Green Iguana Care
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Natural History
The green (or common) iguana (Iguana iguana) is an arboreal (tree-living) and diurnal (daylight-active) lizard
usually found at elevations below 3,000 feet in tropical and subtropical regions from northern Mexico to central
South America. It is most often found in the vicinity of rivers and streams.
Iguanas have short, powerful limbs equipped with strong, sharp claws (for climbing and digging), and a
long, strong tail. They can reach lengths of 6 to 6 ½ feet. A large flap of skin (the dewlap) hangs from the
throat and helps regulate body temperature. Iguanas also have a prominent crest of soft spines (longer in
males) along the midline of the neck and back, beginning at the base of the skull.
Male iguanas tend to be larger and have brighter overall coloration than females. The distinct color of
males is especially pronounced during the breeding season. Males tend to have larger heads than females, in
part because of swollen jowls. Both sexes have 12-13 prominent pores arranged in a row on the underside of
both thighs. These glandular structures secrete a waxy substance with which iguanas mark their territory and
identify each other. As the males mature, their “femoral pores” develop slight outward projections. This
developmental modification probably enables the male to better grasp the female during copulation.
An iguana’s skin is entirely covered with very tiny scales. Iguanas cannot change their coloring (as
chameleons do), but certain areas of their skin can become darker when exposed to direct sunlight. Young
iguanas are pale green with black-ringed tails. They mature to a lighter, more earthy color, usually with dark
vertical bars on the body and tail.
Vision, hearing and the sense of smell are acute. In their natural environment, iguanas tend to be very
wary, hiding or fleeing at any sign of danger. Iguanas are somewhat clumsy but accomplished tree climbers.
They tend to bask by day on tree branches, often over water. When frightened or threatened, they usually
drop (sometimes from great heights) into the water below. Being excellent swimmers, they quickly make their
way to protective cover by pressing their front limbs along their sides and swishing their powerful tails from
side to side. Iguanas can also safely land on the ground and run to protective cover after jumping from
substantial heights. When threatened or cornered, iguanas can defend themselves with astonishingly quick,
whip-like lashes of their tails and with their claws and jaws.
Iguanas mate in January or February. After a pregnancy of about 2 months, the female digs in moist sand
or soil, usually near the base of a tree, and deposits 25-40 eggs. The hatchlings, measuring 25-30 centimeters
long, emerge in about 2 weeks. They grow 15-24 centimeters a year and attain sexual maturity in about 3
years.
An interesting, but unfortunate, fact is that the iguana is widely hunted throughout its range for its tender
white flesh and for its alleged aphrodisiac properties. Central American natives refer to the green iguana as
“bamboo chicken.” Because it is timid and relatively slow, it is easily captured. Its eggs are also collected and
eaten by local hunters.
Requirements in Captivity
DIET: In its natural environment, the green iguana is almost completely herbivorous (plant-eating) from
the time it hatches. Despite this, captive juvenile iguanas should be fed a relatively large proportion of animal
protein. Older iguanas should receive a greater proportion of vegetable matter in their diets.
Juvenile iguanas should be fed daily. A good diet consists of 1 part animal protein (water-packed tuna,
cooked chicken, hard boiled or scrambled egg, Purina Trout Chow, dog food) added to 2 parts vegetable
material (broccoli and its leaves, Swiss chard, spinach, alfalfa sprouts, beet, collard, mustard and turnip greens,
carrot tops and thawed, frozen mixed vegetables). Chop all of the ingredients into a size that can be easily
handled by the young iguana. Then mix them thoroughly and store the mixture in the refrigerator in an air-
tight container. Once or twice a day, offer a small amount of this mixture after it has been liberally sprinkled
with an appropriate vitamin-mineral supplement.
Particular attention to calcium supplementation is essential because young, growing iguanas are very
prone to calcium deficiencies. Nekton-MSA, Reptical or Vita-Life should be used to supplement all juvenile
iguanas. Growing iguanas may also be fed “expanded” guinea pig or rabbit pellets (pellets allowed to expand
by absorbing water), either plain or as a top dressing over vegetables. This is a convenient way to add
necessary vitamins and minerals (contained in the pelleted food) to the iguana’s diet.
Older iguanas should be fed 2-3 times per week and can be offered the same items as listed above. In
addition, live crickets, mealworms and pinky (neonatal) mice can be offered in small numbers, though many
experts believe that feeding live food invites exposure to undesirable bacteria and possible transmission of
parasites. Plant material, such as dandelions (flowers and leaves), clover, rose petals, and flowers of hibiscus,
carnation and nasturtium, should be offered as well. Many health food stores carry dried dandelion and other
edible herbs that can be offered to captive iguanas all year round. Fresh fruit (bananas, berries, apples,
peaches, pears, plums) can occasionally be included in the diet.
If a captive iguana is to benefit from live insects (crickets, mealworms), careful attention must be paid to
how these insects are reared and fed before they are offered as prey. Mealworms, for example, are often
reared in wheat middlings and/or wheat bran, which are calcium deficient. Mealworms nourished on such
calcium-poor material consequently become calcium-deficient and so, too, will iguanas feeding on them, often
resulting in metabolic bone disease.
