Housing
Garter Snakes can be housed in various types of enclosure, depending on your personal preference. Many people favour aquarium style glass tanks, while others choose a shelving or stacking system, using plastic storage boxes. Whatever your choice it's important to ensure your enclosure is escape proof. Garter Snakes are notoriously active and inquisitive, and will take advantage of the slightest flaw in the design of their enclosure to make good their escape.
There is much debate as to the minimum size of an enclosure, the concensus seems to be that the length plus the depth (front to back) of the enclosure should be at least equivalent to the length of the snake. I prefer to move away from the idea of a minimum; My vivaria each measure 48"X18"X24" high, which is adequate to house a group of Garter Snakes in each enclosure.
All my Garter Snakes are housed in custom built wooden vivaria, with sliding glass doors to the front. Ventilation is provided by plastic air vents positioned in the back wall of each vivarium. Overhead fluorescent strip lights on electronic timers to control the photo period, provide a strong natural looking light.
Many people favour loose substrate in the bottom of their enclosures, a system which has many advantages. Others prefer disposable substrate such as newspaper or kitchen towel. My Garter Snake enclosures are fitted with natural slate floors. Slate is impermeable, hygienic, easily wiped clean, retains heat well, cannot harbour parasites and is aesthetically pleasing. Experience has taught me that slate is the best substrate system for me, although a degree of DIY skill is required for it's installation.
Each vivarium must be provided with a water bowl which should be at least large enough for your snake to fully submerge itself without flooding the floor of the enclosure; permanently wet substrate can be very harmful to your snake, more on that subject later. The water should be replaced on a daily basis, more frequently if it becomes soiled.
This basic enclosure can be furnished with various hides, logs, rocks, artificial plants etc. to your personal taste. The important thing about these furnishings is that they should provide adequate hiding opportunities for your Garter Snake, and should be steady enough or securely fixed so that they cannot roll or shift and injure your snake.
Heating/Temperature
Ideally, a thermal gradient should be provided for the snake. That is to say, there should be a range of temperatures within the vivarium, so that the animal can choose the temperature at which it feels most comfortable. This can be most easily achieved by placing the thermostatically controlled heat source (whether that be an under-floor heat mat, or overhead basking light) at one end of the enclosure, so that the temperature drops as the snake moves away from the heater. The optimum temperature range should be from around 20C at the cool end, to 30C at the warmest end. You will notice that your snakes seek out the warmer areas early in the mornings and immediately after feeding. The heat source should be switched off at night, in all but the coldest of situations.
All my vivaria are provided with under-floor soil warming cable, which is controlled with a variable thermostat. This is fixed at one end of the enclosure. Plug-in timers switch the heating off during the hours of darkness.
Feeding
In nature Garter and Ribbon Snakes are opportunist feeders, preying predominantly on amphibians, earthworms and small fish, they may also take the occasional small rodent, if the opportunity were to present itself. An amphibian diet is difficult to provide in captivity, but these snakes can be persuaded to accept a slightly altered diet.
I feed all my Garters on a diet of fish, usually trout or salmon strips(approx 60%), frozen/thawed pinky or fuzzy mice (approx 35%) and earthworms (approx 5%) when I can get them. A good quality multi-vitamin (Nutrobal) and calcium supplement is added every third or fourth feeding.
Adult snakes are fed once or twice per week, babies are fed every second day.
Sometimes a Garter Snake might be initially reluctant to accept pinky mice. This can be dealt with by means of 'scenting'; the pinky is rinsed to remove much of it's natural scent, it is then thoroughly rubbed all over with a food item acceptable to the snake (fish or earthworm), so that the pinky takes on the scent of this preferred food item. Once the snake has learned to accept pinkies this way, the amount of scenting can be gradually reduced, if desired.
It should be noted that there are a number of 'feeder' fish (including Goldfish) that are unsafe to feed to Garter Snakes. This is because they contain an enzyme (thiaminase) which destroys the thiamin in the snakes' diet. Thiamin is necessary for the production of vitamin B3 in the body. Vitamin B3 is necessary for the synthesis of calcium. In short, a Garter Snake fed on Goldfish (and other thiaminase containing fishes), will not be able to take up calcium. This results in spasms, seizures and ultimately, death.
It can be difficult to be sure which fish contain this enzyme and which do not. For this reason, I recommend using only trout or salmon, both of which are safe and readily accepted by most captive Garter Snakes.
Breeding/Brumation
Breeding Garter Snakes is not difficult. The only requirement is a healthy specimen of each sex, they will happily take it from there! These are ovo-viviparous snakes, that is they retain the membrane-like eggs inside the body until the moment of hatching, then parturition occurs. This is referred to as 'live birth', but there is no umbilical connection to the mother, as in mammals etc.
Certain Garter Snake species (most notably the Checkered Garter Snake Thamnophis marcianus) are known to reproduce more than once a year, but usually mating takes place in the early Spring and the babies are born live 90 to 120 days later. Litter size varies from 5 to 50, more usually between 12 and 30 (the record is 92!) depending on species and the size and age of the female.
The young are independent from the moment of birth, and have the same requirements as the adults, only feeding should be more frequent.
The males of some species are known to cannibalise the young. So it is advisable to separate the mother from any other snakes you may have prior to parturition. The babies should be separated from the mother as early as possible, to avoid accidental crushing and so the babies are not accidentally eaten during routine feeding.
If you wish to deliberately breed your Garter Snakes, you can significantly increase the chances by brumating (hibernating) your snakes, although this is not always necessary. Brumation is simply a case of keeping them in the dark at reduced temperatures for a period of time. This cool period stimulates the production of sex cells in their bodies, and so increases the chances of a successful mating in the Spring. The length of the brumation period and the temperature at which it should be conducted varies between species and sub-species, depending on the climatic conditions of their natural range in the wild. For example the Red-Sided Garter Snake, Thamnophis sirtalis parietalis, with much of its home range in Canada, will require lower brumation temperatures and longer brumation periods than the Checkered Garter Snake, Thamnophis marcianus, with its home range in Texas. Lowland Mexican species will not require any brumation period, other environmental cues, such as the appearance of a particular food source, will trigger mating behaviour in these forms.
On occasion a Garter Snake may stop feeding during the winter months, although this does not always happen. If this fasting continues for a significant length of time, but activity levels remain high, your snake may begin to lose weight. In this case it would be advisable to give a brief period of brumation in order to trigger the feeding response, irrespective of whether or not you wish to breed from this snake.
