IGUANAS

Green Vegetables

For the green vegetable, use whole fresh green beans, snap peas or snow peas, that is, the peas and their edible pods. Wash the pods well, tearing off any stems. Chop them by steel-knifing them in the processor or chop by hand. Remember to process or hand-chop until the pieces are small enough to be easily swallowed by a lizard who gulps his food rather than chews it.

To vary the flavor and smell, you can occasionally throw in a small amount of broccoli, bok
choy, or Brussels sprouts.

Orange Vegetables

For the orange vegetable, concentrate on the winter squashes. These are the hard squashes that, when cut open, reveal their deep-to-pale orange flesh. Winter squashes include acorn, banana, delicata, Hubbard, kabocha, pumpkin, spaghetti and turban.

These squashes are called winter squashes because, when kept in dark, cool, dry places, they will stay fresh for several months. Those harvested during the mid- to late summer will stay fresh throughout the winter months when stored this way. This makes it easy for most of us to stock up on fresh pumpkins or other squashes when they are on sale, making fresh squash available throughout the winter to our iguanas.

To make cutting into the harder squashes a little easier, microwave them until they are just soft enough for you to cut into pieces. Peel the squash, and then cut into lengths that will fit through the food processor's or other shredder's feed tube. If grating y hand, cut into sections that are comfortable for you to hold safely.

Some iguana owners have reported that kabocha squash brings out blue accent skin colors on some iguanas, more so than other winter squashes. All squashes are high in carotenoids which, in other species, are known to bring out some latent coloring.

Crookneck and scallop squashes, both soft summer squashes, are fine to use in season. They have the soft skins and flesh that are eaten, raw or cooked, without removing their seeds.

The two squashes that are not suitable for use as anything other than an occasional treat are cucumbers and zucchini. Both are poor, nutritionally speaking.

Carrots and sweet potatoes can also be fed, but they do contain oxalates, so use them occasionally, sticking to winter squashes as your primary orange vegetable. Yams are okay occasionally, as well; however, they contain oxalates as well as saponins, so should be used even less frequently than the carrots or squash. All of these vegetables should be shredded. If you are also using a parsnip, which is a seasonal vegetable in some regions of the country, the parsnip can be shredded at the same time as the orange vegetable.

Other Vegetables

Your iguana may enjoy some of the following vegetables that may be used in small amounts. These should be considered as flavorful additions to the Basic Salad, not a replacement for the more nutritious vegetables. Try mushrooms, bell peppers, onions, green onions, other root vegetables, cactus pad, star fruit, asparagus, okra, and just about anything you see in the produce department that looks interesting. Some of these vegetables have oxalate, oxalic acid, and other chemicals that you don't want too highly represented in your herbivore's diet, so do go easy on them.

Fruit

Fruit is used more for color and moisture than it is for its nutritional contribution to the overall salad. Just as some vegetables are more nutritious than others, so too are some fruits better than others in this regard.

Many types of fruit are suitable for the salad: raspberries, blueberries, mulberries, strawberries, pears, plums, mangos, papayas, cherries, apricots, cantaloupe, prickly pear cactus (nopales) and kiwi (both skinned) are all good fruits. As you may have noticed, most of these represent the most expensive fruits found in the market, or are only available seasonally.

Fortunately, most markets have frozen blueberries, strawberries and cherries all year, and you can sometimes find frozen mango and berries at specialty stores such as Trader Joe's. Figs are the highest in calcium, with dried figs highest of all. Unfortunately, fresh figs are rather expensive unless you are lucky enough to have a tree. Dried figs are available in grocery stores during the November-December holidays, but can often be found throughout the year at health food stores. Dried figs must be soaked in water to rehydrate them before feeding them out to your iguanas.Fruits should be steel-knifed or finely chopped, then mixed in with the vegetables.

Fruits suitable for occasional treats include banana (high in phosphorous), carambola (star fruit; high in oxalates), melons, berries, and grapes. Hard fruits should be shredded. Berries, melons, and grapes should be chopped into smaller pieces. If the grapes have large seeds (such as Globes), remove them before serving to small iguanas.

Do not feed the melon skin, banana skin (unless you buy organically grown bananas - all others are treated with a fungicide to retard mold growth on skin). Do not feed papaya, pear, apple, plum, peach, nectarine, or other seeds. The tiny seeds in berries, seedless grapes, and bananas are fine.

Some iguana keepers have reported that their hatchlings became impacted after several weeks of eating fruits with lots of tiny seeds, such as figs and raspberries. Along with making sure that all dried fruits are thoroughly reconstituted, alternate these seeded fruits with ones from which you can easily remove the seeds.

Adding the Alfalfa

The goal is to have the alfalfa dispersed evenly throughout the Basic Salad. Depending on the form of alfalfa you are using, you may need to do a little work to it to get the alfalfa ready to mix in.

