Green Iguana Care Sheet
Green iguanas originate in South and Central America. Despite their name green iguanas can be marked in a range of colours such as blue, black, orange, black or even pink. The Latin name for the green iguana is Iguana iguana. Green iguanas are popular pets but are extremely challenging to care for properly with many being left in rescue centres each year.
The green iguana lives near water, swimming using strokes of the strong tail. They will also climb several metres up into trees, jumping down into water to escape predators or using the spiny tail to whip when frightened. When it is cold the iguana will spend more time on the ground to try to stay warm. The iguana is diurnal (active during the day) and a herbivore (eats both plants and flowers). It forages for food in trees and on the forest floor.
The green iguana is a very large lizard, commonly growing up to 1.5m in length or, less commonly, up to 2m. This happens very quickly and so you need to plan how you will accommodate your pet’s rapidly changing needs. Much of this length is the powerful, spined tail which can give a painful whip if the animal feels threatened.
Iguanas are very variable in colour and often change colour as they move from being a juvenile to an adult.
Never handle your iguana by the tail as it can break off easily. Although it may regrow it usually will not look the same.
The dewlap is the skin in the throat region which the iguana is able to flare out when it is feeling threatened or territorial. The body is covered in fine scales and should have an iridescent sheen when the animal is healthy.
The iguana has strong jaws and very sharp teeth which can break skin if the iguana bites. These teeth are attached to the inner aspect of the jaw.
Iguanas have the ability to see UV light, unlike humans. This allows them to detect the vital UV light rays in sunlight that create vitamin D within the skin whilst basking. They also have excellent day vision, both close up or at a distant. However they have poor sight in dim lighting.
It is difficult to distinguish males from females among hatchlings and juveniles. When they become adults, sexual differences become more apparent. The males generally have larger heads, thicker dorsal spines and larger jowls. The larger femoral pores of males also help to distinguish them from females.
Enclosure: Vivaria (glass walled or fronted enclosures) are most commonly used to house iguanas. If wood is used to make the vivarium this should be properly sealed to facilitate cleaning. The vivarium should not be kept in direct sunlight as they can easily overheat. Ensure that the vivarium is secure and well ventilated. The enclosure should be as big as possible but a tank measuring 4ft x 2ft x 2ft is the minimum size for a juvenile. Adults will require much larger enclosures, which can often be best built to fill an entire room.
Substrate: The substrate is what lines the bottom of the cage. An ideal substrate is one that is inexpensive, aesthetically pleasing, easily cleaned, absorbent, and digestible if swallowed. Substrate can be flat newspaper, sheets of brown wrapping paper, reptile matting or cork or slate tiles. DO NOT use cedar shavings, gravel, crushed corn cob, kitty litter, wood shavings, or potting soil that contains vermiculite, pesticides, fertilizer, or wetting agents. In particular, avoid Calcisand. Although this is commonly sold as safe for reptiles it can cause eye problems and intestinal blockages. Sand easily sticks to food and so can be ingested, building up in the intestines, particularly in young iguanas and so is not recommended.
Landscaping and ‘Furniture’: Branches for climbing and basking under the secondary heat source should be secure. These branches should be of various sizes, clean and non-toxic. Some of the branches should be as wide as the width of the iguana. Boards covered with indoor/outdoor carpet also make good climbing posts. Flat-bottomed, smooth rocks are a good addition to the habitat, and can help wear down the toenails, which in captivity, may need to be clipped occasionally.
Reptiles like a place where they can hide. This could be an empty cardboard box, cardboard tube, or flower pot. The hiding places should provide a snug fit and should be at different heights in the enclosure. If your iguana does not use its hiding place, try a different one or move it to a different location. If possible offer more than one hide.
Appropriate plants in the enclosure can provide humidity, shade, and a sense of security. They also add an aesthetic quality to the enclosure. Be sure they are nontoxic. Dracaena, Ficus benjamina, and hibiscus are good choices. Be sure the plants have not been treated with pesticides and the potting soil does not contain vermiculite, pesticides, fertilizer, or wetting agents. Washing the plant with a water spray and watering it thoroughly several times to the point where water runs out of the bottom of the pot, should help remove toxic chemicals, which may have been used. Keeping purchased plants in a different part of the house for a while before putting them in the enclosure will also be helpful. Edible plants can be grown specifically to be eaten by the iguana.
