The Green Iguana (Iguana iguana) is a large arboreal lizard originating from the tropical rainforests of Central and South America. In fact, it is one of the largest New World lizards with an adult measuring between 1.2-1.5m or more. This is therefore, not an ideal animal for a novice reptile owner, and any potential owner should consider the space requirement, expense, and dangers of owning such a lizard.
Males can be easily distinguished from females by their pronounced dewlap, having a larger broader head and row of spiny crests, as well as a row of large femoral pores.
Green iguanas belong to the Order Squamata, Suborder Sauria/Lacertilia, Family Iguanidae, Genus Iguana.
A wooden / chipboard vivarium with sliding glass doors provides the most appropriate setup for an iguana, being easy to clean, insulate and keep secure. The minimium recommended size for an adult iguana would be 1.8m length x 1.8m width x 1.2m height, but obviously these lizards will enjoy as large an enclosure as it is practical to keep.
Inside the vivarium, a hiding place should be provided which may be half a log, a purpose built cave or even just an empty box with a hole cut in the side. Branches of different lengths and diameter should also be placed around the vivaruim to allow iguanas to climb up and bask as they would in the wild.
Iguanas are generally pretty solitary, and can be aggressive if kept together, so adults should be kept alone.
A vivarium should be “spot-cleaned” daily to remove any droppings, dead insects or uneaten greens. Once a week, the whole vivarium can be cleaned with a disinfectant suitable for reptiles (further details of suitable disinfectants can be obtained from your vet). It is important to always wash your hands thoroughly after handling reptiles as they can carry Salmonella.
It is important to use a substrate that is easy to keep clean and replace, and is not going to cause a problem if accidentally eaten. Newspaper therefore makes the ideal substrate, but another alternative would be a substrate which retains humidity well such as cocoa fibre. Wood chips or shavings should never be used as they commonly cause intestinal blockage in lizards.
Reptiles are not capable of regulating their own temperature so it is very important to keep their environment at an appropriate temperature at all times. A temperature gradient should therefore be provided, giving your reptile a hot end where they can bask and a cooler end to which they can retreat.
There are several types of heat sources available for vivariums including ceramic heaters (infra red light bulbs), tube heaters, reflector bulbs (incandescent spot lights) and heat mats. Incandescent spot lights will provide the ideal basking spot for your iguana, but should not be used as the sole heating source whereas heat mats are more useful in providing a background heat for the whole vivarium.
It is important whichever form of heating is chosen, to always monitor it carefully with a thermometer, and use some form of thermostat so that temperature can be accurately controlled. Heat sources should also be protected with a wire mesh guard or similar safety device if they are within an iguana’s reach.
The ideal temperature range at which to keep a iguana would be 25-30°C (77-86ºF) in the daytime, with a basking spot of 36°C (97ºF), and temperatures falling no lower than 21°C (70ºF) at night.
This should ideally be measured with a hygrometer and kept moderately high (50-70%) for iguanas that are used to a humid environment. This can be achieved by misting the vivarium with warm water several times a day.
Iguanas need to have access to both UVA and UVB rays, which many supposedly “full spectrum” reptile bulbs do not supply, so it is important to check this before purchasing a bulb. UVB rays are very important to allow a reptile to produce Vitamin D, which is essential for the absorption and use of calcium. Without this lizards are at risk of developing Metabolic Bone Disease, which can often be fatal.
Various different types of UVB lights are available. It is important to check the percentage of UV supplied by the bulb. Lizards such as iguanas require at least 5% UV output. UV lights should be left on for 12 hours daily and replaced every 6 months.
Iguanas are herbivores, naturally browsing on fruits, leaves and blossoms, and in captivity should be fed a varied diet with vitamin and mineral supplementation. Suggested plants are listed on a separate diet sheet. Fresh food and water should be supplied once daily.
Iguanas generally live between about 10-15 years.
Signs of Health
A healthy iguana will be bright and alert with clear open eyes and nostrils and a clean vent. Skin should be undamaged with no sign of parasites, and shedding should occur regularly. Your iguana should also be keen to eat, and pass faeces at least every 2-3 days. It is important to become familiar with your iguana’s normal appearance, movement and behaviour, in order that signs of illness can be noticed at an early stage.
It is advisable to take your iguana to a vet who routinely deals with reptiles for a general health check and faecal sample at least once a year.
Signs of Illness
Reptiles will often not show obvious signs of illness until they are very sick, but you should look out for any changes in appetite or faeces passed, as well as changes in weight, behaviour, skin colouration (dark colouration can often indicate stress or illness) or breathing. Other signs of illness include discharges from the eyes, nose or mouth or problems with shedding.
If you have any concerns, do not hesitate to contact a reptile vet as soon as possible.
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This caresheet is only intended as a general guideline, so please ask for further information. Written and researched by Joanna Hedley BVM&S MRCVS