Alfalfa tablets have to be ground into a powder (a pill crusher, or coffee or nut grinder work well). If the alfalfa came in pull-apart capsules, pull them apart and empty out the powder, and discard the empty capsules. If you bought alfalfa leaf tea in tea bags, just tear open the bags and empty the contents into a storage container and add to the salad as needed. To add the these forms of alfalfa to the Basic Salad, just mix the alfalfa in with the prepared vegetables and fruit.

If you are using the alfalfa pet food/bedding pellets, the pellets should break down in the juices of the vegetables and fruit. If the pellets do not break down within a few minutes, you can add some water to the salad, or soak the pellets briefly before mixing into the salad. If the pellets still don't soften enough to fall apart on their own, stop using that product and switch to another brand or, better yet, a powder or leaf product made for humans.

Tofu

Some people recommend the use of tofu, a plant protein source made from soybeans. The problem with tofu is that it is high in fat, and fat impedes calcium metabolism. Iguanas fed tofu on a regular basis often develop metabolic bone disease, especially if any other part of the D3-calcium-phosphorus triad is out of balance. If you eat tofu and want to give your iguana a bit of it when you are making some for yourself, then by all means feel free to do so. It should not be fed on a regular basis, however, and when fed, fed in very small quantities.

There is a nonfat tofu cake available that would be great for use except for the other problem associated with regular tofu (soy) use. Tofu contains goitrogens, phytochemicals that interfere with the thyroid gland's uptake of iodine from the diet. Over time (and it may be a period of several months, depending on how much other highly goitrogenic foods are being fed), the thyroid gland will malfunction, causing hypothyroidism when fed in excess. (This is a risk for humans, as well, something that many people with hypothyroidism do not realize - and something that is of special concern as hypothyroidism is one of the leading undiagnosed or misdiagnosed health problems affecting women today.)

Edible Flowers and Potted Plants
There are several edible flowers that you can grow yourself or buy in the produce (not flower!) section of the grocery store or plant nursery. Hibiscus, roses, and nasturtium both grow almost anywhere. In cold climates, hibiscus can be grown in a tub and moved indoors to overwinter them.

Iguana Salad - the Basic Salad

The Basic Salad is the vegetable, alfalfa and fruit mixture. It is made from fresh, raw vegetables including at least one green and one orange vegetable, parsnip, and alfalfa (for protein and color), and a fruit (for moisture and color. The Basic Salad provides a significant amount of the protein, calcium and fiber iguanas require. The recipe is in this article.

The Basic Salad is just part of the total diet. It is served along with the leafy greens. If at first your iguana ignores the Basic Salad and eats only the greens, try withholding the greens until he starts eating the Basic Salad. Once he is eating the salad without hesitation, then you can re-introduce the greens.

BASIC SALAD RECIPE

While the proportions of food types remains the same, the actual amount of the food you make will increase as your iguana grows bigger and consumes a greater quantity of food. The following recipe makes approximately 3.5 cups of Basic Salad:

1/2 cup shredded green beans
1/2 cup shredded squash
1 medium parsnip, shredded*
1/4 cup minced fruit
Alfalfa**
Multivitamin and calcium supplements

* If parsnips are a seasonal vegetable where you live, you can use 1/2 cup shredded asparagus, trading off with 1/2 cup drained, rinsed, and chopped canned cooked lima beans, plus additional calcium to make up for the lousy calcium: phosphorus ratio in beans. Cooked beans are acceptable for short term use only due to their phosphorous content and other chemicals that can impede the uptake of minerals and trace elements. Asparagus is comparable in protein to parsnip, but does contain oxalates, so should not be a long-term staple.

** The quantity of alfalfa you use will depend upon the alfalfa product you are using. You want to add about 15 grams of protein. That is about 1/2 cup of alfalfa rabbit pellets, or about 1/4 cup or less of alfalfa powder or leaf tea.

Be sure to prepare the foods in very small pieces, finely chopped, minced or shredded, as appropriate for the type of food. The smaller the pieces, the more they can fit into their stomachs, and the more efficiently it can be digested. The salad, however, does not need to be pureed to a mush. While individual iguanas may eventually develop a preference as to the size of shred/mince they prefer, most do fine when the shreds or mince are about the size of cooked white rice grains.

Serving the Salad

Make the salad accessible. Another common mistake new iguana owners make is to buy for their tiny hatchling the food and water bowls typically sold in pet stores. These bowls are so tall that the iguanas cannot easily see into them, let alone get to the contents. The result is that it can take longer for the iguanas to figure out that there is something for them in those bowls. Given that this is a highly stressful time for iguanas, there is no reason to add to that stress by using inappropriate servers for their food and water.

Serve the salad on a plate, jar lid or, for larger iguanas, in wide-mouthed shallow bowls or crocks, with the leafy greens piled nearby.

