Most of you will know the word “hibernation”. This is the resting period during the cold months. For reptiles the word “brumation” is the right one for this phenomena. Bears hibernate, reptiles brumate.
During hibernation the body temperature is kept “normal” thanks to the fat-reserves the animal has. A hibernating animal will loose a fair part of its weight during the winter months.
Reptiles lower their body temperature and their metabolism gets very slow. Reptiles do not loose much weight during the winter months.
So… hibernation in reptiles is called brumation.

But, how do you do that … brumating your garter snakes? I will try to explain this here.

When the days are getting shorter and the night temperature gets somewhat lower, you will notice that your snakes are getting less active. Especially when you do not heat the terrarium during the night (heating the terrarium for garter snakes during the night is, in principle, never necessary). Under these circumstances the garter snakes in the wild will start preparing themselves for the brumation. Their instinct “tells them to do so”.

In the terrarium you can make a choice whether you let the snakes brumate or not. I am personally in favour of brumating the snakes. This is a normal part of their natural behaviour. Next to that I love it when they are “sleeping”. Gives me more time to do other things and to renovate the terrariums, etc.
Next to that I see that the animals look healthier after a brumation of a few months.

Thamnophis sirtalis tetrataenia and T. s. sirtalis, erythristic during a check…

The most important question you have to ask yourself before you start a brumation is: are my snakes healthy and well nourished?
It is  better when you do not place weak snakes with a poor nutritional status in brumation, especially when you are unsure and inexperienced.
On the other hand, it may also be that bad eating animals after brumation are much greedier. A brumation can sometimes literally be beneficial.
Some breeders place their not-eating young in brumation with the intention that they start eating after they wake up. The results are often very good. Important: Ask  an experienced garter snake keeper for advice if you are unsure.

I will write down what I usually do when I brumate my garter snakes. Then it’s probably clear for everyone.

the preparation
The preparation…

In November (no fixed date, but when it’s most convenient for me and when the night temperatures are getting low enough) I start the preparations. Initially, the only thing I do is stop feeding the snakes. After a week I shorten the day length with a few hours per day. You can also start using lamps with a lower wattage in combination with this. I do not do that, cause I only use 25 watt lamps and I cannot get lower than that. I always make sure there is a place in the terrarium where them temperature stays 30 °C. (86 °F.) or higher. This is important, because the snakes must be able to digest all their food and empty their intestines!
The reducing of the day length I do as follows. I start with switching the lamps on half an hour later and switching them off a half hour earlier. I repeat this every second or third day.
After 10 days or so their intestinal system is empty cause you have not fed the snakes during this period!
Not feeding the snakes in this period is of vital importance!!
If there are food residues left in the intestinal system during the brumation, they will start to rot and the snake will die!

Two weeks after you stopped feeding the snakes you turn of all the lamps. When the terrarium is in a light place, for example, near a window, you can hang a cloth over it so it will get dark in the terrarium. One or two days later you can take the snakes out of the terrarium and place them in the brumation box(-es). This can be a small, plastic terrarium or a “curver-box” or something similar. It is important that it is moisture resistant and impossible for the snake to escape.


Bucket with snakes that wait on the weighing to house them in the right boxes...
Bucket with snakes that wait on the weighing to house them in the right boxes…
Bucket with snakes that wait on the weighing to house them in the right boxes
Bucket with snakes that are waiting to be weighed…











As a substrate in the boxes I use wood shavings (the stuff that is used in cages of rabbits and hamsters, etc.) I saturate these shavings with water and on the bottom of the box there is always a small layer of water present during the brumation.
In this way I do not have to add more water during the months the snakes are brumating in it. I brumate the snakes in a refrigerator at 4 – 6 °C. (39 – 43 °F.) When I check the boxes there always hang condensation drops on the sides and the lid. This means that it still is wet enough.
In  principle it cannot be too wet during the brumation. When it is to dry, your snakes will loose weight caused by dehydration. Very wet is good, to dry is bad in the brumation boxes! I personally do not place drinking bowls in the boxes. There is enough water in the box.

