The behavior of dogs is shaped in part by instinct that is selectively bred. View photos of popular dog breeds and learn about their hard-wired behaviors.

The two-part special "Dogs That Changed the World" tells the epic story of the wolf's evolution, how "man's best friend" changed human society and how we in turn have radically transformed dogs.

See a slideshow about working dog breeds.

The selective breeding that created the hundreds of modern dog breeds has put purebred dogs at risk for a large number of health problems, affecting both body and behavior.

Discover ancient dog breeds from around the world on our Interactive Map.

Before you make your decision to get a puppy, think carefully. Here are some tips on achieving puppy love.

An incisive look at the breeding, behavior, and training of humankind's best friend, including useful pointers on how to avoid mistakes when selecting a puppy.