Do Turtles Need Light at Night?

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Do Turtles Need Light at Night

Lights are important for every living being because it helps with the circadian rhythm.

The first thing that we need to cover is that turtles are ectothermic, and the importance of this fact is that all turtles do something called thermoregulation.

This means that they rely on their environment to regulate their body temperature.

So, let’s say a turtle lives in an area where it is very cold outside and it can’t absorb enough heat from its surroundings. One way for this turtle to keep warm is to bask in the sun.

This indicates that turtles can only spend a certain amount of time under the sun and still manage to do fine with the amount of heat that they managed to absorb throughout the day.

Turtles don’t need to have the lights on during nighttime hours, even though most species of turtles are nocturnal animals.

They are awake at night only because they try to avoid most predators during the day, but if he feels safe in his turtle habitat he won’t care to stay awake during the night.

Let’s explore more the question do turtles need light at night and clear some confusion while were at it.

Why Do Turtles Need Light?

turtles basking in the sun

Turtles are cold-blooded animals therefore they need to bask in the sun during daytime hours for them to regulate their body temperature.

Basically, as mammals, we humans maintain our constant body temperature, however, turtles rely on outside light sources in order to raise or lower their body temperature depending on what they need. 

They can raise their body temperature in order to increase metabolism or lower them to be more inactive. Turtles achieve this by moving to different areas of their surroundings to warm up or cool down.

This can be done through radiationconvection, or evaporation of body fluids. It may be either raised or lowered by the conduction of heat to or from the substratum or the air.

  • Conductive heat is usually gained or lost when in direct contact with an object that has been exposed to radiant heat and its surface is hot. For instance, when a turtle basks in the sun he gains heat through conduction, and when he buries himself in the sand, heat is lost.
  • Radiation occurs when an animal absorbs heat from an object which emits it. In this case, turtles absorb heat from the sun.
  • Evaporation is when a liquid turns into a gas and cools down the animal, or when a gas turns into a liquid and warms him up.
  • Convection is when heat travels through currents of air, and this happens on land when the turtle is basking in the sun.

When he moves to an area where there is an absence of currents, this means that his body temperature will start to decrease.

This is why you can see turtles basking on logs, rocks, or even your furniture because they need the sun to make them warm, and this is how they regulate their body temperature.


RELATED READ: The Best UVB Light for Turtles

But What if There isn’t Enough Sunlight in the Daytime Hours to Warm your Turtle?

Then you need to provide a heat lamp or another source of heat that will do the job. Just like we mentioned before, you are not providing light for your pet turtle, but heat.

Therefore, turtles don’t need light at night to regulate their body temperature.

What’s The Point of Light Then?

Lights are important for every living being because it helps us with our circadian rhythm.

Circadian rhythm is our internal 24-hour day and night cycle that regulates our lives.

If you are talking about nocturnal animals, even though they’re awake at night, they still need light to regulate their circadian rhythm.

We can say that diurnal animals have a normal cycle of activity and rest during the day and night, however, nocturnal animals are active during the night only.

There is a thing called crepuscular animals that are active during both day and night, but mainly during twilight hours.

Turtles are nocturnal animals that spend most of their days hiding in the dark, so they need light to be able to adjust their circadian rhythm.

Turtles are not active during daylight hours because this is when most predators are awake.

RELATED READ: The Best Turtle Basking Platforms

Why Does Your Turtle Need UVA and UVB Light?

vitamin D pathway

First of all, before we explain why your turtle needs UVA and UVB lights you need to understand what is UV and what is the difference between them.

There are three types of UV radiation that are classified according to their wavelength:

  • UVA (315-400 nm) – accounts for approximately 95 percent of the UV radiation reaching the Earth’s surface. It penetrates deeper into the skin and produces a rapid tanning response.
  • UVB (280-315 nm) – is very biologically active but cannot penetrate beyond the superficial skin layers. It is responsible for delayed tanning and burning.
  • UVC (100-280 nm) – the most damaging type of UV radiation. However, it is completely filtered by the atmosphere and does not reach the earth’s surface

Each of the UV radiations differs in their biological activity and the extent to which they can penetrate the skin.

