SELECTING A PET SNAKE

Snakes are elongated, legless animals with dry, scale-covered skin. Their skin is unusually elastic, which allows it to stretch when large prey items are swallowed. Snakes are rather unique because of these features and because they lack moveable eyelids and external ear openings. Snakes may be only a few inches to several yards long.

Snakes inhabit a wide variety of ecologic habitats: land, trees, underground, fresh water, and salt water. They are found on every continent except Antarctica. No native snakes are found on the islands of Hawaii, Iceland, New Zealand and Ireland.

Some snakes are rare, endangered and protected by law. These snakes may only be kept by zoos and legitimate herpetologists with the appropriate permits. This is also the case with venomous snakes, which should not, under any circumstances, be kept by the average hobbyist. The most common snakes kept by enthusiasts are the many and varied constrictor species (boas, pythons, rat and milk snakes, etc), and the racer, gopher and garter species. The husbandry and dietary requirements for these types of snakes vary considerably. Further, some of the same species (notably the boa constrictors and pythons) reach very large sizes in captivity , and their considerable space requirements must be anticipated.

Usually, an individual eager to own a snake already has a species preference in mind because of some familiarity with it (friend owns a snake of the same species, etc) or because of an inexplicable attraction to a species' physical appearance, size, activity or habits. Before you acquire a snake, you should carefully consider the following recommendations:

Snake temperaments vary among species and among individuals of the same species. Certain snake species almost always retain a gentle, docile nature when they are raised from infancy (boa constrictors). In fact, a healthy young boa constrictor makes the most suitable pet among the tropical snake species available. Other species (the larger pythons) are unpredictable and tend to be quite pugnacious as they mature, whether or not they are handled frequently. Reticulated and Burmese pythons are especially unpredictable when they are anticipating being fed. Snakes of these types, especially those handled infrequently, become conditioned to associating feeding with human contact and often cannot distinguish the difference between these two situations. The small Ball python has the most predictable and even temperament of all of the python species.

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HOUSING YOUR SNAKE

Enclosure and Space Requirements

As a general rule, snakes require relatively little space because of their limited and nonexertional activity. Generally speaking, the size of the enclosure should allow inclusion of certain required items (discussed below) and still allow the snake adequate space to stretch out and move about. Snakes will use both the horizontal and vertical space within their enclosure if provisions are made for this activity.

Aquaria or other similar glass or plexiglass-lined enclosures are usually most suitable because they allow optimum visualization of and safety for the occupant(s), and help to maintain desirable environmental temperatures and generally high relative humidity levels. Wire-lined enclosures may afford adequate visualization of the snake but certainly cannot contribute to the maintenance of desirable environmental temperature and humidity levels. Further, such enclosures promote injuries to the rostrum (nose and surrounding tissues) as snakes repeatedly attempt to "escape" through the wire mesh.

Any enclosure used must have a secure top and be escape-proof. All hinges and locks should be secure. All snakes are potential "escape artists" and many (especially the California King snakes) can escape from almost any apparently secure enclosure.

Floor Coverings and Enclosure Items

Unprinted newsprint, butcher paper, paper towels, terrycloth towels and indoor-outdoor carpeting are the most suitable materials for covering the bottom of a snake's enclosure. In fact, the first two materials mentioned can be cut to size and placed many layers thick onto the floor of the enclosure. When the top layer(s) are soiled, they can be easily removed, leaving clean, dry paper. This makes cleaning of the enclosure very quick and efficient. If indoor-outdoor carpeting is used, it is best to have 2-3 pieces cut to the correct dimensions. This way, replacements can be used while the soiled piece is cleaned and disinfected.

Under no circumstances should pea gravel, kitty litter, crushed corncob material or wood shavings be used. These are unquestionably more visually aesthetic than most of the materials mentioned above; however, they are unsuitable because they trap moisture and filth, provide unlimited "hiding places" for external parasites, and make enclosures very difficult to clean. Furthennore, these types of particulate matter are easily and inadvertently eaten while the snake is feeding. This can cause mechanical injury to or obstruction of the digestive tract.

Various objects should be included within a snake's enclosure that occupy its vertical area. These include sturdy branches of various hardwood trees or those fabricated from artificial materials, driftwood, grapevine, hanging ropes, and shelves situated along the sides of the enclosure.

