Lighting FAQ
This FAQ is a reflection of my experience and educated opinions on the matter and generally reflects the general consensus of the experienced forum members and experienced enthusiasts. Much credit is given to those with more experience than I who are always offering their expertise such as Kinyonga, Laurie, Jannb, Carol, Chris Anderson, Olimpia, Sandrachameleon, Trace etc.
Q: What is UVB and do chameleons need it?
A: (Ultraviolet) UV light rays are emitted by the sun in forms of UVA, UVB, and UVC based on frequency. UVA is visible and helps regulate behavior and activity of chameleons. UVB is invisible but critical to the formation of vitamin D3 in the skin of reptiles which allows them to absorb calcium from their food. UVC is invisible, harmful and usually not present in significant amounts. Chameleons MUST have UVB light to survive and lack of UVB will lead to Metabolic Bone Disease (see health section), severe deformation and death. UVB can be given through unfiltered sunlight (UVB does not penetrate glass or plastic well) or through commercially available linear or CFL UVB bulbs. After about 6 months of use the bulbs will stop emitting adequate levels of UVB even though they are still shining so it important to change the bulbs every 6 months unless you have a UVB meter to measure its UVB output.
More information:
Lighting for Chameleons - Part 1
Lighting for Chameleons - Part 2
Q: Which UVB bulb does my chameleon need?
A: The numbers on the UVB bulbs corresponds to the percentage of light that is UVB. 2.0 bulbs are designed for reptiles that receive little UVB, such as those in the lower layers of thick forests where sun doesn’t penetrate well. 5.0 bulbs are designed for reptiles that receive moderate amounts of sunlight like those in the upper levels of forests that get dappled sunlight throughout the day, like chameleons. 10.0 bulbs are designed for desert animals that receive high levels of unfiltered sunlight for most of the day. More is not necessarily better in this case. Just like you going out into the sun too long unsafe levels of UVB can burn chameleons or hurt their eyes.
See Lighting for Chameleons - Part 2 for more information.
Q: Do I still need a special UVB bulb is my chameleon's cage is next to the window so its getting real sun?
A: Glass blocks over 98% of UVB rays (which is why you don't get sunburned sitting by the window) so sitting your chameleon by the window does not provide any UVB rays unless it is open and there is no glass between the sunlight and your chameleon. The heat from the sun through a window can actually be a danger to your chameleon.
Q: Why do I have to change the UVB bulb every 6 months even if it still looks like its working fine?
A: The bulbs that give off UVB rays also give off regular UVA like regular light bulbs do. Over time they slowly give off less and less of the crucial UVB until it below the limit that chameleons needs to make vitamin D. However they will still look like they are working fine because they are still giving off UVA and since we cannot see UVB rays you can't judge when that lower limit has been met. Tests with a UVB meter have consistently shown that UVB levels start to get dangerously low by 6-9 months on average for the available brands of UVB bulbs. Some last longer and some run out sooner than that, but without a UVB meter it is impossible to know where your bulb stands. Therefore it is 'better safe than sorry' to replace the bulbs approximately every 6 months to avoid UVB levels dropping too low.
Q: Can I use Compact UVB bulbs or will it blind my chameleon?
A: At one time there was a manufacturing problem with the ReptiSun CFL UVB bulbs so that they emitted unsafe levels of UVB and even UVC rays, which corresponded to health problems like eye problems and burns in reptiles. This manufacturing issue was identified and corrected by the manufacturer several years ago and thus we have not seen problems with it since then unless someone unluckily picked up an older bulb from before correction. The ReptiGlo CFL UVB bulbs were never associated with these harmful effects. The linear ReptiGlo or ReptiSun bulbs have never had any health problems associated with them either.
Q: Do I need a basking bulb if I have a UVB bulb?
A: Generally yes. Reptiles are ectotherms, meaning they need to absorb heat from their environment to regulate their own body heat since they cannot produce it. Therefore a temperature gradient in their cage is essential to good health. They need a warm place to bask in order to digest food properly but they also need cooler places to cool down so they do not overheat since they can’t sweat or pant. A basking bulb provides warmer temperatures at the top of the cage but should not be so hot that it heats the entire cage. Your chameleon will utilize different temperature zones throughout the day depending on its metabolism and needs.
