by Zach Brinks
What lighting is important for your pet reptiles or amphibians? What exactly is UV light, and why do my reptiles or amphibians need it? What are the best ways to provide UV light? Throughout this blog, these questions (and hopefully many more!) will be answered. While much debate surrounds the use of UV light as it pertains to keeping reptiles and amphibians, it is commonly accepted that many species of herps greatly benefit from routine exposure to UV light, and it is absolutely vital to some.
Before it’s possible to make an informed decision about lighting and your pet reptile or amphibian, there are several important terms you should be familiar with.
What is the Electromagnetic Spectrum?
The Electromagnetic Spectrum is simply the range of frequencies of electromagnetic radiation. The Electromagnetic Spectrum includes gamma rays, x rays, ultraviolet light, visible light, infrared light, microwaves, and radiowaves. For the purposes of this article, we’ll concern ourselves with UV light.
What is CRI?
CRI stands for the Color Rendering Index, which is a measure of a light source’s ability to reproduce color in comparison to a natural light source (typically compared to daylight). In general, the higher the CRI the better for daytime use with our pets. The higher the CRI, the more vivid things appear to us.
What is Color Temperature?
Measured in kelvins (K), color temperature is a way for us to compare the color of light produced by artificial means to that of what we’re trying to mimic in nature – mainly, daylight. Daylight has a kelvin measure of approximately 5780K. In reptile and amphibian enclosures, a color spectrum of 5500-6500K is ideal for most species of diurnal reptiles and amphibians.
What is a Lumen?
The lumen is the SI unit of luminous flux, which measures the amount of visible light emitted by a source. While lumens measure the amount of light produced by a light source, more lumens do not necessarily equate to a brighter environment. To measure that we use lux.
What is a Lux?
Lux is simply one lumen per square meter. It is a measure of visible light over an area. While lumens measure the visible light output of a source, lux actually quantifies the level of visible light in an area. Foot candles are also commonly used in the US to describe light levels. One foot candle equals one lumen per square foot, or a little less than 11 lux.
What is Full Spectrum lighting?
Concerning reptile and amphibian lighting, full spectrum lighting is simply a marketing ploy attempting to make the light source in question sound more balanced or complete than it really is. While full spectrum bulbs do emit light across many wavelengths of the electromagnetic spectrum, the light emitted is by no means balanced. While sunlight is considered full spectrum, the vast majority of bulbs advertised as full spectrum do not supply the same benefits of sunlight. When it comes to choosing correct lighting for reptiles and amphibians, consider full spectrum lighting as a sales gimmick and nothing more.
What is UV light?
UV light is an abbreviation for ultraviolet light, which has a wavelength of 400 – 10 nanometers, shorter than visible light. As far as reptile keeping is concerned, there are 3 types of UV light – UVA, UVB, and UVC.
UV light is naturally found in sunlight, and is the basis for life on earth. Organisms utilize UV light for photosynthesis, which makes up the base of most food chains on earth. The planet’s ozone layer blocks almost 80% of the UV light emitted from the sun from reaching the planet’s surface, mostly at the more harmful, shorter wavelengths. Still, we all have experienced UV light – that’s what causes sunburns.
What is UVA light?
UVA (400-315 nm) makes up about 95% of the UV radiation that reaches the surface of the earth. Humans cannot see UVA, but many species of reptiles can. While humans have 3 types of cones in their eyes that allow for color vision, reptiles have 4 types of cones, with the 4th cone detecting UVA. Many reptiles also can detect UVA with their pineal gland. Therefore, it should come as no surprise that reptiles denied UVA tend show less interest in food and an overall reduction in activity.
To visualize how a lack of UVA would affect your pet reptile, imagine yourself going through life colorblind. Think of all the vivid colors you would miss out on. Many brightly colored foods would be much less appetizing. You’d have a reduced perception of the environment around you, and your overall well being would be greatly diminished. UVA should be provided for all diurnal reptiles when possible.
What is UVB light?
UVB (315-280 nm) is the spectrum of UV light most reptile and amphibian keepers are concerned with. UVB plays a vital role in the production of Vitamin D3 in your pet reptile or amphibian’s body, which facilitates uptake of dietary calcium and fights maladies such as metabolic bone disease. Without UVB, reptiles and amphibians (and you!) cannot efficiently utilize calcium, and will eventually end up deficient in this vital mineral. A lack of calcium results in poor or improper bone growth, and can result in metabolic bone disease. Proper calcium levels are also vitally important to ensure proper function of the nervous system.
While the relationship of UVB, Vitamin D3, and calcium is well known, UVB plays other important physiological roles too. Exposure to healthy levels of UVB light are important for normal functioning of the immune system, cell growth, blood pressure, and even insulin secretion.
Keep in mind that low levels of UVB are present in the shade on a sunny day, and many nocturnal reptiles and amphibians are probably exposed to UVB in nature. Animals that eat whole vertebrates, such as snakes, may not need UVB, as they receive Vitamin D3 from their prey. For most species of reptiles and amphibians, dietary supplementation of Vitamin D3 does NOT provide the same benefits as UVB lighting.
