Wintering land and semi-aquatic turtles
Wintering turtles is a complex and delicate process that every keeper of wintering species should understand. But before diving into the details, let’s clarify the terms wintering, hibernation, and brumation.
Wintering is a state of rest, i.e. falling into a winter sleep – hibernation or brumation. In breeding conditions, this term is also used to refer to the entire process of preparing animals for winter sleep.
Hibernation is a commonly known term meaning winter sleep. It is a physiological process during which the body undergoes a deep numbness and slowing down of vital functions. Many animals hibernate to survive harsh conditions, low temperatures, and food shortages. In mammals, hibernation is a prolonged, uninterrupted sleep that requires significant energy to wake from, as the body must warm back up to normal temperature.
Brumation is similar to hibernation but applies specifically to amphibians and reptiles. During brumation, animals may occasionally wake and move around before returning to rest.
Which turtle species brumate?
Primarily, turtles from temperate and Mediterranean climates undergo brumation in the wild. For these cold-blooded animals, winter brings temperatures too low for normal activity and a scarcity of food. In these conditions, brumation becomes the best survival strategy.
Among commonly kept species, the following brumate:
- Chrysemys picta (painted turtle)
- Rhinoclemmys pulcherrima (ornate or painted wood turtle)
- Species of the genus Testudo: Testudo graeca (Greek tortoise), Testudo hermanni (Hermann’s tortoise), Testudo horsfieldii (Russian/steppe tortoise), and Testudo marginata (marginated tortoise)
- Terrapene carolina (common box turtle)
Is wintering turtles necessary in captivity?
For species that brumate in the wild, this dormant period plays a crucial role in regulating growth, nutrition, immunity, and reproduction. Many are sensitive to daylight changes and, even under artificial lighting, notice the shorter days of winter triggering lethargy and the instinct to wintering.
Wintering turtles acts as a natural “pause button”. Metabolism, life processes, and growth slow down. The turtle requires little or no food, and its body cycles remain in balance. Skipping wintering can disrupt these processes and may shorten its lifespan.
Benefits of wintering turtles
When done correctly, wintering offers several advantages. But only if done properly. Otherwise it may disrupt various bodily processes and affect life span.
- Proper development – brumation influences the endocrine system and organ growth, ensuring healthy development in proportion to the turtle’s size and age.
- Controlled maturation – prevents premature sexual maturity, which can strain the body and cause reproductive issues, especially in females.
- Reproductive readiness – many turtles begin mating soon after waking, making wintering a natural trigger for breeding cycles.
- Biological rhythm alignment – supports the turtle’s natural seasonal patterns, improving overall well-being.
- Longevity – by slowing metabolism and aging processes, wintering helps turtles live longer.
- Better immunity – acts as a restorative rest period, boosting immune function after waking. Exposure to cooler temperatures also increases resilience to environmental changes.
- Weight control – captive turtles have less exercise and easier access to high-energy food, which makes it easier for them to store excess fat. The rest period helps maintain proper weight, as the turtle does not eat or eats smaller amounts of food for a significant part of the year. In addition, during brumation, they consume small amounts of energy, burning fat tissue.
- Reduced nutrient deficiencies – during winter, access to fresh food is limited and, despite the availability of substitute foods (dried food and pellets), mineral or vitamin deficiencies may occur in the turtle’s body. Natural rest minimizes this risk because the turtle does not need food during this time.
- Lower care costs – less food, reduced lighting, and energy savings during the brumation period. It also eliminates the need to provide a balanced and varied diet, which is difficult to achieve in our climate zone during winter.
Risks of wintering turtles
Improper wintering can be dangerous, especially for sick or weakened turtles. Common risks include:
- Excessive weight loss – most often, this is caused by incorrect brumation temperatures. If the temperature is not properly controlled and periodically rises above a certain level (specific to each species), the turtle’s metabolism speeds up. Elevated temperatures and accelerated metabolism can cause the turtle to wake, become active, burn excessive energy, and deplete its fat reserves. As you can imagine, such a turtle may not survive the entire process, which is why monitoring its weight is so important.
- Food retention and poisoning – this can occur if the turtle has not been properly prepared for brumation for example, if the preparation period was too short, it was given too much food, or it did not receive warm baths to empty its bowels. If the digestive system is not cleared before brumation, it will not empty later, and the contents will remain in the intestines. At such low temperatures, digestion does not function properly, and the food begins to rot. This releases harmful toxins that slowly poison the turtle’s body and can seriously impact its health.
- Respiratory distress – the cause is the same as with poisoning. Gas buildup from rotting food can press on the lungs.
- Dehydration – caused by overly dry substrate or air.
