By Dr. Stahl - Stahl Exotic Animal Veterinary Services
Old world chameleons are becoming increasingly popular as pets. Increased importation over the last several years, coupled with the successful captive breeding of several different species, has made these lizards readily available.
Anatomical features such as rotating eye, projectile tongues, zygodactyls feet and laterally compressed bodies make chameleons unique when compared with other lizard species. Herpetoculturist should have a thorough understanding of the specific husbandry needs of these specialized lizards. Knowledge of proper caging, lighting, temperature requirements and nutritional needs is critical for chameleons to thrive.
Chameleons are extremely fragile and notoriously difficult to maintain in captivity on a long-term basis. Their management is specialized. For example, most chameleons need a daytime/nighttime temperature differential(at least 5-7degrees Celsius) and require caging with good airflow. There is a direct correlation between enclosure design and time spent caring for these lizards and the success of the herpetoculturist. Chameleons should be observed daily for subtle changes in their behavior such as a change in color, decreased appetite, decrease activity level, or their positioning in the cage. These changes may be the first indication of poor husbandry, stress, or medical problems. Successfully managing any medical condition in an Old Word Chameleon requires that the problem be identified early. Once a chameleon becomes debilitated, the prognosis is usually grim.
It is extremely important for the herpetoculturist to develop a working relationship with a veterinarian who has reptile experience, to consult with and/or to present the chameleon for examination. This is particularly important if there are any indications of a medical problem or if there are any changes in the behavior that may indicate a health problem. Waiting until the chameleons are visibly ill, as evidenced by dramatic weight loss and dehydration(e.g., enopthalmia[sunken eyes]), usually results in limited success for both the veterinarian and the herpetoculturist.
Husbandry and Management
It can be difficult to maintain chameleons in captivity long term unless their environmental needs are adequately met. Improper temperature ranges, lighting, caging, hydration or types and size of food items can make it difficult for chameleons to thrive. Poor husbandry also exacerbates or leads to extreme stress and, subsequently, infections and non-infectious diseases.
In order to properly evaluate current husbandry techniques and to set up an ideal environment, the herpetoculturist must be aware of the needs of the particular chameleon species they are keeping. This is important because husbandry requirements differ dramatically between species. Conditions under which one species thrives may be detrimental to another species. Therefore, the herpetoculturist must research the literature for the environmental conditions of a particular chameleon's natural habitat and its specific husbandry requirements(de Vosjoli, 1990, 1994;Ferguson and Blades, 1991;Martin, 1992;Schmidt, 1994; de Vosjoli and Ferguson, 1995; Le Berre, 1995)
Temperature preferences differ among species, though two primary groups exist. The montane/highland group includes chameleons which prefer cooler daytime temperatures between 21-26 degrees C with a focal basking site up to 28-29 degrees C and a night temperature drop as low as 13-16 degrees C. Species of Chamaeleo such as the Jackson's chameleon(C. jacksonii), panther chameleon( C. pardalis), Fischer's chameleon (C. fischeri), mountain chameleon (C.montium), and Parson's chameleon (C. parsonii) are included in this broad group(see Table 1 for species specific temperature's).
The lowland/tropical group of chameleons prefer higher temperatures in the range of 26 - 31 degrees C with basking sites reaching 34-38 degrees C and night temperatures as low as 18-19 degrees C. Species of Chamaeleo within this group include the flap-necked chameleon(C. dilepis), graceful chameleon(C gracilis), Senegal chameleon(C. senegalensis), Meller's chameleon(C. melleri), Oustelet's chameleon(C. oustaleti) and the Yemen or veiled chameleon(C. capyptratus).
Most Chamaeleo species are native to areas of high humidity. Even some of the desert species such as C. calyptratus inhabit areas with high humidity. Generally montane/highland species will require a higher humidity than chameleons in the lowland/tropical group. A relatively high humidity range of 50-75% is appropriate for most chameleons. However, adequate ventilation must not be sacrificed to maintain this humidity, or respiratory and skin disease may occur.
Chameleons should be kept in a large cage with plenty of ventilation and different sized branches and plants for climbing and hiding, or they may be kept "free" but confined to large potted plants. Screening is the preferred caging material, but sharp edges must be eliminated. Use plastic-coated screening or PVC mesh rather than metal screening. Aquariums(large and vertically-oriented are best) can be suitable for some small species and juveniles. A variety of plants such as ficus and pothos should be provided. Particulate substrates, such as sand and gravel, are not recommended because they may be accidentally ingested by chameleons when using their projectile tongues to capture prey items. Newspaper, other paper sources or topsoil can be used as substrate. In any case scrupulous hygiene is critical.
