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MEDITERRANEAN SPECIES , (e.g. Testudo graeca
and Testudo hermanni)
Hibernation is an absolute essential element of
tortoise ecology. The age / size of the tortoise determines the length of
time that the tortoise will hibernate for until they reach full maturity at
approx 10 year. The bigger the tortoise, the larger their fat reserves hence
why young tortoises will only hibernate for a few weeks.
It is only a myth when people say that your
tortoise should not be hibernated for the first few years. All tortoises
that hibernate naturally in the wild should also be given the chance to do
so in captivity. The thought of having to hibernate a tortoise scares a lot
of people because of what's involved. Even the most experience keepers still
get nervous when this time of year comes around. Believe me, if you follow
the correct advice on pre and post hibernation, your tortoise will do fine.
Any tortoise that is under weight, or has an
illness such as worms, infections or wounds which have not yet healed, or is
egg-bound, should be over-wintered. Be sure to carry out your
Pre-Hibernation health checks prior to hibernating your tortoise.
IS YOUR TORTOISE FIT TO HIBERNATE?
In order to survive
hibernation, tortoises need to have built up sufficient reserves of
body fat; this in turn stores vitamins and water. Without fat,
vitamins and water, tortoises die of starvation or dehydration.
Adequate reserves of body fat are vital to tortoises in
hibernation as they live off these reserves. If these reserves run
out too soon then the animal's body will begin to use up the fat
contained within the muscles and internal organs. This also will
eventually become exhausted. At this point the tortoise will
simply die in hibernation. All this can be avoided by using a
simple method of testing which is quick, accurate and saves lives. It is
called the 'Jackson
Ratio',
which was developed by the late Dr. Oliphant F. Jackson, MRCVS, a
leading veterinary surgeon and an expert on reptile physiology,
medicine and treatment.
PRE HIBERNATION
Before you start your
tortoises wind down, make sure you record their weight. This will
help you to calculate how much weight your tortoise has lost at the
end of the wind down period.
At the beginning of
the wind down period, tortoises need to have normal day length and
temperatures that are approximately the same as summertime. This
will keep their digestive systems working fully and therefore pass
any recently eaten matter through the system. You may find, due to
the weather, that they are slightly slower than they were in the
summer but be prepared for some pleading looks. DON'T give in!
During week 2, you
can keep the temperatures the same as week 1 but in lesser
quantities. Therefore, you should be aiming to turn the heat / UV
lamps on a little later in the morning and off a little earlier in
the evening. This will simulate their shorter day lengths in the
wild. Towards the end of week 2, make the "daylight hours" shorter
still making it a gradual process.
By week 3, you will
find that your tortoise is coming out from his hiding place less and
less. You can now leave the basking lamps off completely and just
have a gentle background heat available such as a ceramic heater or
your central heating if it is inside the house.
During the beginning
of the final week, any background heat should be turned down to a
bare minimum. You will probably find that the tortoise is not coming
out at all now and is inactive. Towards the end of this week, give
your tortoise its final bath (not warm enough to stimulate him) and
make sure he is thoroughly dried. Place the tortoise in the box that
he will be hibernating in. Place the box in a cool place such as an
unheated room or a safe outbuilding. If you are using the fridge
method, this will cool him down further which will more closely
match the fridge temperature. At the end of the 4 weeks (and as long
as he isn't still passing anything in his bath water), the tortoise
should be ready to go into its hibernation quarters.
Finally, make sure you
weigh your tortoise again before it goes into hibernation as this is
classed as their pre-hibernation weight. This is vitally important so that you
can monitor how much weight your tortoise is loosing during hibernation.
HIBERNATION
For the
next stage, we recommend the fridge method for hibernation. It is
the most stable and safest method today. It does sound off putting,
and scary, but this method has been proven the most successful by
many tortoise keepers and organisations.
Firstly,
you will have positioned your fridge in a location that is not going
to be affected by the outside / freezing temperatures. One thing to
remember, if your fridge is in an environment where the temperatures
are aloud to drop below freezing, then so will the temperature
inside your fridge. A normal room inside the house where
temperatures don't fluctuate much is ideal. You will have to to give
yourself at least 4 weeks prior to hibernation to ensure that you
have had enough time to get the temperature inside the fridge
stable.