Ideally, you should rear all insects destined to be fed to your iguana on a poultry laying ration (usually
containing 8-12% calcium) for at least one week before they are sacrificed. Add slices of sweet potato to the
mealworm or insect container to provide necessary moisture. Crickets and mealworms may also be lightly
sprayed with an aerosolized vegetable oil and then dusted with a vitamin-mineral supplement just before they
are offered to the iguana.
INTESTINAL INOCULATION: A fairly recent discovery has provided a probable explanation for the
premature deaths of young iguanas despite apparently adequate diets. In the wild, young iguanas obtain
needed intestinal bacteria and protozoa by eating the feces of adult iguanas. The microorganisms acquired
this way are essential for digestion of plant material. Baby iguanas are not born with these microbes, so
young iguanas reared in captivity never acquire them.
All newly acquired, domestically raised (not wild-caught) iguanas should receive fresh feces from a healthy,
parasite-free adult iguana (preferably wild-caught). One dose should inoculate the iguana for life. Some
veterinary hospitals are prepared to assist new iguana owners with this process.
HYGIENE: Next to adequate nutrition, no other aspect of husbandry for captive reptiles is more important
than sanitation and hygiene. Many bacterial and fungal diseases of captive reptiles result from their daily
exposure to fecal contamination and a damp, filthy environment. In the wild, reptiles have acres of land and
water over which their feces and uneaten food can be scattered. They rarely, if ever, come in contact with this
material. This is not the case with captive reptiles. Owners of captive reptiles engage in a continual struggle
to prevent bacterial build-up caused by continual deposition of waste products and uneaten food.
An iguana’s cage floor or aquarium bottom can be covered with clean newspaper (unprinted preferably) or
butcher paper. The next best material is indoor-outdoor carpeting. Paper towel squares can also be placed
end to end to cover the entire bottom of the enclosure. When one of the squares becomes soiled, it can be
easily removed and replaced without disturbing the entire floor of the enclosure. Under no circumstances
should pea gravel, corncob material, wood shavings, sand, kitty litter or sawdust be used. None of these items
promotes adequate cleanliness, and they may be eaten while the iguana is feeding, resulting in intestinal
impaction.
Iguanas are frequently displayed on moss. Even though this is visually attractive, it is a poor husbandry
practice because this material remains continually damp, promoting serious skin infections.
A captive iguana’s environment must be kept fastidiously clean and dry. Any object that becomes soiled
with feces or urine should be removed and cleaned or replaced as soon as possible. The enclosure should be
set up so that it can be easily cleaned. Human nature dictates that the more time it takes to clean the cage
and the more complicated the task, the less often it will be done. Make the enclosure functional rather than
beautiful.
Reptiles are highly susceptible to poisoning from pine oil cleaners, such as PineSol and Lysol. These
household cleaners must be avoided.
VISUAL SECURITY: A hiding place into which a captive iguana can retreat and be free from constant visual
scrutiny should be provided. Visual security can be provided by supplying cardboard rolls (from toilet paper or
paper towels) for small iguanas or cardboard boxes for large iguanas. Optimal visual security can be provided,
however, by strategic placement of artificial plants. Because iguanas like to climb and bask, some of the
branches and artificial plants provided should be arranged to allow this activity above the floor of the
enclosure. Silk artificial plants are visually pleasing and easy to clean and maintain, and also withstand the use
of disinfectants.
FOCAL HEAT SOURCE: All reptiles require a warm environment to raise their body temperature and
increase their metabolic rate and activity level. The optimal environmental temperature to provide for captive
iguanas in their enclosure is between 85 and 103 F.
SUNLIGHT AND ARTIFICIAL SUNLIGHT: Captive reptiles rarely receive adequate exposure to ultraviolet (UV)
light, especially when they are housed indoors. Captive reptiles, especially iguanas, must receive direct
sunlight to benefit from its UV component. Ultraviolet light is necessary to properly absorb dietary calcium.
Window glass and plastics filter UV light. Consequently, reptiles must be housed in screened or wire
enclosures during the time they are to be exposed to direct sunlight. Also, a shaded area must be provided so
the iguana can avoid heat stroke from overexposure to sunlight.
An alternative to direct sunlight for reptiles housed indoors is an artificial UV light source, such as a
Vitalite. To approximate a natural photoperiod, it is best to supply 10-12 hours of daylight and 12-14 hours of
darkness each day, with a gradual increase in the number of hours of light supplied in the spring and a gradual
decrease in the number of hours provided in the fall and winter months.
WATER: Water can be made available to captive iguanas in a variety of ways. A standing water source,
such as a filled ceramic dish, can be available for bathing and drinking. Spraying water on artificial plants and
allowing the iguana to lap up this moisture is another suitable strategy.