Generally, chameleons should be housed separately, with a visual barrier between cages to reduce stress and territorial behavior. Several juveniles can be housed together during growth, if interactions are minimized by providing adequate foliage.
Radiant heat sources, such as one or two incandescent spot lights (not to exceed 75W each) or ceramic heaters, should be strategically placed to allow the chameleon to bask. Substrate heat source, such as hot rocks and heating pads, are not useful. Chameleons should always be provided with a thermal gradient, cage furnishings/branches positioned to allow access to cooler or shaded areas and good air flow.
Ultraviolet irradiation is important for chameleons to thrive. When the weather is suitable, natural sunlight is best, if a screened enclosure is available. Aquariums should never be used in direct sunlight. Two broad-spectrum fluorescent tubes used together (e.g. Vita-Lite®, ZooMed UVB-310®, ESU Daylight®, etc.) or one bulb in combination with a black-light bulb are helpful for chameleons kept indoors. These bulbs must be no further than 30 cm from the chameleons to be useful and should be replaced every six to seven months. Other UV-emitting bulbs are experimental (i.e., low wattage mercury vapor lamps, sun-lamp bulbs) but they may prove helpful. Use caution as these UV-emitting bulbs can result in injury or death if the chameleon is over-exposed.
Due to their diet, captive chameleons are prone to problems involving metabolism of calcium and its association with phosphorous. A calcium: phosphorous ratio of 2:1 is adequate, but since most insects are high in phosphorous and low in calcium (inverse ratio), the insects must be supplemented with calcium. Several feeding methods can be sued to minimize nutritional problems:
Offering insects in a container (that they cannot climb out of) within the chameleons enclosure is recommended. This allows the herpetoculturist to quantify the number of prey items consumed each day. Additionally, the chameleon can locate and consume prey items more easily and the insects will not stress the chameleon by crawling or chewing on it. Also, "dusted" insects will stay coated better in a powdered supplement when confined to a container. The supplement can also be placed in the container, allowing the chameleon to pick up the powder during feeding.
- Feeding a variety of appropriately sized, soft-bodied insects, such as crickets, flies, butterflies, wax-moth (Galleria sp.) larvae and adults, and net sweepings.
- Feeding feeder insects a balanced diet prior to feeding them to chameleons (gut-loading). Cricket diets, dry dog kibble, or Layena® by Purina, etc. combined with oats, are a few options. Some of the most promising result shave come from feeding insects a diet of leafy green vegetables and crated carrots (high in vitamin A precursors), alfalfa, and crushed dried beans or bean sprouts (sources of vegetable protein).
- A few of the larger species, such as C. parsonsii,, C. pardalis, and C. oustaleti, may be fed a single newborn or weanling mouse weekly. Generally these rodents have a better calcium to phosphorous ratio than insects.
- Supplementing insects by dusting them with a calcium/vitamin D3 powder, such as Rep Cal®. Additionally, a multivitamin, such as Vionate®, Reptivite®, or SuperPreen®, etc. can be used. Any vitamin/mineral supplements that contain fat-soluble vitamins must be used with caution, as overdosing can result in organ toxicity. Some of the most promising results have come from routine daily use of phosphorous-free, calcium-only supplements with occasional use of vitamin D3 (e.g., three to four times weekly for juveniles, twice weekly for adults) and multi-vitamin supplements (e.g., one to two times weekly for juveniles, every other week for adults).
- deVosjoli and Ferguson (1995) recommend (for growing juvenile C. pardalis) a gut-loading cricket diet consisting of a grain base with a 1-4% calcium content and vitamin A and D at 50-100 I.U. of each vitamin per gram of cricket food.
- Providing natural sunlight (best) when housed in screened enclosures (but making sure to provide shade to avoid overheating) or by using broad spectrum and/or black lights to promote endogenous synthesis of vitamin D3.
Another effective feeding method is to hand-feed (and hand-water) chameleons. Although time consuming, this allows the herpetoculturist to know exactly how much the chameleon is eating and drinking. Additionally, it reduces stress by creating a positive reaction for the chameleon when approached by a human carrying food.
The amount of food that should be fed to chameleons to maintain good health is not well documented. Generally, ad libitum, feeding for young, growing chameleons is recommended. Ferguson (1991, 1994) found that growing C. pardalis consumed their body mass in prey items weekly when fed ad libitum. By contrast young, C. pardalis that were fed a limited diet were unable to thrive, and eventually died. Ferguson found that adult C. pardalis, both male and female, could maintain their body weight and successfully reproduce by eating an average of 30-50 adult crickets per week.
