Tortoise hibernation (brumation): which tortoises hibernate and how to do it safely
TUREFF• •0
Many Mediterranean and Horsfield's tortoises naturally hibernate, sometimes called brumation, through the colder months. Done well, it is a normal part of their year. Done badly, it can cause serious illness or death. This guide covers the general principles; your vet, ideally one experienced with reptiles, should be part of the plan every year.
Which tortoises should hibernate?
- Species: Mediterranean species such as Hermann's, spur-thighed and marginated tortoises, and Horsfield's tortoises, usually hibernate. Tropical and many African species, such as red-footed, leopard and sulcata tortoises, do not hibernate and can die if made to.
- Health: only healthy tortoises of a good weight should hibernate. A tortoise that is ill, underweight, lethargic or has not been eating well in late summer should not be put into hibernation. Some keepers and vets advise caution with very young tortoises.
If you are unsure of your tortoise's species or health, keep it awake and warm over winter and get advice. Missing a hibernation is far safer than hibernating a sick tortoise.
See a vet first
A pre-hibernation health check is widely recommended. A vet may check body condition, eyes, mouth, shell and breathing, and may test a droppings sample for parasites. Book this well before you plan to start winding down, so there is time to treat any problem.
Winding down
Before hibernation the tortoise needs to empty its gut, because undigested food can rot inside it during the cold. Keepers gradually reduce food over a period of a few weeks, while keeping the tortoise warm enough to digest what it has eaten and continuing to offer water and soaks. The length of this fasting period depends on size and species, so get specific guidance for yours.
Where to hibernate: the fridge method
What matters most is a steady temperature that is cold enough to keep the tortoise dormant but never freezing. The Royal Veterinary College's guidance puts the target at around 5°C. Freezing can blind or kill a tortoise, and temperatures that rise too high can wake it and burn through its reserves.
Many UK keepers and vets favour hibernating in a dedicated fridge, because it holds a stable temperature that sheds, garages and boxes often cannot. Points keepers usually make:
- Use a separate fridge, not the family kitchen fridge that is opened all day.
- Check the temperature with a reliable thermometer, ideally one you can read without opening the door.
- Allow ventilation by opening the door briefly on a regular basis.
- Put the tortoise in a ventilated box with suitable insulating material.
Other methods exist, such as insulated boxes in a cool, frost-free room, but they need careful monitoring of temperature swings.
Weigh regularly
Weigh your tortoise before hibernation and regularly during it, many keepers do so weekly, and write the results down. RVC guidance suggests an adult typically loses around 1% of its starting weight per month. Faster loss, or a tortoise that urinates during hibernation, may mean something is wrong and it should be woken up and seen by a vet. Ask your vet what limits they want you to use.
How long?
The appropriate length varies with species, age and health. Rather than following a fixed calendar, agree a plan with your vet and be ready to end hibernation early if there is any concern.
Waking up
After waking, the tortoise needs warmth, light, and water to drink straight away. Bathing in shallow lukewarm water encourages drinking. It should start eating within a short time; a tortoise that does not eat after hibernation needs prompt veterinary attention.
Have a question about winding down your tortoise this autumn, or a hibernation routine that works for you? Share it in the comments.