Dogs entertain humans with their intelligence, charm and ability to perform tricks.

Through selective breeding and training, humans minimize dogs' inclination to view cattle and sheep as prey to serve as herders.

Search and rescue dogs with astute noses use their sense of smell to save lives.

Working dogs in police and military roles bring down bad guys whether it's a criminal or enemy.

Therapy dogs are trained to provide affection and comfort, and can be seen in hospitals, retirement homes, nursing homes, hospices and therapists' offices.