The bathtub is a wonderful and practical recreational area for a pet iguana. Swimming is great fun to
observe and provides excellent exercise for the iguana. The tub is also a practical, relatively escape-proof
“holding area” for the iguana while its enclosure is being cleaned. The tub should be filled so that its
shallowest portion allows for submersion of about 2/3 of the iguana’s body. The water should be warm and of
a temperature comfortable for a human bather. Iguanas may be allowed to occasionally swim in chlorinated
swimming pools as long as the activity is closely supervised and the iguana is thoroughly rinsed off with fresh
water afterwards.
CAGE MATE: A cage mate for an iguana is not advisable. Iguanas are not particularly sociable animals and
are quite territorial. The addition of a cage mate invites unnecessary aggression and fighting.
Diseases Requiring Veterinary Attention
METABOLIC BONE DISEASE: (Fibrous Osteodystrophy) The most common disease of captive iguanas
results from gross malnutrition. Most new iguana owners are not given proper dietary information when they
buy their iguana. In fact, many are given incorrect information. The most common mistake is feeding lettuce
(usually iceberg lettuce) to the exclusion of other important dietary items (see the section on Diet). Lettuce
provides adequate amounts of moisture but is a nutritionally barren food otherwise. The problem is often
aggravated by vitamin D3 and calcium deficiencies, which result from inadequate exposure to direct sunlight or
artificial ultraviolet light and lack of vitamin-mineral supplementation.
Signs of metabolic bone disease include general listlessness, an enlarged, swollen lower jaw, difficulty in
eating, and markedly firm, swollen limbs and tail. Unfortunately, these desperately ill iguanas appear well-fed
and chubby, and veterinary care is not often sought until it is too late. Sometimes the back, tail or legs are
fractured or deformed. These problems usually receive more immediate veterinary attention.
Iguanas with metabolic bone disease should be treated by a competent reptile veterinarian. If the patient
refuses all food offered except lettuce, the lettuce must be top dressed with a suitable vitamin-mineral powder.
Iguanas that have become “lettuce junkies” (consume lettuce to the exclusion of all other foods) must be
encouraged to accept and feed on more nutritionally complete food items. Some iguanas accept items that
resemble lettuce, such as spinach and beet greens, and then may be more accepting of other foods offered.
Another way to wean an iguana from lettuce involves sprinkling the more nutritious items (cut up in small
pieces) over the preferred lettuce leaves. Usually the iguana will feed on both simultaneously. With each
feeding, the proportion of nutritionally superior food items should be increased and the amount of lettuce
decreased until the iguana has fully accepted a more nutritious variety of food. After 2-3 weeks, a vitamin-
mineral powder can be sprinkled over the food to ensure nutritional adequacy. If such a product is used during
the transition period, it may cause the iguana to refuse all food, including the lettuce. This would be
undesirable.
PARALYSIS OF THE REAR LEGS: A disease resulting from vitamin B1 deficiency causes paralysis of the rear
legs and tail. This problem is treated with injectable B vitamins and dietary improvement, including vitamin-
mineral supplementation. Rear limb paralysis may also result from mineral (especially calcium) deficiencies that
cause fibrous osteodystrophy of the spinal column. Injectable calcium is also necessary in the therapy of this
problem.
NOSE ABRASIONS: One of the unfortunate consequences of captivity is injury resulting from repeated
attempts to escape. Iguanas tend to push and rub their noses against the walls of their enclosure as they
repeatedly pace back and forth. This constant trauma results in chronic ulceration of the nose (rostrum),
whether the walls of the enclosure are made of glass or wire mesh. Nose injuries may result in serious and
often permanent deformities that may cause long-term problems.
Preventing this problem is difficult, but providing adequate visual security (hiding places) and other
additions to the enclosure (artificial plants, branches, rocks) help to minimize it. A visual barrier of dark paint or
plastic film placed on or along the lower 4 inches of the enclosure’s walls often inhibits pacing and rubbing.
THERMAL INJURIES: Serious burns often result when iguanas contact unprotected heat sources within
their enclosures. Exposed light bulbs and heat lamps are most often responsible for these accidents. Neither
of these appliances is actually necessary. If they are installed in an iguana’s enclosure, they must be outfitted
with a protective device to prevent burns.
BACTERIAL INFECTIONS: Blister disease: Chronic exposure to bacterial contamination from poor sanitation
and hygiene is the most common cause of bacterial infections in captive iguanas. Blister disease results when
an iguana is confined to a moist, filthy enclosure. The disease is characterized by blisters, especially on the
underside aspects of the body, that develop into seriously infected wounds. Aggressive antibiotic therapy is
necessary to successfully treat affected iguanas.
Dry Gangrene of the Tail or Toes: Another sign of serous, body-wide bacterial infection is dry gangrene of
the tail and often the toes. The dry gangrene usually slowly moves up the tail from its tip. One or more toes
may have the same type of progressive problem simultaneously. The disease can be controlled with
aggressive antibiotic therapy, strict hygiene and good husbandry.
