“Have You Seen the Light?... Getting Reptile Lighting Right!” by
Dr Shane Simpson B.V.Sc.(Hons), GCM(VP), CMAVA
Table of Contents
Introduction .............................................................................................................................................. 3 What is Light? ......................................................................................................................................... 3 Infrared Light ............................................................................................................................................ 3 Visible Light .............................................................................................................................................. 3 UV Light ................................................................................................................................................... 4 UVA ............................................................................................................................................ 4 UVB............................................................................................................................................. 4 UVC ............................................................................................................................................ 4
Lighting Terminology ................................................................................................................................ 5
Reptile Vision ........................................................................................................................................... 6 Types of Reptile Lights .............................................................................................................................. 6 Ceramic Heat Emitters ................................................................................................................. 6 Incandescent Lights ...................................................................................................................... 7 Regular Incandescent ...................................................................................................... 8 Infrared Bulbs ......................................................................................................... 8 Night/Moonlight Bulbs ............................................................................................ 8 Basking Spot Lamps ................................................................................................. 8 Water Resistant Spot Lamps....................................................................................... 9
Halogen ........................................................................................................................ 9 Mercury Vapour ........................................................................................................................ 10 Mercury Halide ......................................................................................................................... 10 Light Emitting Diode ................................................................................................................... 11 Fluorescent Lights ....................................................................................................................... 11 Tubes ......................................................................................................................... 12 Compact Lamps............................................................................................................ 13
UV Meters .............................................................................................................................................. 14 Ferguson’s Zones ................................................................................................................................... 15 Do Snakes and Nocturnal Animals Need UV Light? ............................................................................. 17 Mercury and Light Disposal ................................................................................................................... 17 Choosing The Right Lights...................................................................................................................... 18
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A small number of lights are manufactured with the alternative Bayonet style mount.
Reptile Vision To fully appreciate the importance of providing adequate light to reptiles it is useful to look at their visual system because it gives us a very good indication of what they require when it comes to lighting. Vision relies on two types of light receptors located in the sensory part of the eye called the retina. Rod cells simply
detect light and send messages to the brain which are converted into an image. Like in almost all animals they are the most common type of receptor found in the reptilian eye and function best at low light levels. The second type of light receptor is called a cone and they are responsible for colour perception. Humans normally have three types of cone cells with each type sensing different ranges of wavelengths of light. These three cone types allow humans to see wavelengths of light from 400 to 700nm (i.e. visual light). The variation in their response to a particular wavelength of light is interpreted by the brain as a different colour. Reptiles also have these same three types of cone cells but they also possess a fourth type that is able to see UVA light. This means that reptiles not only are able to see in colour very well but they can also see UVA! Like humans most reptiles are unable to see infrared light for two reasons. They lack receptors that detect light with a wavelength in the infrared range. In addition infrared light does not have enough energy to penetrate the eye and activate the cone cells anyway. But this is not all when it comes to reptile vision. Certain reptile species have a structure located on the top of their heads called the parietal eye or third eye. This structure is also a light receptor and is closely associated with a part of the brain called the pineal gland. These structures react to factors such as changes in day length and the sun’s position in the sky by altering certain hormone levels. This results in the animal adjusting its activity levels, daily and seasonal behaviours (e.g. reproductive cycle) and thermoregulation requirements. There are even light sensitive areas in the reptilian brain that respond directly to light being transmitted through the skull.
Types of Reptile Lights As anyone who keeps reptiles is aware there is a daunting number of different types and brands of lights on the market. Having an understanding about how the different lamps work and what type of light they produce will go a long way to ensure you get your reptile lighting right. Reptile lights can be classified into a number of different types. These are:
Ceramic Heat Emitters (CHE) While strictly a heating device CHE’s are included here because they are technically infrared lights and can be combined with other types of lighting to ensure the proper 6
promoted as producing UVA but the actual amounts are very small. The shape of the bulb and the internal reflector in the
light allows the light and heat to be focussed on a particular area to create a basking site. Examples include Reptile One Day Light Heat Globe, ExoTerra Intense Basking Spot, Exo-Terra Daylight Basking Spot and Zoo Med Repti Basking Spot Lamps. d.
Water Resistant Spot Lamps
These types of lamps are simply basking spot lamps that are made with a thicker glass to prevent shattering should water get onto their surface. They are ideal for aquatic or high humidity terrariums. Examples include the Exo-Terra Swamp Basking Spot. 2.
Halogen
The second type of incandescent globes available are called halogen globes. Like regular incandescent globes these are made of a tungsten filament inside a glass bulb. A small amount of halogen gas such as methyl bromide is contained within the bulb. This greatly increases the life of the bulb because it results in a chemical reaction that reduces the breakdown of the tungsten filament. The filament also reaches a higher temperature and can produce a higher light output and a whiter light. These lamps are more efficient and longer lasting than regular incandescent lamps. Examples include Exo-Terra Halogen Basking Spot and Zoo Med ReptiHalogen. Zoo Med also produce a “splash proof” halogen light called Repti Tuff. Reptile One have released a range of halogen globes that include a Moonlight, Infrared and Daylight globe. In addition to these Reptile One globes they also produce a Neodymium halogen globe. The Exo-Terra Halogen Basking Spot is also a Neodymium globe. Neodymium is a mineral that is added to the glass to give it a slightly purple colour. This glass filters the light to achieve more red and green output resulting in red and green objects looking brighter and more intensely coloured. These lamps are therefore very good for heating and providing light to animals that contain a lot of red or green colouration. A particular type of halogen globe that has been used by some in the reptile industry is the “dichroic light”. These come in both 12 volt (MR16) and 240 volt (GU10) versions. The name comes from the type of reflector these lights have that is designed to reflect visible light forward but all infrared light to pass through and exit through the back of the bulb. The halogen globe is made of quartz glass to withstand the high temperatures created and is sealed behind a regular glass safety cover to provide protection should the globe explode. There have been reports that these types of bulbs produce useful amounts of UV light but this is blocked by the glass safety cover. As such it has been suggested that the cover can be removed. There are several problems with using these lights including: These lamps produce a huge amount of heat and at the distance needed for safe basking temperatures the UVB levels are inadequate. Tests have shown that at a distance of 20cms from the globe the UVB output was satisfactory but the temperatures may reach as high as 137°C. If the lamps are moved to create a basking spot of 40°C there is negligible 9
Light literally means life to reptiles.
Every aspect of their lives is governed by it. Whether that light be provided by the sun or by artificial means, reptiles are literally solar powered. Reptile keepers must be very conscious of providing their animals with the correct types of light, in the correct form and for the correct length of time. Failure to do so has the very real potential of causing both short and long term health issues. The subject of reptile lighting is quite possibly the most misunderstood aspect of reptile husbandry. It is
not surprising that there is much debate and confusion about this topic! This E-Book provides an overview of the various types of lighting available for reptiles and the ways that they can be incorporated into enclosures to get it right!
The Reptile Doctor Š2014
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