Hibernation/Brumation in Tortoises

Henry our Mediterranean spur-thighed tortoise has called it a year! He has tucked himself in and settled down to a long deep slumber that should last until the daffodils are well and truly up. It is a state that I sometimes feel slightly envious of, especially as I struggle out of bed in the dark and cold of an English winter. Brumation (the technically correct term for hibernation in reptiles) is an adaptive mechanism designed to survive periods of limited resources, i.e. less food and water in winter and differently from mammals, reptiles don’t live off fat stores during these periods of sleepfulness they slow down their metabolism so that they hardly use any energy.

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Brumation/hibernation is triggered by the dropping temperature, reduced sunlight and daylight hours. It is a process that should take several weeks of gradual winding down, reducing food intake, evacuation of gut contents and eventually settling into a cosy spot to see out the winter months. It is important that they fully empty their digestive system as food left sitting in the stomach would otherwise putrefy, rot and be a cause of toxicity to the tortoise. Tortoises should always be in good health prior to hibernation, a tortoise that has been unwell during the year may be better to see out winter in the comfort of a vivarium (indoor, temperature controlled area). The actual location of the hibernation doesn’t need to be an expensive set-up but some thought should go into it. It needs to be a monitored, well protected box/enclosure that can be kept at a reasonably controlled temperature. Typically two containers are used – a smaller one inside a larger container both filled with bedding/straw/newspaper/soil, the tortoise is placed into the inner container so that it is never too near the edge of the outer container which may get too cold. Air must be able to pass through to allow ventilation and ideally a thermometer should be used to monitor that the temperature is neither too cold nor too warm (ideally between 3 and 7 degrees C). Some people use a fridge to keep their tortoises in. It can be a perfectly reasonable location as long as you remember to let some fresh air in regularly and don’t scare your dinner guests with threats of reptilian cuisine. Tortoises can be quite vulnerable when they are hibernating so if you are using an outdoor shed or building a rodent free location is vital.

Tortoises should be weighed regularly during hibernation, 1% weight loss per month is considered a maximum amount which should be allowed before waking and feeding should commence. Otherwise tortoises will sleep for 3-4 months and wake as the weather starts to warm. They should be encouraged to drink daily as soon as they are roused and up to temperature and should be eating within a week of being awake.

If you are worried about hibernating your tortoise because they are too young, too small or have been unwell then have a chat to a vet who deals with exotic pets (not all vets will be used to or knowledgeable about dealing with reptiles). Likewise if your tortoise is slow to recover and eat after hibernation then get them checked to make sure they don’t have any health issues – respiratory disease, mouth rot and dehydration are common.

Meanwhile Henry will miss out on Christmas, New Years Eve and ‘The Ashes’ cricket series this year, if Australia don’t beat England this time then I will be wishing I had joined him in the shed this winter.