UV lighting for reptiles is a hot topic and one that was fairly misunderstood for a long time. Now the hobby's understanding of UV light and the animals requirements has improved there is much more information available to help prevent pet owners from getting it wrong. Near enough all animals that are kept in captivity require some level of UV exposure to mimic a natural environment.
What is UV light?
UV lights used in captivity are replicating the natural sunlight that all animals that live outside are exposed to. The 2 waves of light that are important to animals health are UVA and UVB.
UVA
UVA in simple terms is visible light and is responsible for 95% of the suns UV rays. UVA is important for reptiles as it assists them in regulating natural behaviours such as feeding. Animals that would naturally feed during dawn and dusk require UVA light to follow such a feeding pattern. As well as assisting in other natural behaviours such as mating.
UVB
Like us, a reptiles skin is responsible for producing vitamin D. Upon providing your pet with UVB, you are recreating its natural exposure to sunlight whereby the UV penetrates the skin. Under the influence of the correct temperatures within the vivarium, it allows the pro vitamin D3 which your reptile has produced to change to pre vitamin D3. It is impossible for the body to absorb and use calcium without Vitamin D. It is recommended to provide your pet with a natural way of creating D3 alongside supplementation, to prevent against commonly seen and preventable diseases such and MBD (Metabolic Bone Disease) and calcium deficiency.
UVI
To measure the amount of UV rays that a given source is producing, we use a guide called the UV index. The same guide that weather reporters use to advise on the suns strength. The UV index, or UVI goes from 1 up to to 11+ and reptile keepers can use this guide to measure the wavelengths that allow our reptiles to produce their own vitamin D3. As our pet reptiles originate from different habitats all over the world and have different lifestyles, they are subjected to differing amounts of UV exposure.
Ferguson Zones
To make things a little simpler, the UVI has been condensed into 4 zones, known as the Ferguson Zones named after the Herpetologist that studied common pet reptiles basking UVI's. Most species kept in captivity can now be divided up into the 4 Ferguson Zones making it much easier for the keeper to provide their pet with the correct level of UVB.
Zone 1
Zone 1 mainly includes animals that are crepuscular, or active at dawn and dusk. It includes a UVI range of 0.7-1.4. Commonly kept reptiles that belong in the Zone 1 range-
Leopard Gecko
Crested Gecko
Pacman Frog
Fire Bellied Toads
Corn Snake
Pueblan Milk Snake
Fire Salamander
African Bull Frog
Cave Gecko
Axolotl
Emerald Tree Boa
Childrens Python
Henkels Leaf Tail Gecko
Tomato Frog
Red Eye Tree Frog
Reticulated Python
Satanic Leaf Tailed Gecko
Sinaloan Milk Snake
Solomon Island Boa
Green Tree Frog
Viper Gecko
Woma Python
Poison Arrow Frog
Mountain Horned Dragon
Mourning Gecko
Burmese Python
Zone 2
Zone 2 includes all occasional basking species that thermoregulate. It includes a UVI range of between 1.1-3.0 . Commonly kept reptiles that require Zone 2 levels of UV include-
Asian Water Dragon
Electric Blue Day Gecko
Jacksons Chameleon
Fire Skink
Royal Python
Gargoyle Gecko
Kenyan Sand Boa
Rat Snake
Rough Green Snake
Tri Coloured Hognose
Western Hognose
Mellers Chameleon
Moorish Geckos
New Caledonian Giant Gecko
Ornate Box Turtle
Painted Wood Turtle
Whites Tree Frog
Red Foot Tortoise
Taiwan Beauty Snake
Razor Back Musk Turtle
Garter Snake
Fiji Banded Iguana
African Fat Tailed Gecko
Hog Island Boa
Gopher Snake
Golden Mantella
Mexican Black Kingsnake
Nelsons Milksnake
Plumed Basilisk
Pancake Tortoise
Pink Tongue Skinks
Zone 3
Zone 3 includes all partial sun baskers that are thermoregulators. It includes a UVI range of between 2.9-7.4. The most commonly kept species that require Zone 3 levels are-
Bearded Dragon
Hermanns Tortoise
Yemen Chameleon
Green Iguana
Leopard Tortoise
Tegu
Berber Skink
Ackie Monitor
Collared Lizard
Tree Monitor
Carpet Chameleon
Cuban Knight Anole
Curly Tailed Lizard
Eyed Lizard
Emerald Swift
Rankins Dragon
Panther Chameleon
Parsons Chameleon
Reeves Turtle
Painted Turtle
Red Eared Slider
European Pond Turtle
Greek Spur Thighed Tortoise
Horsfield Tortoise
Hinge Back Tortoise
Gold Dust Day Gecko
Lace Monitor
Indian Star Tortoise
Kimberely Rock Monitor
Mediterranean Pond Turtle
Oriental Garden Lizard
Radiated Tortoise
Zone 4 Zone 4 includes all sun worshippers that remain in the sun far longer than zone 3 animals. It includes a UVI range of between 4.5-8. The most commonly kept species that require Zone 4 levels are-
Chuckwalla
Blue Spiny Lizard
Butterfly Agama
Cuban Rock Iguana
Desert Horned Lizard
Lesser Earless Lizard
Marginated Tortoise
Moroccan Uromastyx
Occelated Uromastyx
Ornate Uromastyx
Red Head Agama
Rhino Iguana
Saharan Uromastyx
Spiderman Agama
Starred Agama
Sungazer Lizard
Your reptiles enclosure should include a natural gradient, not only for heat but also for UV light. This means having a basking side that is suitable for your species and matches its Zone requirements right down to an area that receives 0 UV such as a hide. It is important that all animals in all Ferguson Zones can retreat away from the "sun" when they want to. Most UVI readings are taken from around 30cm from where the animal will be basking. It is important to take into consideration anything that may be blocking the UV light source and reducing its efficiency such as guards or mesh vivarium lids. UV light bulbs do lose there effectiveness over time and it is important to change them according to the manufacturers instructions. As a general rule compact bulbs and T8 bulbs should be changed every 8 months and T5 and Mercury Vapour bulbs every 12 months. Hopefully this makes it a bit easier for you to chose the correct lighting for your pet reptile. If your pet is not listed please get in touch and we can recommend an appropriate bulb for you.