What is UVC light?
UVC (280-100 nm) is filtered out by the ozone layer and does not normally reach the surface of the planet. UVC is harmful to living cells, and is often used in butcher shops and laboratories to limit microorganism growth. UVC should never be used in your reptile or amphibian enclosure.
What light(s) do my reptiles or amphibians need?
The lighting demands of a specific species of reptile or amphibian vary greatly, and are largely dependent on two factors: the natural habitat of the animal and the behavior of the animal
The natural habitat of the animal in question play an important part of selecting proper lighting for your reptile or amphibian. Consider when the species in question is active in it’s native environment, and where it lives. Nocturnal reptiles are going to have much less demand for lighting than animals active during the day, while animals that live on the rainforest floor will be adapted for dimmer conditions than a diurnal lizard that inhabits a desert. In general, animals that inhabit deserts will appreciate a brighter captive environment than terrestrial species found in the rainforest, with species inhabiting grasslands or deciduous forest falling somewhere in the middle. Brighter environments generally equate to higher UVA and UVB needs, but there are exceptions.
The behavior of the animal also plays an important role in determining the proper lighting for your reptile or amphibian. Diurnal animals will require more light and UVB than nocturnal animals in most situations. Some nocturnal creatures, such as White’s Tree Frogs and some geckos, commonly sleep exposed to sunlight during the day, during which they absorb UVB radiation. Snakes, on the other hand, have evolved to fulfill their Vitamin D needs via their diet, and most species do not require UVB exposure for a healthy life. It’s important to properly research the individual needs of the specific species of reptile or amphibian you plan on housing when making a decision on lighting.
What Kinds of light bulbs are there for reptiles and amphibians?
In general, lighting products can be categorized into 3 basic groups : UV lighting products, ambient lighting products, and heating products that produce light. Most UV and heat/basking bulbs produce visible light. Additionally, several products exist on the market that fit into more than one of these groups.
UV bulbs – UVB lighting will provide much needed UVA and UVB for your reptile or amphibian pet. UVA aids in your reptile’s vision, and your pet will show an increase in appetite and natural behaviors. UVB facilitates your pet’s ability to utilize dietary calcium. There are several types of UV bulbs on the market.Linear fluorescent bulbs are an old standby, and come in a variety of sizes that will fit in shop lights, aquarium hoods, etc. Generally, the animal should be able to bask within 12-18” of the bulb, and the bulb should be replaced every 6 months. Compact Fluorescent bulbs share many characteristics of the linear fluorescent bulbs, but can be utilized in a screw-in incandescent socket, such as that found in most dome clamp lamps. Mercury Vapor bulbs use a screw-in incandescent socket as well, and produce both UV and heat. They should be used with a wire clamp lamp, and replaced once a year. Metal Halide bulbs require a special fixture, but they produce some of the best quality UV light available (next to the sun, of course!). Metal halide bulbs also produce heat and high quality 6500K visible light, and only need to be replaced every 2 years! While shopping for UVB bulbs, you’ll notice many brands place a number after the name of the bulb (ie 2.0, 5.0, 10.0, etc). The number simply reflects the amount of UVB produced by the bulb. The higher the number, the more UVB produced.
Basking bulbs – Most basking bulbs on the market today produce some UVA as well, and are often called ‘full spectrum’ bulbs. Basking bulbs are a great source of heat and ambient light for your reptiles. Some amphibians, such as White’s Tree Frogs, will benefit from a basking light, as well. A temperature gradient is needed by ectotherms (commonly called ‘cold blooded’ animals, including reptiles and amphibians) in order to regulate their internal body temperature. Many different kinds of basking bulbs are available on the market. Incandescent basking bulbs are your basic screw-in bulbs, and come in both globe/showcase (your typical round lightbulb) form, as well as a ‘spot’ or ‘tight beam’ type with a built in reflector. Incandescent basking bulbs typically last about 3-4 months. Halogen basking bulbs are more efficient at producing heat than standard incandescent types, and generally last about 6 months.Red (Infrared) or Moonlight bulbs provide very little light, but do provide heat. These bulbs are great for providing a heat source for nocturnal species of reptiles, such as leopard geckos or ball pythons, or for increasing the ambient temperature of a habitat. Red (Infrared) and moonlight bulbs typically last 3-6 months, depending on how many hours a day they are used. Ceramic heat emitters produce no light and are a more diffuse heat source. Under the proper conditions (mounted socket so the bulb is not moved when hot, wire fixture), ceramic heat emitters can last years.
Ambient/visible lighting sources abound lately, and there seems to be more available every day. Largely due to increased popularity of vivaria and aquaria, visible light sources (as discussed here) do not emit heat or UV, but instead provide ambient light to an enclosure. Visible lighting sources can be used to establish a photoperiod (a regular day/night cycle, vital for the wellbeing of all reptiles and amphibians. Generally, visible lighting sources in the 65-6700K range are best. Fluorescent and Compact Fluorescent bulbs are a popular choice, and widely available at many home improvement stores. More costly but much more efficient, HOT5 or LED lighting, which produce more light for the wattage.