A crossbreed or crossbred usually refers to an animal with purebred parents of two different breeds, varieties, or populations. Crossbreeding refers to the process of breeding such an animal, often with the intention to create offspring that share the traits of both parent lineages, or producing an animal with hybrid vigor. While crossbreeding is used to maintain health and viability of animals, irresponsible crossbreeding can also produce animals of inferior quality or dilute a purebred gene pool to the point of extinction of a given breed of animal.
The term is also used at times to refer to a domestic animal of unknown ancestry where the breed status of only one parent or grandparent is known, though the term "mixed breeding" is technically more accurate. The term outcross is used to describe a type of crossbreeding used within a purebred breed to increase the genetic diversity within the breed, particularly when there is a need to avoid inbreeding.
In general use, the term hybrid is commonly used to refer to plant breeding, such as that of maize, though "hybrid" is also used to describe crosses between animals of the same genus but different species, such as the mule. "Crossbred" is more often used to refer to animal breeding within a single species.
A pet (or companion animal) is an animal kept for a person's company, as opposed to livestock, laboratory animals, working animals and sport animals which are kept for economic reasons. The most popular pets are noted for their attractive appearances and their loyal or playful personalities. Their pedigree may also be a factor.
In some cases pets may also provide their owners with benefits, such as providing companionship to elderly adults who do not have adequate social interaction with other people. While some people believe in the physical and emotional benefits of owning a pet, scientists are currently working to verify these ideas with medical studies. There is now a medically approved class of "therapy animals", mostly dogs, that are brought to visit confined humans. Pet therapy utilizes trained animals and handlers to achieve specific physical, social, cognitive, and emotional goals with patients. Walking a dog can provide both the owner and the dog with exercise, fresh air, and social interaction.
The most popular pets are dogs and cats, but there are also rodent pets, such as gerbils, hamsters, chinchillas, fancy rats, and guinea pigs; avian pets, such as canaries, parakeets, and parrots; reptile pets, such as turtles, lizards and snakes; aquatic pets, such as tropical fish and frogs; and arthropod pets, such as tarantulas and hermit crabs.