- Infections – resulting from poor health or inadequate acclimation before brumation. The turtle’s body needs time to adapt to lower temperatures. Too rapid changes can lower its immunity.
- Death – illness, parasites, or extreme weight loss can make waking impossible.
Good condition is essential
A turtle being prepared for brumation should be in excellent health. Poor condition always carries risks. For this reason, you should maintain its good health and provide proper care year-round, paying close attention to any concerning symptoms. If the species naturally experiences seasonal changes in diet and environment, it’s worth replicating these conditions in captivity to better prepare its body for wintering.
Before wintering, check for internal and external parasites. Even turtles kept exclusively indoors are at risk of parasite exposure, for example, through food. If necessary, deworm the turtle and eliminate any external parasites.
If your turtle has been ill and you’re uncertain about its condition after recovery, consider having a blood test performed or simply skip wintering that year. In some cases, you can also postpone or shorten the brumation period. Never brumate a turtle that is sick or visibly weakened, as this can endanger its life. In such situations, it’s best to refrain from wintering for that season.
Hibernation box (hibernaculum)
A hibernation box is the container in which a turtle will spend its brumation period. For land turtles, it should be large enough for the animal to turn around freely and burrow into the substrate; in most cases, dimensions 1.5-2 times the turtle’s carapace length in both length and width are sufficient. The height should be similar to these measurements. The container must have ventilation to allow proper air circulation.
Fill the container with substrate deep enough for the turtle to bury itself completely, which helps maintain stable temperature and humidity around its body. For xerophilic species, a slightly moist 1:1 mix of sand and peat is recommended, with humidity maintained at 50-60%. For species that require higher humidity, a 1:1:1 mix of sand, peat, and sphagnum moss is typically used, allowing humidity levels of 65-75%.
Young turtles are particularly sensitive to dehydration during brumation, so they can also be placed in the above mixture, or alternatively in sphagnum moss or dry leaves. In their case, humidity should reach up to 95%.
For semi-aquatic turtles, the hibernaculum should be slightly more spacious, with a water depth at least equal to the length of the turtle’s carapace.
Choosing the brumation site
The key, and most challenging task during brumation is maintaining a constant temperature in the hibernation box. It must neither be too low nor too high. For each species, acceptable temperature fluctuations are typically only a few degrees Celsius, making the safe range very narrow.
Wintering turtles in a fridge
Because temperature stability is essential, a standard food refrigerator or cooler set to the required temperature range is often recommended. However, for mature individuals of larger species, such a refrigerator may not provide enough space for a sufficiently large hibernaculum. In that case, other options should be considered, such as purchasing a larger refrigerated counter.
It is crucial to ensure proper air exchange inside the device. Installing an aeration pump (such as an aquarium pump) to push fresh air inside is recommended. This requires fitting both an inlet and an outlet hose in two separate locations so that fresh air can flow through the entire interior. In addition, the refrigerator should be opened every two days and ventilated for one minute.
Wintering turtles in the basement
Brumation can also be carried out in a cold basement, attic, enclosed balcony, or farm building, provided the temperatures remain stable and suitable throughout the winter.
In recent years, however, winters in Poland have often been unusually warm, which can cause temperatures in such spaces to rise too high for turtles. If you choose this method, you must monitor the temperature continuously. Investing in a thermometer that records daily minimum and maximum readings is highly recommended to avoid missing any extreme fluctuations.
During periods of severe frost, temperatures in these rooms may drop below zero. In such cases, a heating cable or heating mat connected to a thermostat set to the correct temperature range will help maintain safe conditions.
Wintering turtles outdoors
The final option is to winter a land turtle outdoors, in a well-insulated shed within its outdoor enclosure. While this may seem like a risky approach, a properly constructed shed can provide safe conditions for the turtle. The main advantage is that the turtle can remain in its enclosure year-round and hibernate naturally. The main drawback, however, is the unpredictability of the weather in Poland, not only in winter but also in autumn and spring, when turtles may become active and take advantage of warm days. If you choose this method, it is essential to monitor both weather conditions and the temperature inside the turtle’s shelter. A heating mat connected to a thermostat can help maintain safe temperatures during severe frosts.
Turtles brumating this way are not placed in a separate hibernation box, the shed itself serves that purpose, allowing them to emerge in spring when conditions are right. Inside the box, the turtle should be able to burrow into the ground, where the temperature remains more stable. On top of the ground inside the box, prepare a thick insulating layer of dry leaves or straw. Covering the entire box with a pile of branches and leaves, while leaving an entrance corridor for the turtle, provides additional insulation.
The box walls should be insulated (e.g., with Styrofoam) to help maintain stable internal temperatures, reducing the impact of sudden temperature changes outside. This setup allows for safe brumation, but it does make it difficult to check the turtle’s weight and health. Such checks are best performed when the outside air temperature matches the turtle’s optimal brumation temperature, so as not to disturb the conditions inside.