Some iguana keepers use paper, foam or plastic plates so that the iguana can get right up to (and into) their food. Be careful using paper plates as, when soggy, they are easy to tear and the iguana may end up eating pieces of the paper. Foam plates have no defense against a juvenile or adult iguana's teeth, which are easily able to tear pieces off, intentionally or otherwise. The best option, is a plastic plate. Sturdy plastic plates, designed to be used indefinitely, can usually be found in the houseware aisles of most supermarkets and super-drugstores.

Serving Size

Experience will tell you how much of the salad and greens to offer. Hatchling iguanas appear to eat very little, so start them off with a tablespoon or so of mixed salad and a small pile of greens. If they finish eating what you feed them in the morning feeding, give them a little more. When they regularly eat and finish their second serving, increase the amount you give them in their first serving.
Some iguanas of all ages will graze again in the afternoon, especially during warmer weather. Some hatchlings will come down at night and eat a little. Try putting some fresh food out in mid afternoon or early evening to see if your iguana is interested. Once hatchlings are a couple of months old and acclimated to you, they will stop coming down for midnight snacks.

Iguanas will eat less in the days just before and after their shed starts, an event that occurs on average every 4 to 6 weeks. They will also taper off during the winter months, and during breeding season

Iguana Age and Expected Size

There is no way for someone who has not had a great deal of experience with iguanas to tell how old they are (and, even then, experienced folks can only make an approximate guess). Iguana growth is determined by diet, heat and activity, as well as by the population characteristics in the population from which the iguana was taken or bred. That being said...

Effects of Diet and Care on Growth Age/Size Norms

The following table represents the sizes and weights typical of properly fed and housed iguanas. Most people are amazed at how big iguanas get, and how big they’re less-than-adequately cared for iguanas should be. This is because the captive care information that has been available through pet stores and pet trade books has served to retard their growth and development, through poor diet, inadequate temperatures, and lack of sufficient space to exercise.

svl = snout-vent length
stl = snout-tail length
Iguana tails range from 2.5-3 x the svl.

Females are generally smaller than males. There is some regional difference in size/mass so actual size will be dependent upon where the iguana was originally from, but overall will be well within the above ranges.

Effects of Diet and Care on Iguanas

Here are some age and size examples from some of my iguanas. The measurements and weights in the list below reflect the iguanas as they were in 1994. Some of these iguanas have gone on to new families; other have sadly just gone, victims of their early poor care and diet. Their ages are based on what their prior owners told me.

So, as you can see, there is some great disparity between ages. I have had Sylvia the second

Longest. Freddy I got a year ago, and the others all came to me since February, most since June of 1997. All were fed diets consisting mainly of lettuce, monkey chow, banana, spinach, broccoli or commercial iguana foods. (August 1997 update: Zeik, Freddy, Merlin, Lito, Sylvia and Elvys have since died of kidney failure. Ziggy died of complications arising from spinal fracture and compression due to severe metabolic bone disease. Wally is now 18" svl and 10+ lbs. The others have been adopted out, with new iguanas having come to fill the basking areas. (If I tend to get a bit testy about people feeding animal protein and monkey chow, it is because I've seen kidney failure in action, held the iguanas through their seizures, then held them while the lethal injection - administered to cut short the pain and fear - did its job.)

My older small males all have well developed hemipenal structures with enlarged femoral pores and well-developed spikes and dewlaps - quite obviously male. Captive males become sexually mature at about 1.5 years but their male characteristics other then femoral pores don't really begin to get bigger than females (and the hemipenal bulge become visually apparent) until 2+ years. Despite this fact, however, 4 igs (Merlin, Ziggy, Lito and Gecko) came to me with their owners either not knowing their gender or having decided (or been told by pet stores and vets) that it was the opposite of what it was.

In February 1995, I took in another little iguana. Rugwort, at 20 to 22 months of age, who was 7" svl, and his lower jaw was blown out by fibrous osteodystrophy until it was twice the width and depth of the rest of his head. Weighing in at well under half a pound, his hind legs were grossly swollen from the metabolic bone disease, and also his spine had already started to go crooked. For over 6 months I had been urging his owners (primary caretaker: a 13-year old boy) to get him to a reptile vet. They never did, just watched while he got sicker, weaker, more and more swollen as his bones lost ever more density. By the time they finally decided that the cat food they were shoving down his throat wasn't going to make him any better, they asked me to take him. Rugwort's MBD became fully resolved, though his lower jaw and head were misshapen, and he had a bit of a Quasimodo-like hump in his back. He was quite active, climbing and running. Despite the fact that Wally always chased him off, he always tried to remain in close proximity to him, and always managed to sleep next to him (or under him, as Wally used him as a pillow) at night. Rugwort hit sexual maturity by 2.5 years of age, with distinctive femoral pores and hemipenal bulges. As of August 1997 he was 11" svl.

