HIBERNATION TIPS
John G Wills
Testudo Hermanni Boettgeri (Hermann Tortoise) originate from the Balkans, Turkey and Southern Germany. In their natural environment they hibernate from late October to mid/late March each year. They bury themselves in their natural substrate. Their physiology adapts to the process by slowing their heart rate thus reducing their oxygen consumption so they can survive for the long weeks under the soil.
In this country there are generally two methods to replicate this natural phenomenon…
It is impossible to accurately regulate the temperature with the traditional method so I recommend and personally use the refrigerator method that is completely controllable and safe if you follow a few simple rules as specified.
When to hibernate
For the adult tortoise they usually start eating less and slowing their activity rate by Oct each year. Around this time it is wise to observe you tortoise closely for this alteration in behaviour, decrease in appetite and begin to prepare them for hibernation.
Preparation for hibernation
Withdraw your tortoise food supply 21 to 28 days (or 2–3 weeks: Highfield 2002) before your planned hibernation (Tom Palmer 2001).
Continue with the heat and light regime that your tortoise I used to. In the 2nd week of the starvation period reduce the light and heat to about 6 hours per day, provided that the background temp is about 15oC or above.
After several days without food the tortoise will become ravenous. Remove anything form the pen that they could eat or attempt to at, this includes the substrate! DO NOT allow children or others who might be tempted to feed them to have access to them. Even a small amount of food during this period could lead to fatality during hibernation.
It is essential that you ensure they have access to a good water supply at this time up to the day of hibernation. This ensures that they are fully hydrated prior to the hibernation process beginning. Bathing and drinking will aid evacuation of the gut. Juveniles can be encouraged to drink by giving a warm bath. Note the bowel activity carefully as the starvation period progresses; and check the reduction in stools still being produced; this will cease when the tortoise is ready for hibernation.
Length of Hibernation
For hatchlings in their first winter, hibernate them during January and February. They will be larger and stronger by December and can easily and safely withstand a short hibernation. Jan and Feb usually see a scarcity of wild food and feeding with domestic substitutes will do more harm than good. March sees a new growth of wild food. Tom Palmer suggests a general guide of the following hibernation lengths…
1st winter 2 months
2nd winter 3 months
3rd winter 4 months
4th winter full hibernation for just over 5 months
The Tortoise Trust has an excellent and extensive booklet about hibernation that I recommend you seek out. This is available free of charge. The Trust also sells a video ‘Safer Hibernation and your Tortoise’.
Hibernation
Remove the tortoise into a cold room for 24 hours. Place each tortoise individually into a small margarine tub or similar with plenty of holes in the lid. Put a small piece of kitchen towel on the base and insulate boxes well with shredded paper. Gently place them into the fridge for their natural rest.
The second method of preparation is to allow the juvenile tortoises to bury themselves in a tray of substrate; this is then transferred to a cool room. No boxes are used. This method has the advantage of allowing a more stable temp by way of the thermal mass of soil that surrounds the tortoises (thereby deceasing sudden core temp fluctuations) and there is slightly less danger of dehydration occurring.
Juveniles require the same temp for hibernation as adults. 4oC - 6oC is recommended. Due to their small body mass juveniles are very susceptible to changes in temperature, they can freeze or become too warm very quickly. Therefore extra precautions are necessary. It is essential that you use a reliable thermometer at all times to check temperature daily. I strongly recommend that you read Andy Highfield’s article on Refrigerator Hibernation for the correct fridge to use, its setting up and position etc. for a safer hibernation process. Remember that your fridge unit should be placed in a room that remains above 10oC at all time as the tortoises will freeze within the fridge if the room falls below that of the set fridge temperature.
Open the refrigerator door for a minute or two at least 3 times per week for adequate ventilation.
Check after a few hours that they are not on their backs. After several hours they will become comatosed. Observe them once a week or so, occasionally defecation may occur – remove any deposits.
When the hibernation term is complete…
Sources
Tortoise Trust ‘Safer Hibernation and your Tortoise’
Highfield A, 2002 ‘Hibernating Juvenile Tortoises’
Highfield A, 2002 ‘Refrigerator Hibernation for Tortoises & Turtles’
Palmer T, 2001 ‘ Care of Hatchling Tortoise’
If you want to copy any information on these pages please contact
contact@hermann-tortoise.co.uk
Copyright © Andy Southard / John Wills