For decades dogs
(Canis familiaris) have been used to aid humans in tasks
such as hunting, herding and guarding. Dogs have also been used
to enhance the quality of life of individuals with disabilities.
This includes guiding and alerting people with impaired vision
or hearing, and retrieving dropped items for the physically challenged.
More recently, the concept of dog-assisted therapy has evolved
into tremendously successful programs in the areas of physical
rehabilitation and psychological recovery. However, as society
has moved from small rural communities to increasingly large urban
and suburban centers, the role of dogs as mere companions has
increased. More than 30 million Americans live with one or more
dogs, the majority of whom are kept as social companions.