This page explains everything you need to know about how to set up a pet garter snake’s cage. This includes how big it should be, how to make it escape-proof, what it should contain, how warm it needs to be (and how to heat it), as well as whether it’s a good idea to keep more than one snake in the same cage.
It’s organized into the following subsections:
Providing a proper cage for a garter snake is second only to feeding in the amount of misunderstanding out there. The two most common mistakes that beginning garter snake keepers make is to provide a cage that is too big — I once saw someone write that they thought a 70-gallon tank was a good size for a baby snake — or too wet: while garter snakes are frequently found near water, they’re definitely not aquatic.
In general, a garter snake needs a cage that is clean, dry and escape-proof, has the right furniture, and is the right size. Here’s how to give it to your snake.
The cage should be neither too large nor too small. Too small, and the snake can’t get enough exercise and its health will suffer. Too large, and the snake will feel exposed and insecure. A good guideline is to make sure that the length plus width of the cage is somewhat larger than the total length of the snake. (For example, an aquarium tank that is two feet long by one foot wide could house a snake up to three feet long.)
A baby garter snake’s cage should be no larger than five gallons (and could even be half that size); in general, a garter snake less than a year old can live comfortably in a five-gallon tank. An adult male about 60 cm (two feet) long will do well in a 15-gallon tank, and a full-grown female or a breeding pair should be all right in a 25-gallon tank. More room is certainly better within reason, and you’ll need more room if you’re using a planted terrarium instead of basic caging, but it’s very unlikely that a single garter snake will ever need anything more than a 35-gallon tank.
Snakes are very good at escaping their cages. They can crawl through openings that seem too small for them. As a rule of thumb, if a snake can work its way in past its eyes, it can get all the way out.
This is to say that preventing your pet snake from escaping is very, very important. Not just because your neighbours will freak out and your landlord will saying ominous things if your snake gets loose, but because the snake itself is in danger, if only from the cat.
For that reason the cage must be absolutely escape-proof. Lids should be securely attached and fit tightly: snakes are strong enough to push them off otherwise. Even though garter snakes, since they aren’t constrictors, don’t have the same muscle strength as a boa or a python, or even a corn snake or a kingsnake, you shouldn’t underestimate their ability to get loose.
Glass aquariums should have screen lids with tabs that fit under the plastic rim of the cage, or snap-on grilles (so long as the snake is big enough that it can’t get between the grilles). Any mesh or grille in the lid should be small enough that the snake can’t squeeze through. (Remember what I said about the eyes.)
Baby snakes in a five-gallon cage should probably have a screen lid rather than a grille. Plastic “Critter Keeper” or “Desert Den” cages work well generally, so long as the snake isn’t too small to get through the circular holes for electrical cables. I’ve used them with smaller male garter snakes as well as young snakes.
And the herper’s standby for smaller snakes — Rubbermaids with air holes melted in the sides and lids with a soldering iron — will also work for small single snakes so long as the melted holes aren’t too big for the snake to get through.
Cages don’t need a lot in the way of furniture. A beautifully planted cage, with logs and plants (real or otherwise) and realistic-looking water dishes looks very nice, but the snake doesn’t care — it’s more for the keeper’s pleasure. A snake’s needs are very basic: a clean cage with a place to hide and a source of water.
We’ll talk about the clean cage in the next section.
To feel secure, all snakes need a place to hide — what reptile keepers call a hide box. This should be reasonably solid and relatively small: the snake should be able to curl up tightly within it, and if it can touch the sides of its hiding place when it’s curled up, so much the better. Formed plastic boxes that fulfill this requirement are available in pet stores, as are hollow half-logs. You can also repurpose other things and make them into hideboxes, such as used containers, even cardboard. Bear in mind that they will get soiled quickly and will have to be replaced often if they can’t be cleaned.
Garter snakes need a water dish in their cage. The water needs to be kept relatively fresh and it shouldn’t run dry. This is not only because the snake needs to drink from time to time, but also because the water dish allows the snake to cool down by soaking. On hot days pet snakes often spend their time soaking in their water dishes. (See Heating and Lighting below for a discussion of overheated snakes.)
But even though garter snakes are often found near water in the wild, they should not be kept in semi-aquatic conditions. Garter snakes aren’t aquatic; it’s their prey that’s aquatic. They don’t need to swim; a water dish large enough for the snake to curl up in is enough. The cage needs to be kept dry. If not, the snake can come down with blister disease.
However, newborn snakes can be prone to dessication (drying out), and sometimes the air is too dry and they have shedding problems. In that case, provide a humidity box. This is simply a hidebox containing some dampened sphagnum moss. It may help keep the rest of the cage drier if this box has a bottom to it, as well as a lid with a hole cut into the top.
Other than that, if you want to provide rocks or branches for the snake to climb on, go ahead (so long as they’re clean and sterile). They’re not necessary.
Substrate and Cleaning
Substrate is what you put on the bottom of the cage. Many different kinds of substrate are possible: everything from a planted terrarium to paper towels or butcher’s paper. Other popular substrates include wood shavings (aspen is best, pine is probably all right, but never use cedar), cypress mulch, bark nuggets, or indoor/outdoor carpet.
Planted, naturalistic terrariums may be pretty, but a simpler cage is easier to clean. Garter snakes defecate frequently, and unless you change or clean a garter snake’s cage frequently, the cage will smell quite ripe in short order. It therefore makes sense to make the cage easy to clean! I recommend keeping them on paper towels, which can be replaced cheaply and quickly when soiled.
You shouldn’t have to change the cage more than once a week. More snakes in a cage will make it messier faster, of course, and a fish- and worm-based diet is messier and smellier than a mouse diet — either of these circumstances will necessitate more frequent changes.
