The most traumatic time for a tortoise owner is at the end of the summer when nights draw in, temperatures start to drop and the first thoughts of hibernation come to mind.
Over many years using different methods of hibernation we have developed a relatively safe hibernation technique which if followed correctly should take most of the worry out of hibernation.
PREPARING FOR HIBERNATION
Although tortoises would normally hibernate in the wild from their first year as hatchlings it is not recommended for beginners to do so at such a delicate age. Its recommended to keep hatchlings up to three years old (or up to 100mm plastron length) awake during winter in a heated vivarium.
Older tortoises can be hibernated safely providing they are of good weight, are generally healthy, and have shown no signs of respiratory problems. It is very important to weigh your tortoise using Komodo Reptile Scales and work out the weight to size ratio (refer to Jackson’s ratio graph).
Remember that our summer months are much shorter than southern Europe where they naturally live and to help extend the summer and reduce the time spent in hibernation it’s always best to use a vivarium. The main reason to use a heated vivarium is that in spring when tortoises wake up the outside temperatures are not stable enough. In a vivarium, tortoises can be kept in a stable environment which will stimulate its appetite and help it recover safely from its hibernation.
In the autumn as early as the first week in September night temperatures start to become cold and many tortoises stop eating, this is far too early for tortoises to start their hibernation. Again by using a heated vivarium you can extend there summer to the end of October by maintaining a constant temperature.
At the end of October, you can start to reduce the night and day temperatures slowly over a couple of weeks until the tortoise shows no signs of feeding due to its body temperature being to cool.
Continue reducing the temperature and start counting the days from when they last fed. After two weeks of not feeding the tortoise should have emptied its stomach contents and will be ready for hibernation.
KEY TO SUCCESS
The main issue of safe hibernation is to be able to maintain the tortoise’s body temperature between 3 & 7 degrees C and not to allow it to fluctuate. This will keep the tortoise’s metabolism stable and prevent it from burning off calories and losing body weight during hibernation.
I have found in the past when hibernating tortoises the old fashion way in a box with straw, hay or newspaper, they frequently wake during the winter months and tend to be in poor condition when they wake up in spring.
This is due to our winters being long and generally mild which can fluctuate daily. Also, by keeping your tortoise in straw, hay or paper the air circulating around your tortoise will fluctuate its body temperature. This will take it in and out of sleep and will unnecessarily burn off calories and lose bodyweight. It will also cause dehydration which can lead to kidney failure.
Remember that dehydration kills tortoises in hibernation, not starvation as many people think.
We have been using the following technique for many years and have found it to be the most natural and safe way to hibernate your tortoise.
Using a large strong plastic box at least 30 cm deep and with a strong clip-on ventilated lid, fill it halfway with relatively dry garden compost or fine soil. Even when it feels relatively dry to the touch it will naturally have some moisture content which will help prevent dehydration in hibernation.
Once you have gone through the last stages of cooling and your tortoise hasn’t eaten for about two weeks it should be ready to be placed in the hibernation box. If the tortoise is still very active try cooling it for another week.
Place the tortoise in the box and let him settle for a couple of hours, then put some more loose soil in the box around the edge banked up the sides. As the tortoise moves around over the next couple of days it will bury itself, don’t worry it will not suffocate. In fact, at this stage, their breathing is so slow that enough air will filter through the soil but not enough to cause any problems with fluctuating air temperatures.
Clip on the ventilated lid and place the box somewhere that stays cool between 3 – 7 degrees C. I have found that brick buildings like outside garages are the best places to keep it as it tends to stay very cool and is protected from the frost which is very important.
It is a good idea to use a min-max thermometer just underneath the soil in the hibernation box with the tortoise so that you can check the temperature every couple of weeks. If it is at the lower end of the range (3 – 4 degrees C) you may wish to place the box higher up away from the floor as it will be one or two degree’s warmer away from the floor, or on the other hand, if the temperature is at the higher end of the scale (6 – 7 degrees C) place the box closer to the floor or on the floor. You may wish to check this from time to time during the winter.
WAKING UP IN SPRING
Tortoises tend to start waking up around March when the weather becomes very mild and we start to get the first sunny days of spring. This is a perfect time to let your tortoise wake up naturally.
By moving the hibernation box to an area that is slightly warmer your tortoise will start slowly moving around the box, this may take a couple of days. At this stage, you should get your vivarium warmed up to the mid 70’s f (22-24 degrees C).
After the first two or three days of movement it is important to remove the tortoise and bath it in lukewarm water for about ten minutes to re-hydrate it and then return it to the warm vivarium. This should be done every day for about ten days and during that time (every other day), you should increase the temperature one or two degrees until the low 80’s f (26-28 degrees C) is achieved.
Again the reason we use vivariums in the spring is that between spring and summer temperatures are very unstable. In April we get a lot of rain and frost which are both dangerous to tortoises.
Don’t forget they can still go outside when its fine warm weather but should always go back into their vivariums at night and stay there if the following days are wet and cold. This is to help extend their summer.
Many tortoises that wake up in spring and are left outside sometimes try to go back to sleep in April because its cold, wet and sometimes frosty, which is not a good idea. Once they are awake they should stay awake.
IMPORTANT NOTES TO REMEMBER
Vivariums are one of the most important things to have when keeping tortoises as they can be used to extend the summer and reduce hibernation time.
Remember that you must make sure your tortoise has emptied its stomach before hibernating.
The hibernation box must be strong with a vented clip-on lid and stored between 3 – 7 degrees C in a rodent-free place.
Make sure you use soil or compost which will prevent dehydration, temperature fluctuation, and weight loss.
Don’t forget to bath your tortoise every day when it wakes up in spring to re-hydrate it and help it recover from the hibernation.
Always remember that tortoises are cold-blooded creatures that depend on you to provide the right conditions for them to survive long term.
Only put them outside when its dry warm weather and never leave them outside in damp wet and cold conditions.