Creating a home for your iguana

Creating a home for an iguana is more than throwing together a 10-gallon tank, a hot rock, and some pretty bark on the ground. (In fact, that is exactly what you should not do!) It is also more than a 30-gallon tank with a tropical rainforest backdrop and some plants and branches.

In creating a home, we must provide for the iguana not only as it is today, but as it will be in the months and years to come. The captive environment needs to provide a safe place for your iguana to be when you aren't around as well as when you are. The iguana environment needs to be functioning independently of your own environment when it comes to temperatures and humidity.

That means that if it is -10° F (-23° C) outside, and 65° F (18° C) inside your home, it still must be 75° to 88° F (24°-31° C), with a basking area of 88° to 95° F (35° C) during the day, and 70° to 84° F (21-28° C) at night, in the iguana's environment. If you don't leave your air conditioning on while you are at work on days when the outside temperature tops 100 F, you still have to make sure your iguana's environment maintains the iguana's required gradient, no matter how hot it gets in the rest of your home. Iguanas, like all other reptiles, can be killed temperatures that are too high (hyperthermia) just as they can by temperatures that are too low (hypothermia).

Meeting the iguana's environmental needs means you need to provide the right type of lighting and heating, no matter how much it costs. It means that you must keep the humidity up as much as you can without risking health problems and structural damage. It means providing the photoperiods (daytime light/night time dark cycles) he needs, not what may be more convenient for you due to your school, work or sleep schedule.

Enclosure

The costliest initial mistake made by iguana keepers is starting off with too small an enclosure. Enclosures aren't cheap to begin with, but you save nothing by buying too small an enclosure when you get your iguana. Kept properly, iguanas grow fast and need lots of room to move around in while they are doing that growing.

When you start off with the usual 10 to 40 gallon enclosure, it may look large enough to you, but it isn't large enough to provide the thermal gradients they need, nor the open space they need just to move around in without constantly banging into food bowls, water tubs, branches, etc. Finally, as you will find later when reading about taming and socialization, iguanas are highly territorial. Keeping them in a too-small enclosure at any age intensifies their reaction to their territory being invaded, even when the "invader" is your hand and arm putting in fresh food and water. This territorial response kicks in about the time that the iguana finally realizes that you aren't going to eat him. So, to give both of you the best opportunity early in the relationship, start off with a large enclosure, even if the iguana initially looks "lost" in it. Hide boxes and visual screens will give him secure-feeling places to go when he's feeling over-exposed to prying eyes during the first couple of months of getting acclimated to his new world.

Start with at least a 60-gallon US (50 gallon UK) tank with a secure lid or a similarly sized wood and glass/Plexiglas front- or side-opening enclosure. Glass enclosures are available with a securely fixed screen across half the top of the tank and a hinged glass lid securing half of the top. These tanks are easily cleaned and disinfected. While a 60 gallon tank may seem huge for that teeny baby iguana, a properly cared for hatchling will outgrow that enclosure by the end of its first year, and outgrow a 100 US / 83 UK gallon tank by the end of 18 months (see Determining Iguana Age and Size).

Think 3D

A key factor overlooked by many iguana owners is that the iguana lives in a three dimensional environment and thus requires a three-dimensional thermal gradient. A warm-to-cool gradient running from side-to-side and front-to-back are two of the dimensions; the third dimension is from bottom to top. Due to their preference for basking in high places, the basking area is best placed near the top of the warmest end of the tank. The heat will dissipate as it spreads down and across the tank. To prevent the tank from getting too cool on the warmer sides of the gradient, an undertank heating pad and additional heating light or element can be used when and where appropriate. The larger the enclosure, the easier it is to establish the gradients.

Location, Location, Location

Where you set the iguana's enclosure up is as important as how you set it up. If you set up the tank where the TV or music is blaring, people are rushing around, kids yelling, dogs barking - all of this will frighten and stress your new iguana.

Too far out of the swing of things is also a problem, as iguanas, especially when they aren't yet tame, tend to fall into the "out of sight, out of mind" category. Garages and stuck on a back porch is also not a good idea. Garages tend to be too cold and dark, or too hot and dark, as do porches. There also isn't much human activity to watch in either place.

What most people who keep iguanas fail to realize is that iguanas are relatively intelligent lizards who, like too many large animals kept in mind-numbing captivity is that captivity is, well, mind-numbing. Just as zoos have started to develop behavioral enrichment programs for their residents, so, too, must iguana keepers keep in mind that iguanas not only need to be kept in conditions that promote their physical health, but that their mental health needs must be addressed as well.

Place enclosures where iguanas can look out of a window when there are no humans around. Movement and activity attract their attention, so plant a garden with plants that attract birds and butterflies, or hang bird feeders to attract seedeaters or humming birds. (Hint: hummers are easier to watch when they are at rest, so buy hummingbird feeders that come with perches).

