In general, it’s not always necessary to hibernate a tortoise. Provision must be made to keep its environmental temperature between 25-30C during the day and 22-25C at night if they are to stay awake. Care should be taken not to over feed during this time as this may result in obesity. Too rapid a growth rate and shell deformities can result from keeping growing tortoises awake over winter. Breeding females, however, do require a hibernation period.
Not all species of tortoise need to be hibernated. Those species that we hibernate in the UK are:
- Hermann’s tortoise (Testudo hermanni),
- Mediterranean spur-thighed tortoises (Testudo graeca , Testudo ibera),
- Horsfield’s/Russian tortoise (Testudo horsfieldi)
- Kleinmann’s tortoise (Testudo Kleinmanni) and
- Marginated tortoises (Testudo marginata).
The process of hibernation begins when natural day length changes in Aug/Sept. Light intensity decreases and temperatures begin to fall at night, causing the amount of food intake to decrease.
It is advisable to delay hibernation until November or December with the use of heat and UV lamps to avoid an overlong hibernation that can result in depleted energy stores, dehydration and accumulation of toxins. The length of hibernation will vary depending on the tortoise’s life stage, health and size. First hibernation for young tortoises should be no sooner than their second, third or fourth winter and then only for 2-6wks (mainly dependent on the owners confidence). In the wild, tortoises will hibernate for up to a maximum of three months. Avoid hibernation if the tortoise is very young or has health problems.
Preparation is key to successful hibernation. Ensuring a good diet throughout the year, dandelion, timothy grass clover, plantain, water cress coriander, pea leaves, chicory etc. There is a plant database for tortoises which is www.thetortoisetable.org.uk. Some greens contain oxalates that prevent calcium absorption so should be used in small quantities, if at all (chives parsley, spinach, beet leaves, bok choy). It's also advisable to use a good quality calcium and vitamin D3 supplement such as Nutrobal.
Your tortoise will start the process itself by reducing its food intake and becoming less active. It's then advisable to have a pre-hibernation health and weight check by the vet in September/October. A check for disease, parasites (worms – usually a faecal flotation) and injury will be carried out. In the female a radiograph/ultrasound can be taken to ensure no eggs present before hibernating. All food should be removed 4-6wks prior to hibernation date to allow intestines to empty. Drinking should still be encouraged with daily shallow bathing. It is important to provide a cooling period for the tortoise before hibernation.
There are two methods of hibernation: a refrigerator or a well-insulated box (no hay or straw).
Using a fridge to hibernate a tortoise may seem odd but can provide a safe and reliable hibernation chamber, avoiding some hazards of traditional methods, such as frostbite and rodent injury. It is essential to ensure that the refrigerator temperature is stable, correct for the species, and regularly monitored. Whichever method used, hibernating your tortoise for too long is the greatest risk factor for post hibernation problems
Tortoises should be hibernated between 5-8C. Below this, changes in water density may affect the eyes resulting in blindness as well as freezing other tissues. Above this the tortoise will be more active and use body stores quicker than it should. A fridge or drink cooler makes it easier to control the temperature especially when using a digital temperature probe. It is advisable to set this up a few weeks before hibernation.
During hibernation the tortoise should be weighed weekly. This allows an opportunity for a change of air in the fridge and monitoring of the animal. There will be a small weight loss in the first couple of weeks, but it should become stable by the third week, if not seek veterinary advice. Total weight loss should not exceed 5%of starting weight. If the weight has dropped or the animal has urinated then the tortoise should be brought out of hibernation.
- Only hibernate the correct species of tortoise.
- Do not hibernate unhealthy tortoises.
- Only hibernate for max 12wks in adults.
- Fridge hibernation 5-8C
- Weigh regularly
Towards the end of their hibernation period take the tortoise out of its cooled environment and gradually warm it up, feeding on the second day out and giving daily warm baths to encourage rehydration and waste elimination. If the appetite has not returned in 72hrs then veterinary advice should be sought.
Category: Small Animals