Do Tortoises Need UVB Light?

The information is current and up-to-date in accordance with the latest veterinarian research.

People often think a heating lamp is all the tortoises need, and they ignore the UVB bulb. Well, those keepers are doing it absolutely wrong, which can cost them their pets. Let me explain it in simple terms.

Tortoises need UVB light as much as they require heat. Insufficient UVB can raise health issues like metabolic bone disease, soft scutes, lumpy limps, deformed jaws, weak bones, etc. Besides, the pets will not meet the usual body growth and experience digestion issues and low immunity.

Catch more details below.

Key Takeaways

  • UVB lamps are mandatory for indoor tortoises, while outdoor pets depend on the sun.
  • Tortoises suffer from weak bones, brittle shells, deformed jaws, and MBD without sufficient UVB.
  • 10 – 12% UVB bulbs are suitable for tortoises.

Why Do Tortoises Need UVB Light?

Tortoises of any kind require UVB rays for healthy physical growth and building a solid immunity system. The sun is the natural source of both heat and UVB exposure.

Therefore, tortoises in the wild and outdoor habitats will absorb UVB rays radiated directly from the sun. But the pets in the indoor pens barely get enough access to the sunlight. Hence, they are in need of artificial UVB light to lead a healthy life.

But what is the significance of the UVB lights in a tortoise’s lifestyle? What happens if there is no UVB source in the pet’s enclosure? Let me explain.

1. UVB Rays Produces Vitamin D3

Vitamin D3 has 3 primary functions. Such as,

  • Bone and shell formation
  • Calcium absorption
  • Balancing calcium and phosphorus ratio

Imagine you feed your tortoise sufficient calcium supplements. But all those mineral intakes will go to waste if there is not enough vitamin D3 present in the pet’s meals. As a consequence, the creature will experience weak bone formation, slow physical growth, and low immunity.

Owners often think vitamin D3 supplements will solve this deficiency. But in reality, there is no need for supplements. The UVB rays from the sun or the artificial UV bulb produce enough vitamin D3 in the tortoise’s system.

2. The Bulb Promotes Calcium Absorption

Calcium is a must for bone and shell growth for tortoises. A lack of calcium will only lead to soft shells and weak bone formation. Besides, calcium has a significant role to play in gravid tortoises.

See, eggshells are mainly composed of calcium minerals. Hence, if the mother suffers from calcium deficiency, the eggshells will be too fragile. As a result, the egg yolk may get ruined.

Thus, you must ensure a proper calcium source for the tortoises. Supplements are mandatory even when you add calcium-rich items to the diet.

Well, as I have said, calcium absorption is not possible without sufficient vitamin D3. The most efficient way of producing this vitamin is by setting up a UVB bulb in the enclosure. The vitamin will increase calcium absorption in the tortoise system, allowing the pets to build a solid skeleton and shell.

3. It Is The Ultimate Trick To Prevent & Cure MBD

I am sure you are familiar with different shell problems in tortoises. MBD, or metabolic bone disease, is one of the severe bone issues in reptiles. Insufficient UVB exposure is mainly responsible for this health condition.

Tortoises can not produce enough vitamin D3 without UVB rays. Thus, the calcium absorption is not up to the mark and the calcium: phosphorus ratio also looks imbalanced.

As a consequence, tortoises suffer from a soft shell and lumpy bone growth. Some symptoms of MBD are,

  • Limping
  • Limb fracture
  • Softening of bones and jaws
  • Soft scutes
  • Lumps and bumps along the spinal cords, limbs, and jaws
  • Loss of appetite

You can easily cure and prevent this disease by exposing the tortoises to UVB lights or rays.

4. A Link To Growth, Immunity & Digestion

It is evident that tortoises require UVB lights to have a normal growth cycle. Without sufficient UVB rays, the pets will experience low immunity, which will make them vulnerable to diseases. Frequent illnesses will definitely hamper the usual growth of the tortoises.

One report says that baby tortoises without UVB lights will not survive even 1 year. If the hatchlings live by any chance, they will have an undeveloped body and low immunity. As a result, they may have a shorter lifespan than expected.

Furthermore, there is a link between the tortoise’s digestion system and UVB rays. Apparently, sufficient UVB in the habitat promotes healthy and sound digestion.

Sings That The UVB Bulb Is Not Working

You can not rely on one UVB light for more than 1 year. In fact, in some cases, the bulbs lose their efficiency in less than 6 months. Therefore, it is mandatory to keep checking whether the lamps are working or not.

Hold a radiometer directly under the UVB bulb on the basking platform. Ensure the enclosure has its lid on to get an accurate reading. Radiometers provide UVB values in microwatt/ cm2.