More info on temperature gradients.
Q: Which basking bulb should I use for my chameleon?
A: There are many specialty “daylight basking bulbs” available for purchase at pet stores to provide heat and suitable levels of UVA. These often cost $15+ and the exact same benefits can be gained from regular household incandescent bulbs found at grocery stores for much less. Most hobbyists use household incandescents. The wattage depends on your ambient temperatures so you may have to do trial and error to find the one that produces the temperature for you. 60watt bulbs are a good starting point.
Q: How long should I leave the lights on?
A: Chameleons should have at least 10-12 hours of uninterrupted UVB light every day as they would in the wild for proper metabolism. After this time they need the equivalent uninterrupted darkness, as they would have in the wild.
Q: Should I use a night light?
A: Chameleons have a parietal (third) eye, which exists as a photoreceptive scale on the top of their head. This senses light in the environment and helps regulate basking and activity even when your chameleon’s eyes are closed. Light at night can still disturb them while their eyes are closed because of this. So the blue or red night lights available are not recommended for this reason. A temperature drop at night is normal and good for metabolism so unless your ambient temperatures are less than 60 degrees you do not need supplemental heat at night. Better options for night heating are ceramic heat emitters (no light) or space heaters.
Q: Should I put the lights inside or outside the cage?
A: Always put any light fixtures and bulbs completely outside of the cage!! Reptiles can be burned very quickly if they get too close to a hot bulb, and they will even crawl up and sit on the bulb without realizing they are being burned. The damage from a burn can be severe, even life threatening. Even when you think you have it in a safe place where they couldn't get to it they almost always find a way. Always put all light fixtures outside of the cage.
Q: If the UVB lights mimic the sun for my chameleon, are they also really good for plants in its cage?
A: While some plants can grow well under the UVB and basking bulbs of your chameleon alone, the UVB bulbs are low intensity and many plants will do much better with a light better suited for plant growth. These are labeled 6000k - 6500k for the color spectrum they emit, rather than a particular type of ray like UVB, and are higher intensity for plant growth. They can be purchased from most home improvement stores.
This FAQ is a reflection of my experience and educated opinions on the matter and generally reflects the general consensus of the experienced forum members and experienced enthusiasts. Much credit is given to those with more experience than I who are always offering their expertise such as Kinyonga, Laurie, Jannb, Carol, Chris Anderson, Olimpia, Sandrachameleon, Trace etc.
Q: What is UVB and do chameleons need it?
A: (Ultraviolet) UV light rays are emitted by the sun in forms of UVA, UVB, and UVC based on frequency. UVA is visible and helps regulate behavior and activity of chameleons. UVB is invisible but critical to the formation of vitamin D3 in the skin of reptiles which allows them to absorb calcium from their food. UVC is invisible, harmful and usually not present in significant amounts. Chameleons MUST have UVB light to survive and lack of UVB will lead to Metabolic Bone Disease (see health section), severe deformation and death. UVB can be given through unfiltered sunlight (UVB does not penetrate glass or plastic well) or through commercially available linear or CFL UVB bulbs. After about 6 months of use the bulbs will stop emitting adequate levels of UVB even though they are still shining so it important to change the bulbs every 6 months unless you have a UVB meter to measure its UVB output.
More information:
Lighting for Chameleons - Part 1
Lighting for Chameleons - Part 2
Q: Which UVB bulb does my chameleon need?
A: The numbers on the UVB bulbs corresponds to the percentage of light that is UVB. 2.0 bulbs are designed for reptiles that receive little UVB, such as those in the lower layers of thick forests where sun doesn’t penetrate well. 5.0 bulbs are designed for reptiles that receive moderate amounts of sunlight like those in the upper levels of forests that get dappled sunlight throughout the day, like chameleons. 10.0 bulbs are designed for desert animals that receive high levels of unfiltered sunlight for most of the day. More is not necessarily better in this case. Just like you going out into the sun too long unsafe levels of UVB can burn chameleons or hurt their eyes.
See Lighting for Chameleons - Part 2 for more information.
Q: Do I still need a special UVB bulb is my chameleon's cage is next to the window so its getting real sun?
