When humans still lived primarily in hunter-gatherer societies, dogs were among the first domesticated animals. And as the ...

dogs as we know them are domesticated wolves. Not only their behavior changed; domestic dogs are different in form from wolves, mainly smaller and with shorter muzzles and smaller teeth.

Biologists who compared the facial muscles of dogs and wolves report that dogs have facial muscles that allow them to lift their inner eyebrows, making their eyes appear large or sad. The study ...