The word amphibian comes from the Greek word for “double-life,” referring to the fact that amphibians start life in water breathing through gills before maturing into lung-breathing land animals, although most never stray too far from water. The class Amphibia is composed of only 3 orders. The order Anura, a word that refers to tailless amphibians, includes frogs and toads ( All.see table Similarities and Differences Between Frogs and Toads). This is the largest order, with more than 3,500 species. The order Caudata, or amphibians with tails—salamanders, newts, and sirens—has about 375 species ( All.see table Some Common Salamanders and Newts). The Gymnophiona order is made up of caecilians: legless, tailless amphibians that spend most of their time burrowing. It has about 160 species.
Chinchillas are members of the rodent family. Their scientific name is Chinchilla lanigera. They originated in the Andes mountains of South America. During the eighteenth century, chinchillas were hunted for their fur and faced extinction until laws banned hunting them. Today there are about 3,000 ranches throughout the United States and Canada that breed chinchillas, and chinchillas are increasingly popular as pets.
The domestic ferret is part of the Mustelidae animal family that includes weasels, badgers, and minks. However, unlike these wild species, ferrets are fully domesticated and would likely starve if released outside. Ferrets have been in captivity for more than 2,000 years and are used as hunting animals in Europe, Australia, and New Zealand. They have become popular pets over the last decade in the United States.
Aquariums bring the beauty and wonder of the underwater world into your home. Although the average fish owner may not typically think of veterinary care for fish, aquatic medicine is becoming more mainstream, especially with the growth in popularity of the Japanese koi and Chinese fancy goldfish show industries. These show-quality fish can cost thousands of dollars, and veterinary care is common. Although a relatively small number of veterinarians throughout the United States work with fish, the numbers are increasing. To find a veterinarian who works with fish, contact the American Veterinary Medical Association or your local veterinarian for a recommendation.
Domesticated gerbils, Meriones unguiculatus, originated in the deserts of North Africa and central Asia and are sometimes referred to as Mongolian gerbils or Mongolian desert mice. Gerbils are relatives of mice and rats and have been bred as pets since the 1960s. Gerbils are known for their curious and mild temperament. Because they have almost no odor, require very little space, and are easy to care for, they make excellent pets. Gerbils are very social creatures, so they do best in the company of other gerbils.
Guinea pigs, also called cavies, are members of the Caviidae family, a group that includes several species of rodents from South America. All cavies are social animals that prefer to live in groups. The domestic guinea pig species, Cavia porcellus, does not exist in the wild. Related species live in the wild on grassy plains and feed on vegetation including grass and leaves. Domestic guinea pigs are popular pets and valuable research animals.
Hamsters are rodents (members of the biological order Rodentia) and are distant relatives of mice and rats. Hamsters are small, almost tailless, relatively clean, affordable, easy to care for, and popular as pets.
House mice (scientific name Mus musculus) originated in the central and southern regions of Asia. Because they are very adaptable, they have spread all over the world. House mice were domesticated by Europeans and Asians who began to selectively breed them for their fur and coloring.
Potbellied pigs are members of the Suidae family of animals. They are relatives of the pigs grown commercially for pork. The breed originated in Southeast Asia and was introduced to the United States in the mid-1980s; since then, they have become popular as pets.
Rabbits are small mammals in the family Leporidae. The European, or Old World, rabbit (Oryctolagus cuniculus) is the only genus of domestic rabbits. Wild rabbits and hares include cottontail rabbits (Sylvilagus) and the “true” hares or jackrabbits (Lepus). In Western nations, rabbits have been kept as pets since the 1800s. As pets, they need a considerable amount of care and attention. Many different breeds of rabbits are available; common differences between breeds include size, color, and length of fur.
Pet rats (scientific name Rattus norvegicus) originated from the Norway rat, found on the streets of cities and in the fields of rural areas. The Norway rat became domesticated in Victorian times and people began to selectively breed them for their fur and color. Rats have a long history in association with humans, although not always very pleasant. Some cultures regard rats benevolently; they are the first sign in the Chinese zodiac and are considered gods in some Indian religions. In Europe they were considered creatures of darkness, death, and disease because of the belief that they transmitted the plague. Today we know that it was not rats, but rather the fleas they harbored, that carried the infection.
Reptiles can be easily recognized by their horny or scaly skin. The class Reptilia has 4 orders. The order Rhynchocephalia includes only 1 living species, the tuatara, which is native to New Zealand. The order Crocodilia includes alligators, caimans, crocodiles, and gharials (a crocodilian species native to the Indian subcontinent). The order Testudines contains tortoises and turtles, also called chelonians. The order Squamata includes lizards and snakes.
Sugar gliders (scientific name Petaurus breviceps) are small marsupials, mammals that nurse their offspring in pouches on their stomachs. Kangaroos, koalas, opossums, bandicoots, and wombats are also marsupials. These exotic pets come originally from Australia, Indonesia, and New Guinea and were first brought to the United States in the 1990s.