Iguanas have the same body temperature as their surroundings. They come from arid woodland and desert environments, and require supplemental heat to be healthy and carry out their bodily functions such as digestion. They prefer 80-90°F during the day and temperatures in the 70’s at night. If a reptile is cold, it cannot properly digest its food and is more likely to become ill. Lizards like a temperature gradient so if they are cold, they can move to a warmer part of the cage and vice versa. Place a good quality thermostat in the cage at the level the iguana spends most of its time so that the temperature is automatically regulated.
Primary heat source: A primary heat source is necessary to keep the temperature of the entire cage within the proper range. Ceramic infrared heat emitters or panels which produce heat, but little visible light, can be used. Alternatively, a series of incandescent lights over the cage can be used but at night these lights will need to be turned off and another heat source may be needed depending on the ambient temperature. For larger enclosures, a space heater or separate room thermostat can be used to keep the room at the appropriate temperature. Fire alarms should be placed in rooms where lights or other heat sources are used.
Secondary heat source: A secondary heat source creates more heat in specific areas of the cage to provide a temperature gradient. To best supply this gradient, the secondary heat source should cover only 25-30% of the surface of the enclosure. There are also special ‘basking lights’ available. Either type of light should shine down on a particular basking area from outside the cage or from behind a guard. The temperature under the light in the area in which the iguana would be basking should be 95-100°F. Hatchlings housed in smaller aquariums will require lights of lower wattage, or the temperature may become too warm very quickly. Do not use hot rocks as heat sources. Like the primary heat source this heat should be under the control of a thermostat to keep temperatures within the correct range.
Visible white light: In addition to heat, incandescent bulbs also provide visible white light. A combination of fluorescent and incandescent light fixtures can be used to provide visible light to all areas of the enclosure.
Ultraviolet light: In addition to heat and white light, iguanas must have access to natural sunlight for good health. This is because they need a certain spectrum of ultraviolet (UV) light called UVB. UVB is necessary for the iguana to make Vitamin D. No artificial light is as good as sun in providing UVB, so when the outside temperature on a sunny day is over 70°F, place your iguana outside in a secure screen or wire cage with a locking door. Provide some shade and a hiding place within the enclosure. UV rays do not penetrate window glass so iguanas placed in a sunny window are not receiving UV light but do risk overheating.
When an iguana does not have access to bright sunlight, special lights are used to provide the UVB light. Fish/aquarium and plant ‘grow’ lights, either incandescent or fluorescent, do NOT produce UVB. You need a light which emits light in the 290-320 nanometer range. Lights producing only UVB, and lights which produce a combination of UVB and white lights designed specifically for reptiles are available. These UVB light sources should be replaced every 6 months.
Remember that UV light cannot penetrate glass, so when overhead UVB light sources are used, the top of the enclosure must be a wire mesh that is not too fine. It is recommended that the UVB light source should be less than 18 inches from where the iguana spends most of its time; 10-12 inches is optimal.
The areas illuminated by the incandescent basking light and the UV light should overlap. If the iguana spends almost all his time basking under the incandescent light, and the UV light is at the other end of the cage, he is not going to receive any benefit from it.
Water and humidity
Although iguanas receive most of their water requirement from the food they eat, fresh drinking water should be available at all times in a shallow bowl that cannot be tipped over. Proper humidity is necessary for proper shedding. When the background humidity is low, mist your iguana with water several times a week. Most iguanas appear to enjoy soaking in a tub of water. Be sure the iguana is able to get in and out of the container easily. You will need to clean the container and replace the water regularly (at least daily), since your iguana may urinate or defecate in the water. In fact, water usually stimulates them to eliminate, so immersing them in water is a part of the treatment for constipation.
The cage and food and water bowls should be cleaned routinely. Rinse the items well after cleaning. Iguanas can harbour the bacteria Salmonella which is dangerous to people as well as other potentially seriously harmful organisms. Be sure to wash your hands after handling your pet or its equipment. Children, the elderly, pregnant or sick should not come into direct contact with reptiles or contaminated materials. Always seek prompt medical attention should you become unwell.
