Lighting, Temperatures & Humidity Levels

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Lighting

There is a common myth that because leopard geckos are “nocturnal,” they don’t need any light at all to see or function, and providing light will burn their eyes. I repeat: This is a myth!

Leopard geckos are crepuscular, which means that they most active at dawn/dusk. While their eyes evolved for low light conditions, and they tend to be much more active during the night than during the day, this does not mean that they do not need lighting as part of their enclosure setup.

In fact, having a light on in the tank helps regulate their day/night cycle, which is good for their mental health and stimulates appetite. According to the UV Tool by Frances Baines, light should be provided for 14 hours/day during the summer, which simulates their optimal photoperiod. To simulate the change of the seasons, reduce the amount of light to 12 hours during winter.

Daytime light is also nice for viewing; occasionally leopard geckos will come out during the day to bask. This is not unusual — many nocturnal species have been observed basking, especially in the morning.

What about UVB?

There are three types of ultraviolet radiation produced by the sun: UVA, UVB, and UVC. UVC destroys DNA and is blocked by Earth’s atmosphere, but nearly all animals on the planet have evolved to depend on the other two wavelengths. Reptiles in particular benefit from exposure to UVA for their eyesight and UVB for healthy metabolism, specifically vitamin D synthesis and calcium metabolism.

Many leopard gecko keepers will tell you that leopard geckos “don’t need UVB.” This is partially true. Since they are most active when the sun is either weak or not present, they are not as dependent on UVA and UVB as diurnal species. However, mounting scientific evidence is proving this assumption incorrect and outdated — when offered, leopard geckos and other nocturnal species will bask under and benefit from UVB lighting.

*UVI measurements are per recommendations from Frances Baines, D.V.M.

Warning: UVB bulb output declines over time, even when the visible light remains.

T5 bulbs last 12 months before requiring replacement, and T8 bulbs last 6 months before requiring replacement. UVB bulbs not produced by Zoo Med or Arcadia are likely to have shorter lifespans and may not have a reliable output.

For more information on the benefits of UVB lighting for leopard geckos, please read this paper which was published in the March-June 2018 volume of the Journal of Herpetological Medicine and Surgery.

What about night bulbs?

Black or red lights are not needed for nighttime heat, and can interfere with your gecko’s day/night cycle. In fact, blue lights are known to potentially damage reptiles’ eyes! It is best to save your money and not purchase one.

Temperatures

Leopard geckos, like all reptiles, need a temperature gradient in their terrarium for best health.

  • Basking surface temperature: 94-97°F (34-36°C)
  • Warm hide temperature: 90-92°F (32-33°C)
  • Cool end: 70-77°F (21-25°C)

At night, leopard geckos can tolerate a drop in temperature down to 60°F (16°C). Studies show that a nightly drop in temperature is healthier than maintaining the same temperatures as during the day, and is greatly beneficial for a reptile’s long-term health. If your home is very cold and you need to provide a nighttime heat source, do not use a colored night heat bulb. Contrary to popular belief, reptiles do see the light from these bulbs and it can disrupt their sleep/wake cycle. A better alternative is a ceramic heat emitter mounted inside of a wire cage-type fixture. CHEs are very good at increasing ambient (air) temperature inside of a cold enclosure.

Leopard geckos prefer to hide in warm shelters during the daytime, using their warmth to “charge” themselves for nighttime activity. Ideally a leopard gecko should have minimum 2 hides placed at different spots around the enclosure to facilitate thermoregulation: one on the warm end near the heat source, and one on the cool end.

  • PRO TIP: Pinpoint your surface temperature gradient with a temperature gun like the Etekcity Lasergrip 774. They’re the most precise option on the market — plus fun to use!

What is the best way to heat a leopard gecko enclosure?

BEST: Halogen Heat Lamps

In nature, warmth is delivered to reptiles from the sun (above), and they will retreat underground to get cooler, not warmer. Heat lamps supply heat in a way that works with a leopard gecko’s instincts, replicating nature in captivity. Halogen bulbs are particularly excellent because they produce Infrared A and Infrared B, which are the same wavelengths of heat produced by the sun. These wavelengths penetrate deep into your gecko’s body, providing a more efficient form of heating and reducing the amount of time your gecko needs to bask.