Mouth Rot: Bacterial infection of the mouth is often the result of malnutrition and a debilitated, weakened
condition. Signs of mouth rot include swelling, inflammation and accumulation of pus within the mouth,
increased salivation, and difficulties in eating. Treatment involves identifying the offending bacteria and giving
appropriate antibiotic therapy. Providing vitamins, fluids and forced feeding are also essential.
Abscesses: Bacterial infections may settle in one or more areas and result in abscess formation. Reptile
pus is not liquid, but it is of a cheesy, sometimes rubber-like consistency. Consequently, treatment of
abscesses by a veterinarian involves opening up the pus-filled abscess and manually cleaning it out. Antibiotics
are then infused directly into the cavity and also given by injection.
Bacterial infections of reptiles require injectable antibiotics to eliminate the bacteria from the body as
rapidly as possible. When therapy is delayed or insufficient, bacteria multiply and spread throughout the body,
usually resulting in internal abscesses. Antibiotic therapy then is much less successful. Initial and periodic
white blood cell counts are necessary to properly monitor the progress of the patient and to detect any relapse.
Parasite Problems: Parasites may be found externally (mites), within the gastrointestinal tract (worms,
protozoa), and within the blood (malaria-type parasites) of captive iguanas. Parasites represent a significant
burden in addition to the inevitable stresses of captivity endured by all pet iguanas, and should be treated by a
veterinarian specializing in reptiles. Iguanas weakened by malnutrition and chronic bacterial infections are
particularly susceptible to the detrimental effects of parasites.
Viral Infections: Though viruses probably cause disease in iguanas, only a few have been specifically
identified in this capacity. With continued interest and research in iguanas, our understanding of viral
infections will be enhanced.
Organ Failure: Failure of vital organs often accompanies advancing age, and may also be a consequence
of gout and severe bacterial infections. If possible, blood samples should be collected to allow evaluation of
vital organ function. Treatment by a veterinarian is usually guided by the results of diagnostic testing.
BLADDER STONES: Minerals in the urine may precipitate and form stones within the urinary bladder of
iguanas. The iguana may exhibit no signs of illness or may strain during urination and act listless. If the stone
becomes very large, the abdomen may become enlarged. The droppings may also contain blood. A radiograph
(x-ray) is necessary to confirm the diagnosis. Abdominal surgery is necessary to remove the stone.
EGG-BINDING: Egg-binding can be a life-threatening condition. It results when a pregnant female cannot
expel one or more eggs from the reproductive tract. Causes of egg-binding include malnutrition (especially
mineral imbalances), various diseases, mummification of the eggs, and large or malformed eggs. Physical
examination and radiographs (x-rays) are necessary to diagnose this problem. The veterinarian may select a
medical and/or surgical approach to relieve this serious condition, depending on the circumstances.
SWOLLEN JAW: See Metabolic Bone Disease.
BROKEN TAIL: Though iguanas do not shed their tails like some other lizard species, tail fractures,
dislocations and other serious injuries may occur. Care must be taken to firmly restrain the tail when an iguana
is picked up and held. A veterinarian can treat soft tissue injuries according to the severity, and can “set” and
splint the fractured tail if necessary.
BROKEN TOES: An iguana’s toes are very vulnerable to injury, especially when iguanas are housed in
screened or wire enclosures. It is very easy for toes and/or toenails to become entrapped within the wire
mesh, resulting in fractures, dislocations, torn nails (with subsequent bleeding), and injuries to the skin and
scales of the toes. These injuries often occur during attempts to remove a panicked iguana from its enclosure.
Great care should be taken when overcoming the animal’s grip on the wire mesh. Twisting of the iguana’s
body against this steadfast grip often causes serious injuries to the feet and toes. A veterinarian should be
consulted at once if such injuries occur.
A Comment Regarding Sharp Claws
Iguanas are usually quite docile and enjoy handling. You, however, may not always enjoy the activity
because of the scratches inflicted by sharp claws, powered by very strong limbs. An iguana’s claws should be
periodically dulled by an experienced veterinarian or veterinary technician. A cautery instrument or high-speed
grinding tool is usually employed for this task.
Veterinary Examination
A thorough initial examination is the cornerstone of a health care program for the pet iguana. All newly
acquired iguanas, regardless of age, should be thoroughly examined by a veterinarian as soon as possible.
Besides a complete physical examination, a blood work-up and stool examination should be included. The
advantage of this thorough initial work-up is that current and potential medical problems can be identified and
treated before they become serious.
For More Information
A wealth of additional useful information may be obtained by joining a herpetological organization. Most
publish newsletters or bulletins on many matters relating to reptiles and amphibians, and there are many e-
mail lists and news groups as well.
Society for the Study of Amphibians and Reptiles
(SSAR)
Marion Preest, Secretary
Joint Science Department
The Claremont Colleges
925 N. Mills Ave.
Claremont, CA 91711
909-607-8014
mspreest@jsd.claremont.edu
www.ssarherps.org
The Minnesota Herpetological Society
Bell Museum of Natural History
10 Church St. SE
Minneapolis, MN 55455-0104
612-624-7065
www.bellmuseum.org/herpetology/Main.html
The green (or common) iguana (Iguana iguana) is an arboreal (tree-living) and diurnal (daylight-active) lizard
usually found at elevations below 3,000 feet in tropical and subtropical regions from northern Mexico to central
South America. It is most often found in the vicinity of rivers and streams.
