Do All Tortoises Hibernate?

Although hibernation is commonly referred to as a ‘deep sleep’ it’s actually a state of dormancy. Unlike sleep, which is primarily a mental change, hibernation is defined as a state of greatly reduced metabolic activity, heart rate, breathing and lowered body temperature. 

It’s a way for many animals, including tortoises, to conserve their energy during periods of extreme cold or when food is scarce. 

To maintain their essential bodily functions, they rely on energy stored in their fat reserves, which they obtain by eating extra food prior to hibernation. Specifically, ‘brown fat’ is used during hibernation because it allows animals to maintain a constant internal environment through non-shivering thermogenesis.  

During hibernation, the endocrine system plays a vital role in regulating the metabolism that occurs, through releasing various hormones. 

Cold-blooded animals such as tortoises, however, do not undergo ‘true hibernation’ but rather undergo a process called ‘brumation’. This differs because cold-blooded animals cannot regulate their own body temperature, so they must find a place that will stay warm. 

Nonetheless, the terms hibernation and brumation are often used interchangeably and for the sake of continuity, this article will refer to tortoise dormancy as hibernation. 

Why Do Tortoises Hibernate?

Increased survival probability is the underlying cause for the evolution of hibernation. This state of dormancy is an adaptation whereby animals use a variety of physiological strategies in order to survive inhospitable environments. 

Animals that developed the ability to hibernate had better chances of survival and reproduction, hence this life-history trait was selected for and passed down through consecutive generations over millions of years. Over time, variations of this trait evolved and there are now three known types: true hibernation, brumation and torpor. 

For tortoise species which do hibernate, numerous benefits are obtained. Firstly, hibernation is beneficial to a tortoise’s health as it allows for metabolic and physiological rest and supports their immune system and digestive health. 

Additionally, hibernation helps regulate a tortoise’s biological processes such as growth and reproduction. Finally, numerous research suggests the survival and longevity of hibernating tortoise species is greater than those that do not hibernate. 

Species That Hibernate

Tortoise species that naturally hibernate in the wild include:

1) Russian Tortoise (Testudo horsfieldii)

Russian tortoises, also known as  Horsfield tortoises, are native to arid regions of Central Asia, inhabit dry, rocky areas and deserts. They typically have tan colored shells with dark brown or black patches and are not considered endangered. 

Popular as pets, these small tortoises are known for their hardiness and manageable size.

2) Hermann’s Tortoise (Testudo hermanni)

Hermann’s tortoises are found in the warm, Mediterranean regions of Southern Europe, thriving in scrublands and forests. They are characterized by their vibrant black and yellow carapace.

Unlike some species, they are not endangered, though habitat loss poses a threat. They are favored as pets for their gentle nature and appealing size, however, like all domestic pets, Hermann’s tortoises require proper care and a suitable environment to flourish in captivity.

3) Greek Tortoise (Testudo graeca)

Greek tortoises are aptly named after the Mediterranean regions in which they naturally inhabit and are adapted to live in arid, scrubby areas and rocky hillsides.

Also known as Spur-thighed tortoise, their distinctive features include a tan carapace with darker patches and slight flaring of the marginal scutes, and of course, thigh spurs. 

They are a popular choice for pet owners, largely due to their manageable size and relatively easy care requirements.

4) Marginated Tortoise (Testudo marginate)

The Marginated Tortoise gets its name from the distinctive, flared, and serrated edges of its carapace (shell), which appear as pronounced margins and are almost entirely black with yellow highlights. These margins give the tortoise its descriptive common name, highlighting its unique shell shape. 

This species is native to the mountainous regions of Greece and the Balkans. Like many tortoise species, it faces threats from habitat loss, illegal pet trade, and human encroachment. 

5) Kleinmann’s Tortoise (Testudo kleinmanni)

Kleinmann’s Tortoise, also known as the Egyptian tortoise, is critically endangered. Native to arid regions of Egypt and Libya, this species faces severe threats from habitat destruction, over-collection for the pet trade, and human activities. 

Conservation efforts are crucial for its survival, including habitat protection and breeding programs. It is characterized by a tan carapace with black outlines around the scutes. 

6) Desert Tortoise (Gopherus agassizii)

The Desert Tortoise is easily recognizable with its highly-domed carapace that’s black or gray with little patterning. 