A: Glass blocks over 98% of UVB rays (which is why you don't get sunburned sitting by the window) so sitting your chameleon by the window does not provide any UVB rays unless it is open and there is no glass between the sunlight and your chameleon. The heat from the sun through a window can actually be a danger to your chameleon.
Q: Why do I have to change the UVB bulb every 6 months even if it still looks like its working fine?
A: The bulbs that give off UVB rays also give off regular UVA like regular light bulbs do. Over time they slowly give off less and less of the crucial UVB until it below the limit that chameleons needs to make vitamin D. However they will still look like they are working fine because they are still giving off UVA and since we cannot see UVB rays you can't judge when that lower limit has been met. Tests with a UVB meter have consistently shown that UVB levels start to get dangerously low by 6-9 months on average for the available brands of UVB bulbs. Some last longer and some run out sooner than that, but without a UVB meter it is impossible to know where your bulb stands. Therefore it is 'better safe than sorry' to replace the bulbs approximately every 6 months to avoid UVB levels dropping too low.
Q: Can I use Compact UVB bulbs or will it blind my chameleon?
A: At one time there was a manufacturing problem with the ReptiSun CFL UVB bulbs so that they emitted unsafe levels of UVB and even UVC rays, which corresponded to health problems like eye problems and burns in reptiles. This manufacturing issue was identified and corrected by the manufacturer several years ago and thus we have not seen problems with it since then unless someone unluckily picked up an older bulb from before correction. The ReptiGlo CFL UVB bulbs were never associated with these harmful effects. The linear ReptiGlo or ReptiSun bulbs have never had any health problems associated with them either.
Q: Do I need a basking bulb if I have a UVB bulb?
A: Generally yes. Reptiles are ectotherms, meaning they need to absorb heat from their environment to regulate their own body heat since they cannot produce it. Therefore a temperature gradient in their cage is essential to good health. They need a warm place to bask in order to digest food properly but they also need cooler places to cool down so they do not overheat since they can’t sweat or pant. A basking bulb provides warmer temperatures at the top of the cage but should not be so hot that it heats the entire cage. Your chameleon will utilize different temperature zones throughout the day depending on its metabolism and needs.
More info on temperature gradients.
Q: Which basking bulb should I use for my chameleon?
A: There are many specialty “daylight basking bulbs” available for purchase at pet stores to provide heat and suitable levels of UVA. These often cost $15+ and the exact same benefits can be gained from regular household incandescent bulbs found at grocery stores for much less. Most hobbyists use household incandescents. The wattage depends on your ambient temperatures so you may have to do trial and error to find the one that produces the temperature for you. 60watt bulbs are a good starting point.
Q: How long should I leave the lights on?
A: Chameleons should have at least 10-12 hours of uninterrupted UVB light every day as they would in the wild for proper metabolism. After this time they need the equivalent uninterrupted darkness, as they would have in the wild.
Q: Should I use a night light?
A: Chameleons have a parietal (third) eye, which exists as a photoreceptive scale on the top of their head. This senses light in the environment and helps regulate basking and activity even when your chameleon’s eyes are closed. Light at night can still disturb them while their eyes are closed because of this. So the blue or red night lights available are not recommended for this reason. A temperature drop at night is normal and good for metabolism so unless your ambient temperatures are less than 60 degrees you do not need supplemental heat at night. Better options for night heating are ceramic heat emitters (no light) or space heaters.
Q: Should I put the lights inside or outside the cage?
A: Always put any light fixtures and bulbs completely outside of the cage!! Reptiles can be burned very quickly if they get too close to a hot bulb, and they will even crawl up and sit on the bulb without realizing they are being burned. The damage from a burn can be severe, even life threatening. Even when you think you have it in a safe place where they couldn't get to it they almost always find a way. Always put all light fixtures outside of the cage.
Q: If the UVB lights mimic the sun for my chameleon, are they also really good for plants in its cage?
A: While some plants can grow well under the UVB and basking bulbs of your chameleon alone, the UVB bulbs are low intensity and many plants will do much better with a light better suited for plant growth. These are labeled 6000k - 6500k for the color spectrum they emit, rather than a particular type of ray like UVB, and are higher intensity for plant growth. They can be purchased from most home improvement stores.