Iguanas have short, powerful limbs equipped with strong, sharp claws (for climbing and digging), and a
long, strong tail. They can reach lengths of 6 to 6 ½ feet. A large flap of skin (the dewlap) hangs from the
throat and helps regulate body temperature. Iguanas also have a prominent crest of soft spines (longer in
males) along the midline of the neck and back, beginning at the base of the skull.
Male iguanas tend to be larger and have brighter overall coloration than females. The distinct color of
males is especially pronounced during the breeding season. Males tend to have larger heads than females, in
part because of swollen jowls. Both sexes have 12-13 prominent pores arranged in a row on the underside of
both thighs. These glandular structures secrete a waxy substance with which iguanas mark their territory and
identify each other. As the males mature, their “femoral pores” develop slight outward projections. This
developmental modification probably enables the male to better grasp the female during copulation.
An iguana’s skin is entirely covered with very tiny scales. Iguanas cannot change their coloring (as
chameleons do), but certain areas of their skin can become darker when exposed to direct sunlight. Young
iguanas are pale green with black-ringed tails. They mature to a lighter, more earthy color, usually with dark
vertical bars on the body and tail.
Vision, hearing and the sense of smell are acute. In their natural environment, iguanas tend to be very
wary, hiding or fleeing at any sign of danger. Iguanas are somewhat clumsy but accomplished tree climbers.
They tend to bask by day on tree branches, often over water. When frightened or threatened, they usually
drop (sometimes from great heights) into the water below. Being excellent swimmers, they quickly make their
way to protective cover by pressing their front limbs along their sides and swishing their powerful tails from
side to side. Iguanas can also safely land on the ground and run to protective cover after jumping from
substantial heights. When threatened or cornered, iguanas can defend themselves with astonishingly quick,
whip-like lashes of their tails and with their claws and jaws.
Iguanas mate in January or February. After a pregnancy of about 2 months, the female digs in moist sand
or soil, usually near the base of a tree, and deposits 25-40 eggs. The hatchlings, measuring 25-30 centimeters
long, emerge in about 2 weeks. They grow 15-24 centimeters a year and attain sexual maturity in about 3
years.
An interesting, but unfortunate, fact is that the iguana is widely hunted throughout its range for its tender
white flesh and for its alleged aphrodisiac properties. Central American natives refer to the green iguana as
“bamboo chicken.” Because it is timid and relatively slow, it is easily captured. Its eggs are also collected and
eaten by local hunters.
Requirements in Captivity
DIET: In its natural environment, the green iguana is almost completely herbivorous (plant-eating) from
the time it hatches. Despite this, captive juvenile iguanas should be fed a relatively large proportion of animal
protein. Older iguanas should receive a greater proportion of vegetable matter in their diets.
Juvenile iguanas should be fed daily. A good diet consists of 1 part animal protein (water-packed tuna,
cooked chicken, hard boiled or scrambled egg, Purina Trout Chow, dog food) added to 2 parts vegetable
material (broccoli and its leaves, Swiss chard, spinach, alfalfa sprouts, beet, collard, mustard and turnip greens,
carrot tops and thawed, frozen mixed vegetables). Chop all of the ingredients into a size that can be easily
handled by the young iguana. Then mix them thoroughly and store the mixture in the refrigerator in an air-
tight container. Once or twice a day, offer a small amount of this mixture after it has been liberally sprinkled
with an appropriate vitamin-mineral supplement.
Particular attention to calcium supplementation is essential because young, growing iguanas are very
prone to calcium deficiencies. Nekton-MSA, Reptical or Vita-Life should be used to supplement all juvenile
iguanas. Growing iguanas may also be fed “expanded” guinea pig or rabbit pellets (pellets allowed to expand
by absorbing water), either plain or as a top dressing over vegetables. This is a convenient way to add
necessary vitamins and minerals (contained in the pelleted food) to the iguana’s diet.
Older iguanas should be fed 2-3 times per week and can be offered the same items as listed above. In
addition, live crickets, mealworms and pinky (neonatal) mice can be offered in small numbers, though many
experts believe that feeding live food invites exposure to undesirable bacteria and possible transmission of
parasites. Plant material, such as dandelions (flowers and leaves), clover, rose petals, and flowers of hibiscus,
carnation and nasturtium, should be offered as well. Many health food stores carry dried dandelion and other
edible herbs that can be offered to captive iguanas all year round. Fresh fruit (bananas, berries, apples,
peaches, pears, plums) can occasionally be included in the diet.
If a captive iguana is to benefit from live insects (crickets, mealworms), careful attention must be paid to
how these insects are reared and fed before they are offered as prey. Mealworms, for example, are often
reared in wheat middlings and/or wheat bran, which are calcium deficient. Mealworms nourished on such
calcium-poor material consequently become calcium-deficient and so, too, will iguanas feeding on them, often
resulting in metabolic bone disease.