This tortoise species is listed as vulnerable, with some populations classified as threatened. 

Native to the Mojave and Sonoran Deserts in the southwestern United States and northern Mexico, it faces significant threats from habitat loss, disease, climate change, and human activities. Conservation efforts focus on habitat protection, legal protection, and public education to help preserve this species.

7) Gopher Tortoise (Gopherus polyphemus)

Native to the southeastern United States, the Gopher tortoise inhabits dry, sandy uplands. 

Listed as vulnerable, with populations in the western part of its range considered threatened, this species has a domed shell that is tan, brown or gray in color.

Major threats include habitat destruction, fragmentation, and human activities. Conservation efforts include habitat management, legal protections, and relocation programs to support population recovery.

8) Berlandier’s Tortoise (Gopherus berlandieri)

Also known as the Texas tortoise, Berlandier’s Tortoise is not currently classified as endangered but is considered a species of concern. 

Native to southern Texas and northeastern Mexico, it features a dark brown to black shell with yellow horned scutes and skirting. This species faces threats from habitat loss, human activities, and illegal collection and conservation efforts focus on habitat preservation, legal protection, and public awareness to ensure its survival.

Tortoises That Do Not Hibernate

For some tortoise species, hibernation is not required due to their natural habitat’s consistent warm climate, which lacks the seasonal temperature drops that trigger the need to conserve energy. 

Typically, these are species that hail from tropical or subtropical regions and remain active year-round, relying on stable environmental conditions to maintain their metabolic processes and daily activities.

What follows is a list of popular non-hibernating tortoise species.

1) Sulcata Tortoise (Geochelone sulcata)

One of the larger tortoise species, and commonly kept as pets (when space permits), Sulcata Tortoises have domed shells with scutes that are dark around the edges and light in the center. They also feature thigh spurs (shown in the picture below).

Native to the hot, arid regions of the African Sahel, Sulcatas do not hibernate because their natural habitat maintains warm temperatures year-round. These conditions support continuous activity and feeding, negating the need for a hibernation period.

2) Leopard Tortoise (Stigmochelys pardalis)

Leopard tortoises are named after their highly patterned black and tan carapace that resembles the spots of a leopard.

This non-hibernating species is native to the warm, arid regions of eastern and southern Africa, where their natural habitat provides consistent temperatures year-round, allowing for continuous activity and feeding. 

3) Red Footed Tortoise (Chelonoidid carbonaria)

The Red-Footed Tortoise is a medium-sized tortoise and is easily distinguishable by its dark shell with lighter, star-like patterns and distinct red or orange scales on its legs and head.

Native to South America’s tropical forests, this species is popular as a pet due to its manageable size and striking appearance.

4) Yellow Footed Tortoise (Chelonoidid denticulatus)

The Yellow-Footed Tortoise is a sizable species indigenous to the humid tropical forests of South America. Distinguished by its dark, domed carapace adorned with yellowish-brown star-like patterns and yellow scales on its limbs and head, this species is notable for its adaptability and ecological importance. 

Their dietary habits are omnivorous, consuming a variety of vegetation, fruits, and small invertebrates, contributing significantly to forest ecology through seed dispersal. Despite its resilience, habitat destruction and illegal pet trade pose substantial threats to its population stability.

5) Radiated Tortoise (Astrochelys radiata)

Native to Madagascar, the Radiated tortoise is renowned for its stunning, high-domed shell with intricate, yellow star-like patterns radiating from the center of each dark scute. 

This critically endangered species prefers dry, spiny forests. Highly sought after for its beauty, it faces severe threats from habitat loss and illegal wildlife trade. 

6) Indian Star Tortoise (Geochelone elegans)

The Indian Star Tortoise is native to India, Pakistan, and Sri Lanka, and is known for its striking, high-domed shell with distinctive star-like yellow patterns radiating from the center of each dark scute. The carapace is black with bright yellow patterning that resembles stars.

Preferring dry, scrubby forests and grasslands, this non-hibernating species is threatened by habitat loss and illegal pet trade. 

Preparing for Hibernation

If you own a hibernating tortoise species you should seek advice from a reptile veterinarian prior to hibernation. They will conduct a full, physical examination and make sure your tortoise has reached its optimum pre-hibernation weight, is free from any intestinal parasites and has no signs of internal or external illness of injury. 

