In the Greater Toronto Area, most of us have met a garter snake. Coiled in a garden bed, slipping through the grass at a conservation area, or making a surprise appearance at a backyard gathering — Eastern garter snakes (Thamnophis sirtalis sirtalis) are Ontario’s most common snake, and for many people they’re the first snake they’ve actually held. For a lot of reptile keepers, that roadside encounter is also where the hobby started.
Captive-bred garter snakes have been quietly gaining popularity in the Ontario hobby for good reason: they’re diurnal (active during the day), they stay a manageable size, they’re cool-tolerant enough for Canadian homes, and they eat earthworms — one of the cheapest, most accessible feeder options available. They’re also one of the few snake species that spends visible time exploring its enclosure during daylight hours rather than hiding in a log for 23 hours a day.
That said, garter snake care has a few quirks that surprise new keepers — especially around diet (thiaminase in certain feeder fish is a genuine health risk), humidity requirements, and the musk-and-defecation defence response that makes early handling sessions memorable in a way you won’t forget. This guide covers all of it.
Important note: Wild garter snakes are protected under Ontario’s Fish and Wildlife Conservation Act. This guide is written entirely for captive-bred animals. If you find a wild garter snake in your yard or local park, the best thing you can do for it is observe, appreciate, and leave it alone.
Key Takeaways
- Diet: Earthworms are the primary staple. Pinky mice work for adults. Avoid goldfish, rosy reds, and other thiaminase-containing fish as regular feeders — thiaminase destroys vitamin B1 and causes serious neurological problems over time.
- Temperature: Garter snakes prefer cooler conditions than most pet reptiles — a basking spot of 85–88°F (29–31°C) and a cool side of 65–72°F (18–22°C). Canadian room temperatures handle the cool side without supplemental cooling.
- Source captive-bred only: Wild-caught garter snakes are legally protected in Ontario, often carry heavy parasite loads, and typically never tame down fully. Buy from a reputable breeder.
- Adult size: 60–90 cm (24–36″); females grow noticeably larger. This is a manageable snake for keepers of most experience levels.
- The musk is temporary: Newly acquired garter snakes musk and defecate defensively — this is normal and almost always resolves with consistent, patient handling within a few weeks.
Meet the Garter Snake
The Eastern garter snake (Thamnophis sirtalis sirtalis) is the species most commonly kept as a pet in Ontario, though several other Thamnophis species and subspecies (including the red-sided garter snake, T. s. parietalis, and the Plains garter snake, T. radix) are also available in the captive trade. All have broadly similar care requirements.
In the wild, garter snakes occupy a remarkably wide range of habitats — meadows, forests, wetland edges, urban parks, and suburban gardens. They’re semi-aquatic, frequently found near water, and highly adaptable. They’re also one of the few snake species known to tolerate cool temperatures that would be fatal to tropical reptiles, which makes them one of the better-suited snakes for Canadian homes that don’t maintain tropical ambient temperatures year-round.
Wild populations in Ontario give live birth (viviparous), producing litters of 10–40 young in late summer. Captive-bred litters are typically smaller. The young are fully formed miniature adults capable of feeding on small earthworms and fish from their first week of life.
Enclosure Setup
Size
Juvenile garter snakes can be started in a 10-gallon (37-litre) aquarium or equivalent tub. Adults need a minimum of 30–40 gallons (113–151 litres) of floor space — a 36×18″ footprint is a good starting point for a single adult female (the larger sex). Garter snakes are more active than many pet snakes, so they use the floor space you give them.
Unlike arboreal species, garter snakes are ground-oriented and semi-aquatic — floor footprint matters more than height. A 4′ (120 cm) long enclosure for adult females gives room for a proper thermal gradient and a large water feature without the snake spending its whole life pressed against a wall.
Substrate
Topsoil mixed with coconut coir (70/30 ratio) is an excellent naturalistic substrate that holds burrowing tunnels, maintains moisture well, and supports live plants if you want a bioactive setup. Cypress mulch is another solid option. Avoid cedar, pine, and other aromatic wood shavings — the oils are toxic to reptiles. Paper towel works for quarantine or sick animals.
Maintain substrate moisture at the humid side without making it soggy — garter snakes need a moisture gradient in their enclosure, with drier spots for basking and a slightly moister substrate under hides and near the water dish.