Ideally, you should rear all insects destined to be fed to your iguana on a poultry laying ration (usually
containing 8-12% calcium) for at least one week before they are sacrificed. Add slices of sweet potato to the
mealworm or insect container to provide necessary moisture. Crickets and mealworms may also be lightly
sprayed with an aerosolized vegetable oil and then dusted with a vitamin-mineral supplement just before they
are offered to the iguana.
INTESTINAL INOCULATION: A fairly recent discovery has provided a probable explanation for the
premature deaths of young iguanas despite apparently adequate diets. In the wild, young iguanas obtain
needed intestinal bacteria and protozoa by eating the feces of adult iguanas. The microorganisms acquired
this way are essential for digestion of plant material. Baby iguanas are not born with these microbes, so
young iguanas reared in captivity never acquire them.
All newly acquired, domestically raised (not wild-caught) iguanas should receive fresh feces from a healthy,
parasite-free adult iguana (preferably wild-caught). One dose should inoculate the iguana for life. Some
veterinary hospitals are prepared to assist new iguana owners with this process.
HYGIENE: Next to adequate nutrition, no other aspect of husbandry for captive reptiles is more important
than sanitation and hygiene. Many bacterial and fungal diseases of captive reptiles result from their daily
exposure to fecal contamination and a damp, filthy environment. In the wild, reptiles have acres of land and
water over which their feces and uneaten food can be scattered. They rarely, if ever, come in contact with this
material. This is not the case with captive reptiles. Owners of captive reptiles engage in a continual struggle
to prevent bacterial build-up caused by continual deposition of waste products and uneaten food.
An iguana’s cage floor or aquarium bottom can be covered with clean newspaper (unprinted preferably) or
butcher paper. The next best material is indoor-outdoor carpeting. Paper towel squares can also be placed
end to end to cover the entire bottom of the enclosure. When one of the squares becomes soiled, it can be
easily removed and replaced without disturbing the entire floor of the enclosure. Under no circumstances
should pea gravel, corncob material, wood shavings, sand, kitty litter or sawdust be used. None of these items
promotes adequate cleanliness, and they may be eaten while the iguana is feeding, resulting in intestinal
impaction.
Iguanas are frequently displayed on moss. Even though this is visually attractive, it is a poor husbandry
practice because this material remains continually damp, promoting serious skin infections.
A captive iguana’s environment must be kept fastidiously clean and dry. Any object that becomes soiled
with feces or urine should be removed and cleaned or replaced as soon as possible. The enclosure should be
set up so that it can be easily cleaned. Human nature dictates that the more time it takes to clean the cage
and the more complicated the task, the less often it will be done. Make the enclosure functional rather than
beautiful.
Reptiles are highly susceptible to poisoning from pine oil cleaners, such as PineSol and Lysol. These
household cleaners must be avoided.
VISUAL SECURITY: A hiding place into which a captive iguana can retreat and be free from constant visual
scrutiny should be provided. Visual security can be provided by supplying cardboard rolls (from toilet paper or
paper towels) for small iguanas or cardboard boxes for large iguanas. Optimal visual security can be provided,
however, by strategic placement of artificial plants. Because iguanas like to climb and bask, some of the
branches and artificial plants provided should be arranged to allow this activity above the floor of the
enclosure. Silk artificial plants are visually pleasing and easy to clean and maintain, and also withstand the use
of disinfectants.
FOCAL HEAT SOURCE: All reptiles require a warm environment to raise their body temperature and
increase their metabolic rate and activity level. The optimal environmental temperature to provide for captive
iguanas in their enclosure is between 85 and 103 F.
SUNLIGHT AND ARTIFICIAL SUNLIGHT: Captive reptiles rarely receive adequate exposure to ultraviolet (UV)
light, especially when they are housed indoors. Captive reptiles, especially iguanas, must receive direct
sunlight to benefit from its UV component. Ultraviolet light is necessary to properly absorb dietary calcium.
Window glass and plastics filter UV light. Consequently, reptiles must be housed in screened or wire
enclosures during the time they are to be exposed to direct sunlight. Also, a shaded area must be provided so
the iguana can avoid heat stroke from overexposure to sunlight.
An alternative to direct sunlight for reptiles housed indoors is an artificial UV light source, such as a
Vitalite. To approximate a natural photoperiod, it is best to supply 10-12 hours of daylight and 12-14 hours of
darkness each day, with a gradual increase in the number of hours of light supplied in the spring and a gradual
decrease in the number of hours provided in the fall and winter months.
WATER: Water can be made available to captive iguanas in a variety of ways. A standing water source,
such as a filled ceramic dish, can be available for bathing and drinking. Spraying water on artificial plants and
allowing the iguana to lap up this moisture is another suitable strategy.