This is because, during the hibernation process your tortoise is vulnerable, so you must ensure they are healthy and resilient enough to withstand long periods without food. 

Here is a brief, step-by-step guide of how to prepare for your tortoise’s hibernation:

1. Health Check – take your tortoise to the vet to make sure they are set for a healthy hibernation.
2. Environment – gradually begin to reduce the temperature of your tortoise’s environment to mimic the natural seasonal changes. 
3. Diet – gradually reduce your tortoises food intake before completely stopping feeding 2 weeks before hibernation. This allows time for your tortoise to fully empty its digestive tract, as undigested food can rot and cause health issues. 
4. Hydration – soak your tortoise frequently to ensure they remain hydrated during hibernation. 
5. Set-Up – ensure you have an appropriate set-up for your tortoise to hibernate in. 
6. Weigh your Tortoise – Immediately before hibernation you should weigh your tortoise. This will help you to better monitor your pet during and after hibernation. 

Hibernation Environment

It’s important to create a safe and appropriate hibernation space for your tortoise. 

Firstly, you need to choose a location with a cool and stable temperature. Ideally tortoises should be kept between 3^oC and 7^oC during hibernation, with 5^oC being the optimum temperature. 

Additionally, moderate humidity levels of around 50% to 60% are suitable for most tortoise’s species, although some very arid thrive on lower levels of around 40%. Be sure to check the optimum conditions for your specific tortoise breed. 

Finally, the hibernation environment must be dark, quiet and safe, to prevent any disturbances that could prematurely wake your tortoise. 

Hibernation Boxes and Materials

There are two main methods that can be used to hibernate your tortoise:

Fridge Method

A fridge is a great place to hibernate your tortoise as it provides a cold and controlled environment. 

Place your tortoise in a plastic container that is slightly larger than itself. Line the bottom of the box with either kitchen paper or a mixture of sand and soil. 

Make sure the lid of the container has plenty of air holes. Open the fridge door for a minute or so a few times a week to allow oxygen flow.

Box Method

Place your tortoise in a lined, plastic box that has a lid with air holes. 

This container should be placed in a large, cardboard box that is half filled with an insulating material, such as polystyrene. 

Completely cover and surround the plastic box containing your tortoise with the insulating material to help reduce any temperature variations.

During Hibernation

During hibernation you should weigh your tortoise weekly.  If your tortoise drops more than 10% of its body weight, or passes urine during hibernation, it must be woken up early.

Additionally, if your tortoise wakes up during hibernation, allow this and do not put it back to sleep.

You should also monitor the temperature of your tortoise’s hibernation enclosure. If the temperature drops below 0^oC, your tortoise is at risk of freezing to death. 

Conversely, if the temperature exceeds 10^oC, your tortoises’ metabolic rate will be too high, and its energy reserves will be used up too quickly. Warm temperatures also run the risk of waking your tortoise up early from its hibernation. 

Hydration and Nutrition

Dehydration is a big risk during hibernation. To ensure your tortoise remains hydrated throughout the hibernation process, you should soak your tortoise daily in the weeks leading up to hibernation. This is because tortoises obtain most of their moisture by absorbing water through their skin. 

As soon as your tortoise begins to wake, the first thing you should do is place it in a warm bath. A warm bath will encourage your tortoise to drink, re-hydrate and flush its system of toxins. 

Providing some glucose in the water is a great way to quickly increase your tortoise’s energy levels. You should bathe your tortoise for 20 to 30 minutes twice a day. 

Once your tortoise is hydrated and warm, it’s time to feed it. Offer plenty of succulent foods to aid re-hydration. Resume feeding your tortoise its normal, balanced and healthy diet after a day or two. 

Post-Hibernation Care

As the external temperature begins to warm toward 10^oC, it stimulates the tortoise’s metabolism to return to its normal rate, causing the wake-up process to begin.

At this point you will need to remove your tortoise from the fridge or its hibernation box and place him in a warm location that is above 10^oC. Then, gradually increase the heat until your tortoise is at room temperature. 

Your tortoise will begin to stir and eventually fully awaken from its long sleep. I recommend a post-hibernation check-up to ensure the process went smoothly. 

Citations

The Royal Society Publishing – Hibernation Evolution 

Australian Academy of Science – What is Hibernation 

Royal Veterinary College – Hydration

Rochford Veterinary Surgery – Hibernation Environment