Turtle Hibernation & Brumation: Complete Guide

Brumation — the reptile equivalent of hibernation — is the area of turtle keeping that causes the most anxiety for new owners. Done correctly it’s one of the most natural parts of keeping temperate species. Done badly it kills the animal. Marcus and Linda have brumated their tortoises annually for over a decade and this is the protocol we use and recommend.

This guide covers brumation for both tortoises (Hermann’s, Greek, Russian, Marginated, box turtles) and hardy aquatic species (sliders, painteds, snappers, Reeves, musks, mud turtles in temperate climates). Tropical species (red-foots, Sulcatas, softshells, mata mata) don’t brumate and shouldn’t be cooled.

What brumation actually is

Brumation is a slowdown of metabolism in response to cooling temperatures — not the same as mammalian hibernation. The animal:

• Reduces heart rate and breathing dramatically.
• Doesn’t eat or drink for the duration.
• May surface briefly (aquatic species) or shuffle position (tortoises) but mostly stays inactive.
• Burns very little energy — weight loss across a winter is typically 5–10 %.
• Resumes normal activity when warmed.

Wild populations of temperate species brumate for 3–6 months annually. Captive specimens that never brumate often develop subtle long-term issues — reproductive problems, shorter lifespans, lower vigour. We brumate ours because the evidence suggests it’s healthier long-term.

Should you brumate?

Brumate if:

• Your species is temperate (Mediterranean tortoise, US/European hardy aquatic turtle, box turtle).
• The animal is healthy and at appropriate weight.
• You can provide the right conditions (we’ll cover this).
• You’re willing to do the pre-brumation work (vet check, fasting, weighing).

Don’t brumate if:

• Your species is tropical (red-foot, Sulcata, mata mata, softshell, sideneck, snake-neck, anything from a warm-only native range).
• The animal is sick, underweight, or otherwise compromised.
• The animal is under 12 months old (some keepers brumate hatchlings; we think the risks outweigh the benefits at that age).
• You can’t reliably maintain the brumation temperature.

Pre-brumation: late summer to early autumn

Preparation starts 6–8 weeks before brumation:

1. Vet check. 4–6 weeks before. Reptile-experienced vet looks for parasites, respiratory issues, dental/beak problems, body condition. Don’t skip this.
2. Weight tracking. Weigh the animal weekly and record. You’ll compare against post-brumation weight in spring.
3. Maximise feeding. Late summer is the time to fatten reserves. Increase feeding frequency and variety for healthy animals.
4. Faecal check. A vet faecal exam catches parasitic issues that get worse during brumation. Treat any infestation before cooling.

Fasting: 2–3 weeks before brumation begins

The animal must enter brumation with a clean gut. Undigested food in the gut during brumation ferments and causes fatal infections.

• Tortoises: stop feeding 2 weeks before cooling begins. Continue providing water access and warm temperatures during the fast.
• Aquatic turtles: stop feeding when water temperatures drop below 16 °C consistently. They’ll already be eating less by this point.
• Soak tortoises in shallow warm water (25 °C) during the fasting period — once or twice a week. Helps clear the gut and keeps hydration up.

Cooling: the transition to brumation

Gradual cooling over 2–3 weeks, not a sudden drop:

• Week 1: reduce ambient temperature to 12–15 °C. Turn off basking lamps. Reduce photoperiod to 8 hours.
• Week 2: 8–12 °C. Photoperiod 6 hours.
• Week 3: 4–8 °C. Lights off. Animal is entering full brumation.

Brumation itself

Tortoises — three accommodation options

• Fridge box (recommended for UK/cool-climate keepers): a dedicated tortoise fridge set to 4–7 °C. Most controllable temperature. Tortoise in a substrate-filled plastic box with hay bedding, lidded but air-holed. Open the door for 2–3 minutes daily for air exchange.
• Insulated outdoor hide: for warmer southern climates, a buried wooden box with deep substrate where the tortoise digs in. Natural method but harder to monitor.
• Garage or cellar: if you have an unheated space that consistently stays in the 4–8 °C range through winter. Less common in modern insulated homes.