The bathtub is a wonderful and practical recreational area for a pet iguana. Swimming is great fun to
observe and provides excellent exercise for the iguana. The tub is also a practical, relatively escape-proof
“holding area” for the iguana while its enclosure is being cleaned. The tub should be filled so that its
shallowest portion allows for submersion of about 2/3 of the iguana’s body. The water should be warm and of
a temperature comfortable for a human bather. Iguanas may be allowed to occasionally swim in chlorinated
swimming pools as long as the activity is closely supervised and the iguana is thoroughly rinsed off with fresh
water afterwards.
CAGE MATE: A cage mate for an iguana is not advisable. Iguanas are not particularly sociable animals and
are quite territorial. The addition of a cage mate invites unnecessary aggression and fighting.
Diseases Requiring Veterinary Attention
METABOLIC BONE DISEASE: (Fibrous Osteodystrophy) The most common disease of captive iguanas
results from gross malnutrition. Most new iguana owners are not given proper dietary information when they
buy their iguana. In fact, many are given incorrect information. The most common mistake is feeding lettuce
(usually iceberg lettuce) to the exclusion of other important dietary items (see the section on Diet). Lettuce
provides adequate amounts of moisture but is a nutritionally barren food otherwise. The problem is often
aggravated by vitamin D3 and calcium deficiencies, which result from inadequate exposure to direct sunlight or
artificial ultraviolet light and lack of vitamin-mineral supplementation.
Signs of metabolic bone disease include general listlessness, an enlarged, swollen lower jaw, difficulty in
eating, and markedly firm, swollen limbs and tail. Unfortunately, these desperately ill iguanas appear well-fed
and chubby, and veterinary care is not often sought until it is too late. Sometimes the back, tail or legs are
fractured or deformed. These problems usually receive more immediate veterinary attention.
Iguanas with metabolic bone disease should be treated by a competent reptile veterinarian. If the patient
refuses all food offered except lettuce, the lettuce must be top dressed with a suitable vitamin-mineral powder.
Iguanas that have become “lettuce junkies” (consume lettuce to the exclusion of all other foods) must be
encouraged to accept and feed on more nutritionally complete food items. Some iguanas accept items that
resemble lettuce, such as spinach and beet greens, and then may be more accepting of other foods offered.
Another way to wean an iguana from lettuce involves sprinkling the more nutritious items (cut up in small
pieces) over the preferred lettuce leaves. Usually the iguana will feed on both simultaneously. With each
feeding, the proportion of nutritionally superior food items should be increased and the amount of lettuce
decreased until the iguana has fully accepted a more nutritious variety of food. After 2-3 weeks, a vitamin-
mineral powder can be sprinkled over the food to ensure nutritional adequacy. If such a product is used during
the transition period, it may cause the iguana to refuse all food, including the lettuce. This would be
undesirable.
PARALYSIS OF THE REAR LEGS: A disease resulting from vitamin B1 deficiency causes paralysis of the rear
legs and tail. This problem is treated with injectable B vitamins and dietary improvement, including vitamin-
mineral supplementation. Rear limb paralysis may also result from mineral (especially calcium) deficiencies that
cause fibrous osteodystrophy of the spinal column. Injectable calcium is also necessary in the therapy of this
problem.
NOSE ABRASIONS: One of the unfortunate consequences of captivity is injury resulting from repeated
attempts to escape. Iguanas tend to push and rub their noses against the walls of their enclosure as they
repeatedly pace back and forth. This constant trauma results in chronic ulceration of the nose (rostrum),
whether the walls of the enclosure are made of glass or wire mesh. Nose injuries may result in serious and
often permanent deformities that may cause long-term problems.
Preventing this problem is difficult, but providing adequate visual security (hiding places) and other
additions to the enclosure (artificial plants, branches, rocks) help to minimize it. A visual barrier of dark paint or
plastic film placed on or along the lower 4 inches of the enclosure’s walls often inhibits pacing and rubbing.
THERMAL INJURIES: Serious burns often result when iguanas contact unprotected heat sources within
their enclosures. Exposed light bulbs and heat lamps are most often responsible for these accidents. Neither
of these appliances is actually necessary. If they are installed in an iguana’s enclosure, they must be outfitted
with a protective device to prevent burns.
BACTERIAL INFECTIONS: Blister disease: Chronic exposure to bacterial contamination from poor sanitation
and hygiene is the most common cause of bacterial infections in captive iguanas. Blister disease results when
an iguana is confined to a moist, filthy enclosure. The disease is characterized by blisters, especially on the
underside aspects of the body, that develop into seriously infected wounds. Aggressive antibiotic therapy is
necessary to successfully treat affected iguanas.
Dry Gangrene of the Tail or Toes: Another sign of serous, body-wide bacterial infection is dry gangrene of
the tail and often the toes. The dry gangrene usually slowly moves up the tail from its tip. One or more toes
may have the same type of progressive problem simultaneously. The disease can be controlled with
aggressive antibiotic therapy, strict hygiene and good husbandry.
