A pet or companion animal is an animal kept for companionship and enjoyment, as opposed to livestock, laboratory animals, working animals or sport animals, which are kept for economic reasons. The most popular pets are noted for their loyal or playful characteristics, for their attractive appearance, or for their song. Pets also generally seem to provide their owners with non-trivial health benefits; keeping pets has been shown to help relieve stress. There is now a medically-approved class of "therapy animals," mostly dogs, who are brought to visit confined humans. Walking a dog can provide both the owner and the dog with exercise, fresh air, and social interaction.
A particularly problematic combination of economic hardship combined with a love of animals contributes to this problem in parts of the rural United States.[4] In an average year, a fertile cat can produce three litters of kittens, with up to 4 to 6 kittens in each litter. Based on these numbers, one female cat and her offspring could produce up to 420,000 cats over a seven year period if not spayed or castrated. There are also major overpopulation problems with other pet species, such as birds and rabbits. Local humane societies, SPCAs, and other animal protection organizations urge people to neuter their pets and to adopt animals from animal shelters instead of purchasing them from breeders or pet stores.
