General Care of Green Iguanas
Susan Horton, DVM
iguanas are very popular pets. They are perhaps one of the most
misunderstood and poorly kept of all reptile pets. They can reach
considerable size. Recorded weights and lengths of adult male
iguanas have been as much as 20 pounds and 7 feet respectively.
Certainly not every iguana will become such a giant. But when
considering an iguana’s environmental needs, such size factors
should be taken into account. They also have specific temperature,
humidity, lighting, and dietary needs. These topics will be
covered in this handout. At the end of this handout, a list of
informative green iguana books is provided.
Keep in mind your cute little hatchling iguana
will someday be much bigger. You may start with a small 20-gallon
aquarium now, but one day you will need a custom cage or room
dedicated to his reptilian needs. Surfaces of your chosen
enclosure should be smooth. Iguanas will rub their scales off
their noses and hurt their feet if their enclosure is made of
wire. Wood may be used so long as it has been sealed with exterior
polyurethane varnish (such as marine varnish or similar). Allow
the coating to cure for several days and air it out well before
inhabiting it. Molded plastic and acrylic cages work well until
the iguana out grows them. Iguanas should never be kept loose in
the house. There are to many dangers this way, such as animal
attacks, accidental injuries, and chilling.
Your iguana will need branches to climb on.
Chose branches of appropriate diameter and strength to support his
weight. Branches from outside can bring in pests. I suggest either
baking at 320 for 20 minutes or drying out over the outdoor gas
grill for 30 minutes. Keep branch away from flames (for the
obvious reasons). Choose hard wood always. Pine and cedar will
smoke heavily when baked! I usually use maple or oak.
Security is especially important for small
iguanas. For these little guys I suggest covering half the
exterior of the cage with paper or towels to provide a safe refuge
from perceived predators (i.e. you, the dog, the cat, etc).
Eventually you can remove this covering, once the little guy has
acclimated to his new surroundings (6 months or so). Silk plants
may look nice in the cage, but most iguanas will eventually try to
eat them. They can be placed outside the cage instead.
I recommend newspaper or outdoor carpet.
Newspaper should be changed often. If you choose outdoor
carpeting, have several pieces. This way you can be sanitizing one
and still have another to place in the cage. I do not recommend
any particulate bedding, (corncob, wood chips, wood shavings,
etc.). It is swallowed easily by iguanas. Intestinal blockage will
lead to death if not addressed quickly. Particle bedding also
hides a mess well. The moisture from spilled water, feces and
urine build up in particulate bedding and will promote bacterial
infections in your iguana.
An iguana can not digest properly or have a
competent immune system with out the ideal heat. He is an
ectotherm, which means he is the same temperature as his
surroundings. The preferred optimum temperature zone (POTZ)
temperature for green iguanas is 85 to 95. The ideal nighttime
temperature is 80-85. A gradient within the enclosure is ideal.
This way the iguana can heat up and cool down as his body
requires. Maintaining temperature is difficult. Most enclosures
require a heating mat applied outside the cage with a thermostat
to maintain nighttime temperatures. For basking, a reflector with
appropriate wattage bulb will do. A branch should be provided
under the bulb. For iguana rooms, a space heater can be used.
Build a protective barrier around it so the iguana can’t get
burned. Protect your iguana from burns by using a thermometer to
figure out the high and low temperature areas of your cage before
you place him in it. Never allow the iguana to touch the heat mat
or bulb directly. Severe burns will occur. Hot rocks are not
appropriate. Your iguana is a basker, meaning he gets his heat
form basking in the sun. The hot rock will not heat the enclosure
and will promote burns and dehydration for your iguana. Do not
place a glass enclosure in direct sunlight. It will overheat and
cook your lizard. Lights should go off at night. I use timers on
Humidity and water
Iguanas should be provided with a large water
bowl. I recommend a large lasagna pan or cat litter box. It must
be cleaned daily. Iguanas generally use their water bowl as a
toilet, thus requiring frequent changes. Humidity is difficult to
maintain in most iguana enclosures. Daily misting will help.