Mouth Rot: Bacterial infection of the mouth is often the result of malnutrition and a debilitated, weakened
condition. Signs of mouth rot include swelling, inflammation and accumulation of pus within the mouth,
increased salivation, and difficulties in eating. Treatment involves identifying the offending bacteria and giving
appropriate antibiotic therapy. Providing vitamins, fluids and forced feeding are also essential.
Abscesses: Bacterial infections may settle in one or more areas and result in abscess formation. Reptile
pus is not liquid, but it is of a cheesy, sometimes rubber-like consistency. Consequently, treatment of
abscesses by a veterinarian involves opening up the pus-filled abscess and manually cleaning it out. Antibiotics
are then infused directly into the cavity and also given by injection.
Bacterial infections of reptiles require injectable antibiotics to eliminate the bacteria from the body as
rapidly as possible. When therapy is delayed or insufficient, bacteria multiply and spread throughout the body,
usually resulting in internal abscesses. Antibiotic therapy then is much less successful. Initial and periodic
white blood cell counts are necessary to properly monitor the progress of the patient and to detect any relapse.
Parasite Problems: Parasites may be found externally (mites), within the gastrointestinal tract (worms,
protozoa), and within the blood (malaria-type parasites) of captive iguanas. Parasites represent a significant
burden in addition to the inevitable stresses of captivity endured by all pet iguanas, and should be treated by a
veterinarian specializing in reptiles. Iguanas weakened by malnutrition and chronic bacterial infections are
particularly susceptible to the detrimental effects of parasites.
Viral Infections: Though viruses probably cause disease in iguanas, only a few have been specifically
identified in this capacity. With continued interest and research in iguanas, our understanding of viral
infections will be enhanced.
Organ Failure: Failure of vital organs often accompanies advancing age, and may also be a consequence
of gout and severe bacterial infections. If possible, blood samples should be collected to allow evaluation of
vital organ function. Treatment by a veterinarian is usually guided by the results of diagnostic testing.
BLADDER STONES: Minerals in the urine may precipitate and form stones within the urinary bladder of
iguanas. The iguana may exhibit no signs of illness or may strain during urination and act listless. If the stone
becomes very large, the abdomen may become enlarged. The droppings may also contain blood. A radiograph
(x-ray) is necessary to confirm the diagnosis. Abdominal surgery is necessary to remove the stone.
EGG-BINDING: Egg-binding can be a life-threatening condition. It results when a pregnant female cannot
expel one or more eggs from the reproductive tract. Causes of egg-binding include malnutrition (especially
mineral imbalances), various diseases, mummification of the eggs, and large or malformed eggs. Physical
examination and radiographs (x-rays) are necessary to diagnose this problem. The veterinarian may select a
medical and/or surgical approach to relieve this serious condition, depending on the circumstances.
SWOLLEN JAW: See Metabolic Bone Disease.
BROKEN TAIL: Though iguanas do not shed their tails like some other lizard species, tail fractures,
dislocations and other serious injuries may occur. Care must be taken to firmly restrain the tail when an iguana
is picked up and held. A veterinarian can treat soft tissue injuries according to the severity, and can “set” and
splint the fractured tail if necessary.
BROKEN TOES: An iguana’s toes are very vulnerable to injury, especially when iguanas are housed in
screened or wire enclosures. It is very easy for toes and/or toenails to become entrapped within the wire
mesh, resulting in fractures, dislocations, torn nails (with subsequent bleeding), and injuries to the skin and
scales of the toes. These injuries often occur during attempts to remove a panicked iguana from its enclosure.
Great care should be taken when overcoming the animal’s grip on the wire mesh. Twisting of the iguana’s
body against this steadfast grip often causes serious injuries to the feet and toes. A veterinarian should be
consulted at once if such injuries occur.
A Comment Regarding Sharp Claws
Iguanas are usually quite docile and enjoy handling. You, however, may not always enjoy the activity
because of the scratches inflicted by sharp claws, powered by very strong limbs. An iguana’s claws should be
periodically dulled by an experienced veterinarian or veterinary technician. A cautery instrument or high-speed
grinding tool is usually employed for this task.
Veterinary Examination
A thorough initial examination is the cornerstone of a health care program for the pet iguana. All newly
acquired iguanas, regardless of age, should be thoroughly examined by a veterinarian as soon as possible.
Besides a complete physical examination, a blood work-up and stool examination should be included. The
advantage of this thorough initial work-up is that current and potential medical problems can be identified and
treated before they become serious.
For More Information
A wealth of additional useful information may be obtained by joining a herpetological organization. Most
publish newsletters or bulletins on many matters relating to reptiles and amphibians, and there are many e-
mail lists and news groups as well.
Society for the Study of Amphibians and Reptiles
(SSAR)
Marion Preest, Secretary
Joint Science Department
The Claremont Colleges
925 N. Mills Ave.
Claremont, CA 91711
909-607-8014
mspreest@jsd.claremont.edu
www.ssarherps.org
The Minnesota Herpetological Society
Bell Museum of Natural History
10 Church St. SE
Minneapolis, MN 55455-0104
612-624-7065
www.bellmuseum.org/herpetology/Main.html