Chameleons generally will not drink from standing water. Visually stimulating the lizards by misting or by using drip systems or air bubbling systems will encourage drinking. Some commercial misting systems are now available, but herpetoculturists should be aware that these water sources may harbor bacteria. All watering systems must be kept meticulously clean. Routine (once or twice monthly) disinfecting with bleach is recommended at a dilution of 1:32 (bleach: water) with a contact time of at least 15-20 minutes and a thorough rinsing afterward.
For tropical species, misting the cage several times daily will help increase humidity. However, there must be significant air flow in the enclosure or this can lead to health problems.
In addition to daily visual observations, herpetoculturists should closely examine every chameleon in his/her collection at least once a week to look for any signs of problems. Chameleons should be weighed monthly, consistent weight loss or a sudden 10-20 % drop in weight may indicate a problem.
A visual exam, without touching or disturbing the chameleon, should be initially be performed. In particular, the lizard's alertness should be noted. Chameleons are typically very observant and should be keenly aware of your presence. Also note posture, color and ability to ambulate.
The physical exam should proceed as with any other animal. Use a systematic approach, starting with the head and working toward the posterior:
If any abnormalities are noted, the chameleon should immediately be presented to a veterinarian (experienced with reptiles) for examination. Often, diagnostic testing may be performed by the veterinarian to obtain additional information. Fecal exams, bacterial culture and sensitivity, blood work (usually collected from the tail vein), radiographs and biopsy are all beneficial in helping to reach a diagnosis. Your veterinarian may decide to use anesthesia (isoflurane gas) to minimize stress to the chameleon while diagnostic samples are collected and/or surgical procedures are performed.
- Eyes: Eye problems can be early signs of sinus/respiratory infections or nutritional problems. Look for enopthalmia, which is usually an indication of dehydration/emaciation.
- Oral Cavity: The tongue, glottis and the glands at the commissure of the mouth should be examined. Abscesses and stomatitis are common. Look for asymmetry in the mouth as an indication of a problem.
- Skin: Examine for asymmetry, swellings and ulceration, especially of the mouth, rostral projection (if present) and the feet. The loss or damage to toes and nails may lead to infections. Gently remove any retained shedding skin from the feet, toes and tail.
- Musculoskeletal system: Examine body condition, symmetry, bones and strength of grip. This is an important indicator of nutritional status. Loss of muscle mass is usually seen first over the pelvis and tail base.
If a chameleon dies, a thorough necropsy and histopathology should be performed to help determine the cause of death. This information is useful in helping the herpetoculturist with disease management of other chameleons in the collection and it provides valuable feedback on husbandry practices, such as diet.
Metabolic Bone Disease (MBD) and Other Nutrition-Related Disorders
Clinical signs of MBD in chameleons include stunted growth, deformed or fractured bones, soft mandibular/maxillary bones, spinal deviations (which may lead to paralysis) and death. Metabolic bone disease is more commonly seen in young, growing chameleons or adults maintained indoors. Treatment for chameleons diagnoses with MBD is similar to the protocols used for other lizard species. Your reptile veterinarian will likely recommend the use of parenteral (injectable) calcium and vitamin D3. Additionally, an oral calcium and vitamin D3 supplement, such as calcium glubionate, may be used for longer supplementation. However, the most important part of managing MBD is improving the calcium content of the chameleon's diet and providing vitamin D3.
Organ toxicity associated with fat-soluble vitamins is another common nutrition-related disorder. Chameleons kept indoors have been found to have problems with vitamin D3 and vitamin A in particular. A relationship exists between these two vitamins and their amount of supplementation in chameleons. The exact requirements for vitamin A and D3 are currently unknown. Ongoing research may help us to better understand their relationship and how we should properly supplement. Some things are worth noting:
- The exact requirements for vitamin A and D are no the same for all chameleon species and are higher for growing juveniles and reproductively active females.
- Excessive vitamin A supplementation may result in interference of vitamin D3 metabolism, leading to MBD.
- Excessive vitamin A supplementation may result in organ toxicity (kidney and liver) sometimes causing gular edema and reproductive problems such as sterility.
- Inadequate amounts of vitamin A may cause eye problems, neurological dysfunction, spinal kinking, dysecdysis and the formation of hemipenal plugs.
- deVosjoli and Ferguson (1995) reports that 37.5 I.U. of vitamin A for the female C. pardalis.
