Biology
Garter snakes have adapted to many different environments in the wild including scrubland and forests, and they are usually found near water. They are commonly available as captive-bred, but they are also wild-collected. We strongly advise that you only obtain captive-bred or rescued animals. These snakes are now available in many captive-bred colour morphs.
Garter snakes are diurnal (awake during the day) and very active. They are not venomous and eat small rodents, fish, invertebrates and amphibians in the wild.
Most species can grow to around 100 cm long and are fairly slender. They can live for 10 years or more and grow quite quickly. Before getting a garter snake, you must be sure that you are able to provide the correct care and associated costs for the animal’s entire life.
Environment
Garter snakes can be kept as a communal species or singly. The vivarium must be secure to prevent escape, and free from hazards that might cause injury. It should be made from sealed wood or glass. Good ventilation is essential to prevent the build-up of harmful bacteria which can cause respiratory infections, and it should be made from a solid material that is easy to clean.
Snakes need to fully stretch out in their vivarium and to have at least a third of their length for the width and height, so a 100 cm long garter snake will need a 100 cm long by 33 cm by 33 cm vivarium as a minimum.
If you're keeping several snakes in the same vivarium, you will need to increase the size to make sure they all have enough space to move around and enough resources.
The vivarium should be placed in a safe location away from draughts and sources of heat, such as radiators or direct sunlight, as these can affect the temperature.
Temperature
Reptiles are ectothermic, meaning they use their environment to warm up and cool down, so you need to create a thermogradient. This means positioning the heat source at one end of the vivarium, leaving the opposite end cool so that the snake can move around to regulate its temperature.
To create a basking-zone - the warmest part that the snake can reach - position a heat lamp at one end of the enclosure pointing downwards. Heat lamps must be guarded to prevent burns, or injuries, should the bulb shatter. A thermostat, a simple device that regulates the temperature, must be used with all heat sources. With a heat lamp you will need to use a dimming thermostat.
Adjust the thermostat and check with a digital thermometer that the basking zone is 28 to 32oC. The cool end should be 22 to 24oC. A reptile heat mat on one side of the vivarium, with an on/off thermostat is recommended for a smaller enclosure, such as for hatchlings.
Thermostats are not always accurate, so record the basking-zone and cool end temperatures daily using one digital thermometer at each end. An infrared thermometer can also be used to check the temperature in the basking-zone and cool end daily. You can turn off the heat at night to simulate night-time when it can safely drop to around 16oC. If the room temperature drops lower than this, you will need a non-light emitting heat source at night, such as a ceramic heater or heat mat, with a correctly set up thermostat.
Humidity
The correct humidity is essential to keep your snake’s respiratory system healthy and for normal skin shedding. Use a hygrometer to measure the humidity inside the vivarium, which should be around 50 to 60%. If it is too low, you can spray the inside with clean water. If it is too high, the vivarium will need more ventilation.
Light
Reptiles use natural daylight to set their day and night patterns. Sunlight contains visible light and ultraviolet (UV). Part of this is UVB, which allows reptiles to make vitamin D3 in their skin, vital for them to store and use calcium. Another part is called UVA, important for their vision, and appetite.
Create a photogradient, from light to shade, by grouping your light with the heat source so the cool end is more shaded, just as in the wild. Fit a low output, 2-7% reptile UVB tube, around one half of the vivarium length, into the roof of the vivarium in the hot end.
Use a reflector of the correct length to direct the light onto your garter snake. UVB decreases with distance, so follow the UVB tube manufacturer’s recommendations regarding distance between the lamp and the snake. The UVB output decreases over time so the UVB output should be checked regularly using an appropriate UV Index (UVI) meter positioned at the level of the animal directed towards the UV lamp.
Garter snakes need a gradient of UVB in their enclosure, ranging from UVI 1.0 in the basking-zone to zero in the shade. Some morphs of garter snakes, like albinos, will need lower UVB levels, with a gradient from 0 in the shade to a maximum of 0.7 in their basking zone.