Aquatic turtles can also brumate outdoors, but they require a sufficiently deep water body with a muddy bottom that will not freeze completely.
Stages of proper wintering turtles
Proper wintering consists of three stages, each of which is extremely important and cannot be skipped.
Stage One – preparation for brumation
A turtle’s body needs a signal that winter is approaching in order to prepare for brumation. You cannot move a turtle from 30°C to 4°C overnight. The tank temperature should be gradually lowered to allow proper adaptation. About 4-6 weeks before brumation, begin to gradually reduce both temperature and daylight hours, and stop feeding the turtle. Give the turtle a warm bath once a week to help empty its digestive tract. Around 2 weeks before brumation, give the turtle its last baths, and if it no longer defecates, move it to a cool (a few degrees Celsius) and dark room. Leave a bowl of water and, if possible, lower the temperature gradually. After this period, transfer the turtle to the hibernation box and place the entire tank in the hibernation area.
Stage Two – brumation
During this stage, the turtle remains at the brumation temperature, usually 3-5°C. Ideally, the temperature should remain constant throughout the winter, although periodic drops to 1°C or increases to 10°C are not critical. Temperatures above 10°C cause the turtle to wake up and its metabolism to accelerate. Constant monitoring of temperature is essential, and action should be taken if it approaches these limits. Even though nothing appears to be happening, the turtle’s health and the conditions in the hibernation box should be checked regularly. Depending on the species, age, and condition of the individual, this stage can last from 2 to 5 months.
Stage Three – awakening from brumation
Awakening is essentially the reverse of Stage One, but occurs more quickly. Remove the hibernation box and allow it to warm gradually to room temperature. The turtle should become active and surface on its own. If it remains buried after the substrate has warmed, carefully remove it. Place the turtle in a bright, warm area and provide fresh water to drink. If the turtle does not drink, placing it in shallow water usually stimulates drinking. Replenishing fluids and flushing out toxins accumulated during brumation is extremely important.
As the temperature rises, the turtle’s metabolism and appetite increase. From the first days of activity, the turtle should have access to food. A healthy turtle will usually eat within 7 days of becoming active. If it does not, poor health is the most likely cause, and a veterinarian should be consulted. During the first few days, monitor the turtle to ensure it is eating and defecating properly. Warm baths can help stimulate defecation if needed.
Checking the turtle’s health and conditions during wintering
During wintering, it is important to regularly check the turtle’s health and the conditions in the hibernaculum. Weekly checks are recommended, as this allows you to detect any abnormalities early and respond in time. During health inspections, look for:
- Discharge from the nose, mouth, or eyes – may indicate various infections.
- Discharge from the cloaca – could be a sign of incomplete emptying of the digestive tract or other issues.
- Lumps, swelling, or other skin abnormalities – may indicate infections or subcutaneous abscesses.
- Mold – requires replacing the substrate, often caused by poor air circulation.
In addition, you should:
- Check humidity – ensure the substrate is sufficiently moist.
- Replace some water for semi-aquatic turtles – every 2-3 weeks, keeping it at the same temperature as the hibernation box water.
Monitor the turtle’s weight once a month. Normal weight loss for a healthy individual is 0.5-1% per month, with a maximum of 10% over the entire brumation period. Greater weight loss indicates that brumation is not proceeding properly.
Temperature should be continuously monitored.
If any health problems or excessive weight loss occur, brumation must be interrupted and the turtle awakened. Continuing brumation under such conditions can worsen health or even be fatal. After waking, take the turtle to a veterinarian to diagnose and treat the issue.
Based on personal experience and literature.
Literature
- Reptile database: https://reptile-database.reptarium.cz.
- Online encyclopedia: https://en.wikipedia.org.
- https://eden.opole.pl/zwierzeta-towarzyszace/zolwie-ladowe/.
https://www.terrarium.com.pl/bezpieczniejsze-zimowanie-twojego-zolwia/.
https://www.terrarium.com.pl/trachemys-scripta-troostii-zolw-zoltolicy/#Zimowanie.
https://www.terrarium.com.pl/zimowanie-w-lodowce-zolwi-ladowych-i-wodno-ladowych/.
https://turtles.pl/hibernacja-zolwi-ladowych-proces-usypiania-na-zime/?srsltid=AfmBOoruIUqscdNtAZTeNo8Do89g-MONwHC_nMDHVdiobbGKKOdBSqNq. - Schuiten B. I. 2008. Zwierzęta w terrarium, tłum. Borycka-Zakrzewska J. (Wydawnictwo REA, 2011), 107-120.
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