The domestic dog, scientifically known as Canis lupus familiaris, generally lives 10-13 years, though lifespan varies significantly by breed and size. Small breeds such as the Chihuahua and Toy Poodle often live 15 years or more, while giant breeds including Great Danes, Mastiffs, and Newfoundlands frequently have shorter lifespans of 6-10 years. The American Kennel Club recognizes approximately 200 breeds, organized into groups reflecting their original purposes: Sporting, Hound, Working, Terrier, Toy, Non-Sporting, Herding, Miscellaneous, and Foundation Stock.
Different breeds have very different needs and temperaments, making breed research essential before acquiring a dog. Breeds often recommended for first-time owners include the Labrador Retriever, Golden Retriever, Cavalier King Charles Spaniel, Poodle, and Bichon Frise. Higher-energy breeds like the Border Collie, Australian Shepherd, Belgian Malinois, and Jack Russell Terrier require substantial physical and mental engagement. For those concerned about shedding, breeds like Poodles, Bichons, Yorkies, Maltese, and Portuguese Water Dogs shed less, though no dog is truly hypoallergenic since all produce dander to some degree.
Breed also influences working drives and health predispositions. Many breeds retain strong instincts for herding, retrieving, or scenting, which is why activities like nose work and agility can be so fulfilling for them. Genetic predispositions are common, with breed-typical risks including hip dysplasia, where the hip ball and socket don't fit properly, and brachycephalic syndrome, which causes breathing issues in flat-faced breeds like bulldogs and pugs. It is also important to distinguish between working roles: a service dog is trained to perform specific tasks for a person with a disability and has public access rights in the United States, while an emotional support animal provides comfort without specific task training and generally lacks those access rights. A therapy dog, by contrast, visits hospitals and schools to provide comfort to others.