Garter Snake Care Sheet

Scientific Name: Thamnophis marcianus

Country of Origin: North America

Potential Adult Size: 45-120cm (18-48 inches)

Average Life Span: 10+ years

Dietary Requirements: Carnivorous

Distribution: North America, Canada, Central America

Natural History

Garter snakes are a small and thin species found in cooler climate throughout America and Canada. They are extremely successful and often have a varied diet dependant on what is available in that region. They inhabit many different environments including woodlands, forests, fields and grassland. They are almost always centred on regions close to streams, ponds or wetlands.

This little snake will eat almost anything they can get a grip on in the wild but their natural diet normally comprises of amphibians, small fish or small mammals.

Southern USA
Northern United States of America

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Garter snakes come from a moderately warm environment so they struggle with the cold of the UK. To insulate against this we recommend keeping the snake in a wooden vivarium. Due to the temperature gradient required we would normally select an enclosure a minimum of 3 x 2 x 2ft with large vents and glass sliding front doors.

All of this ventilation should ensure that heat and humidity is lost from one side of the enclosure to the other while keeping the basking spot itself at a consistent temperature.

Garter snakes can be a little shy when they are young. We still use the full-size enclosure to make sure that the correct temperature gradient is in place but we will provide more decorations to begin with.


Naturally, garter snakes would be experiencing temperatures of around 85of in the sun. We try to provide this heat over 1/3 of the enclosure while letting the rest of the enclosure cool to 70of on the opposite side. To achieve this we attach a basking lamp to the ceiling of the enclosure on one side. This is controlled by a dimming thermostat to make sure that the temperature is kept correct throughout the day. Garter snakes will be able to reach the top of their enclosure without decorations to climb on so the basking lamp must be surrounded by a guard. The basking lamp is left on for 10-12 hours per day.

At night, all of the lights should go off and the enclosure should be completely dark. This should make sure that the snake has a clear day and night cycle.

Though at this point the sun has gone down, there would still be rocks, paths and roads that have warmed up in the day and that will radiate heat for much of the night. To provide this warmth throughout the night without introducing light to the enclosure we lay a heat mat under the basking area. The heat mat will warm objects around it providing a warm patch of ground for the garter snake to rest on. To make sure that the heat mat remains the correct temperature it is controlled by a simple on/off thermostat set to 75of. The heat mat is buried under around an inch of bedding, the sensor for the thermostat is then rested on the bedding covering the heat mat so that it can track the surface temperature of that patch of floor.

During the day your temperatures will be much too warm and the heat mats thermostat should keep it off automatically. The heat mat will only begin to heat once the temperatures have dropped below 75of at night time.

Though the thermostats we sell are very reliable it is always best practice to monitor your temperatures with a thermometer. A 5of variance on the basking spot is nothing to worry about as long as your cool side is still cool. A simple dial thermometer on each side should be sufficient but digital probe thermometers are much more accurate.

baby Garter snake
Baby Garter Snake
adult Garter snake
Adult Garter Snake

UVB Lighting

Garter snakes do not require UVB to use the calcium in their diet like other reptiles but it is still a beneficial addition to the enclosure. The snake would naturally be exposed to UV from sunlight in the wild and as we are trying to emulate nature in our enclosures we recommend providing some UVB.

A 5% T8 UVB tube, 2-5% T5 UVB tube or more powerful but smaller unit should be sufficient. The UV tube should be mounted to the ceiling at the back of the enclosure to provide a light gradient running parallel to the temperature gradient. There will be times when the snake will want less or no UVB so partial and full hiding spots should be placed all along the width of the enclosure.


Garter snakes thrive in a low humidity environment with hard decorations to climb over and bask on. When selecting the bedding we try to ensure that the pieces are unlikely to increase the humidity of the enclosure. In-store we normally use a coarse beech woodchip as it is clean, cheap, easy to spot clean and dust-free. If you prefer a more natural-looking decoration a soil/clay mix would be perfect. If you plan to keep the snake in a bio-active enclosure a nutrient-rich soil and clay mix with some sand for aeration would be perfect.

Garter snakes love the warmth coming from their basking lamp but they also appreciate secondary belly heat which will radiate from warm objects. Natural rocks like slate are perfect for this, so are heavy artificial ornaments. These decorations can be placed under and around the basking area and should warm up nicely. If the lamp is too low there is a chance that natural rocks could get too hot so you are best to check the surface temperature to avoid burns.

As discussed in the lighting section there will be times when the snake does not want any UV and needs a bit of shade. To ensure that the snake can get away from the light whenever necessary we advise spreading full and partial cover throughout the enclosure. Examples of full cover decorations would be caves, flat cork pieces or any other ornament that provides a shady spot to rest. Examples of partial cover would include tall plants, trailing plants.

Diet & Water

Garter snakes are carnivorous and should be fed frozen thawed foods. Though they are opportunists we have found that mice are the best diet for a garter snake.

As hatchlings, garter snakes should be fed weekly on defrosted pinky mice, as the snake grows the food size should be increased until the snake is taking large mice or even jumbos. Adult garter snakes can be fed once every two weeks as they can become overweight if fed weekly.

More exotic alternative diets like gerbils, hamsters, multimammate mice or chicks could be used if the garter snake won't take anything else but they aren't as nutritious as the mice, it can be difficult to find them in the size required and they aren't always as available.

We always include a large water bowl in the cool end of the snake's enclosure. You might notice the snake use it for bathing, this is usually to cool down or to help loosen its shedding skin. Both the water bowl should be kept on the cool side of the enclosure to prevent it from raising the humidity in the enclosure.


If you keep a male and female together, they may breed. You do not need to do anything to encourage this. As long as they are healthy and the conditions are good, it will happen naturally. You need to consider whether you want this to happen before introducing the pair. Garter snakes bear live young and they usually have a lot of them per clutch.

If you are breeding the snakes you will need another enclosure set up exactly like your main set up so you can separate the babies from the adults. It is a good idea to approach a local reptile shop before embarking on this to make sure you have a place to send the babies when they are ready or you may become inundated with snakes.


Garter snakes, as with most pets, require a clean environment to thrive. We recommend a spot clean as often as possible (every day) and a full clean every 4 weeks or so. If you are keeping the snake in a bio-active enclosure you can spot clean and monitor the enclosure. It may still be a good item to change out the bedding a few times per year.

When cleaning the enclosure you should remove your animal, all decorations and all of the bedding. Once the enclosure is clear you can spray it all over with a reptile friendly disinfectant. These usually work very quickly and only need to be left for around 30 seconds, instructions can normally be found on the disinfectants packaging. Once the disinfectant has done its work it can be wiped away from the surfaces with a paper towel. In some cases, you might want to repeat this process a second time to ensure that the enclosure is thoroughly cleaned.

Your decorations can be cleaned in a similar method, simply spray them down with the disinfectant and rinse thoroughly with water before drying them off and putting them back into the enclosure. We recommend this process is done during the day time to make sure that the snake will be going back to a warm vivarium for at least an hour before the basking lamps are turned off for the night.