The lamp must also be replaced according to the manufacturer’s instructions. UV lamps must always be guarded to prevent burns, or injuries should the bulb shatter. Turn off all lights at night. Lamps can be controlled using a simple plug-in timer; 12 hours on during the day and 12 hours off at night.
Cleaning
Other than the predator avoidance behaviour - musking in garter snakes, they should not be dirty or smelly. However, poorly maintained enclosures can become dirty quickly and pose a health risk to you and your pet.
Animal waste must be ‘spot cleaned’ as soon as it appears. Once a month, use a reptile-safe disinfectant, available from pet shops, to fully clean the vivarium and decoration, then rinse off well. Be careful as reptiles can carry Salmonella. Wash your hands before and after handling or cleaning equipment to reduce the spread of infection between you and your snake.
Diet
Water
A dish must be provided for drinking, filled with clean, fresh water, replaced at least daily. This should be large enough to allow the snake to bathe. Sometimes the snake will foul the water in which case it must be changed as quickly as possible. Garters will also often sit in the water bowl for long periods, which is quite normal. You can also spray the vivarium with a little clean water to allow the snake to collect droplets of water as they would in the wild.
Feeding
Garter snakes will eat a large variety of food types in the wild. A varied diet of defrosted mice or rats, fresh or defrosted fish, and commercially available earthworms is suitable for these snakes. If you only feed filleted fish then your snake will miss out on nutrients such as calcium, so it’s important that whole vertebrate prey are included as a main part of the diet.
Choose fish which contain very little or no thiaminase because snakes can develop vitamin B1 (thiamine) deficiency if fed fish high in the enzyme thiaminase. Salmon and trout are suitable as they lack thiaminase. Speak to your reptile vet about other safe fish to feed.
Earthworms must be purchased from a reputable reptile food supplier, not collected from outside as those could have parasites. Note that some snakes will not readily consume earthworms.
Regularly weighing your snake is important to ensure your snake is maintaining a healthy weight. Feed your snake inside their vivarium, using tongs to offer the prey. Garter snakes shouldn't need supplements for their diets, as long as they're fed good quality prey.
Behaviour
Enrichment
It is important to provide opportunities for natural behaviour in captivity, called enrichment. Garter snakes are active and will climb if given the opportunity, so provide branches for this. If using natural branches, sterilise them with boiling water or in a hot oven first.
You can add moss, stones and securely placed rocks to create hiding places. Garters are associated with water so require a water bowl large enough for them to fully submerge themselves. Small plants for climbing can be used, as can waterfalls or filtered ponds in larger vivaria.
Make sure that the land area is kept dry to prevent skin problems.
Snakes will typically hide in small spaces such as animal burrows in the wild. Include several hides, but at least one at either end of the vivarium, so that the snake can choose the temperature without having to compromise feeling secure.
Hides must be large enough for the snake to fit inside but not so large that its body does not touch the sides when coiled up. A hide containing moistened moss, called a humid hide, provides variation in humidity within the vivarium.
Garter snakes can be fed several small food items placed around the vivarium to keep them stimulated.
Substrate
Substrate is the term used for the floor covering in your vivarium. It is important as it provides something for the snake to burrow under which helps it to feel more secure. Substrate also stops mess from spreading, though you must still clean it as soon as it appears.
Substrates such as organic soils or soil/sand mixes made for reptiles are recommended for garter snakes. It is not recommended to use sand alone as it may irritate the skin. Dry, natural leaves can be added to provide cover and create a more naturalistic environment. Sterilise leaves with boiling water and then allow them to dry before use. A clean mix of 60% soil, 30% sand and 10% leaves is suitable for healthy snakes.
Paper towels or newspaper can be used when you first get your snake, so that you can monitor its health more easily, but this does not allow for natural behaviour, so it is recommended to only use this as a temporary substrate.
