Chapter 37 Overview of Reptiles as Pets
Like birds, reptiles hold a special place in the hearts of many pet owners. They are different from a dog and cat, they require little space, and they are quiet. Many reptiles make very good pets if properly maintained; however, as with birds, many owners purchase reptiles without knowledge of their needs. This results in the needless death of many of these pets. Many different species of reptiles exist and a discussion of all of them is beyond the scope of this book. The technician is referred to several good texts on reptile medicine for detailed information. In this section, we will cover the general husbandry requirements and specific diseases for the most common reptiles kept as pets.
For many years, pet stores have been the prime source of information concerning captive reptiles. Veterinarians have played a smaller role in this area (either from lack of a desire to have these animals as patients or lack of knowledge). Today, the Internet has created an owner who requires better medical care for these valuable pets than generally provided by the pet store. It is time for veterinarians who are interested in these species to step forward and improve their care.
Most reptiles are purchased from pet stores or private breeders. All new reptiles should be quarantined for a minimum of 60 to 90 days to prevent introduction of disease into the collection. During this period, the animals should be given a complete physical examination, including performing diagnostic laboratory testing to rule out disease, parasites, or nutritional problems. The quarantined animal should be housed in a separate area of the house; should be fed, cleaned, and handled last; and should have no exposure to animals already in the collection until it is proved free of disease. New animals should be housed separately because many reptiles are carnivores and may eat cage mates when stressed.
Each species of reptile has what is known as the “preferred optimal temperature range” in which they thrive. It is important, therefore, for the owner to know what species is being kept and what that temperature range is. The preferred optimal temperature ranges for some frequently kept reptiles are as follows:
This generally means that the entire environment must be at this temperature, not just the floor of the cage or the house. Heat lamps, heat tape, and hot rocks have all been used to maintain these temperatures.
Reptiles come from a variety of climates. Some require increased humidity, and some desert conditions; some reptiles are carnivores, whereas others may be herbivores. Most will require exposure to full-spectrum light or sunlight.
Most reptiles are kept indoors in cages. The cages are generally made of wood, wire, glass, or Plexiglas. Whatever the cage is constructed from, it should be easy to clean and disinfect, and it should be strong enough to contain the animal. A locking mechanism will prevent the accidental escape of the animal. The cage should have adequate “cage furniture” to allow for basking or hiding. It should have a source for clean water for drinking or bathing. That is, the cage should replicate the natural environment of the animal. Owners should avoid sand, wood shavings, or kitty liter as a substrate for the cage because they may be swallowed by the pet and are difficult to clean. Newspaper or indoor/outdoor carpet provides for easy cleaning in most cages. Some reptiles require nonporous materials that will allow for burrowing. The cage should be designed to provide temperature gradients that will provide both cooler and warmer areas for the pet. It should also have an artificial full-spectrum light source. Many reptiles kept as pets will eventually reach large sizes and will need even larger habitats, thus the eventual size of the animal should be kept in mind when choosing a cage.
Many beginning owners will not be familiar with the dietary requirements or feeding habits of their pet. It is important that they receive correct information concerning diet, methods of feeding, and number of feedings. The following comments are general; however, exact dietary requirements will be discussed with each species.
In general, all snakes are carnivores. They will eat pinky mice, adult rodents, chickens, ducks, and rabbits (depending on the size of the snake). Some lizards are also carnivores and require insects or small rodents for food, whereas others are herbivores and have little requirement for protein (meat). Many reptiles will not feed unless the prey is presented alive; others prefer killed prey. Adult snakes generally eat one to three times per month, whereas iguanas and other lizards eat daily. It is important for the owner to know the requirements for the species being kept as a pet. Handling snakes after feeding can result in regurgitation of the entire meal and, eventually, loss of condition. All food sources should be fresh and clean. If frozen, they should be allowed to thaw in the refrigerator rather than in the microwave. Powdered vitamins can be hidden in or dusted on the food if desired.
Reptiles require water for drinking and bathing (soaking). The water bowl should be large enough to allow the animal to submerge its entire body. The sides of the container should be low enough to provide easy entry. Water containers must be cleaned daily because many reptiles will defecate when soaking. The bowls should be disinfected weekly. Misting systems can help increase the humidity in the habitat for those species from rainforest environments.
Zoonoses are diseases that can be transferred from pets to humans and vice versa. Owners and veterinary staff should be aware of some pathogens when handling reptiles. Adults that are immunosuppressed (chemotherapy or cancer and AIDS patients) or young children are at greatest risk for infection. Humans come into contact with the infectious organisms when handling the pet, while cleaning the cage, or from airborne dust from feces and cage bedding. Caught wild animals frequently have parasites that are infectious to humans as well. For these reasons, certain precautions should be taken when keeping reptiles as pets. Avoid housing the animals in the kitchen or other areas where food is handled. Always wash your hands after handling the pet, and never let children kiss the pet. Wear protective clothing when cleaning the cage, and properly dispose of all cage bedding and uneaten prey. Do not allow reptiles to soak in bathtubs or sinks used for humans, do not ignore bite wounds from your pet, and have your pet examined frequently to screen for potentially harmful organisms.
The most recognized zoonosis of reptiles is salmonellosis. This Gramnegative rod causes severe intestinal diseases in people and can be fatal. Many cases of salmonellosis can be traced to turtles and other reptiles. EVERY REPTILE SHOULD BE CONSIDERED POSITIVE FOR SALMONELLA UNTIL PROVED OTHERWISE BY LABORATORY TESTING. Other enteric bacteria isolated from reptiles include Clostridium, Klebsiella, Enterobacter, Escherichia coli, Pasteurella, Pseudomonas, and others. Protozoa, Cryptosporidia, and pentastomes are also passed from reptiles to humans.
Although not truly a zoonotic problem, venomous reptiles represent a threat to humans. The majority of owners should NEVER keep venomous reptiles as pets. Venomous reptiles present a danger to both the owner and those living in the surrounding environment. Even highly trained persons have been seriously injured handling venomous reptiles.
The anatomy of the snake is unique because everything is linear in design (Fig. 37-1). Snakes have a three-chambered heart whose position is somewhat variable in that it is movable within the rib cage to allow for passage of large food items. Snakes have both renal and hepatic portal circulatory systems. They have an abdominal vein that runs along the ventral midline. Snakes have two lungs, but the left one is usually smaller than the right. The trachea opens on the midline of the tongue as in the bird. The digestive system is linear from the oral cavity to the cloaca. Six rows of teeth are generally present and are replaced throughout the life of the reptile. Paired kidneys are located in the dorsal caudal abdomen. They are lobulated and elongated, and the ureters empty into the cloaca. Like birds, snakes pass urates with their feces. All male snakes have two intermittent organs (hemipenes), which lie in invaginated pouches on the ventral surface at the base of the tail. The depth of these pouches is used in sexing snakes; the deeper pouches are found in male snakes, the more shallow ones in female snakes.
Figure 37-1 Gross anatomy of the snake, ventral view.
(From Mader DR: Reptile medicine and surgery, ed 2, St. Louis, 2006, Saunders, by permission.)