Visual Security

It is very important to provide some privacy for a captive snake. Many snakes will not feed without the privacy afforded by some degree of visual security. This can be accomplished by providing a "hide box" into which the snake can retreat when it feeds or at other times when privacy is desired. Visual security can also be provided by the use and strategic placement of silk artificial plants (and trees if the enclosure is large enough to accommodate them). Silk plants are visually pleasing and easy to clean and disinfect They require minimal maintenance, help to augment the relative humidity level of the enclosure if the foliage is frequently misted, and can complement a snake's ability to camouflage itself, thereby providing visual security.

Climatic Considerations

Tropical snakes kept in captivity (boa constrictors, pythons, etc) require relatively warm temperatures and high relative humidity. Daytime temperatures should range between 80 and 85 F. Nighttime temperatures can fall between 70-75 F without creating problems for most snakes. Native American snakes do well when maintained at 70-80 F.

Relatively large enclosures can be supplied with heat lamps or heaters equipped with thermostats, whereas small enclosures may be adequately heated by placing a heating pad directly underneath them. Exposed heat sources must be shielded to protect snakes from serious burns as they attempt to warm themselves by coiling next to them. Large and small enclosures should also provide the snake a focal (spot) source of warmth. Small snakes should be offered a hot rock. Large snakes can use one or more well-protected and water-proofed heating pads. These appliances allow the snake direct, but safe, contact with the heat source, which helps to raise their body temperature. This allows the snake to be more active and increases their rate of digestion. Check these appliances frequently for malfunction and periodically check the snake for evidence of burns because snakes generally do not move away from heat-generating appliances even if they are being severely burned.

Lighting

Ideally, it would be advantageous for all captive reptiles to be housed in such a way that they could be exposed to and benefit from direct, unfiltered sunlight during the daylight hours every day. This represents the healthiest and most natural situation. Unfortunately, this set of circumstances can rarely be fulfilled by hobbyists because it is neither practical or possible. The next best solution is to use an artificial ultraviolet light source rather than fluorescent or incandescent lightbulbs. One or more Vitalites (Duro-Lite Lamps, Duro-Test Corp, Lyndhurst, NJ 07071) should be used to illuminate the enclosure during the daylight hours. To approximate a natural photo-period, 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 in the spring and a gradual decrease in the fall and winter months.

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FEEDING THE PET SNAKE

Water

Water should be provided at all times. Most snakes drink infrequently but use a suitably sized container for immersing themselves and soaking. Another advantage for including a relatively large water container is that water evaporation contributes to the relatively humidity of the enclosure. This is especially true if the enclosure is glass or plexiglass-lined. The water container should be roomy enough to allow adequate soaking and heavy enough so it cannot be easily overturned.

Water containers must be thoroughly and regularly cleaned. Failure to do so encourages bacterial proliferation. Snakes drinking and soaking in this water soon become ill. Use Roccal-D (Winthrop Veterinary , NY , NY 10016) to disinfect the snake's enclosure and furnishings at least once every 2-4 weeks.

Food

Before specific feeding recommendations are made, it is very important to make several points and cautions regarding the feeding of captive snakes. The most respected herpetologists and experienced snake hobbyists all agree that captive snakes should be fed dead or incapacitated prey whenever possible. This is because such prey cannot injure the feeding snake. Providing killed prey that has been frozen is convenient and economical for the hobbyist. Snakes may be induced to eat thawed, frozen prey animals by clipping hair from the coat of a live rat and rolling the proposed food in it just before feeding.

Though freezing, thawing and subsequent feeding of whole prey animals is a common practice among hobbyists and herpetologists, some experts believe that such food sources should be "gutted" (eviscerated) before they are frozen. This greatly reduces the possibility of generalized bacterial contamination of the carcass. To replace those nutrients within the viscera that would otherwise be lost, the hobbyist can place a gelatin capsule filled with a vitamin/mineral/ amino acid supplement (Nekton- Rep: Nekton Products, W. Gennany) into the body cavity before feeding the thawed prey animal to the snake.

Rodents (rats and mice in particular) left unattended and unobserved within an enclosure with a supposedly hungry snake sometimes turn on the "diner" and inflict serious bite wounds on it. These "dinner becomes the diner" incidents are most likely to occur when a snake is ill or otherwise uninterested in feeding.

If snakes do not accept freshly killed or well- thawed frozen prey, the live prey must be stunned so that it is sufficiently incapacitated and unable to injure the snake. Live rodents can be placed in a paper bag, which is then swiftly slammed down on a countertop to stun the rodent inside. If such an incapacitated animal is offered to a snake that is generally accustomed to receiving its food in this fashion and the snake refuses it, the prey animal can be killed and frozen, and offered at a later time.

