Warming up after Brumation (Hibernation)

The Tortoise Myth Busters - Episode 8

https://www.youtube.com/watch?v=iSuuFrDzdwk

As usual, let's start by looking at some of the (very confident!) misleading advice seen on this subject:

• "If you warm a tortoise up too fast it will die from the shock"

• "Never take a tortoise from a cold area and warm it up right away. Allow at least 8 hours for it to gently adjust"

• "Warm your tortoise up slowly, over several days"

This is really poor advice and in no way at all refelects what really happens in nature. Furthermore, it places the tortoise at serious risk as being kept at sub-optimal temperatures just after emergence compromises their immune systems. Just as in nature, they really need to reach 'operating temperatures' quite quickly.

There a number of facts to consider. The first is that tortoises are very well 'designed' to act as efficient solar collectors. They can easily raise their body temperatures to +10°C to +12°C by basking. So, if the air temperature is 20°C they can easily attain a good basking temperature of +30 Celsius. Also, OVERNIGHT temperatures in the wild in early spring can be surpriosingly low. See an earlier article in this series for more detail: Overnight temperatures of Mediterranean tortoises in the wild.

In that article we described how a juvenile emerged after a night where ambient temperatures fell to -0.5 Celsius but by basking soon elevated its core body temperature to +25.3 Celsius. This ocurred within less than 25 minutes! Just one example where this myth of 'too/rapid' warming is completely wrong.

Also, routinely overnight, the temperature often reaches single digits just before dawn upon emergence, but within a very short time indeed tortoises easily elevate their body temperatures to between 30-32°C by basking (they are very good at using orientation and varying degrees of contact with the substrate to achieve the desired result).

A typical daily temperature and relative humidity cycle in the natural habitat immediately following tortoises waking from brumation.

In the above graph, we again notice overnight ambient (air) temperatures to just above 5°C but rapidly rising to 20°C where basking enables them to raise their own temperature to fully functional levels. By late morning or early afternoon ambient temperatures can be so high that they seek retreat.

The main message to take from this data, however, is that tortoises often start from just over 5°C (lower in some cases) each and every morning in early Spring, and very rapidly elevate their temperartures to over 30°C within 30-40 minutes. If 'rapid' warming was 'dangerous', this would not be the case.

Note also the HUMIDITY CYCLE. It is important to understand the theory and principles involved here, as this is often badly misunderstood. See our in-depth explanation: Understanding Humidity for Tortoise Keepers.

One other thing mentioned in the video was the ground proximity effect. This is another factor that is often overlooked and misunderstood but makes a huge difference to tortoises. You cannot simply rely upon ambient temperatures, and even less upon general climate charts. Yes, we've covered that in a previous 'Myth Busters' too! Can you rely on general climate information to know what your tortoise needs?

One other factor is that in nature tortoises do not normally emerge until the temperatres are indeed capable of meeting their needs.

This chart is from a buried probe right next to a naturally brumating wild tortoise here in Spain. Notice the dramatic 'swings' in temperature each day.

Diurnal variation measured next to a brumating Testudo graeca graeca

This does raising interesting questions about why exactly they remain brumating, or even decide it is time to dig down for winter as their body temperatures get much higher than you might expect. We have covered this topic in a separate video called 'Brumation Mysteries'

Obviously, captivity is often very different and they may well need extra help to warm up adquately. There are several approaches to this. Our 'Climate Frame' design is highly efficient, for example, even in cold climates.

Failing to allow tortoises to warm up adequately can lead to serious health problems.

Even a simple suspended 150w halogen flood lamp will suffice temporarily. For longer term use a combination of halogen, UV-B tubes and HID lamps is advised, to produce a balanced and adjustable combination of heat, visible light, UV-B and UV-A, but as a means to just get a tortoise warmer on emerging, even a simple lamp can be a life-saver. Do be aware however, that basking lamps are not ideal and do present problems of their own, hence we highly recommend trying to make as much use as possible of natural, unfiltered sunlight. If you do use lamps, larger, more powerful lamps from further away are much better and safer than under-powered lamps used too close.

To the basic question of whether 'warming up too quickly' is dangerous, however, we hope that this puts your mind at rest. It is just another of those internet 'myths'.

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