrestrial bedding ventilated and free of standing water, with a humid hide separate from the bathing dish. Change dirty water and dry spills: a large container must not soak all the litter. Measure beside hides separately from the water surface.
Feeding
Thamnophis sirtalis can use rodents, earthworms and suitable fish in rotation. Do not apply the long feeding intervals of large boas or a goldfish-only diet.
Recommended foods
The tiers describe dietary use: rotate foods within each tier rather than treating them as an absolute nutritional score.
| Food | Dietary role | Benefits and limits | Preparation |
|---|---|---|---|
| Whole captive-bred thawed rodents | Main choices | Skeleton, organs and muscle together supply nutrients absent from meat alone; select prey size according to swallowing ability and the portion specified for the species. | Thaw completely in a refrigerator in a container separate from human food, then warm in a sealed bag in warm water. Do not microwave or refreeze. |
| Earthworms from controlled cultures | For rotation | Soft prey with a generally more favourable mineral balance than unsupplemented crickets; particularly useful for amphibians. They are not a reason to eliminate all variety. | Rinse and cut only if required for mouth size. Avoid dyed fishing bait, cultures on contaminated manure and collection from treated soil. |
| Identified whole fish with low thiaminase risk | For rotation | Fish are not interchangeable: some contain thiaminase, which can cause vitamin B1 deficiency when used as the regular diet. | Use identified species, such as trout, from a food supply chain. Avoid goldfish and mixes with unspecified species. Freezing does not remove thiaminase; fillets are not equivalent to whole fish. |
| Boneless meat and organs alone | Avoid / not a staple | Do not replace whole prey: muscle meat is calcium-poor and a liver-only diet can supply excessive vitamin A. | Do not use steak, boneless chicken or processed meats as the regular diet. |
Meals by age and size
| Stage and size | Frequency | Amount per meal |
|---|---|---|
| Neonates and growing juveniles | Every 3–5 days | One small whole prey item suited to the mouth; for neonates use earthworm pieces or portions of complete prey offered separately. Stop before the body becomes greatly distended. |
| Subadults and adults | Every 4–7 days; fish or earthworm portions may require closer meals than rodents | One whole prey item per meal, with a diameter close to the snake’s widest body section and only a slight visible post-meal bulge. Increase prey size gradually; do not stack large prey items to accelerate growth. |
Adjusting portions
Weigh before feeding and compare several measurements, not the weight immediately after a meal. Maintain defined muscle without fat folds; extend intervals if weight becomes excessive. Refusal with weight loss, regurgitation or breathing difficulty needs veterinary assessment.
Preparing and offering meals
Thaw completely in a refrigerator in a container separate from human food, then warm in a sealed bag in warm water. Do not microwave or refreeze.
Offer with tongs on a clean surface in its enclosure; avoid moving the snake for every meal. Remove refused prey. Leave undisturbed for at least 48 hours afterwards with continued access to the correct thermal gradient.
Calcium and vitamins
A diet of correctly raised, well-fed whole prey normally does not require calcium or multivitamins added to every meal. Do not inject prey with vitamins or try to compensate for a meat-only diet with improvised doses.
If fish or invertebrates form much of the diet, have calcium and vitamin B1 provision formulated; do not dose pure thiamine at home or treat powder as a remedy for unidentified fish.
Daily care
First days
Keep retreats accessible and observe without opening them to look for the animal. Check climate readings from outside, offer scheduled food and record actual intake. Prepare the scales and container before weighing so the transfer stays brief; compare weight with earlier records rather than relying on appearance alone.
Cleaning
Keep animals and equipment away from kitchens and food areas, use tools dedicated to each enclosure and wash your hands with soap and running water after handling animals, food, tank water or furnishings. Quarantine new arrivals separately and agree the duration and checks with a veterinarian before introducing them to established animals.
Handling
Before a transfer, prepare an open container and an access route. Allow the animal to enter where possible; if support is necessary, support its body without gripping the tail and minimise time out of the enclosure. Stop repeated attempts to grasp it and allow withdrawal to a retreat.
Checks
Record weight, appetite and behaviour; consult a veterinarian experienced with the species if changes persist. For laboured breathing or wounds, contact them promptly without waiting for symptoms to persist.
Breeding
Sex, maturity and readiness
Confirm T. sirtalis and origin: the name garter snake covers many species. Females are described as maturing around two years, but development and condition must also be suitable; their larger size relative to males does not mean obesity.
Start a record for each breeding animal with identity, origin, documented age and previous weights. Compare the weight trend with growth and body condition; delay introductions for animals still growing rapidly, losing weight or recently acquired. Use stated ages as guidance alongside these checks. If sex cannot be identified reliably, obtain assessment by qualified personnel before pairing.
Preparation and seasonal cycle
In temperate populations mating follows winter rest. Adapt any artificial season to origin; after warming, check feeding and hydration before introductions rather than recreating masses of snakes in one enclosure.
Before encounters, prepare and test offspring enclosures and have first foods available. Check records for regular adult feeding and good body condition, then verify access from exposed areas to retreats. If the species protocol includes seasonal changes, adjust settings gradually and record the response. Record night-time air, surface and egg temperatures separately, noting where each is measured. Keep water available throughout preparation.
Courtship and mating
The male follows scent cues and seeks contact along the female’s body. Use controlled introductions with room to withdraw; sperm storage means a birth does not necessarily identify the last introduced male as the father.
Pregnancy and preparation for birth
It is live-bearing and can produce many offspring: prepare housing and food for all of them beforehand rather than an incubator. The pregnant female needs dry hides, water and thermal choice; record appetite and condition without palpating the abdomen.
Gestation and birth
Gestation is described around 2–3 months, with litters often numbering 10–40 and considerable variation. First copulation alone does not determine the birth date; retain access to warmth without overheating the entire enclosure.
Maintain the usual gradient, shelters and free access to water; the female must be able to move away from warmth. Prepare a cleanable surface and observe without repeatedly moving her. Count offspring after birth has finished; do not pull membranes, cords or still-attached young. Remove birth material after the animals have separated.
First meals and juvenile care
Neonates need very small prey: offer suitable portions of cultured earthworms and, within the feeding rotation, suitable whole fish or proportionate rodents. Check every feeding and prevent two neonates grabbing the same item; avoid a diet consisting only of thiaminase-containing fish.
During the first weeks, monitor each youngster: a feeding group does not guarantee that every individual eats. Record intake, droppings and weight at regular intervals to follow growth and adapt housing and food size. Provide separate accommodation if competition prevents an individual from feeding or size differences become marked. Document repeated independent meals before transfer to another keeper.
Female recovery
After reproduction provide water and the usual balanced diet, initially in manageable portions; monitor weight, activity and return of appetite. Keep supplements and lighting consistent with the feeding guide. Avoid further introductions until the previous condition has recovered; later clutches may occur without another mating. Persistent straining, weakness or protruding tissue require veterinary attention, without squeezing the abdomen.
Equipment and example diary
Prepare the female’s enclosure, dividers or neonatal enclosures according to the species’ social structure, shelters, accessible water, thermostat and probes, scales and first foods. An incubator is unnecessary: reserve space and time for monitoring offspring and mother.
A consistent diary using actual dates helps follow reproduction in Thamnophis sirtalis. Start with adult identity, weight and condition, then record observed encounters, laying or birth and development conditions. After emergence record the first meal actually accepted and each youngster’s growth while continuing to follow female recovery. Over time these records help identify your lineage’s pattern without turning approximate durations into deadlines.