Water
This is non-negotiable: garter snakes are semi-aquatic and need a water feature large enough to soak and swim in. A large, heavy ceramic water dish (at least 20–30 cm wide for adults) is the minimum; a proper water section with river rocks and a plant shelf is the ideal. They’ll use it regularly, both to drink and to thermoregulate through soaking. Clean the water dish every few days — garter snakes defecate in their water dish more reliably than almost any other pet snake.
Hides and Decor
Provide at least two hides — one on the warm end, one on the cool end — so the snake can thermoregulate without feeling exposed. Flat cork bark pieces, half logs, and commercial snake hides all work. Add a humid hide (a hide filled with damp sphagnum moss) near the cool end to support shedding.
Garter snakes appreciate decor that lets them partially conceal themselves while remaining visible — a layer of leaf litter, a few sturdy branches for climbing (yes, they climb occasionally), and dense ground cover make for a more active, less stressed animal. Our reptile enclosure setup guide covers the fundamentals of building a functional gradient with hides and decor in more detail.
Temperature and Humidity
Garter snakes are one of the most temperature-tolerant pet reptiles available — they remain active down to around 10°C (50°F), though they stop feeding and become sluggish below 15°C (59°F). In captivity, aim for:
- Basking spot: 85–88°F (29–31°C)
- Warm ambient: 75–80°F (24–27°C)
- Cool side: 65–72°F (18–22°C)
- Night drop: Down to 60–65°F (15–18°C) — fine; garter snakes tolerate this readily
In a typical GTA home, the cool side is handled by ambient room temperature for most of the year. A 60–75-watt incandescent or halogen bulb over a basking spot creates the warm end. Avoid ceramic heat emitters as the sole heat source — garter snakes benefit from visible daylight cycles, and a heat emitter doesn’t provide light. An under-tank heat mat on a thermostat can supplement basking on cold nights but shouldn’t replace the overhead gradient.
Humidity should sit between 50–70%, with slightly higher humidity (70–80%) during shedding periods. The large water dish and topsoil substrate naturally maintain this range in most setups without additional misting.
Lighting
Garter snakes are diurnal — they’re active during daylight hours and benefit from a consistent light cycle. A 12-hour light/dark schedule maintained year-round (or seasonal variation if you want to replicate Ontario’s natural photoperiod) keeps them on a healthy rhythm.
UVB lighting is increasingly recommended for garter snakes. As a diurnal species that basks openly in the wild, they encounter significant UV exposure in their natural environment. A Arcadia Forest 6% or Reptisun 5.0 tube on a 12-hour timer provides meaningful UV exposure without overheating the enclosure. Whether garter snakes strictly require UVB in captivity is still debated — keepers have raised healthy animals without it for decades — but UVB access appears to support better colouration, appetite, and vitamin D3 synthesis, particularly in darker winter months in Ontario.
Diet and Feeding Schedule
Earthworms: The Core Diet
Earthworms are the most nutritious, most sustainable, and most widely accepted staple for captive garter snakes. Canadian nightcrawlers (Lumbricus terrestris) from bait shops or hardware stores work well; smaller red wigglers (Eisenia fetida) are suitable for juveniles and can be home-composted for a steady supply. Earthworms are high in protein and fat, gut-load passively (if kept in soil), and are available year-round in Ontario from fishing bait retailers.
Wash purchased earthworms briefly in cool water before feeding to remove any pesticide residue from garden centre bait stock. Wigglers from a home composter are generally safe without washing.
The Thiaminase Problem with Feeder Fish
Garter snakes eat fish in the wild, and many captive animals eagerly accept feeder fish — but not all fish are safe as regular feeders. Goldfish, rosy reds, and most common bait fish contain thiaminase, an enzyme that destroys vitamin B1 (thiamine) in the snake’s digestive system. Fed exclusively or frequently, thiaminase-containing fish cause a progressive neurological condition: twitching, loss of coordination, seizures, and eventually death. This is one of the most common dietary mistakes made with captive garter snakes.
Safe feeder fish options include guppies, platies, and whole frozen silversides (low thiaminase). If you want to use fish, use these — or offer fish only occasionally alongside earthworms as the primary diet.
