After the hot and heady days of summer and as the days shorten and the temperature starts to drop is when us tortoise owners start to think about hibernating our reptile friends. It is essential that your tortoise in is in optimal condition before hibernation to try and ensure that they will wake up raring to go !
I inherited my tortoise, Martin, from a great uncle who had dedicated his whole life to breeding tortoises and disputing Darwinism. Every year I worry about Martin going into hibernation and I am still very much in awe that he can spend the winter in the fridge and wake up fresh as a daisy in the spring. It is also quite fun when people go to get the milk out and see a tortoise in the salad drawer at the bottom of the fridge.
Not all tortoises will hibernate – tropical tortoises such as leopard tortoises or red footed tortoises will not hibernate and are kept at constant temperatures and humidity all year round.
The Mediterranean species such as spur-thighed or Herman tortoises will have periods of hibernation during the cooler months in their native climate and so are programmed to benefit from a period of hibernation when we keep them as pets.
Preparation for hibernation
It is essential that a tortoise is in optimum health and is prepared for hibernation. In the wild their metabolism will start slowing down in October . We would generally recommend a hibernation length of no more than 12 weeks at a temperature between 4 and 7 degrees Celsisus.
A pre hibernation check list is a good idea before hibernating a tortoise.
- Weigh your tortoise (ideally they need to be at optimum weight pre hibernation as they may lose 10% of their body weight during that period)
- Measure your tortoise. The carapace length is a useful piece of information and together with the weight of your tortoise can be used in a formula called the Jackson Ratio to ascertain whether your tortoise is a healthy weight for its size and thus suitable for hibernation. If your tortoise falls below the curve on the Jackson graph then it would suggest that it is underweight for its size and therefore it may be unwise to hibernate that animal or that a shorter period of hibernation may be indicated.
- A faecal sample will show whether your tortoise has any gastrointestinal parasites and should be treated before hibernation.
- The temperature should be gradually reduced from 25 to 10 degrees C over a period of 3-4 weeks and during this period the food intake will reduce to ensure that the gut of your tortoise is empty during the period of hibernation. Regular warm baths help to encourage defaecation and maintain hydration at this time.
- Your tortoise should have no external signs of injury or disease as during hibernation their immune system is more vulnerable and less able to protect them against disease.
The ideal temperature for hibernation is between 4 and 7 degrees C and a fridge is the ideal place to keep this environment constant. If the temperature gets too low then your tortoise may suffer from frostbite or eye damage and if the temperature rises above this then your tortoise will awake from hibernation and become more active using up its energy reserves.
During the period of hibernation
- Open the fridge door regularly to ensure adequate air flow and ventilation
- Check the temperature of the fridge on a regular basis for the reasons outlined above
- Weigh your tortoise weekly. It is expected that the animal may lose up to 10% of its body weight during hibernation .Any more than this then the hibernation period should be stopped.
If a fridge is not available then a small box within a larger insulated box in a garage or outbuilding may suffice but due to the unpredictability of the English winter then maintaining the correct temperature during the period of hibernation can be difficult.
More to follow on waking up your tortoise and things to look out for in a post hibernation check.
If we can advise you on hibernating your tortoise then please contact the surgery on 01825764268 and one of our vets or nurses will be able to help you.