Place the enclosure in a room where, when people are home, they can watch people doing relatively quiet things and where the lights and noise quiet down during the iguana's night period. This means the room needs to be dim, if not completely dark after sunset. Bright lights and loud noise going on during the iguana's sleep period is just as disruptive to animals as it is to humans: just because the person (or iguana) is sleeping through it doesn't mean that long-term health problems aren't brewing.

Effective Heating Equipment
Iguanas in warm-to-hot climates generally do well with a heating pad made for humans. Placed under one-half of the tank or in the basking area of a larger enclosure, this may be all the heat your iguana needs to boost the heat to basking temperatures in that area of the enclosure during the warmest summer months (always use thermometers to check this, however).

Lighting

When it comes to reptiles, especially diurnal herbivorous reptiles, nothing's ever easy. Lighting is a prime example of "not easy". If you get it right, you will have a healthy iguana (well, assuming you get the diet and temperatures and all that other stuff right!). Get it wrong, and your iguana may end up with behavioral problems, increased incidence of illness, and broken bones.

The types of lighting you will be dealing with are those appropriate for daytime and for night time use, and those used to provide the ultraviolet B wavelengths that are critical for proper calcium metabolization. First, however, we will talk about the day/night cycles and their impact on health.

No Guessing Allowed

One thing I have learned is that it is impossible to accurately guess what the temperature is in a reptile's enclosure or area. There are, however, a variety of thermometers that will take the guesswork out of assuring that your iguana's temperature gradients are being maintained.

Pet stores sell high range, self-adhesive thermometers that go up to 105° F (40.5° C). They are okay, but tend to malfunction often.

Any regular thermometer can be securely taped to the enclosure; these are often found at reduced prices at biological supply houses and inexpensive ones at hardware stores. Make sure the iguana cannot get at glass thermometers as they may be knocked or clawed down and broken. Get at least two - one for the cool side and one for the warm. Ideally, you need a third one at the basking area.

The thermometers must be placed at the same level as the iguana's regular basking and sleep areas. Putting a thermometer several inches above the area will give you a reading that could be quite different than the temperature where the iguana actually spends its time. Placing a fourth thermometer in the room itself will give you an idea, over a period of time, of how changes in the room air temperature affects the temperature inside the iguana enclosure.

The placement of the enclosure within a room or house can also affect how well it heats up or retains heat. If placed on the floor or in a part of the house that stays cool even during hot weather, you are going to have to work harder getting and keeping the proper temperatures. Conversely, getting too hot can also a problem. As the highest a self-adhesive thermometer goes is 105° F, if your thermometer is reading 105° F, it may well be much hotter than that in the enclosure, hot enough to cause your iguana severe problems, including fatal hyperthermia.

Photoperiods

Iguanas, like all other terrestrial vertebrates, operate on a daily cycle that includes a distinct dark period (night, also called scotophase) and light period (day, also called photophase). The two daily periods are generally referred to as photoperiod.

In the tropics, the day light period is equal in length to the night dark period, both being 12 hours long. The farther north or south you get from the equator, seasonal changes: the days becoming shorter and nights longer in winter, with the opposite happening during the summer. Since our iguanas are tropical lizards, their daily photoperiod should be on a 12:12 photophase:scotophase cycle.

Why be concerned about the number of hours of dark and light? Because if we do it wrong, it will affect the iguanas stress levels, immune and endocrine function, digestion, growth and development, and more. In short, just about every facet of the iguana's life. We know from research on many types of animals and humans that various neurochemical and endocrine processes take place during the dark of night, and that if there is no dark during the periods that the brain expects dark, these processes are disrupted. We also know that when daylight is delayed, or shortened, that other types of disruptions occur, including sleep disorders that cause similar problems.

Many iguana owners have school or work schedules such that they are up when most people are asleep, and sleep when most people are awake. While a human can chose to keep an altered day/night schedule and accept the health risks that go along with it, we cannot impose such schedules on our iguanas. For example, your iguana's daytime lights need to go on around 6 A.M., even if that is when you are just going to bed. They need to be fed in the mid-morning hours, even if that's your time to be asleep. In other words, we must figure out ways to conform to their schedule, not force them to conform to ours, when ours is so drastically different from theirs.

Regular Daytime Lighting

Iguanas need bright (not glaring) white light, starting early in the morning, both to keep their endocrine and other systems functioning well, but also because it helps them, visualize their environment better. Iguanas, like many animals, can see some of the wavelengths in the ultraviolet A range. This affects how they see colors, and enables them to see more color gradations than we humans do. This is important as it affects the colors of their food, and food seems to be more attractive to them when they are supplied with ultraviolet A light, either from artificial lighting or when fed in sunlight.

Fortunately, providing ultraviolet A is quite simple: any household incandescent light bulb provides it. In addition, household incandescents provide another important factor in the iguana's captive environment: heat. While you can buy light bulbs made specifically to provide captive reptiles with heat and visible light, they are more expensive than household bulbs despite not doing much more for the reptiles than do household incandescents.