Pinky Mice
Adult garter snakes readily accept frozen-thawed pinky mice (newborn mice), and many keepers use them as the simplest staple once the snake is large enough. Pinkies are high in protein and fat, widely available, and easy to store frozen. They’re safe from a thiaminase standpoint. Offer frozen-thawed pinkies with feeding tongs — wiggle to stimulate the feeding response.
Supplements
Dust earthworm and fish meals with a calcium supplement 2–3 times per week. A multivitamin supplement once weekly rounds out any micronutrient gaps. If feeding pinky mice as the primary diet, supplementation needs are reduced — whole prey items contain bone (calcium) and organ tissue (vitamins) naturally.
Feeding Schedule
| Age | Feeding frequency | Food size |
|---|---|---|
| Juvenile (<6 months) | Every 2–3 days | 2–4 small earthworms or guppies per feeding |
| Sub-adult (6–12 months) | Every 3–4 days | 3–6 medium earthworms, or 1–2 pinkies |
| Adult (1 year+) | Every 5–7 days | 4–8 large earthworms, 1–2 pinkies, or a combination |
Always feed with the prey item no larger than 1.5× the widest point of the snake’s mid-body. Remove uneaten food within 24 hours to keep the enclosure clean.
Handling and Temperament
Here’s the honest truth about handling garter snakes: the first few weeks are often unpleasant. When threatened, garter snakes have a two-pronged defence: they musk (a pungent, sulphurous discharge from cloacal glands) and they defecate. Frequently simultaneously. On you.
This is completely normal, it fades with consistent handling, and it’s the reason garter snakes have a reputation as “smelly” snakes that they don’t entirely deserve once they’ve settled. A garter snake that’s been handled regularly for a few months will rarely musk at all.
Approach new animals from the side, not from above — overhead movement triggers a defensive response. Start with very brief 5-minute sessions every other day, letting the snake move calmly across your hands rather than being gripped. As trust builds (measured by reduced musking and relaxed body posture), sessions can extend. Most garter snakes become genuinely handleable within four to eight weeks of consistent, low-stress contact.
Garter snakes rarely bite, but a newly acquired wild-behaved animal may strike. Bites are minor — small, hooked teeth, not fangs — and rarely break skin. Don’t jerk your hand away (this causes more damage); stay calm and let the snake release. Biting almost always stops once the snake settles into its new environment.
Health and Common Problems
Thiamine Deficiency
As covered in the diet section, this is caused by a diet heavy in thiaminase-containing fish. Symptoms: twitching, muscle weakness, spiral head movements, and seizures. If caught early, switching to a thiaminase-free diet and supplementing with thiamine (vitamin B1) can reverse the damage. Advanced cases may be irreversible. Prevent it by never using goldfish or rosy reds as staple feeders.
Retained Shed
A shed that comes off in pieces rather than one piece, or patches of retained skin around the tail tip or face, usually indicates that ambient humidity was too low during the pre-shed period. The fix is simple: add a humid hide (a hide with damp sphagnum moss) on the cool end and maintain substrate moisture. For retained shed that’s already there, soak the snake in shallow warm water (no deeper than mid-body) for 20–30 minutes, then gently roll the remaining shed off with a damp cloth or your fingers.
Respiratory Infection
Signs: open-mouth breathing, wheezing, mucus around the nostrils, laboured movement, and lethargy. Usually triggered by enclosure temperatures that are chronically too cold, or by a respiratory infection contracted at a breeder before purchase (particularly in wild-caught or farmed animals). Respiratory infections in snakes require veterinary treatment — antibiotics, supportive care, and temperature optimisation. Don’t wait it out.
External Parasites (Mites)
Snake mites (Ophionyssus natricis) are occasionally introduced through new animals or contaminated equipment. Check new arrivals carefully by running a white paper towel along the body and looking for tiny moving black or red specks. Mites concentrate around the eyes, the labial pits, and under the chin. Treatment involves treating the animal and completely breaking down and sanitising the enclosure. Our guide to reptile mites covers identification and treatment in detail.
Internal Parasites
Wild-caught garter snakes almost universally carry a heavy internal parasite burden — nematodes, flagellates, and occasionally more serious infections. Captive-bred animals from reputable breeders are typically free of parasites, but a fecal sample tested by a reptile vet is always a good idea for any new snake. Weight loss, regurgitation, and foul-smelling liquid faeces can all indicate parasites.
