While in theory any animal might be a pet, in practice only a small number of species of mammals (especially dogs and cats) and other small animals, such as birds, fish, or lizards, are practical. One reason for this is that large animals are not able to fit inside small dwellings.
Lost pet: Pet leaves home or cannot find its way back, and the owner does not succeed in finding it. Health: Severe health problems make it impossible to have a dog in the house or impossible for the owner to care for the dog. Practice babies: Shelters use this term for animals that have been adopted by couples, and who are then abandoned when the couple splits up, or when a real baby comes along and they no longer have the time or inclination to care for their pet.