Aquatic turtles — underwater brumation

• Outdoor pond (recommended): deep enough (1 m+) that the bottom stays above freezing. Add a pond de-icer that keeps a small surface area open for gas exchange. Critical — turtles drown under unbroken ice.
• Indoor cooled tank: a temporary tank in an unheated room or cool cellar, water 4–10 °C through winter. Slow filtration, no feeding, no lights.

Monitoring during brumation

• Temperature checks daily. A min-max thermometer in the brumation space tells you whether you’ve had unexpected spikes. Above 10 °C the animal wakes up and burns reserves; below 2 °C risks frost damage.
• Weekly weight check (tortoises). Brief lift, weigh, return. Weight loss of more than 1 % per month is concerning.
• Visual check. Animal still in position, no obvious distress, eyes closed but not sunken.
• Don’t disturb otherwise. The whole point is undisturbed cool rest.

Length of brumation

• Hermann’s tortoise: 12–16 weeks.
• Russian tortoise: 14–18 weeks (longest brumation of common pet species).
• Greek tortoise: 10–14 weeks.
• Hardy aquatic turtles: 14–20 weeks for outdoor pond brumation.
• Box turtles: 10–14 weeks, varies by subspecies and origin.

Don’t brumate longer than 18 weeks for any species. Even hardy animals lose too much condition over longer periods.

Waking up: spring transition

Gradual warming over 2 weeks, mirroring autumn cooling in reverse:

1. Move tortoise to a slightly warmer location (8–12 °C). Aquatic turtles — pond ice melts naturally.
2. After a few days, transition to normal enclosure with basking lamp on.
3. Within 3–5 days the animal will start active behaviour.
4. First action: offer warm water. Tortoises soak in 25 °C water for 15 minutes within the first day awake. Drinking is critical after months without water.
5. First food after 5–7 days of active behaviour. Start with small portions, ramp up over a week to normal feeding.
6. Weigh and compare to pre-brumation weight. 5–10 % loss is normal. More is concerning — vet check.

Common brumation mistakes

1. Skipping the vet check. Brumating a sick animal is fatal more often than not.
2. Not fasting properly. Undigested food ferments. Two weeks minimum.
3. Temperature too warm. Above 10 °C and the animal half-wakes, burns reserves but doesn’t feed.
4. Temperature too cold. Below 2 °C risks frost damage; below 0 °C kills.
5. Unbroken pond ice. The single biggest killer of brumating aquatic turtles. Pond de-icers exist for a reason.
6. Trying to brumate tropical species. Red-foots, Sulcatas, softshells, sidenecks — never. They die.
7. Disturbing the animal too often. Check, don’t handle.
8. Not waking gradually. Sudden warming shock kills weakened animals.

Year-round warm-keeping as an alternative

Some keepers don’t brumate their tortoises or aquatic turtles, keeping them at active temperatures year-round. This is a defensible choice — the animal feeds and grows continuously, and you avoid the risks of brumation gone wrong. The downsides:

• Faster aging — not fully evidence-based but anecdotally observed.
• Reproductive issues — breeding usually requires brumation triggers.
• Higher heating costs — running basking lamps and UVB tubes year-round.

For first-time keepers, year-round warm-keeping for the first 2–3 years is reasonable while you learn the species. Move to natural brumation cycles once you’re confident.

Related on Turtle Times

• Mediterranean Tortoise Diet Guide — covers the late-summer feeding ramp-up.
• Outdoor Turtle Pond Construction — pond brumation setup specifics.
• Turtle Health & Feeding Guide — vet-check checklist.
• Turtle & Tortoise Care Index — master husbandry hub.
• Medical issues archive — post-brumation complications coverage.

— Marcus and Linda, Turtle Times. First-time brumation question or post-brumation problem? Contact form — flag “brumation” in the subject. This is the time of year we get the most emails about it.