- Excessive vitamin D3 supplementation can result in organ toxicity (gular edema) metastatic calcification, gout, and pseudo-gout (calcium-like deposit).
- Inadequate amounts of vitamin D3 (either in the diet or by conversion from exposure to ultraviolet light) can lead to MBD.
- Treatment for hypovitaminosis involves immediate supplementation of the low level of vitamin in question either by injection or orally, supportive care with fluids and supplemental heat, if necessary, providing natural sunlight (best) or ultraviolet irradiation and ultimately adjusting the diet and/or UV exposure to attempt to provide the necessary vitamin levels.
- Treatment for hypervitaminosis is more difficult as organ toxicity and damage has usually occurred by the time clinical signs have been noted (e.g. gular edema with kidney damage). Aggressive fluid therapy (see therapy for infectious diseases), exposure to natural sunlight, providing a lower protein diet and using phosphate binders such as Amphogel may be helpful. If hypervitaminosis D and metastatic calcification is suspected.
REPRODUCTION RELATED PROBLEMS
Often, gravid female chameleons will become anorectic when nearing oviposition or giving birth. This may be normal behavior. Some recently imported female chameleons are already gravid when collected. Typically, these females will be debilitated due to the stress of importation and nutritional demands of pregnancy. Providing proper husbandry (including no handling), ensuring the animal is hydrated and providing some nutritional supplementation (gentle force feeding of supplemented insects) may allow them to survive the gestation. Typically an enlarged abdomen and/or gentle palpation will reveal if the chameleon is gravid. Radiographs or ultrasound can be used to confirm the diagnosis.
While it is uncommon in live bearing chameleons, dystocia is common in egg laying species. It may be caused by several factors, including stress, poor nutritional status and malformed eggs. A veterinarian with reptile expertise should be consulted immediately if dystocia is suspected. The use of oxytocin (10-20 I.U./kg intramuscularly or subcutaneously) and/or surgical manipulation may be necessary, as retention of eggs commonly results in death. To decrease the likelihood of dystocia, females need to be in good body condition prior to breeding and egg laying. As many chameleons will ovulate regardless of whether or not they have been bred, females should be kept well fed and hydrated at all times.
Perhaps the most common cause of dystocia is an improper environment/substrate for laying eggs. For all egg laying species it is essential that an appropriate place is provided in the chameleon's enclosure for her to lay her eggs. Otherwise she may retain the eggs and die. Several breeders have found success in using a large bucket of slightly moistened topsoil as a medium for egg laying. Others have had success using potting soil in tub placed within the chameleon's environment. Some chameleons prefer to lay eggs in the soil around the roots of potted trees in their cage (deVosjoli and Ferguson, 1995). Many breeders recommend that a gravid female be left undisturbed, as privacy is important for initiated oviposition.
Males and/or females may become anorectic during the breeding process. This may be normal as social interaction takes precedence during this process. Both males and females can be very aggressive during this time and should be observed closely to prevent trauma. Females of each species display certain colors and patterns when they are ready to mate (deVosjoli and Ferguson, 1995). It is during this time that the male should be introduced into the females enclosure. If the female is overtly aggressive toward the male, he should be removed immediately. Otherwise, they should be separated upon cessation of breeding activity.
Jenkins (1992) describes a toxic hepatitis syndrome that may lead to anorexia and/or death. Insect prey, such as crickets, that ingest moldy foods may take in aflatoxins. These toxins, which are produced by fungi, may cause damage to the liver. Liver changes noted on histopathology include chronic portal fibrosis and bile duct hyperplasia. No successful treatment is known, so proper food management is important in preventing aflatoxicosis. Insect colonies must be kept clean.
Bacterial and parasitic problems are common in chameleons. Also, concurrent unidentified vial infections may complicate both infectious and non-infectious problems. To minimize the spread of infectious disease, new chameleons should be quarantined in a separate room for a minimum of 60 days (preferably 90 days). During quarantine, several fecal samples should be collected and checked for parasites. Specimens should be observed to see if they are feeding and defecating normally (watch for signs of illness as well). The longer the new specimens are isolated, the greater the chance of identifying a problem and keeping diseases from spreading through an existing collection.
The most common bacterial infections I have seen in chameleons include pneumonia, sinus/eye infections, stomatitis and abscesses. Most infections come from opportunistic bacteria that occur naturally in their environment. Remember that water sources and food sources must be well maintained. The most common bacteria cultured from chameleon infections are gram-negative bacteria, such as Pseudomonas, Aeromonas, Klebsiella, Proteus and a host of others. It is extremely important for a veterinarian to perform cultures and sensitivities on these infections. This will indicate the most appropriate choices of drugs to use for treatment. Chameleons, however, are such delicate animals that the window for treatment and resolution may be short.
