Hibernation of the terrestrial tortoise : why, when, how ?
Some tortoises hibernate, others not… This article gives you all the elements to know to manage this delicate moment of the life of a tortoise. Even if these animals can live several tens of years, many individuals die even before reaching the age of one year, for lack of benefiting from the good care. It is therefore important to do the right thing for your turtle.
The hibernation in the tortoise
Hibernation is a strategy adopted by some animals to survive during cold periods. The animal which hibernates takes refuge in a burrow or a cave and sets up a state of hypothermia known as regulated during several days or several weeks. The animal’s body literally lives in slow motion. The goal of this mechanism is to conserve enough energy to get through the winter.
Hibernation affects several physiological functions which are modified to slow down the metabolism: body temperature and breathing rate are the main parameters impacted. It is necessary to distinguish hibernation from wintering. In this last case, the metabolism keeps a certain level of activity in order to allow a quick awakening in case of need. This is, for example, the case of bears, badgers, raccoons and opossums. Hibernation is for warm-blooded animals, such as marmots, dormice, hedgehogs, or some mice.
When it comes to cold-blooded animals, such as frogs, lizards and turtles, the appropriate term is brumation. However, it must be admitted that it is not widely used. Not all reptiles engage in brumation, whether the animal lives in captivity or not. Even in the wild, some reptiles are able to remain active and feed normally throughout the winter without negative consequences for their bodies.
It is important to note that not all land tortoises hibernate, simply because the need to adapt to the environment varies depending on their geographic area of origin. Turtles from Africa do not hibernate because their native climate is always warm. This means that these animals must be kept in a constant temperature environment throughout the year. Other species only need a short period of time during which their metabolism slows down. So it is important to know your turtle’s species and its needs.
In the wild, Hermann’s Ridley turtles hibernate from October/November to about mid-April, starting when they are one year old. During the hibernation, it reduces to the maximum its energetic expenditure. Its internal temperature decreases, its heart and respiratory rates drop and it does not eat at all, settling into immobility.
Which precautions to take before the hibernation ?
In France, most of the present terrestrial tortoises are Hermann’s tortoises. Tamed and correctly looked after, they can reach the age of 50 or 60 years. Unfortunately, about 4 turtles out of 5 die before the age of one year because their owners did not know how to correctly manage the hibernation period. It is thus important to follow the protocol which we indicate you below.
For the turtles of Hermann, the hibernation is essential to the biological functioning. This period is essential to guarantee them a good growth, a beautiful longevity but also a good reproduction. The Greek turtle (Testudo graeca) is, like the Hermann’s turtle, a turtle used to the Mediterranean climate, characterized by relatively short winters and mild temperatures. The hibernation period is therefore generally from November to March. If you keep these species while being located in the North and the East of France, it is advised to place them in terrarium so that the hibernation period is not longer than their natural period.
The Turtle (Testudo graeca iber) and the Steppe turtle (Testudo horsfield) are more resistant and can hibernate in the garden, provided that the ground is arranged.
The turtle can settle in the hibernation phase only if it is in good health. The weight gain during the beautiful season is to be watched because it constitutes an essential indicator, the animal surviving only thanks to its reserves of fat. If the animal weighs less than its theoretical weight minus 10 %, it should not be left to hibernate, otherwise it would die. The good health of the tortoise extends beyond its weight: its carapace must be intact, its eyes must be clear and brilliant, without secretions, like its nose, its cloaca must be clean, and it must be free of any parasite or disease.
A turtle that needs to hibernate can be deprived of hibernation for one or two consecutive years. It will be necessary simply to place it in a terrarium with constant temperature. If the hibernation is not organized during more than two consecutive years, the health of the animal will, on the other hand, be negatively impacted.
How happens the hibernation in the terrestrial tortoises ?
The tortoise can hibernate according to two modes. The first one consists in letting the tortoise hibernate in an outside shelter, provided that temperatures do not go down below 5°C. It is logically autonomous. Your role is limited to protect the site which it chose. The tortoise needs a ground of loose earth in which it can dig to sink in it until a depth of 20 cm. A pile of dead leaves on top helps to isolate the area. It is advisable to add a wire mesh on the top and all around, sunk deep enough, so that rodents cannot access the turtle.
The second mode is artificial because it is you who orchestrate the hibernation. It concerns the turtles which live in terrarium or the turtles which live outside in the North and the East of France, where the winters are the coldest. It is a question of placing the tortoise in a box of hibernation, itself placed in a fresh and isolated place. It can be an unheated cellar, a garden shed, if it is protected from frost, etc. The important criterion is the constancy of the temperature throughout the winter. Ideally, this temperature is 10°C. The range can be from 5 to 12°C. This place should also provide shelter from rodents and flooding.
If you choose this second option, the recommended dimensions for the box are 70 x 70 x 80 cm. A rough assembly of wooden boards may be sufficient. The bottom of the box is filled with a dry substrate in which the tortoise will be able to bury itself easily: straw, moss or dried barks, sand or sterilized ground. It is advisable to monitor the hygrometry and the temperature with the adequate instruments, to make sure that the minimum and maximum are respected.
The days are visibly getting shorter and the temperatures drop significantly from October onwards. You will observe that the activity of the tortoise slows down: it leaves its shelter more rarely and its appetite decreases. If you organize its hibernation, here is what it is advised to make:
If your turtle lives in a terrarium, turn off the heating system to reach a temperature below 18°C for 2 to 3 days,
Give more food to your tortoise during the 6 weeks which precede the hibernation (which date is at the beginning of November if you benefit from a rather favorable climate),
To stop feeding the tortoise during the 10 days which precede its installation in its box,
Every day of these 10 days, bathe the tortoise during 10 mn in a water whose temperature is included between 24 and 26°C, with an aim of stimulating the defecations. It is important that its digestive tract is empty for the hibernation because remains of food in its intestines are likely to form toxic substances for the tortoise.
To manage the exit of the hibernation
The needs of your turtle and the outside temperatures indicate the end of hibernation. Between March and early April, you can remove the turtle from its box and place it under cover. Weigh it. It inevitably lost weight but this loss should not exceed the 10% compared to the weight before hibernation.
The tortoise must be warmed up gradually, the final normal temperature being reached in 2 to 3 weeks. During this period, you also bathe the tortoise in tepid water, so that it hydrates adequately. The quantities of food which are given to him increase little by little. If you have any doubts about its health, you can have it checked by a veterinarian. If all is well, the turtle can return to its usual living space.