If it is not possible to offer anything other than live and fully conscious prey for a snake to successfully feed, the encounter must be carefully supervised. If a snake shows no interest in feeding within 10-15 minutes after the prey has been introduced, the prey should be removed and all of the possible reasons for the snake's lack of interest in feeding should be investigated. If other similar attempts to feed the snake within the next 1-2 weeks are equally unsuccessful, veterinary help should be sought at once.

Snakes acquire a large number of infectious agents from the foods they consume, especially because of the snake's habit of feeding on whole prey items. It is not practical or possible to ensure that all prey animals are absolutely free of disease-causing agents. However, prey animals that are to be fed to captive snakes should appear healthy and come from a reliable source.

Extreme caution should be exercised when feeding snakes. This is especially important if a given snake is expected to be hungry and if human-snake interaction is limited to feeding times. An overzealous and hungry snake is very likely to strike at a person immediately after the enclosure is opened and as the prey item is introduced. Large snakes can be especially treacherous and dangerous at these times because of their ability to overcome and overpower their keepers. Hobbyists and even a few expert herpetologists have been seriously injured or even killed at such times.

Great caution must also be exercised when feeding more than one snake within an enclosure. Serious problems result when two snakes choose to prey on the same food item. If one snake attaches to the front of a mouse and another attacks at the tail end of the same mouse, neither snake will surrender its hold. Both snakes will continue to feed and eventually one will consume the other! When two or more snakes are housed within the same enclosure, they should be fed individually by holding the prey animal in long forceps or tongs. Captive snakes, as a group, usually do not suffer from major nutritional deficiencies, unlike the majority of reptiles kept in captivity. This is largely because pet snakes are allowed to feed as they do in the wild, on whole prey items. The prey species fed to captive snakes are undoubtedly different from those present in the snake's natural environment. Further, the relatively narrow diversity of prey animals that can be fed to captive snakes due to practical and economic considerations is in contrast to the wide variety of prey animals potentially available to wild-living snakes. In spite of these major differences, the incidence of malnutrition and malnutrition-related problems among captive snakes is quite low, markedly contrasting the usual situation with most captive reptiles and their seemingly limitless malnutrition- related disease problems. The potential for malnutrition and malnutrition-related disease tends to be greatest among juvenile snakes fed primarily very immature vertebrate (rodents, birds, reptiles, amphibians, etc) and invertebrate prey species (insects primarily). These food items are not as nutrient-rich as their more adult counterparts.

Feeding schedules for captive snakes vary with the age, species, size, condition and specific requirements of the individual. Generally speaking, pet snakes are usually fed once every 1-2 weeks. Juveniles and adults for which a relatively rapid growth rate is desired can be fed more frequently, providing that environmental temperatures are warm enough to allow complete and thorough digestion. Older snakes are usually fed less frequently, often once every 3-6 weeks. The number of prey animals offered at each feeding is determined by the same factors discussed above with regard to frequency of feeding.
Overfeeding must be avoided because of the risk of obesity. Too-frequent feedings and allowing a captive snake to consume multiple prey animals at each feeding encourages rapid growth. It also leads to obesity in older animals. The relative difficulties in procuring food limits this phenomenon in the wild.

Specific Dietary Recommendations
The variety of snakes kept in captivity is considerable and their food preferences are quite variable. Following is a list of preferred prey animals for the snakes most commonly kept in captivity:
Boa constrictors, pythons, rat snakes, gopher or bull snakes:

Garter snakes, ribbon snakes, water snakes, etc:

Indigo snakes, king snakes, and many racers:

Ring-neck or brown snakes and their relatives:

Racers, vine snakes, coachwhips:

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Shedding is the process by which snakes periodically discard the outer portion of their skin. This activity is under hormonal control and associated with growth. Most snakes shed their skin 4-8 times per year. The frequency of shedding depends upon many factors, including environmental temperature, frequency of feeding, amount fed at each feeding, and activity level. Young snakes shed more frequently than older ones because growth is relatively rapid in the first few years of life.

Healthy snakes usually have little or no difficulty with shedding and tend to shed their skins in one entire piece. Exceptions to this include snakes with injuries to the skin and/or scales resulting in scarring, and snakes housed in enclosures with suboptimal temperature and/or relative humidity levels.

The stresses associated with shedding can be substantial. Sick snakes, those suffering from malnutrition, or those whose health has been directly or indirectly compromised by poor husbandry experience delayed and incomplete sheds. These snakes tend to shed their skins in pieces. In fact, many of the pieces remain adhered to the underlying skin and eyes (retained eye caps).