Respiratory infections in chameleons are typically treated like they are in other reptiles. Often, concurrent eye problems such as conjunctivitis may also be evident and the use of antibacterial ophthalmic drops can be helpful. Nebulization therapy is also useful in treating chameleons with sever respiratory infections. The nebulization of the antibiotic creates a fine mist that is then inhaled into the respiratory system, placing the drug directly into the lung tissue.
Oral lesions (stomatitis) in chameleons may be localized in the commissures of the mouth, tongue or mucous membranes. As with other reptiles, gentle but aggressive debridement and flushing of the lesions is important. Chameleons with respiratory disease or stomatitis will need systemic antimicrobial therapy and supportive care (see Therapy). Additionally, chameleons have acrodont teeth which are not rooted but simply attached to the surface of the mandibular and maxillary bones. This unique dentition creates a gum line along the lateral surface of the mandibular and maxillary bones which can be readily permeable to bacteria (McCraken and Birch, 1994). This predisposes chameleons to periodontal disease and osteomyelitis. Herpetoculturists should examine the mandibular and maxillary areas regularly for signs of discoloration and irregular surfaces, which are early indications of disease. Appropriate parenteral antibiotic and supportive care should be initiated immediately (see Therapy). If bone is involved, surgical debridement may be necessary. Typically these chameleons will require long term dental prophylaxis with an oral cleansing product such as Maxigaurd Oragel to avoid progression and minimized recurrence.
Abscesses may result from damage to the skin such as a scratch or puncture wound or other injury. Typically, the wound is small and heals quickly, but later it becomes noticeably enlarged. Abscesses may become life threatening since osteomyelitis (bone infection) or joint involvement may follow. A veterinarian must perform aggressive surgical intervention for debridement and/or drainage to properly manage abscesses. Torn out or damaged nails will also commonly become abscessed and should be treated similarly. These injuries are usually caused by pulling a chameleon off a branch instead of encouraging them to crawl onto one's hand.
For best diagnostic results of bacterial infections, a veterinarian should culture the trachea in a respiratory disease cases, culture deep within oral lesions for cases of stomatitis and culture the lining (wall) of abscesses.
Nematodes, cestodes, coccidian, flagellates and amoebae are all intestinal parasites of chameleons. Clinical signs of parasitism may include general unthriftiness, weight loss or poor weight gain, anorexia, regurgitation, vomiting and abnormal stools. Additionally aberrant migrating nematodes/cestodes may be found in multiple areas of the body and subcutaneously. Theses may appear as raised areas under the skin are often mistaken for abscesses. They must be surgically removed by a veterinarian.
It is important to have several fecal exams performed on each new acquisition to a collection. All wild-caught chameleons are best prophylactic ally treated with both nematocidal and cestocidal drugs. To ensure that parasites are eliminated, several "negative" fecal samples are necessary.
First and foremost in the treatment of infectious and non-infectious diseases, is the correction of improper husbandry. Supportive care is important while trying to correct the underlying disease. However, the benefits of therapy must carefully be weighted against the amount of stress involved.
Fluid therapy at a rate of 20-25 cc/kg (intracoelomically or orally) is critical if the chameleon is not voluntarily drinking or is dehydrated (suggested by enopthalmia). Nutritional support for anorectic specimens may include tube feeding easily digestible liquid diets with crushed crickets mixed into them. Approximately 0.15-0.25 cc/50 g body weight is a good starting point. In critical patients, the formula should be very dilute and normal hydration should be established first. Because tube feeding is stressful, sometimes it is best to drip small amounts of this formula directly into the mouth. Also, small, freshly killed insects can be gently hand fed to the chameleon. Larger chameleons can also be hand fed newborn mice.
Your veterinarian should be consulted for any antimicrobial and anti-parasitic drug usage in chameleons. Due to the fragile nature of these lizards, an incorrect dosage could result in death. It is imperative for chameleons to be weighed on a gram scale for the most accurate dosing. It should be noted that no pharmacokinetic research has been performed on any drugs used for treating chameleons. Due to the seemingly higher metabolic function of some chameleons (I.e., the lowland tropical group) I have had better success by increasing the frequency of dosing for some antibiotics.
Copyright 2007 by Dr. Stahl
Stahl Exotic Animal Veterinary Services
111-A Center St., South
Vienna, VA 22180