Soaking in the bathtub weekly is also a good idea. The tub should
have warm water to iguana shoulder level. Allow him to soak for
about 20 minutes. Never soak a weak or debilitated iguana without
complete supervision. The enclosure should never have condensation
on the walls. This means you need more ventilation or your cage is
too wet. Skin infections often occur when the enclosure is
excessively moist. A hygrometer will read the ambient humidity.
Ideally, iguanas need 65-75%.
Ultraviolet Radiation B
This is a one of the key elements in keeping
a healthy iguana. Reptiles
produce vitamin D in their skin through exposure to UVB radiation.
Vitamin D is important in calcium metabolism.
UVB wavelength measures 290-320 nm.
When purchasing a UVB source, check to make sure it
provides this wavelength. There
are several fluorescent bulbs to choose from.
Repti-sun fluorescent bulbs or mercury vapor bulbs produce
adequate UVB. The
mercury vapor bulbs produce heat as well as UVB.
They are very intense and penetrate 2 to 3 feet into an
enclosure and up to 12 feet with increased wattage. The amount of
UVB will be diminished if it paces through glass or plastic.
I recommend placing it on screen material.
The iguana should be no more than 12 to 24 inches from the
fluorescent bulb. Exposure
time should be 8 to 10 hours daily.
Fluorescent bulbs need to be replaced every 6 to 9 months
because the UVB production stops about then.
I date my bulbs with a permanent marker to keep track of
This is another key to keeping healthy
iguanas. What you feed
your iguana will determine its lifespan.
Proper nutrition from the start will ensure healthy bones
and kidneys. All food
materials should be adequately washed, chopped and mixed.
Young iguanas need their food finely chopped.
They may be fed twice daily.
As they age, feeding frequency decreases to once a day,
then every other day for adults (3 feet and longer).
Ingredients for sub-adult meals should include items from
Calcium rich vegetables: 40-50% of diet, 2 or more items
per feeding-turnip greens, mustard greens, beet greens, kale,
collards, bok choy, Swiss chard, dandelions, parsley, romaine,
escarole, and spinach. Spinach
must not be over used as it binds iodine and calcium.
Other vegetables: 30-40% of diet, a variety weekly.
Frozen mixed vegetables, squash, zucchini, sweet potato,
bell pepper, broccoli, peas, beans, okra, carrot, and pumpkin.
Grain/fiber: up to 20% of diet.
Boiled rice, boiled pasta, whole grain breads and cereals.
Fruit: contain mostly fructose and fiber.
Dilutes more valuable nutrients in other food items, so
minimize its use. Figs,
papaya, melon, apple, peaches, plums, strawberries, tomatoes,
banana (with skin), grapes, kiwi.
Legumes: more important for young iguanas, up to 5% total
diet. Boiled lentils, navy beans, pinto beans, kidney beans.
Adult Iguanas are
primarily fed the calcium rich veggies with small amounts from the
rest of the list periodically.
Senior Iguanas are primarily calcium rich greens.
Vitamin supplementation is most important in to growing
iguana. A multivitamin
supplement should be used twice weekly.
Examples include Reptivite (Zoo-Med), Reptical (Tetra),
Nekton, and human Centrum. A
straight calcium supplement should be used 4 to 5 times weekly.
This supplement should contain no phosphorus and does not
need vitamin D. Iguanas
seem to be unable to absorb vitamin D well from their diets.
*Older iguanas (adults) require a
multivitamin once to twice monthly.
Calcium may be given once weekly.
Cage cleaning should include thorough scrubbing
and disinfecting. For washing, use non-toxic soaps such as dish
soap. Rinse well. For disinfection, dilute bleach (1:10),
chlorhexadine, or roccal (Upjohn, Kalamazoo). These must be rinsed
very well. Allow cage to air out well before iguana is returned.
Daily removal of food is important.
Here is a list of great references for green
De Vosjoli, P: The Green Iguana Manual.
Lakeside, Ca, Advanced Vivarium Systems, 1992.
M. Kaplan, Iguanas for Dummies. IDG Books
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