The UVB requirements can vary depending on the tortoise species. For example, tropical tortoises like red footed tortoises require a minimum UVB of 20 – 25 MW. The bulb is broken if it can not meet the requirements.

Again, the tortoises themselves will also show signs of insufficient UVB rays in the pen. For example, weak shells, brittle bones, soft scutes, deformed jaws, and bone diseases are mostly seen in these creatures.

Install a new and high-quality UVB bulb if the existing one is broken or damaged.

Do Tortoises Need UVA Bulbs?

See, UV rays are composed of UVA, UVB and UVC. While the UVC is harmful and unnecessary for tortoises, the other 2 exposures are beneficial.

We have already discussed the significance of UVB rays and how it builds a solid skeleton in tortoises. So, what about UVA? Are these rays necessary for reptiles?

Well, yes. Apparently, UVA exposures have an influence on the tortoise’s mood, activity level, and digestion system.

It means insufficient UVA will make the pets stressed, anxious, and grumpy. On the contrary, enough UVA rays keep the tortoises happy, chilled, and relaxed.

Similarly, tortoises are more active when they are exposed to UVA rays. Also, the creatures will enjoy a healthy digestive system because of sufficient UVA.

Luckily, the UV bulbs radiate both UVA and UVB rays together, though the UVB percentage is prominent. Hence, you need not to install a UVA light separately in the pen. Again, if you raise your tortoises outdoors, the sun is enough to fulfill both UVA and UVB requirements.

5 Types Of UVB Lights Available For Tortoises

You will find UVB bulbs of various kinds available in the market. The popular options are,

1. UVB Bulbs

Separate bulbs for heating and UVB rays are the best arrangement possible for tortoises. You can buy a UVB in the form of a fluorescent light strip.

Such strips cover the entire enclosure, and thus tortoises receive UVB from all positions. As the UVB strip looks just like the regular RGB lights, always check the UV percentage on the package.

If you are not into the strip lights, go for corkscrew bulbs. T8 UV lamps once ruled the market, but they are outdated now. Hence, buy a T5 light with fixtures. T5 UV bulbs are thinner and more sustainable.

Remember, as you install UVB bulbs separately, you must also set up a heating lamp. Without sufficient heat, tortoises will shut down their metabolism and daily activities.

2. Combination Bulbs/ Mercury Bulbs

The combined bulbs radiate both heat and UVB rays. So, these lights are perfect if the tortoise habitat has less space. Also, you can save money and energy on these lamps.

While mercury bulbs offer excellent service, there is one issue with the lights. The combination lamps do not come in different percentages. Therefore, you have to adjust the position of the bulb accordingly.

3. Compact Lamps

The compact bulbs are smaller and easily fit in the enclosure. But these lights have low wattage and come in a limited range. Hence, the lamps must be set up closer to the basking dock.

4. Colored Bulb

The blue UVB bulbs are quite popular as they replicate natural light. But you can go with white or fluorescent UVB lamps as well.

5. Tubular/ Linear UVB Bulb

Compared to compact bulbs, linear or tubular lamps appear obsolete. Other than the design, there is no difference in the efficiency of the 2 bulbs.

How To Set Up UVB Light In Tortoise Enclosure

Of course, installing a UV bulb is not rocket science. But you must consider the position of the light during the setup.

Though installing the lamp 30 cm away from the dock is advised, the distance can change depending on the UVB percentage. For example, the lower the percentage, the closer the light should be to the dock.

The bulb package includes a thorough instruction procedure that you can follow.

Frequently Asked Questions

How Much UVB Do Tortoises Need?

UVB lights are available in different percentages. Not all of them are suitable for tortoises. Usually, it is wiser to aim for a UV light of 10 – 12% UVB for your pet reptiles. 14% UV lamp also works for tropical and desert tortoises.

How Long Does The UVB Bulb Last?

The modern UVB lights will last for 12 – 14 months. But it is advised to check the lights every 6 months and replace the lamp every 6 months if possible. The bulbs usually run low on UVB after a period, which demands a replacement.

Do Tortoises Need UVB Rays During Night?

Tortoises do not need UVB light or heating lamps during the night. Instead, keeping both bulbs on for 10 – 12 hours a day is enough to promote healthy growth in tortoises.

Before You Go…

Keepers often get confused when selecting the perfect UVB lamp and heating bulb for their tortoises. So, I have pulled off a perfect buyer guide for them. Just go through the piece to get the best deal on a UVB lamp for your pet.

Basking Light Guide For Absolute Beginners

About Author

Muntaseer Rahman started keeping pet turtles back in 2013. He also owns the largest Turtle & Tortoise Facebook community in Bangladesh. These days he is mostly active on Facebook.


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