Below is an example of a
fridge that we use for hibernation. We bought this larder fridge
brand new in a sale. It is important that you use a fridge that is
going to be reliable. Each hibernation box has it's own digital
thermometer attached to it with the probes placed inside. As you can
see, we have also placed a few bottles of water inside the fridge to
help with the overall mass. We find that this helps towards
temperature stability.
***IMPORTANT*** - DO NOT USE A FRIDGE THAT
HAS AN INTEGRATED
ICE BOX AS THIS CAN HAVE AN ADVERSE EFFECT
ON THE INTERNAL
TEMPERATURE.
Approximate times for winding down and hibernating your tortoise:
|
Age (Yrs) |
Wind Down Period (Days) |
Hibernation Period (Weeks) |
|
2 |
14 |
6 - 8 |
|
3 |
18 |
10 |
|
4 |
21 |
12 |
|
5 |
24 |
16 |
|
6 + |
28 |
19 - 20 |
Once you
are ready to place your tortoise in the fridge, we recommend placing
them inside a cardboard box or plastic tub containing sand and soil.
We also use shredded newspaper. Also check to see that there is not
enough space between the top of the hibernation box and the
underside of the shelf above that would allow your tortoise to climb
out of it's box. If there is, then we strongly recommend putting a
lid on your box and drill / puncture the lid with several small ventilation holes.
We line the shelves with cardboard before placing the box onto them.
It is vital to monitor the temperature with a max/min thermometer
(digital type with a probe is the most accurate). If the temperature
is aloud to fall below 2°C, there is serious danger of the
tortoise's tissues being frozen. Equally, if the temperature gets
over 10°C, the tortoise could become active, start to use energy and
even try to climb out. Around 4-5°C is ideal.
PLEASE NOTE:
Hibernation is an important part of your tortoise's natural cycle
and should only be avoided if they are underweight or sick.
MONITORING
During hibernation, you will need to keep a
regular check on temperatures and how your tortoise is progressing . As a
part of the monitoring process, you will have to weigh your tortoise on a
weekly basis to see how their weight is fairing. A tortoise should lose no
more than
1% of it's pre-hibernation body weight per month. If your tortoise does lose
more than 1% in the first month do not panic. You will find that after a few
weeks into hibernation your tortoises weight loss should slow down and
therefore it will average out over the total hibernation period. If the
weight loss does consistently exceed the 1%, then you need to look into
bringing them out of hibernation as this could indicate a problem. Regularly
check that their substrate area is clean and dry and that there are no signs
of defecation or urination. If your tortoise passes water (urinates)
during hibernation they will loose valuable fluid reserves. Therefore you
will have to bring them out of hibernation. If not done so, it can result in your tortoise
dehydrating and becoming fatal.
Please see below a 'Hibernation Monitoring Spreadsheet' which is available for download.
We designed this spreadsheet to enable easier monitoring of our torts. Each
editable area on the sheet has a drop down box which enables you to pick the
data you require. Alternatively, you can just manually type your data in
yourself. Only data can be inserted into the white areas of the sheet. Green areas will populate
for you automatically when you input your data into the white areas. Many people
have found this sheet to be very useful. We hope you do too.
You can download this sheet by
clicking
HERE
or alternatively you can click on the icon below.
Hibernation Monitoring Spreadsheet
POST HIBERNATION / WAKING UP
Make sure you have the tortoises
enclosure is up and running with heat and UV lamps.
Take the tortoise out
of the fridge but still kept in the box and place it in a heated
room for a short while. The tortoise will soon begin to stir.
As a tortoise awakes, certain biological changes take
place; one of the most important of these is the release into the
bloodstream of a chemical called glycogen, which has been stored in
the liver. This provides extra energy to give the tortoise an
initial 'boost'. Feeding must take place before this is exhausted,
or the animal will begin to decline. As soon as the
tortoise has woken up, take it out of the box and place it under
it's basking lamp. Heat and light are the only things that will
stimulate them properly and get their metabolism up and running
again. This is important for a tortoise, as otherwise they will not
be able to get going and will be lifeless and unable to feed or
drink. After your tortoise has been under it's lamp for about an
hour or so and is more active give your tortoise a nice long warm
bath. Your tortoise will need to flush their kidneys of the toxins
that have built up in hibernation and replenish their water supply.
You may find your tortoise may not do this in it's first bath so
give your tortoise lots of baths over the next couple of weeks.
Drinking is more important than eating in these first few days. Once
your tortoise is active you can offer food. Some tortoises eat
within a couple of hours others may take a few days. Continue with
warm baths daily for about a week.
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