What is hibernation?
Only a few species of tortoise hibernate. These include the Spur Thighed, Hermanns, Marginated and Horsefield tortoises. Some other species aestivate, most do neither.
Hibernation is a particular physical condition in a tortoise triggered by cold weather. Its heartbeat slows down, its breathing nearly stops, and its digestive tract stops working. This metabolic state becomes deeper as the cold spell continues, until after a few weeks, the tortoise appears almost comatose. In the wild, a tortoise will slowly dig its way up and down in the soil to achieve a suitably steady body temperature- going deeper if the climate is colder, and coming shallow as the world warms up (eventually emerging if it is warm enough).
How do I know if my tortoise’s hibernation is the correct length, and
of a good quality?
The optimum temperature for a tortoise in hibernation is a stable 5 degrees C. Suitable places include wine coolers (not ‘fridges), cellars, and brick built garages. Being colder than 3 degrees C risks death, greater than7 degrees C increases the energy used by the tortoise, and therefore reduces its body reserves. Having a hibernation with a severely fluctuating temperature (e.g. a garden shed subject to sunshine) will exhaust and therefore starve the tortoise.
A safe natural method is a fully buried bin filled with soft loam or straw with a waterproof ( not airtight) lid.
The longer a tortoise hibernates, the more bodyweight will be lost. Hibernation therefore should be as short as 6 weeks for juveniles, and no longer than 4 months for experienced adults.
First steps in bringing my tortoise out of hibernation.
Initially, remove the tortoise from the cold environment, and keep in a box in a warm room. Weigh the tortoise. This weight will be the benchmark against which progress is measured during the summer.
Weight loss should be no more than 10% since the autumn. After 24 hours, give a warm bath. This is done by placing the tortoise up to its nose in water (in a sink or bowl), and leaving for at least half an hour. The tortoise may be seen to dip its head under water- the throat will be seen to move as it swallows. Now food can be offered. Good first foods (because of their water content), are the salads such as cucumber, lettuce and tomato. Dandelion is also good for the kidneys. It should not take more than a few days for the tortoise to start feeding.
Second steps: The night box or vivarium
Typically, the tortoise should come out of hibernation before it is warm enough for it to enjoy life outside 24/7. Therefore, if night time temperatures fall below 7 degrees C, the tortoise should be brought in, and kept warm in a heated vivarium, or a simple cardboard box with a heat lamp over head (60w).
The first sign of trouble is if the tortoise is not eating. In this case, ensure that the tortoise is kept warm (its shell should be warm to the touch), and bathe daily. If the salad foods offered are not eaten, there may be underlying issues:
a) Mouth rot (Stomitis)- the tortoise may have a sore tongue, and there is cheese like material in the mouth. This needs to be cleaned out, and antiseptic used. Typically, a vet would do this.
b) Eye infections- there is white material on the surface of the eyeball. The tortoise may seem to be crying, or obsessively rubbing its eyes. This needs to be treated with eye antiseptic (any human preparation will do)
c) RNS (Runny Nose Syndrome). The tortoise’s nose has a wet discharge, which may bubble as the tortoise breathes. Visit a vet.
d) Peritonitis- Infections will often show as a (bloody) discharge from the edges of the shell scutes. This form of external infection can be treated easily, although a trip to the vets is required. Internal infections are often fast moving, and fatal. This can often be suspected where there is a rotten- smelling discharge from the cloaca. Any symptoms such as floppiness, weakness or lethargy must be urgently investigated.
e) Anorexia – this sometimes may indicate kidney or liver failure, however, most common is the fact that a tortoise which does not manage to begin eating soon after hibernation will gradually deteriorate into an anorexic state, taking invasive intervention to cure. This will consist of force feeding, and/or tube feeding.