If you use paper towels, it’s enough to replace them when soiled and rinse off the glass where the snakes have soiled it. If you use shavings, mulch or bark, pick out the urea and feces when you can, then change the cage completely every two to three months or so. Clean the cage thoroughly, using detergent or bleach, or both, every once in a while.
Heating and Lighting
Snakes are cold-blooded. This means they need external heat to run their body metabolism. A snake that is too cold is not only sluggish, it’s also unable to digest its food properly: it may refuse to eat or even throw up its food. A pregnant snake also needs warmth for her babies to incubate.
In general, snakes need to be a little warmer than room temperature. This is especially true in an air-conditioned home, where room temperature is frankly pretty cold. But they don’t like it uniformly warm, either, and it’s actually more dangerous to the snake if it’s too hot than if it’s too cold.
The ideal temperature for most snakes is in the 25-30°C range (about 75-85°F), but it’s important that the snake have the option of warming up and cooling off when it chooses. You give that to your snake by heating one side of the cage, creating a temperature gradient.
You can use a heating pad underneath one side of the cage, or an incandescent or reflector bulb above it. You can use a commercial reptile heating pad, or you can use an ordinary electric blanket, which is less expensive, turned to the lowest setting. Fluorescent bulbs provide light generate little to no heat.
Keep an eye on the heat with a thermometer. Stick-on thermometers aren’t terribly accurate, but they give you a general idea. It’s not important to achieve precise temperatures — remember, these snakes encounter all kinds of temperatures in the wild. As long as it’s somewhere between 22°C (72°F) at the cold end and 30°C (86°F) at the warm end, you’re probably fine.
Temperatures above 33-34°C (91-93°F) are potentially dangerous. A snake that is too warm will usually escape the heat by soaking in its water dish. A snake suffering from overheating will race around its cage with its mouth open. To treat an overheating snake, Rossi and Rossi recommend immersing it in cool running water.
Always, always keep the cage out of direct sunlight. Garter snakes have been killed that way.
Never, ever use “hot rocks” — these plastic rock heaters that are placed inside a cage. They may be dangerous to the snake and are of limited utility: the air needs to be warm, and a cold snake wrapping around a warm rock heater may burn itself.
The jury is out as to whether garter snakes need full-spectrum lighting: some keepers think it isn’t needed, others believe it may help. I’ve never used it, for what it’s worth.
Keeping More than One Snake in the Same Cage
Whether snakes should be housed together or singly is one of the most controversial subjects in amateur herpetoculture. Some keepers argue that the risks inherent in keeping snakes together are too great: you can’t monitor who eats how much and which snake is getting sick; if one snake gets sick, they both get sick; one snake can become dominant over the other and stress it out; there are risks of food fights and even cannibalism.
Others would argue that such risks can be minimized through careful observation: some snakes may not do well together, but others may do just fine. And certainly no snakes should be put in the same cage together without a quarantine period. New arrivals should be kept away from other snakes for a month or two and observed to see if any contagious health problems present themselves.
I don’t think it’s necessarily wrong to keep two snakes together, so long as both of them have checked out as healthy, both are from the same species (and it’s not a cannibalistic species; see below), they both seem to get along, and they’re fed separately (see below). In other words, keeping them together requires more observation and more attentiveness on the keeper’s part than simply keeping every snake one to a cage and forgetting about them. But closer observation and more attention are definitely not bad things!
In any event, garter snakes seem to be somewhat more gregarious than other species: they’re frequently found together in the wild. This is more than can be said for some other commonly kept species, and I suspect that much of the advice to keep snakes separately is based on keepers’ experiences with those other, more solitary species.
The garter snake breeder Phil Blais has noticed that baby garter snakes in particular seem calmer when housed collectively, and my own experience bears out his observations: a young garter housed singly seems more nervous than it was when it had cagemates. So at least in that case it is not only all right to house garters together, but even beneficial.
Obviously a larger cage will be needed if a few snakes are kept together, but there are also more serious things to watch out for.
With some garter snake species, there is a risk of cannibalism, and they should be housed individually. This is especially true of the Western Terrestrial Garter Snake (Thamnophis elegans), the most commonly kept subspecies of which are the Wandering Garter Snake (T. e. vagrans) and the Coast Garter Snake (T. e. terrestris). There have been many reports of Wandering Garter Snakes eating their cagemates. While some have kept this species collectively with no trouble at all, play it safe and keep no more than one per cage. Cannibalism has also been reported in Checkered Garter Snakes (Thamnophis marcianus) and occasionally with Common Garter Snakes (Thamnophis sirtalis). The risk with common garters is probably quite small, and I keep mine collectively, but it has been known to happen, so consider yourself warned.
Food fights are a serious concern when feeding garter snakes, and it’s likely that most reports of cannibalism are as a result of accidents happening during feeding. Garter snakes are very enthusiastic feeders and are attracted to motion. If you’re feeding them together in the same cage, one snake may be attracted to the other snake’s food, and may grab the other end and start swallowing. One may keep going and swallow the other if you don’t intercede. Interceding is not fun. Feed your garter snakes separately: have a couple of small holding cages to feed them in, so that each snake can eat without its cagemate trying to steal its dinner.
Finally, something I’ve noticed with other snakes, when snakes that are fed separately are returned to their cage. I’ve had a couple of incidents with bullsnakes and rat snakes where one snake nipped at the other once they were put back after feeding. This seems to happen when one of the snakes’ meals was particularly messy — blood and guts everywhere — and the snake comes back to the cage smelling a bit too much like food. We’ve tried wiping the messy snake down before returning it to the cage, but these were very large snakes. To be honest, though, I’ve never seen this behaviour in garter snakes. They may be better about it.