Lighting for Reptiles

Key Points

A combination of both light and heat are required for reptiles to be kept healthy and happy. Each specific species may need slightly different lighting, but below are some guidelines for overall good reptile lighting.

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Why reptiles need specific lighting?

Nearly all animals need some exposure to UVB, and reptiles are no exception. However, their need for this UVB is more urgent as, unlike other animals, many reptiles are dependent on this light to meet their calcium needs. This is because, from the UVB light, vitamin D3 is made which enables the absorption of calcium needed for strong bones, and ultimately a healthy reptile.

Without this, reptiles can encounter numerous problems, mainly MBD or Metabolic Bone Disease, which effects bone density and causes symptoms like lethargy, swelling and general weakness.

UVA is also important to reptiles, as some can see in ultra-violet light due to the presence of a fourth cone in their eyes, unlike our three. Therefore, without access to this form of sight, often used to detect others of their species and food sources, the reptile can become stressed and scared.

Also, like humans, reptiles use light to set their circadian rhythms, or body clocks. By making sure the lighting follows what would be present in the wild, your reptile can keep to a natural schedule.

The importance of getting heat levels right

Heating is an important part of this equation, as reptiles thermoregulate and need heat to turn the vitamin D3 into calcium. This means they will sit and bask in the brightest area as this is thought to be the warmest spot, even if it is not, so if you have a light for UVB and a light for heat, they need to be in the same area of the enclosure.

Why natural light is so important for reptiles

Unfiltered natural sunlight is the best type of light for getting your reptile the UVB it needs. In the tropics, light can reach 1,000,000 lux, and even under the rainforest canopy it can be up to 7,000 lux. In contrast, a 40W incandescent can reach up to 50 lux from a metre away, a huge difference for your reptile.

However, before you set up outdoors, there are issues. For example, inadequate temperatures in your region or a lack of outdoor space.  Also, wide mesh can block 20-30% of the UVB, and for small mesh, 40-50%.

So, placing the reptile near a window? Unfortunately, this encounters the same problem as the mesh.  Both windows, and the glass of the vivarium would block the UVB rays and, unless you want to revamp to specialist glass, there isn't an easy solution.

But don't despair.  With the correct lighting and heating, your reptile will still be happy and healthy.

What different types of light can be used for reptiles

There are many different types of lighting and so knowing which to use can be confusing.  These are a few quick points about a few common types but make sure to check what your specific reptile requires.  Also make sure that you follow the instructions and guidelines of each light carefully.


  • Good overhead radiant heat source and visible light which is good for basking reptiles
  • Red-and-yellow colour, so no UVB and only a little UVA so UVB light required
  • Dimmable so light and temperature can be regulated

Basking Lights

  • If 'neodymium' coated, there is no UVB being produced
  • Look similar to spotlights but create a concentrated area of heat, perfect for basking
  • These can come in a Standard or Infrared for nocturnal reptiles
  • Some recommend these guidelines: 40-60 Watt for a 30 inch vivarium, 100 Watt for up to a 36 inch, and 150-200 Watt larger than above

"Daylight" Fluorescents

  • Do not produce sufficient levels of UVB for vitamin D3 synthesis but can improve the general level of light within an enclosure

UVB Fluorescents

  • Often produce the level of UVB found in an outdoor shaded area on a sunny day, therefore is better for some reptiles that need less UVB, or for small enclosures

UVB Compact Fluorescents

  • Not often recommended for vivarium use as the low levels of UVB may not be enough for some reptiles, but if they get too close and/ or have reflectors, the UVB may be too intense
  • Decay more rapidly than the tubes in terms of UVB production.

*Full-Spectrum Fluorescents= Although these say full-spectrum, they might not be, meaning the output of UVB and UVA needs to be checked

Mercury Vapour Lamps

  • Vary in the quality of UVB output so be careful when selecting these
  • Produce significant heat which is good, but cannot be controlled which means they should only be used in large enclosures
  • Inexpensive varieties can produce narrow, hazardous beams of intense UV which can be harmful to your reptile.

Metal-Halide Lamps

  • Specific varieties of these lamps produce both UVA and UVB but not quite in the ratio required. As they produce too much UVA, shades can be used, but this in turn reduces UVB.
  • Can be used as general lighting but they do need an external ballast so positioning is crucial

Infrared Bulbs

  • Best for nocturnal reptiles: they don't perceive the infrared wavelength as daylight and so are not disturbed, but can be viewed.

Flood Lamps

  • Small versions of these are ideal for creating a large basking area

Make sure your reptile has a place to sit in the shade so they can regulate their own intake of UVB, as they can overdose if left too exposed. Also replacements may be more often than regular lamps as the UVB levels may decrease quicker.

The lighting requirements for different reptiles

These are some rough definitions of types of reptiles and the lighting requirements they have.


These reptiles live in really hot places, such as the Mediterranean and spend a lot of time in the sun, meaning they are used to high levels of UVB.


These are species found in the rainforest and so typically only need low levels of UVB.


Iguanas fall somewhere between the two above, as they need high levels of UVB in the early morning and late evening, but shade during the middle of the day.

"Creatures of Dawn and Dusk"

These reptiles bask only very occasionally. Their diets normally contain all the vitamin D3 they need, and if they are having UVB supplements, extra lighting UVB may cause an overdose.


Normally, snakes get all the vitamin D3 they need from their diets, but a little extra low level UVB lighting may be helpful. However snakes are really sensitive to excessively bright artificial light.


Although they spend a lot of time in water, they still need UVB. Positioning a light partially over the water may be a good solution.

How to position the lights

  • The lights need to be overhead of the reptile rather than from the side.
  • UVB lights need to be no closer than 6 inches but no more than 18 inches away from the reptile to avoid skin or eye damage
  • Heat lamps need to be even further away to avoid over-exposure
  • If your reptile gets swollen eyes or refuses to open them, remove the lights and go and see a vet to check the problem.

What alternatives are there to light

An alternative way to get your reptile the UVB it needs is vitamin supplements which are recommended for those who have a deficiency of UVB.

However, too much supplement can cause a hypervitaminosis-D, as they haven't evolved to deal with an excess.

To find out more about using light to help your reptiles thrive, call the team today on 0113 8876270 email

Further Resources:

All the information for this piece were gathered from these sources:

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