Why Your Leopard Gecko Is Always On the Cold Side

Why is my leopard gecko always on the cold side?

Looking after your leopard gecko can be tricky if it’s your first reptile, or it does something out of the ordinary – like only staying on the cold side of their tank. It would have been so easy if your leopard gecko could just say what’s wrong, but, alas, you’ll need to check a few aspects of their tank and them to find out what’s causing this behavior. I’ve looked at the different reasons your leopard gecko may stay in the cold side of their tank. 

Leopard geckos stay on the cool side of their tank if the temperature inside the tank is too high and they’re looking for a spot where they can cool off. Also, it can be that they dislike their warm hide or basking spot, or are starting brumation and are looking for the best place to spend this time.

In this article, we’ll give you the major reasons ‌your leopard gecko may keep to the cool side of the tank as well as how you can fix this and keep your gecko happy and healthy. 

The Main Reason ‌a Leopard Gecko Stays on the Cold Side of the Tank

If you don’t measure your leopard gecko tank’s temperature, the tank could become too hot for your gecko. When this happens, your leopard gecko will want to move away from the heat, and the only way they can do this inside their tank is to move to the cooler side of the tank or to remain in the cool hide. 

This is also why having a temperature gradient in the tank is so important; because the leopard gecko is cold-blooded and relies on its environment for body heat or to cool down, you need to give them a warmer part and a cooler part in the tank. Your leopard gecko should also be able to move freely between these two sides.

The Correct Temperature Gradient Guide For a Leopard Gecko Tank

To give your leopard gecko a tank with the correct temperature gradient, follow the table below:

Leopard Gecko Temperature Gradient Tank GuideBasking Spot Warm Side – Day Cool Side – DayNight
Minimum Temperature 91°F/32°C85°F/29°C75°F/23°C65°F/18°C
Maximum Temperature 104°F/40°C90°F/32°C80°F/26°C74°F/23°C
Leopard Gecko Temperature Gradient Tank Guide

How To Keep a Leopard Gecko Tank At the Correct Temperature 

To keep your leopard gecko’s tank at the correct temperature, you will need to have the right tools for the job:

  • A UVA/UVB lamp 
  • A thermometer 
  • A tank that is set up correctly, with the correct temperature gradient

All of these work together to give your leopard gecko the best environment to thrive in. 

A UVA/UVB and Ceramic Heat Lamp 

Important! You should never put your leopard gecko’s tank in the sun as this can cause the tank to overheat very quickly (just think about a car interior on a hot day and how uncomfortable and even deadly that gets). Rather, use the specially designed bulbs for your leopard gecko

It’s very important that your leopard gecko have a source of UVB light as this is what helps them to produce vitamin D and utilize the calcium that you feed them. Without the necessary calcium they can get metabolic bone disease – which is as horrible and awful as the name suggests. 

If your leopard gecko doesn’t have enough heat, though, they won’t be able to physically function properly. For instance, if they’re too cold they won’t be able to digest their food – which leads to impaction and may lead to death – and they may also die from the cold itself. 

Preventing this from happening, however, is more difficult than simply putting any old lamp on the tank and hoping your leopard gecko will be okay.

My leopard gecko is only in his hide on the cold side

You need to use a proper ceramic lamp and you need to position it high enough above the tank that the temperature inside the tank remains constant and the basking spot and warm end off the tank don’t get too hot. 

To measure the temperature inside the tank, you will need a thermometer – you should never guess whether the temperature is right or not. 

A Thermometer

Now, we don’t mean you should use the kind of thermometer you use to check whether you have a fever. Rather, you need to use a thermometer that’s been specifically created for use in reptile tanks. 

You can use this thermometer throughout the day and night to ensure that the temperature of the tank doesn’t get too high or too low. 

A Heat Mat 

To ensure that the tank remains at the correct temperature throughout the night or winter, don’t leave the light on during the night, but  use an appropriate size heat mat.

Note! You must switch off the heat mat during the day to keep the tank from getting too hot. 

How To Cool Down a Leopard Gecko Tank That’s Too Hot

The fastest way to (safely) cool down a leopard gecko tank that’s too hot is to open the tank and let the hot air circulate with cooler air from outside the tank. This will also keep the tank from cooling down too fast and having your leopard gecko’s body temperature drop suddenly. 

Just ensure that the room isn’t freezing when you do this, i.e. don’t try this in midwinter without having some kind of heating switched on in the room first.

If you need to bundle up just to be in the room, the room is too cold and you risk lowering the temperature inside the tank too much too quickly. Let the room be between 75°F (23°C) and 80°F (26°C) before opening the tank. 

Then, keep a close eye on the tank temperature using a thermometer and close the tank again once it reaches the correct temperature. 

Note: Taking your leopard gecko out of the tank to cool it down could lower their body temperature too quickly. Rather wait for the temperature inside the tank to stabilize and remain at the correct temperature for around half an hour before handling your gecko (if you need to handle them at all at this time). 

What To Do If Your Leopard Gecko Dislikes Their Warm Hide Or Basking Spot 

If you find that the temperature gradient in your leopard gecko’s tank is correct, but they still don’t want to spend time in the warm part of the tank, it may be that they dislike the warm hide or basking spot. 

The easiest thing to do if you think that this is what’s wrong, is to switch the warm hide with the cool hide and see whether they now go into the warm hide. If they do, eureka! Now you just need two of the same types of hides…

It may also be that the hide and basking spot are difficult to get to and your leopard gecko must basically do acrobatics to get to them. Try to rearrange the cage’s accessories and see what happens. 

Tip: It may also be that you only have a basking spot in the warm side of the tank and not a hide as well. If this is the case, simply add a hide to the warm side of the tank as well. 

How To Choose the Best Hides For Leopard Geckos 

When you pick out a hide for your leopard gecko ensure that:

  • The hide is big enough to fit a fully-grown leopard gecko (you don’t want them feeling cramped or – worse – have them get stuck,
  • The hide is easy to clean and disinfect without getting damaged,
  • The hide is made from a non-toxic material,
  • If the hide is made from wood you’ve sourced yourself, make sure that it’s been prepared correctly to rid it of any pests and pesticides. 

How To Tell If Your Leopard Gecko is Starting Brumation

Finally, your leopard gecko may be staying in the cooler hide or on the cooler side of the tank more and more, as they are getting ready for winter and their annual or almost annual brumation. They’ll also:

  • Seem more lethargic or sleepy – but is alert when handled
  • Eat less or not eat at all 
  • Sleep more – especially during the day or dusk when they are usually most active.

Note: Not all leopard geckos in captivity will brumate like those in the wild. If you find that your leopard gecko doesn’t brumate, you need to ensure that they’re still warm enough (and not too warm) throughout winter.

Conclusion

Although it can be very worrying when your leopard gecko doesn’t want to go to the warm side of the tank, there are some easy steps that you can take that should rectify the problem, like cooling the tank, adding or removing a hide, etc. 

By going through the reasons why your leopard gecko is acting the way it does, you’ll most likely find that it’s nothing much to worry about. However, if you’re still worried – and these steps don’t work, rather get your gecko to the vet for an overall checkup. 

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