Some of the made-for-reptile lights are "color-corrected", that is, tinted to reduce or block the passage of certain visible wavelengths (color) through the glass of the bulb. This does more for the human looking at the reptile, however, than it does for the reptiles themselves. As you purchase iguana supplies throughout the year to replace things as they give out (or break), you will come to appreciate some of the things that work as well (or better) than the made-for-reptile products but are a fraction of the cost of those reptile products. Some made-for-reptile products have no alternatives, such as the UVB-producing fluorescents (see below) or some of the infrared heating devices. The money you save by buying the household incandescents, human heating pads and human vitamins will help offset the cost of the more expensive reptile products.

The lights that produce the heat needed for basking and helping to establish and maintain the daytime thermal gradient is referred to as a "basking" light.

Nighttime

Iguanas really don't need any lighting at night. That being said, the lights from heating pads, electrical outlet plug-in "night lights", and diffuse moonlight (or a street lamp) are acceptable and may in fact help them in case they are startled awake. Many an iguana owner has been awakened at night the sounds of thrashing preceded or followed by a thud, the unmistakable sound of an iguana body hitting a hard surface at some velocity. Iguanas, like other animals, may be disoriented if they are startled awake for some reason.

Iguanas usually need supplement heating at night, though the nighttime temperatures are not as high as they are during the day. Because we cannot use white or other bright lighting at night due to how it disrupts their sleep function, we need to use sources of heat that produce no light or dim light. Examples of such sources include a space heater that warms the room and the enclosure to the required temperatures; an infrared heating device such as a ceramic heating element (CHE) or infrared panel), both of which produce no visible light; or a nocturnal/nighttime light bulb made for reptiles. The latter produce dim bluish or purplish light most diurnal reptiles tolerate well. Some people are able to find opaque red, green or blue incandescent light bulbs at regular lighting stores. These lights produce very dim light.

If you do find these you will need to try the different colors out to see which, if any, your iguana tolerates the best. Some do fine under the green or blue but not the red, for example. Signs of disturbance may include increased restlessness at night; drop in appetite; sluggishness during the day; crankiness; and other signs of being "out of sorts". These signs may take several days to become noticeable, so keep watching for such changes over a period of a couple of weeks or more after you change the bulb.

Cautions
The lights made for fish, reef tanks, and plants, do not produce the ultraviolet and some of the visible wavelengths required by reptiles. Incandescent lights, including those made with neodymium, "rare earth phosphor" and other basking and heating lights marketed specifically for reptiles, do not produce the necessary UV radiation and should only be used to provide heat.

The words "full-spectrum" on the package do not mean the light produces the necessary UVB; in fact, the product may not provide any UVB at all! There are no "truth in advertising" laws regulating the pet care supply industry, nor any requirements or limitations on what words may be used for what purposes. As a result, there is an incredible amount of deception occurring in the industry and has been for years as a result of the booming trade in reptiles.

Safety Issues
The UV radiation emitted by the UVB-producing fluorescents eventually degrades to the point of uselessness long before the fluorescent tube burns out and stops emitting visible light. Therefore, it is essential that these tubes be changed whenever black bands appear around the ends of the tubes, about every nine-twelve months. Some ultra-conservative herp keepers will change their tubes every six months, but this has not proved to be necessary for iguanas.

There may be some health problems for iguana owners who opt for the higher output UVB-producing fluorescents, or mercury vapor lamps (which combine very high output UV and heat and bright white light). Since these products are not made for humans to use and are not considered to be "veterinary devices" they have fallen into a regulatory black hole. Damage to eyes and skin (including cancer), as well as autoimmune disease, are some of the most common health problems associated with regular UVA and UVB exposure in humans and animals. For more information, please read the articles elsewhere at this site.

Overwhelmed?
Most iguana owners come to realize that the issue of UVB lighting is one of the most complex and confusing areas of iguana keeping, and second only to diet in being rife with misinformation and misinterpretation. Please take the time to read the articles elsewhere at this site to get further information on this issue. Discussing your questions with other knowledgeable iguana owners can help clarify some points and figure out ways to best set up the light fixtures in your particular situation. Over time, the mists will clear and this will all become second nature to you and you will find that you are the one helping others.

Equipment to Avoid

In the wild, iguanas are warmed by radiant heat: the tropical sun warms up the air. Resting on branches, the iguanas are bathed in the heat that is available to them wherever they move around in their environment. When they are exposed to the sun, they get warmer; when they move into the shade, they cool off. This is called thermoregulating and is how all reptiles regulate their external and internal body temperatures.

