A turtle that slows down in a cold room in November is doing what its wild relatives do. A turtle that slows down in a warm room is sick. Tell the two apart first. If the water is 75°F or more, or the tortoise table is at its usual temperatures, and the animal has stopped eating for more than two weeks, that is a vet visit, not a winter nap.
Who should never brumate
- Tropical species. Red-footed, yellow-footed, leopard, sulcata and hinge-back tortoises do not brumate in the wild, and cooling one makes it ill.
- Any turtle or tortoise that has been sick, injured, or has lost weight in the past year.
- Any animal you have owned for less than a year, because you do not know what it went into the winter with last time.
- Any animal that has not had a fecal test for internal parasites.
- Hatchlings and small juveniles, unless a reptile vet has looked at the animal and said yes.
Russian, Hermann’s and Greek tortoises and box turtles brumate in the wild. Sliders, painted and map turtles can, but a pet in a heated tank does not need to.
You do not have to
A turtle kept at a steady water temperature and a steady twelve-hour light cycle will not brumate, and veterinary sources note that brumation suppresses the immune system and slows growth. A Royal Veterinary College study of pet tortoises in Britain found that close to one in twelve died during or soon after brumation, with brumation in a garden and uncontrolled temperatures beforehand as the main risk factors. For an aquatic turtle, the safe choice is to keep the water at 75 to 80°F, the dock at 90 to 95°F and the lights on a timer all winter. It will eat a little less in the short days. That is fine.
The checks first
Decide by mid-August. Book a vet exam with a fecal test in late summer. At home, look at the eyes, nose, vent, legs and mouth for swelling, discharge or any white or yellow patches inside the mouth. Weigh the animal on a kitchen scale and write the number down. If anything is off, the animal stays awake and warm this winter.
The wind-down
Stop feeding four to six weeks before the cooling starts. Food left in the gut at low temperature ferments and can kill. Keep offering water and soak a tortoise in an inch of warm water every day or two, because it needs a full bladder going in. Over those weeks shorten the lights by an hour or two a week and let the enclosure cool a few degrees at a time.
Temperatures that work
| Reading | What it means |
|---|---|
| 32°F | Freezing. Blindness or death. |
| 40 to 45°F | The target. Asleep and safe. |
| 50°F | The ceiling. Warmer burns fat and wakes the animal. |
A spare refrigerator holds 40 to 45°F better than any garage or shed. Put a digital probe thermometer inside, keep the animal in a ventilated box of damp soil or shredded paper, and open the door for a minute every day for fresh air. If you use a box in a cold room instead, use a box inside a bigger box with 2 inches of insulation between them, and check the thermometer hourly during a cold snap.
How long
Wild tortoises sleep about ten to twelve weeks. Never more than twenty weeks for a fit adult. Hatchlings, where a vet has approved it, six to ten weeks. Box turtles tend to need less than tortoises.
While it sleeps
Weigh the animal every two weeks. A healthy adult loses about 1 percent of its body weight a month, so a 1,600 g tortoise should be near 1,520 g after five months. Losing faster than that, or urinating in the box, means wake it, soak it and keep it awake and fed for the rest of the winter.
Waking up
Bring the box up to room temperature over a day, then move the animal to its warm, lit enclosure. Soak it in an inch of warm water. Drinking comes before eating. It should eat within a week. If it has not eaten after ten days, or its eyes are swollen or shut, see a reptile vet. The vet will weigh it, check the mouth and eyes, give fluids, and treat the infections that a cold, run-down animal picks up. Starting too late costs weeks of recovery.
What helps
A digital probe thermometer in the brumation box, and a second one on the dock for the turtles that stay awake. A ceramic heat emitter keeps a tortoise table warm overnight for an animal that is skipping the winter. The vet directory lists reptile vets by state.
Sources
- Tortoise Trust: Safer hibernation and your tortoise
- Merck Veterinary Manual: Management of reptiles
- VCA Hospitals: Aquatic turtles, owning
- LafeberVet: Brumation in turtles and tortoises
- Royal Veterinary College: risk factors to tortoises during brumation
Written from these and checked three times before publishing. Not veterinary advice; a reptile vet who can see the animal beats any page.