For permanent housing of snakes, we recommend that owners provide a naturalistic environment and also consider a bioactive system. Keepers can research how to do this using expert books on the topic, or specialist keeper member groups online.
Company
Garter snakes hibernate together in the harsh winter and emerge as a group in the early spring. Because they often come together in the wild, you can keep garter snakes in groups in captivity. When housing any reptiles together you need to make sure each animal has access to the right resources. For example, you will need to make sure to have a large basking zone, so there is no competition for temperature.
Handling
Garter snakes are not keen on being held for long periods. However, they may allow you to hold them for short periods, after they have settled in. Never grab your snake as this could stress it and may lead to struggling, biting or musking – when a strong smell is released from the snake - this is normal predator avoidance behaviour.
The snake can be gently scooped up supporting the whole animal. The snake should not be taken out for so long that its core temperature drops. Five to ten minutes is a safe period, depending on the temperature outside of the vivarium.
Bringing your snake home
Always set up the vivarium and run it for a week before introducing your snake. This will allow time for you to adjust the heating and lighting and add your enrichment without disturbing the snake. Put the carrying container inside the vivarium and carefully to allow the snake to emerge. Secure the vivarium doors and turn the lights off to reduce stress until the following morning when you can check on your snake. Allow time for your snake to become used to its environment for the first week.
Transport
If you need to transport your snake, it's important that it is done safely. Choose a suitable sized carrier. Small snakes such as hatchlings can be transported in ventilated plastic containers with soft, absorbent paper. Adults can be transported in a tightly secured cloth bag, within a well-ventilated plastic tub to prevent injury. Avoid extremes of temperature. The addition of a heat pack may be required but make sure this will not over-heat. Keep transit time to a minimum to reduce stress.
Health and welfare
A healthy garter snake flicks its tongue frequently and has bright eyes. Its skin should be smooth and without blisters, which can be a sign it has been kept too damp.
Shedding
Reptiles have to shed their skin and snakes shed in a complete piece. Shedding is more frequent when the snake is young. The snake may hide away for a period of time and use the humid hide, then it will rub against objects in the vivarium to remove the old skin.
If you notice that your snake still has shed old skin over its eyes after a shed, these eye caps will need removing. A specialist reptile vet can do this safely. If the snake has not shed completely, try bathing it in slightly warm water to soften the skin. Do not try to pull it off as you can damage the new skin.
Issues with shedding are usually husbandry related and can be prevented with adjustments so contact your reptile vet for help.
Brumation
Brumation is a natural energy saving process seen in some individuals during cooler months. It is triggered by the reduction in natural daylight hours and air pressure. They may reduce the amount that they eat during this time; however, they should not lose weight.
Diseases and concerns
It is vital to provide a varied and well-thought-out diet in captivity and that the heating and lighting systems are checked to be working well at all times.
You should also register with a suitably qualified vet.
Look out for abnormal droppings or weight loss. Garter snakes can suffer with mouth rot so be vigilant to any changes there.
Snakes can suffer from external parasites such as mites. Snake mites lodge underneath the scales and consume blood. Mites are very good travellers and can transfer between keepers. If your snake spends unusually long periods of time sitting in the water, it may be an indicator of mites. You may also notice small black specks on the snake or around the water bowl. Mites can carry diseases, so they are a serious concern.
Metabolic bone disease, ‘MBD’ describes a range of nutritional diseases and imbalances in captive reptiles, but it typically involves a lack of available calcium due to a deficiency of vitamin D3. Garter snakes may be more prone to this than snakes that eat rodent prey, so dusting food with calcium powder is important.
Be sure to always follow instructions, otherwise they could get problems from vitamin overdose. For example, with a well-set UVB system, you will not need to provide high levels of dietary vitamin D3.
It is essential that you take time to do some more research into the diseases of garter snakes.
If you do get a garter snake, monitor its health daily and see a reptile vet urgently if you have ANY of the above concerns.