Despite the advertisements showing iguanas happily draped across hot rocks and heated "branches," these products are not suitable for iguanas. Hot rock and sizzle stone manufacturers have jumped on the iguana bandwagon, sticking iguanas in ads for all their products (well, it seems like all of their products!) whether or not that product is suitable for iguanas. Hot rocks and sizzle stones do not heat up anything but themselves and what ever happens to be plastered to them. All too often, their internal temperature regulator fails, and the rock becomes hot enough to severely burn, sometimes fatally, the iguana. This includes all of the "new and improved" models that seem to keep coming out every year. (My question is: if the previous model was so "new and improved," why does the manufacturer feel he has to come out with yet another "new and improved" model?)

Lifestyle

Baby iguanas in the wild start out living in the lower levels of their habitat, making use of branches and roots - and ground - at different heights within that habitat. They spend some time, yet are quite comfortable in trees, scaling higher and higher the bigger they grow.

Iguanas, with their razor-sharp hook-like claw tips, can easily climb trees and even hang vertically, seeming to be equally comfortable with their head uppermost or their tail. That being said, however, when it comes to lounging or sleeping, iguanas are rather like humans and most other animals: they like to lay down flat, all stretched out.

In captivity, this means we must provide and enclosure that is both tall enough so that they can comfortably climb, and wide enough so that we can set up the horizontal gradient and accommodate the iguana's overall length. Along with the height and width, we need to provide large diameter branches installed horizontally, or wide shelves, for them to lay down on comfortably. The width is important for two reasons: your iguana is going to keep growing wider as well as longer and taller, and he will need to turn around when he wants to move to the other side of the enclosure.

By now, if you have a commercial glass tank, you're realizing that it's tough to install shelving in there, let alone climbing room. There are a few things you can do, such as make a hammock attached to the sides of the glass with suction cups fitted with hooks, or construct a shelf by supporting a length of wood on two half bricks or blocks of wood.

What you don't want to do is buy - or build - a coffin, cube or telephone booth. A coffin (long width, short height), cube (square), or telephone booth (tall and narrow) does not allow for the width, height, or thermal gradients larger iguanas need. Cubes and telephone booth-shaped enclosures are too narrow; in the latter style, iguanas end up having to cling to vertical or diagonal surfaces all the time. In coffins that are the necessary length, there is enough room to get the majority of their overall length in the different areas of the thermal gradient, but the iguanas are not provided the opportunity to climb up or down. Such iguanas become weak, are less coordinated, and more prone to injurious accidents when they are allowed out of their enclosures to roam around the room or home. Finally, females who are not permitted the space to climb up and down tall vertical surfaces have more problems laying their eggs.

So, how wide and tall should your iguana's enclosure be? By the end of the iguanas first year (that is, 12 months of age), the iguana will have outgrown commercially available enclosures. That means you have less than 12 months to design and build your own (or have built) an adult-sized enclosure. That enclosure will be at least 6 feet (1.83 m) tall, and the depth at least 3 feet (0.92 m) deep (front to back). The width (side to side) needs to be at least 1.5 to 2 times the iguana's projected overall growth over the life of that enclosure. The following table is based on the information in the Determining Iguana Age and Size article. Figures have been rounded as appropriate.

For those having trouble doing the math, that's an enclosure at least 9 feet (2.75 m) for an iguana 6 feet (1.83 m) long. Most small bedrooms are 9 feet across their width or length, so keep this in mind if you have been thinking that you can easily stash a green iguana in that empty living room corner or on top of your child's desk.

Unsafe And Unsuitable

Do not use walnut or corncob, kitty litters of any kind, wood shavings, gravel, sand, "Calci-Sand", rock, pebbles, bark, "lizard litters", or "iguana-approved bark" or any other particulate matter as substrate. No matter how closely you watch your iguana (keep in mind that you will not be watching them 24 hours a day, 7 days a week!), they will end up ingesting them, on purpose or accidentally.

These substrates can cause injury to the gut wall as they pass through the gut - if they pass through the gut. Too often they get stuck in the gut, causing an impaction (blockage), which prevents food from passing through. The iguana stops eating, is unable to defecate, wastes build up in the system, and trapped food rots causing bacterial infections and gas. While this is going on, dehydration generally sets in as the body tries to move the mass. As the bolus of jammed food and substrate builds, it can perforate the gut, leading to successful emergency surgery (if the owner catches it in time and the iguana is still healthy enough to tolerate the surgery and anesthesia) or death.

Combining Iguana Safety with Human Needs

Choose a suitable substrate that is safe for the iguana and easy for you to clean. Hemmed or well-trimmed artificial grass, indoor/outdoor carpeting, butchers paper or paper towels can all be used. If using the artificial grass or carpeting, always have one or two pieces cut to fit in reserve. When a soiled piece is removed for washing and disinfecting, one of the spare pieces can be put into the tank. The cleaned piece must be completely dry before reusing. Be sure to trim any frayed edges and strings. Newspapers should be avoided: the inks gets into the reptile's skin and the out-gassed fumes, undetectable by most people, when inhaled at close range by the iguana, may cause health problems.