The shedding process is preceded by a period of relative inactivity. This period usually lasts 1-2 weeks, during which time the eyes begin to exhibit a dull, bluish-white appearance. During this period, the snake's vision is impaired, which causes them to be rather unpredictable and sometimes aggressive. The skin during this period tends to have an overall dull appearance. The underlying new skin is soft and vulnerable to damage while the outer layers prepare to slough away.

The eyes again become transparent after 7-15 days and shedding commences. A snake will make use of any rough objects or surfaces within its enclosure to help shed the skin. Shedding commences with the skin of the head. Once the snake has loosened and dislodged the skin surrounding the mouth and overlying the rostrum (nose), it then passes between rough objects that can trap the loose skin and hold it as the snake glides out of the "old" skin. Discarded skin appears dry and tube-like or moist and crumpled in a solitary heap. Many snakes defecate after a successful shed, or consume large quantities of water.

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A NATURAL HISTORY OF GREEN IGUANAS

The green (or common) iguana (Iguana iguana) is an arboreal (tree-living) and diurnal (daylight-active) lizard usually found at elevations below 3000 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 long, sharp claws (for climbing and digging), and a long, strong tail. They can reach lengths of 6-6 1/2 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 blue-green with dark-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 two months, the female digs in moist sand or soil, usually near the base of a tree, and deposits 25-45 eggs. The hatchlings, measuring 25-30 centimeters long, emerge in about two weeks. They grow 15-24 centimeters a year and attain sexual maturity in about three 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.

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CARING FOR THE GREEN IGUANA

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 some 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 one part animal protein (water-packed tuna, cooked chicken, hard-boiled or scrambled egg, Purina Trout Chow, dog food) added to two 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 (Reptical and Vita-Life, Terra-Fauna Products, Mountain View, CA 94042; Reptovite, Verner's Pet Products, Long Beach, CA 90807 ). Nekton-Rep (from West Germany) and other Nekton products are available for sale in some veterinary hospitals.

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.

An alternative method of vitamin-mineral supplementation works well in all but very small iguanas. Empty gelatin capsules can be filled with Nekton- Rep and/or Nekton-MSA powder. The filled capsule is then inserted directly into the iguana's mouth using a pilling device originally designed for use in cats. This direct method of supplementation ensures that the iguana receives its required supplement, and also eliminates the waste associated with sprinkling the supplement on food.

Older iguanas can be fed daily or 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 midlings 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 igua- nas 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 procedure.

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 buildup caused by inevitable 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 hus-bandry 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 environmental temperature to raise their body temperature and increase their metabolic rate and activity level. The optimal environmental temperature to provide for captive iguanas in their enclosures is between 85° and 103° F.

Wild reptiles bask in direct sunlight. Captive iguanas do quite well when a "hot rock" (Sizzle Stone, Terra-Fauna Products) is provided. The iguana has the option of lying on it (totally or partially) to obtain heat as needed. A heating pad may be provided for larger iguanas. Care must be taken to ensure the appliance is functioning properly. Malfunctioning hot rocks and heating pads can cause serious bums.

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 (Duro-Lite Lamps, Lyndhurst, NJ 07071). When an artificial source of ultraviolet light is provided, do not place any glass or plastic partition between the light source and the iguana.

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 afterward.

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.

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DISEASES OF THE GREEN IGUANA 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 counseling 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, article above). 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 fibrous osteodystrophy 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 of sufficient size may be given the supplement directly in filled gelatin capsules, as desccribed in the article above. Iguanas that have become "lettuce junkies" (con- sume lettuce to the exclusion of 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 enclosures 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) helps to minimize it. A visual barrier of dark paint or plastic film placed on or along the lower four 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 serious, body-wide bacterial infection is dry gangrene of the tail and often the toes. The dry gangrene usually moves slowly 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. A suddenly frightened iguana may whip its tail back and forth, injuring the tip against the walls of the enclosure. Such an injury may lead to dry gangrene of the tail.

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 accumulations 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 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. An- tibiotic 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 dictated 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. Droppings may contain blood. A 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, mummi- fication of eggs, and large or malformed eggs. Physical examination and x-rays are necessary to diagnose this problem. The veterinarian may select a medical and/or surgical approach to relieve this serious condition, depending upon circumstances.

Swollen Jaw: See Fibrous Osteodystrophy.

Broken Tail: Though iguanas do not easily 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 their 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 claws to become entrapped within the wire mesh, resulting in fractures, dislocations, torn claws (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.

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 workup and stool examination should be included. The advantage of this thorough initial workup is that current and potential medical problems can be identified and treated before they become serious.

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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.

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