In this table you can see how the weight loss usually goes...
In this table you can see how the weight loss usually goes…

Since 2011 I have four Thamnophis sirtalis dorsalis (3.1) that were born in 2011. The breeder told me that his adult specimen most of the time lie in a water bowl during the brumation. I tried this too with my four juveniles during the brumation of 2011/2012. I placed a water bowl in the brumation box and threw some plastic plants in it. The wood shavings were very wet, like I always do. The young snakes were never seen in the water. Also I never found wood shavings in the water.  In other words… the substrate was most enough for them. The breeders keeps his substrate somewhat drier and that is most probably the reason why the snakes go in the water bowl.
During their brumation of 2012/2013 I did not place a water bowl in the box. All four stayed 2 months in the box in the refrigerator. They all were in perfect health when the brumation was ended. They did not loose any weight. No more water bowls for me in the boxes…

The refrigerator...
The refrigerator…

On the day that the snakes are placed in their brumation boxes, I weigh them (to 1 gram accuracy) and of course I make notes of this for every snake.
On the day I take them out of the brumation boxes (two months or more later) I weigh them again and I compare both weights.
Specimen up to about 50 grams show most of the time no or hardly any weight loss (maximum of 1 or 2 grams). Specimen that are larger and heavier often show no weight loss too or a maximum of 2 – 4 grams.
You can conclude by these data that the substrate in the boxes was wet enough and the

Adult Thamnophis sirtalis dorsalis...
Adult Thamnophis sirtalis dorsalis…

temperature was low enough.
When you notice that there is  relatively much weight loss, the snakes were most probably brumated to dry and/or to warm.  You can use this information for the next brumation.
Is there one specimen in a group of snakes that were in the same box that lost more weight than the others (more than you would expect), than you have to give such a specimen more attention. There can be a special reason (illness, etc) for this unexpected weight loss. If necessary you place it in a quarantine terrarium so you can keep an eye on it.

The first two days that the snakes are in the brumation boxes, I place them on a cool, quiet place (in my case the attic). Then I place the boxes in a refrigerator that is adjusted to 4 – 6 ° C. The refrigerator is an old apparatus that is placed on the attic. In a cold environment it does not use that much energy. I only use it during the brumation months and every now and then when we have a party and need much cooled beer. The largest part of the year it is switched off. A few weeks before the brumation begins I turn it on and test the temperature on a daily base and fine tune it when necessary.

Young Thamnophis sirtalis dorsalis during their first brumation...
Young Thamnophis sirtalis dorsalis during their first brumation…

In spring I place the snakes back in their completely cleaned and equipped terrarium. I always plan ahead where which snake is placed. When you have many specimen this is absolutely necessary. Since 2012 I use a male- and a female terrarium for specimen that are too you to breed or specimen I do not want to breed. The pairs I do want to breed are place together in breeding terrariums from day one after the brumation.
Till a few years ago I removed the boxes with the snakes from the refrigerator and placed them for one or two days on the attic. They were able to slowly adjust to higher temperatures in this way. I also tried the following method: I placed them in their unheated and dark terrariums and switched on the lamps after two days.
Some years I extended the illumination period gradually. Other years I did it without gradation and were the lamps switched on immediately for 12 – 14 hours. I noticed no difference in the behaviour of the snakes.
Since some years I do it like this: I take the boxes out of the refrigerator, take them downstairs to the kitchen and take the snakes one by one out of their boxes. I check them, weigh them (sometimes I take some pictures of them) and place them in a bucket with a lid on it.  When the box is empty I compare the weights with the data from a few months ago.

During a check halfway the brumation…

Then I take the snakes to the attic and put them in the planned terrariums. This is repeated till all brumation boxes are empty. When they are all in place I switch on the lamps, throw away the substrate, clean the boxes and put them away. I observe the snakes for at least an hour and place the data in my computer.
This method works fine. For example, in 2010 one of the makes of T. s. tetrataenia was trying to copulate with one of the females half an hour after they were placed in the terrarium.
This brumation method I also have used with specimen of Elaphe, Pantherophis, Lampropeltis and Nerodia species. I never lost a snake during the brumation period while using this method.
The first week I do not offer food because most snakes refuse to eat in this period. They have to get their system going again, I guess. And a week without food is no problem as you all (should) know…

How you usually find the snakes at the end of the brumation…
During a check halfway the brumation…

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