If you have more than one
Reptiles are territorial and may fight when caged together. A male and female iguana can occasionally be kept together, however, the male may become too aggressive during the breeding season and have to be removed. This also does pose the risk of unwanted breeding. Larger iguanas may keep smaller cage mates away from food and heat sources, and may even see them as food. If housing iguanas together, a larger cage will decrease the
possibility of aggression; nevertheless, monitor the iguanas closely and separate them if there is any sign of aggression. In most cases iguanas are best kept alone.
Temperament and handling
Iguanas tend to be mellow and docile but can give nasty bites, scratches or injuries from the tail. Children should be closely supervised by a responsible adult at all times near reptiles. Iguanas tend to be curious, and will enjoy exploring, so if you can, provide a safe, larger enclosure.
To pick up an iguana, place your hand under its abdomen and gently scoop it up while securing the tail under your arm. Ask someone experienced to show you how to handle your iguana calmly and confidently to avoid scaring or dropping him or her.
Behaviour and body language
To better relate to your iguana, you need to understand what various behaviours and body positions mean. During the breeding season, to display dominance, or if startled or threatened, an iguana may puff out its dewlap. Both males and females will display this behaviour. To appear even more menacing, the iguana may also “gape,” or open his mouth very wide. This can certainly make him look more aggressive, since his mouth is quite large. Another way iguanas show dominance, is to swish or whip their tails.
Male iguanas reach sexual maturity between 15 and 27 months of age, with females delaying puberty by around another year. The female will generally lay around 20-70 eggs in a clutch. If fertile, the eggs will hatch in 10-15 weeks. Unmated females may also lay eggs. During egg laying female iguanas require additional calcium. Although pregnant iguanas may not eat for 2-3 days before laying eggs a sick pregnant iguana should be viewed as an emergency and immediate veterinary care provided.
Because iguanas are herbivores, they need a balanced diet of plant matter. In the wild they would eat over 100 different types of vegetation so make sure your iguana’s diet is varied too. You should not feed your iguana any animal products including meat, dairy products or insects. Some plants can be toxic so makes sure you research any new additions to the diet.
Feed cabbage, kale and spinach only as an occasional treat, if at all. They contain oxalates which can bind calcium and could pose a problem if fed in high amounts.
Plant matter in the diet should consist mainly of green leafy vegetables. Other vegetables can be included, up to 30-40% of the diet. Fruit should make up the smallest portion of the diet, no more than 10%. The vegetables and fruits can be shredded or torn into small pieces and mixed together to encourage the iguana to eat all that is offered, and not just pick out his favourite foods.
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A good quality calcium supplement should be added to the diet every day to ensure that the ratio of calcium to phosphorus is 2:1. For the same reason never use a supplement that also contains phosphorus. You may also add alfalfa powder to the diet in small quantities to increase the calcium and protein content.
Most of the medical problems experienced by iguanas can be prevented by paying close attention to good husbandry and nutrition but they can still develop just as many health problems as any other pet. Often an iguana will try to conceal signs of ill health so if you are worried in any way seek prompt veterinary advice. Common problems to look out for include weight loss, diarrhoea, retained skin especially around the head, eyes and digits, loss of appetite or constipation. Your vet is the best person to advise you about your pet’s health and will be happy to answer any questions you may have. Rather than wait for a problem to occur why not make an appointment for your iguana to have a regular check-up, just as you would with a dog or cat.
Pet insurance is available for bearded dragons and means that financial concerns do not add to the worry of having a sick pet. Please ask a member of staff for a leaflet about exotic pet insurance.
Healthy Pets Plan
We also provide a healthy pets plan for exotic animals to help spread the cost of routine treatments over the course of 12 months. The plan includes faecal screening, worming and parasite treatment as necessary, husbandry checks and consultations, annual health checks, microchipping, claw clipping and other benefits. Please ask a member of staff about the benefits of the healthy pets plan or for a leaflet which details prices and benefits.