Wild Garter Snakes in Ontario: The Rules
Eastern garter snakes are protected under Ontario’s Fish and Wildlife Conservation Act, 1997. It is illegal to capture, possess, buy, sell, or kill wild garter snakes without a permit. This applies even if the snake wandered into your backyard.
If you find a wild garter snake on your property: observe it, appreciate it, and leave it alone. Wild garter snakes eat slugs, insects, earthworms, and small rodents — they’re ecologically valuable and entirely harmless to humans. If a wild snake is injured, contact Ontario Wildlife Foundation or a licensed wildlife rehabilitator in your area.
The captive garter snakes available through reptile breeders in Ontario are legal captive-bred specimens descended from animals bred in captivity for multiple generations. Always ask for proof of captive-bred origin when purchasing.
Frequently Asked Questions
Are garter snakes venomous?
Garter snakes do have mild venom — a Duvernoy’s gland that produces a mild toxin effective on their prey (frogs, fish, earthworms). It is not medically significant to humans. The vast majority of people bitten by garter snakes experience nothing more than minor redness. The much bigger concern with a garter snake bite is bacterial infection from the snake’s mouth, so clean any bite wound thoroughly.
How long do garter snakes live?
Wild garter snakes typically live 4–10 years due to predation and environmental stress. Captive animals regularly reach 10–15 years with good care. Some well-documented captive individuals have reached 20+ years. These are longer-lived animals than many beginners expect.
Can garter snakes be kept together?
Garter snakes are communal in the wild and can cohabitate in captivity — with important caveats. All animals must be quarantined separately for at least 60–90 days before introduction. The enclosure must be large enough that every animal can thermoregulate independently, find its own hide, and access water without competition. Never cohabitate animals of different sizes (smaller animals may be eaten). Watch carefully for feeding competition — separate for meals if one animal consistently outcompetes another.
How big do garter snakes get?
Eastern garter snake adults typically reach 60–90 cm (24–36″). Females grow larger than males — a large adult female may approach 100–110 cm. This is a very manageable size compared to most constrictors kept in Ontario, and it contributes to their appeal as a first snake for many keepers.
Do garter snakes smell?
Freshly acquired or stressed garter snakes musk — releasing a pungent, sulphurous discharge that is genuinely unpleasant. This fades almost entirely with regular, calm handling and a settled environment. A garter snake that’s been in a stable home for a few months is no smellier than any other reptile. The enclosure itself needs regular spot-cleaning (especially the water dish, which they use as a toilet).
What do garter snake eggs look like?
Garter snakes don’t lay eggs — they give live birth (they’re viviparous). A pregnant female will have a noticeably swollen abdomen in the weeks before parturition. Litters are typically 10–40 young in wild animals; captive litters tend to be smaller. Neonates are fully formed miniature adults that begin feeding within the first week or two of life.
Can I keep a wild garter snake I found in my yard?
No — this is illegal under Ontario’s Fish and Wildlife Conservation Act. Wild garter snakes are also typically stressed, parasite-laden, and difficult to keep alive in captivity without extensive veterinary support. Purchase a captive-bred animal from a reputable breeder if you want a pet garter snake.
Where can I buy a garter snake in Ontario?
Captive-bred Eastern garter snakes and other Thamnophis species are available from Ontario reptile breeders, at Toronto and GTA reptile expos, and occasionally through classified listings. If you’d like to adopt rather than buy, it’s worth checking whether any rescues in the area have surrendered garters available — they’re occasionally taken in when keepers move or can no longer provide care. Our guide to buying a reptile safely in Ontario covers how to vet sources, ask the right questions, and recognise red flags.
Consider Adopting Before You Buy
Garter snakes are sometimes surrendered by keepers who underestimated the commitment, found the musking phase too much to tolerate, or discovered they’d accidentally purchased a pregnant female who produced 30 neonates they had no plan for. A surrendered adult garter snake from a rescue is often already settled, eating reliably, and past the early defensive behaviour phase — you’d be getting an animal that’s easier to handle on day one than a juvenile from a breeder, while also giving a snake a second chance at a stable home.
Before you buy, check who might be available through rescue. At Toronto Reptiles, we assess every surrendered animal before rehoming — you know what you’re getting, and we’re available to support the placement after the fact.