Do Tortoises Hibernate in Summer? Understanding Aestivation.

Tortoises don’t hibernate in summer. They only hibernate during wintertime. However, throughout summer, tortoises may aestivate, a period during which the metabolic rate and activity will be lowered. Aestivation happens during the hottest part of the summer.

While tortoises are not the most common pets, they are very complex reptiles, more complex than one would think. On top of requiring a specific diet, an enclosure with specific conditions, and so on; some tortoises species also hibernate.

Hibernation comes with responsibilities that you must fulfil to ensure the safety of the tortoise. However, do tortoises hibernate only in winter? Isn’t it possible for them to hibernate during summer too?

If your tortoise has shown signs of lowered metabolic rate and suddenly became less active during summer, it’s important to know why.

What Is Aestivation?

Aestivation refers to the process of dormancy or inactivity of a tortoise when the temperatures are extreme. During this time, the metabolic rate of the reptile is lowered. This is a process that happens in order to prevent the animal from becoming dehydrated.

When aestivation occurs, the tortoise will spend more time indoors (or underground) and will stay there for several days or weeks at a time. It happens during the hottest part of the summer when temperatures become too high to handle.

If the tortoise had enough food and drink during the spring, it will be able to aestivate without coming to any harm. Once the weather cools down sufficiently, the tortoise will once again be active, exploring its surroundings as normal.

How is this different from hibernation? Well, it’s not too hard to tell the difference. Hibernation happens in winter and occurs as a result of very low temperatures (as opposed to the very high temperatures associated with aestivation) slowing the tortoise’s metabolic rate to a snail’s pace.

The two processes can seem similar because, during these times, the animal doesn’t stay active or doesn’t eat. Still, aestivation and hibernation happen during different periods of the year and for different reasons.

Furthermore, hibernation tends to last for the whole winter, whereas aestivation lasts for a short period of days and weeks, rather than months. During hibernation, tortoises will hide in a warmer place, while in aestivation they will look for a cooler and damper place.

What Leads a Tortoise to Aestivate?

Now, what causes a tortoise to aestivate? Aestivation happens when the conditions are too hot or dry for the tortoise to handle. Under these circumstances, it’s highly unlikely the tortoise will be able to stay healthy, which is why it instinctively chooses to aestivate instead.

Aestivation is a survival adaptation that wild tortoises evolved with over many millions of years. During drought, for instance, food may be scarce, and the same may be said of water. So, the tortoise will dig deep underground and stay there, ideally in a cool, moist burrow. When conditions are more forgiving, it will come outside and start being active again.

This is more of a concern for outdoor dwelling tortoises, though, because they are in direct contact with the heat of the sun and will be influenced by natural drought. It can be a particular concern if they climb or burrow away, in areas where they cannot be seen or found.

This of course is one of the many good reasons why your tortoise should be well contained outdoors.

For indoor tortoises, aestivation is not as much of a concern as temperatures are largely independant of what’s going on outside, meaning they will not need to burrow and hide until it gets cooler.

In a well insulated home humidity shouldn’t get too low (particularly if you have placed some damp sphagnum moss in their hide), nor temperatures too high, and with your usual care regime the animal will have enough food and water.

Is Aestivation Ever Something to Worry About?

If you’re a newbie tortoise owner, then understanably you may start worrying if your tortoise suddenly stops eating in the middle of summer and is less active than usual.

If you keep your tortoise outside and temperatures have been extremely hot recently, then this behaviour is not something you should worry about. Having saide that, it’s only normal in exceptionally hot weather.

Similar to when in hibernation, tortoises will be able to go without water and food for a significant amout of time during aestivation. They may even go for several weeks without food and water, and exibit no sign of ill health as a result.

The only time aestivation might be cause for concern is if your tortoise aestivates regularly during its life, even when temperatures aren’t necessarily that high. Captive tortoises should not really aestivate unless conditions are exceptionally warm for an extended period of time.

Apparent unexplained aestivation is triggered by very unhealthy or even dangerous conditions in captive tortoises. So, if your tortoise aestivates regularly, you should make sure to fix the environment problems around it as soon as you can, for instance when there is a lack of shade or water.

Is Aestivation Necessary?

Tortoises are cold-blooded reptiles. That means that they are unable to regulate their internal body temperature independant of environmental temperature change.

So, being cold-blooded doesn’t mean that reptiles cannot keep warm, but rather that their body temperature fluctuates with the change in environmental temperatures. As such, they need to hibernate and aestivate during different times of the year to maintain a proper body temperature.

Aestivation is helpful in maintaining a cooler body temperature for the tortoise and prevent potential internal body damage. Therefore, it’s very important, especially if the tortoise lives in an area where summer weather is going a little overboard with the heat. Is it necessary, though?

Although it may happen sometimes, aestivation is not ‘necessary’ in the sense that it only maintains health, rather than actively benefits it. It is only needed during extremely hot summer periods, effectively to keep the tortoise ‘safe’.

So aestivation is not beneficial in the way hibernation is. Despite carrying some risks, hibernation stops a tortoise from growing too quickly, and also plays a role in hormonal regulation.

Tortoises only aestivate if they really have to. With that in mind, you should never try to encourage or even force a tortoise to aestivate. You should let it do so only if it is necessary given the conditions.

Final Thoughts

Tortoises might aestivate during summer, and it is not something you should worry about if you keep your tortoise outside for the most part. Aestivation helps cool down the body by keeping it in a colder and moist place when summer days are way too hot. This doesn’t usually happen for indoor tortoises.

It’s important to know that aestivation is different from hibernation and you should prepare for these periods accordingly. If your tortoise does aestivate, then be sure to keep an eye on it so you can be ready to take care of them when they emerge and are short of energy and hydration.

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