Do Turtles Need Sunlight?

Do Turtles Need Sunlight

Like any other living being, turtles require light to do certain activities. Sunlight is the only natural light that turtles have access to when in the wild. In captivity, turtles are often provided with mercury lamps to create sunlight exposure.

As we know, sunlight is crucial for humans, but do turtles also need sunlight? Why do they need it, and what will happen if they are not provided with sunlight?

This article will discuss everything about turtles and their requirements for sunlight. We will also try to find out what will happen if they are deprived of sunlight for a longer period of time. So let’s dive deeper and discuss everything in detail.

Related Article: Do Turtles Need UVA Or UVB?

Do turtles need sunlight?

Yes, turtles need sunlight to survive. Being a cold-blooded animal turtle needs warmth from sunlight to maintain its body metabolism. They also require sunlight to process calcium and prevent any bacterial infection or shell rot. 

What happens if a turtle doesn’t get sun?

Turtles get warmth from the sun. They bask under sunlight to produce vitamin D3, which helps them process calcium. Without proper exposure to sunlight, turtles won’t be able to absorb calcium from the food they eat, and eventually, they will get ill. Shell decay or shell rot, bone decay, shunt growth, premature death are a few negatives when turtles are deprived of sunlight.  

Sunlight is an important part of a turtle’s life. They dry and warm them up under the sunlight. Sunlight helps them produce vitamin D3, which helps them process calcium and other nutrients for healthy living. 

In lack of sunlight, they won’t be able to absorb calcium from whatever they eat. This can result in a lot of trouble for your turtle. Weaker bone, shell rot, slow growth, fungal infection, and even death is possible if your turtle is deprived of sunlight for long. 

Shall I keep my turtle in early morning sunlight?

Yes, it is healthy for turtles to be under the morning sunlight. No matter what time it is, sunlight does not harm turtles, so they can be left under the sunlight during any time of the day. You should try to give your turtle at least 15-20 minutes of direct sunlight daily. As morning sunlight is more bearable, you can leave your turtle even longer. 

Morning sunlight is good for keeping your turtle healthy, but you should keep precautions if you leave your turtle on your lawn. Turtles are curious animals, and they like to roam around. While you can let your buddy roam on your lawn, make sure to keep an eye on them. They can surprise you with their speed if left in an open space. Also, you should be careful of any predators around. 

You need to set up an arrangement, so your turtle has access to shade if they don’t enjoy the sunlight. It is always a good idea to let them choose what they want. They are very delicate animals, and you should never force them to bask. Holding or touching them too much can also lead them to feel stressed. In that case, they will start behaving weirdly and stop eating, deteriorating their health. Be gentle and avoid too much physical interaction with them.

Do aquatic turtles need sunlight?

Every turtle species requires sunlight to do various bodily functions. As aquatic turtles spend most of their time in the water, they are more prone to bacterial or fungal infections. Sunlight due to UVA/UVB rays has antibacterial properties, so it is a natural cure for several diseases of turtles.

Aquatic turtles require sunlight for producing vitamin D3, which helps them process calcium. Sunlight also provides them warmth to maintain their body temperature and metabolism. When water temperatures fall too low, they spend most of their time basking under the sun. Sunlight is also crucial for preventing several diseases like fungal infection or shell rot. 

Do pet turtles need sunlight?

Yes, pet turtles also need sunlight to survive. Turtles produce vitamin D3 from sunlight which helps them process calcium required for their bone and shell. In the absence of sunlight, pet turtles can be provided with UVA and UVB lamps to create a sunlight-like exposure. Though these are not as beneficial as sunlight, it helps them survive in captivity. 

Since pet turtles live inside their tank enclosure, there is a fair chance of developing a bone disease or fungal infection due to a lack of sunlight. Turtles excrete in the water itself, which releases chemicals like ammonia. Smaller tanks accommodate more ammonia in a short duration compared to bigger tanks. Regular water change is such a pain and could not be possible frequently, increasing the chance of turtles developing bacteria on their shell. 

You should provide your turtle with a few hours of sunlight to solve this problem. Alternatively, you can also install UVA and UVB lights in their enclosure and keep them on for 10-12 hours during the day.

Over time UVA/UVB lamps lose their efficiency in producing UVA and UVB rays. So it is recommended to replace the lamp every few months.

Why do turtles need sunlight?

There are 4 main reasons for which turtles require sunlight:

  1. The warmth from the sun helps turtles to maintain their metabolism
  2. UV rays from sunlight work as a natural antibacterial for turtles
  3. Sunlight is required for turtles to produce vitamin D3
  4. Sunlight help turtle maintain circadian rhythm  

The warmth from the sun helps turtles to maintain their metabolism

Turtles are cold-blooded animals. They can not maintain their body temperature like humans. Rather they depend on the surrounding environment for it. For doing certain bodily functions and their metabolism, turtles require a specific body temperature.

When in the wild, turtles warm themselves by basking under the sun. The UVA rays from the sun help them in physical activity, appetite, and breeding behavior. They sit on their basking spot when they feel they need to warm their body. Turtles keep going in and out of the water to maintain a required body temperature. For pet turtles, people use UVA/UVB lamps for the same.

UV rays from sunlight work as a natural antibacterial for turtles

Turtles spend most of their time in the water, so they develop fungus on their shell. If it is not treated soon, the fungus can cause shell rot. It could even cause the premature death of your pet. Sunlight has UV rays which are known for their antibacterial properties. When turtles bask under sunlight, it eventually prevents fungal infection. Also, drying their body in the sun helps reduce the risk of fungal infection to them.

Sunlight is required for turtles to produce vitamin D3

One of the most important reasons why turtles need sunlight is vitamin D3. It is a vitamin produced in turtles when exposed to sunlight. Vitamin D3 is important as it is necessary for absorbing calcium from their food. Lack of calcium can lead to metabolic bone disease and results in limited growth or even premature death of the turtle.

Sunlight help turtle maintain circadian rhythm

Like humans, turtle’s organs also need a balance of work and rest. They follow a biological cycle called the circadian rhythm. This cycle tells their body when to sleep and wake up. It is important to follow so their body organs can work efficiently.

Turtles follow the sun to differentiate between day and night. With the sun’s rising, they wake up and fall asleep when the sun goes down. Good sleep also helps them avoid stress and keeps them healthy.

How long should turtles bask in the sun?

There is no such number ever discovered to answer how long turtles should bask in the sun. Sun is crucial for turtles to live healthily. Ideally, you should let them decide when and how long they want to bask. You can place the turtle tank beside a window from where they can get direct sunlight on their basking spot. Ensure sunlight is not hindered through window glass; otherwise, it will prevent UVA and UVB.

In the wild, turtles have access to sunlight, and they choose how long they want to sunbathe. Different turtle species have different requirements for sunlight. If I talk about aquatic species such as red-eared sliders, then they need more time for basking to dry themselves off. 

For turtles, a minimum of 15-20 minutes of sunlight daily is required for healthy bones. It is merely a calculation, and it varies based on species. However, it would be best to let them decide how long to bask. 


Turtles do need sunlight when in the wild or in captivity. Aquatic species of turtles need more time for basking under the sun as they are more prone to fungal infections. Instead of deciding yourself, let your turtle decide when and how much time they want to spend basking under the sun. Turtle basking time varies based on species. However, you should be giving your turtle at least 15-20 minutes of sunbathing daily. Sunlight helps them produce vitamin D3, which is required for absorbing calcium from their diet. Regular sunlight prevents shell rot and other fungal infections from happening.