My preference is for the easily cleaned and disinfected. Set up properly, your iguana will not be spending much time on the ground, coming down primarily to feed, drink and defecate (unless they do the latter from on high, shifting their vent off the branch and taking aim at the floor). In glass tanks, paper towels, terry cloth towels, bar/glass towels, or butcher paper may be used.

My personal favorite is to line the bottom of wooden enclosures with linoleum. You can buy reasonably priced self-adhesive squares in wonderful colors and patterns at home building supply and tile stores. Large pieces of remnant linoleum can be obtained relatively inexpensively from flooring stores and builder supply stores. They can be cut and fit to the floor, using an appropriate adhesive. The advantage of doing it this way is that you can curve the piece several inches up along the walls, making coved edges. This makes it much easier to thoroughly clean and disinfect as there are fewer sharp intersections for feces and urates to get into, and water spills don't get near to walls.

Mental Health

As mentioned above, we need to take into consideration not only our iguana's physical health, by providing the proper temperatures, day/night cycles, diet, etc., but we also must be concerned with aspects of their mental health and well being.

Privacy

Young iguanas need a place to get out of visual line of sight of the outside their enclosure. In the beginning, this also includes hiding away from you, too.

Provide a hiding place, such as a half-log (available at pet stores) or an empty cardboard box. Both work equally well. The box or log should be big enough for the iguana to hide its entire body inside; it does not have to cover the entire length of the outstretched tail.

If you start off with a small log or box, you will need to replace it with larger ones as your iguana grows. As expensive as the half-logs and other caves are at pet stores, and as fast as iguanas grow, this makes recycling cardboard food and other such boxes an attractive, if not particularly aesthetic, proposition. Most iguanas outgrow their need for a hide box, other than during times of severe stress, by the time they are a year old.

If you really want a pleasing looking hide box, you can cover your recycled cardboard box with contact paper or wrapping paper that comes in rainforest-y designs.

Exercise

Iguanas love to climb, so provide one or more branches, ropes and/or towels for the iguana to climb and bask on. Make sure they are anchored securely so they don't fall with your iguana clinging to them. Heavy objects such as shelves and branches must be securely installed as, when they fall, they may fall on top of the iguana, crushing or at least severely injuring him. This is another major drawback when using glass tanks. There is no permanent way to affix shelves or secure branches and other climbers to the glass that will support the weight and activity of a growing iguana. Another is that, when you have all the things inside the tank that an iguana needs, there is little room left for the human hand and arm that has to get in there to clean and service the enclosure and catch the as-yet untamed iguana.

Height, Height, Height

Iguanas, especially juveniles and adults, feel more secure when they are up high. Expect your iguana to spend most of its time in the upper reaches of its enclosure, and make sure that it is safe and warm for him up there. This means keeping shorter enclosures several feet up off the floor, so the iguana doesn't have to look up at anyone (including other household pets), and reinforces the need for enclosures that are at least 6 feet tall.

Treating Wild-Caught Wood
If you use branches collected from the wild, you will need to treat them first to assure that you do not introduce into your home any critters that belong outdoors. Trees and branches provide a home for loads of bugs, wood-boring beetles, and spiders. You don't want them hatching in your iguana's enclosure--or your own areas, for that matter.

First, clean off any dirt and loose bark. If the branches are small enough to put in your oven, bake them at 200° to 250° F (94° to 120° C) for 2 to 3 hours. Let them cool completely.

If the branches are too big for the oven, place them in a tub of bleach-water solution (1/2 cup [118 ml] household bleach per gallon [3.8 l] of water), and soak for 24 hours. Safely dispose of the solution, then refill the tub with fresh water, and soak again for a day. Let them dry in the sun for 2 to 3 days before use.

Sexual Dimorphism

When animals are sexually dimorphic, it means that the males and females have different external physical characteristics that enable one to tell them apart. Sexually mature humans are obviously sexually dimorphic. Many animals are dimorphic but you need to know what you are looking at. Some are so wildly different that they may appear to be difference species. With reptiles, as with many animals, the physical differences may be so subtle as to almost not be there at all and there is enough natural variation in individual members of the species that it may be almost impossible to be completely accurate without resorting in invasive methods.

Many animals, such as iguanas, start life looking very much alike, with the dimorphic characteristics developing only when the animal has attained sexual maturity. The document on sexing iguanas discusses how you can visually determine the sex of an iguana who is at least one year old, the age at which the femoral pores begin to expand in males. Another male iguana characteristic is the soft bulge in the base of the tail on the ventral (bottom) surface. The bulges that begin to develop around age 16 to 18 months are the inverted hemipenes, the bi-lobed reproductive organs sported by lizards and snakes. They are located in the tail, just south of the vent, and are sometimes everted sometimes during defecation or dominance displays. And, of course, during breeding. Only one lobe is used at a time during copulation.