UV radiation of shorter wavelengths is more harmful than that of longer wavelengths. Shorter wavelength UV radiation, on the other hand, is less able to penetrate the skin.

Light is measured by its wavelength (in nanometers).

Therefore turtles need UVB to help them get their vitamin D3 which also absorbs calcium, and UVA which is needed for the turtle to be able to produce normal amounts of vitamin D3.


RELATED READ: The Best Turtle Tank Heater

What Are Your Turtle’s Light and Temperature Needs?

Now that you know the importance of UV light for your turtle, it’s time to explain what kind of lights he needs.

The first thing is that you need to provide him with UVB light.

UVB lights are also known as “actinic” or “glo-bulb”.

Turtles need to receive UVB rays in order to get their vitamin D3 that they must absorb calcium and also help them with their circadian rhythm.

You should know that turtles absorb calcium with their food, but you don’t always provide them with enough calcium.

Therefore they need UVB rays to absorb the calcium from the sun that will help them build strong bones.

He will also need in the basking area heat lamps and also high-quality heaters to warm up the cool parts of his tank.

The basking area temperatures should be around 85 degrees, and the temperature in the other parts of his tank should be around 75 degrees.

A source of light for him to see throughout the tank is also needed coupling with a light timer so you don’t need to turn off and on the light every day.

Do Turtles Need Heat Lamps All The Time?

They will bask only when they need to absorb UVB and heat, however, you should know that they will not always need heat lamps.

All the year long turtles will use their environment to regulate their body temperature, but some of them will move to sunnier areas to bask.

How Long Should a Turtle Basking Light Be On?

Basking lights should be turned on for 12-14 hours, but make sure the basking area isn’t too hot.

He needs to be able to leave the basking area when he’s too hot.

Do Baby Turtles Need Light?

Baby turtles need to be able to absorb UVB rays so they can have strong bones too.

Exposure to artificial sunlight is the best way to ensure that the baby turtle will be able to get its vitamin D3 and calcium.

The best way to set up artificial lighting for baby turtles is with a UVB light that is fixed to the top of the tank since baby turtles love to bask.

However, they will need another basking lamp that will help them regulate their body temperature.

Do Baby Turtles Need Light at Night?

Baby turtles need to sleep at night since they are not exposed to the sun, however, if you provide them with infrared lamps during the night they will be able to sleep.

They will have a much better quality of sleep since they are not cold during the night like most people think.

Types of Light for Turtles

The UVB and UVA lights can be provided using different types of bulbs and lamps and these are:

  • Mercury vapor lamps – They can be used to provide UVA and UVB lights in the right ratio, but the problem is that the turtles may receive too much heat.
  • Two Lamp System This is used to provide both UVA and UVB lights using two different bulbs, but one of the lamps must be controlled by a light meter
  • Viewing lights If your turtle spends a lot of time in the water, viewing lights can help you see him during the day.
  • Nightlights – If you see that your turtle sleeps more throughout the day and it’s more active at night you can provide him with a nightlight.

RELATED READ: How to Set Up a Turtle Tank

Tips When Using UVB Light

  1. The UVB lights are hot! When handling the light, be careful not to burn your hand. They can also harm your eyes, so don’t look at them directly at any time.
  2. Check the UVB bulb you’re buying for its amount of light. The best range is between 2.5% and 5%. 10% is far too much for most turtles. To ensure you’re putting the light in the correct spot, verify the recommended distance on the packaging.
  3. UVB bulbs should be replaced at least every six months. They don’t last long, and the quantity of UVB radiation will decrease, putting your turtle’s health in danger.
  4. A glass or plastic tank cover blocks UVB light from reaching the inside of a turtle tank. You cannot utilize a UVB lamp with a glass or plastic tank cover because UVB rays are unable to pass through it. Large holes in the meshwork best.


All turtles need light to regulate their body temperature and absorb vitamin D3 so they can have strong bones.

Artificial lighting is the best way for a baby turtle’s to get these things because exposure to natural sunlight isn’t always possible, but you want a UVB light that produces enough light.

Some types of lights are mercury vapor lamps, two lamp systems, or viewing lights.

Night-time lights should only be provided only if you see your turtle being more active at night and if you want to see him in action in the middle of the night.