Choosing which bulb to use can be tricky, since wattage and brand determine how much heat it will produce — for example, a 50w Zoo Med Repti Halogen bulb should achieve the right temps around 12″ away from the source. The Philips 90w Halogen Flood Light Bulb also works well. When in doubt, buy higher wattage and then use the dimmer to achieve the perfect basking temperature.

Once you have a heat bulb, you will need a lamp to put it in. My favorite is Fluker’s 5.5″ dimmable lamp. The ceramic socket helps make sure that the bulb doesn’t get too hot for the lamp (risking electrical fire), and the dimmable feature enables you to dial down the bulb’s heat output if it gets too warm. Make sure to pay attention to the maximum wattage rating on the lamp!

GOOD: Deep Heat Projectors

Deep heat projectors are another great type of heat bulb that you can use to warm your leopard gecko’s enclosure during the day. They produce Infrared-A and Infrared-B heat wavelengths, which are the same wavelengths that are produced by the sun to warm the Earth. (For contrast, ceramic heat emitters only produce Infrared-C, which is the weakest infrared wavelength.)

This makes them comparable in performance to a halogen heat bulb, so if you need a lightless source of heat, a DHP is the way to go.

Note that DHPs must be connected to a proportional (dimming) thermostat to make sure that they don’t get too hot — the Herpstat EZ1 is affordable, easy to use, and works well with deep heat projectors.

What about belly heat?

If you’re concerned about the people who have told you that leopard geckos need “belly heat,” you can relax. What people are talking about is actually making sure that the gecko’s digestive tract gets the heat energy required for proper digestion. As long as the gecko has an appropriate basking area (and preferably a warm hide) that achieves temperatures of 90-92°F as measured by a digital probe thermometer or temperature gun, then they will get the energy they need for healthy digestion.

If you’re still worried, place a flat piece of stone (like slate tile or flagstone) under the heat source. The stone warms up during the day, and then the gecko can warm itself on it at night. This is what they do in nature, and it works great.

OKAY: Heat mats 

Heat mats were once the go-to way to heat a leopard gecko enclosure. We have better options now (see above), but heat mats can still be helpful for controlling the temperature of your gecko’s warm hide.

If your warm hide is not getting warm enough, add a thermostat-regulated heat mat under the hide box, covered with 1” of substrate to prevent direct contact. Place the thermostat probe inside the warm hide to regulate temperature.

SAFETY NOTE: Heat mats only work properly when they are controlled by a thermostat! Heat rocks and non-thermostat-controlled heat mats run the risk of burning your gecko, so don’t risk it. Non-proportional thermostats like the Jumpstart thermostat work well for regulating heat mats.

leopard gecko temperatures maintained by a heat mat

Don’t forget to use spacers to lift the tank .5″ off the ground, which will help prevent malfunctions. Source: OnlineGeckos.com.

leopard gecko temperature too high - scorch marks from heat mat

This scorch mark was caused by a heat mat. Always use a thermostat!!! Source: ReptileForums.net.

Humidity

Leopard geckos are desert animals, so they need a fairly dry environment to stay healthy. Ideal humidity will be between 30%-40%, which should match the humidity naturally in your home. Housing your gecko in a terrarium with a screen top or equivalent ventilation will help keep it dry.

That being said, leos do need higher humidity for shedding. In fact, shedding problems are the #1 most common health problem experienced with leopard geckos. Instead of bumping up humidity in the whole enclosure (which can actually make your gecko sick), provide a humid hide stuffed full of moist sphagnum moss and placed on the warm side of the tank. The humid hide should provide humidity levels between 70-80%.

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Keep reading:

  1. Introduction to Leopard Geckos
  2. Shopping List
  3. Terrarium Size and Cohabitation
  4. Lighting, Temperature & Humidity Needs (YOU ARE HERE)
  5. Substrate (Bedding) Options
  6. Decorating Your Leopard Gecko’s Enclosure
  7. What to Feed Your Leopard Gecko
  8. Handling Tips & Leopard Gecko Body Language
  9. Common Diseases, Illnesses & Other Health Questions
  10. Additional Resources