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What Light Does A Tortoise Need? (UVA + UVB Lighting)

Last Updated on September 17, 2023 by Samantha Harris

Tortoises require adequate exposure to different types of lighting. They can develop Metabolic Bone Disease (MBD) and difficulty thermoregulating without lighting and the warmth it brings.

Depending on your location, tortoises need natural sunlight for 8 hours a day. Tortoises are ectotherms, so they derive warmth from their living environment.

Tortoises in northern climates or those who live exclusively indoors need UVA and UVB light exposure. You can achieve this with mercury vapor bulbs, fluorescent strip lights, and colored bulbs.

UVA rays aid a tort’s functions, including movement, sleeping, mating, and feeding. UVB rays synthesize Vitamin D3, which allows a tortoise to absorb calcium, leading to stronger shells and skeletons (bones).

However, tortoises are vulnerable to some types of lighting, like LEDs.

Do Tortoises Need Light at Night?

Most tortoise species are diurnal creatures, which means they’re awake during the day and sleep at night.

They don’t need light at night, as lighting a tortoise’s enclosure after sunset can prevent sleep. Tortoises are adapted to wild environments where nights are marked by total darkness.

So, they seek out dark spots, like burrows, to sleep because night-time exposure can lead to insomnia.

Tortoises must sleep for at least 12 hours every day, partly due to their evolution (sleeping in their hideouts kept them safe from predators) and partly because they need sleep like any animal.

Body and muscle development, memory consolidation, and metabolism stabilization are key body functions that can only happen when tortoises sleep.

How Long Should A Tortoise Light Be On?

A tortoise should have about 12 hours of light per day, which is the same as it would receive in its natural habitat. However, it depends on the weather in your region.

If it’s mostly sunny, you can avoid using artificial lights if the tortoise can bask in the sun for 2-3 hours a day, 3 times a week.

According to the American Journal of Veterinary Research, natural light is more effective at stimulating vitamin D3 synthesis than artificial lighting.

If you live in a less sunny region, ensure the tortoise receives adequate artificial light during the day.

how long should a tortoise light be on?

Best Types of Lighting for Tortoises

Get a durable bulb that can satisfy a tortoise’s lighting needs. Here are the different options:

Mercury Vapor Bulbs

Mercury vapor bulbs produce enough UVA and UVB for a tortoise’s requirements.

To minimize the risk of low-quality products, purchase bulbs at pet stores, not hardware stores. Also, ensure the sockets are made of porcelain or ceramic rather than plastic or metal.

Position the mercury vapor bulb about 12-14 inches above the tortoise in a central position.

From that distance, the bulb will emit strong rays to penetrate the tortoise’s skin without being overwhelming. Meanwhile, the central placement ensures the light covers the entire enclosure.

Fluorescent Strip Lights

Many owners use fluorescent strip lights to illuminate their tortoises’ enclosures, mainly because they’re inexpensive. In reality, these long strips also emit UVB rays.

Of course, you need a bulb with a UVB rating to achieve optimal results.

Get longer tubes, as they cover larger surface areas and provide more rays. Ideally, opt for lamps with reflectors because they can project higher quantities of UVB over longer distances.

This ensures the tortoise is covered, regardless of its location in the enclosure.

Colored Bulbs

There are many colored bulbs marked reptile-safe, but they don’t all work due to tortoises’ color vision.

According to Biological Sciences, tortoises have red retinal droplets, so they perceive red colors more than others. For this reason, the most effective bulbs include:

Black/Red Bulbs

These colors are tortoise-friendly and can be left on for hours without the risk of disrupting the tortoise’s circadian rhythm. For this reason, they can be used during the day and night.

White/Blue Bulbs

These are bright and produce higher levels of UV rays.

Most of them are designed to replicate the sun’s natural light, so they’re suitable for use during the day, as they can affect the tortoise’s sleeping patterns.

Ceramic Bulbs

Ceramic bulbs come in various colors and are more effective heating solutions than light bulbs. They work most effectively with other bulbs since they don’t produce enough lighting for diurnal use.

Tortoise Light Requirements by Species

Different tortoise species have varying lighting requirements. Here’s an overview:

Tropical Tortoises

Tropical regions have hot temperatures throughout the year.

So, it’s hardly surprising that tortoises from similar habitats, like red-footed and yellow-footed tortoises, require higher temperatures to maintain their metabolic functions.

Their ideal temperatures are above 97 degrees Fahrenheit. However, they need little lighting. The best UV lights for these species have 5-7% ratings.

Mediterranean Tortoises

Russian, Hermann’s, Egyptian, Greek spur-thighed, and marginated tortoises require warmer temperatures and more UVB lighting (10-14%) to synthesize vitamin D3 for their internal functions.

They need high temperatures (94-100 degrees Fahrenheit) to regulate their body temperature.

European Tortoises

Being more adapted to temperate regions, European tortoises, such as red-eared and Balkan tortoises, require higher levels of UV rays to maintain metabolic functions.

They need 12-14% UVB lighting and a temperature range of 86-93 degrees Fahrenheit.

turn tortoise light off at night

Can Tortoises Handle Infrared Light?

Infrared lights present as little risk to tortoises as ordinary lights, and their dimness doesn’t interfere with their circadian rhythms. There’s no need to use infrared bulbs for tortoises unless it’s winter.

Most infrared bulbs produce 50-250 watts of light, which is high for tortoises. Consequently, position any infrared bulbs at least a meter away from the tortoise to keep it safe.

Since the primary function of infrared bulbs is to provide heat, they shouldn’t be used as a primary lighting solution. That’s true, regardless of how comfortable the tortoise seems.

Also, switch all infrared bulbs off at dawn. Otherwise, the day’s hot temperatures and the heat from the infrared light can trigger heatstroke.

Tortoise Lighting Setup

Follow the guidelines below to use the lighting safely:

  • Maintain a 10-30 inch distance between the tortoise and the light source. Most bulbs for pet use specify the recommended distance on their packaging or instructions.
  • Hang the lights vertically, ideally using metal sockets. This ensures they don’t endure as much damage from the convection currents.
  • Place the UV lights in a central position on the enclosure roof. Meanwhile, infrared lights should be in one corner to allow the tortoise to move away if the heat gets too much.
  • Maintain a clear, unencumbered path between the tortoise and the light bulbs. UVB rays, in particular, can’t penetrate opaque surfaces like glass or plastic walls.

Although higher-end bulbs have longer lifespans, changing them every 6 months is recommended because older bulbs emit lower levels of UVB.

If the tortoise lives indoors or in a region with little sun exposure, the tortoise needs artificial lighting.

By getting colored bulbs, fluorescent strip lights, or mercury vapor bulbs, you can ensure the tortoise absorbs all the light it needs to synthesize the vitamin D3 needed for calcium absorption