Dogs were probably the first animals to be domesticated by humans and are descended from a common ancestor of the Eurasian wolf. Modern dogs have lived with humans for about 16,000 years but proto-dogs have been associated with us for 27,000 to 40,000 years.
People first came to rely on dogs for their keen sense of hearing and smell. These senses help dogs alert people to predators, animals that hunt and eat other animals, as well as assist in hunting for food. Dogs are social animals and through the process of domestication have also come to rely on humans for companionship and security. This close association with humans throughout history has led people to breed dogs for specific traits and abilities that serve a wide range of human needs.
Dogs need people who look out for their welfare and make an effort to learn about how to handle and care for them properly.
People value dogs as hunters and helpers, guides and guards, entertainers and therapists, and even sometimes as fashion accessories. In some cultures, dogs are also an important source of food. In North America, people value dogs as pets, best friends and members of the family.
Cats have not undergone the same long process of domestication and breeding as dogs have. Because cats are not fully domesticated, traits that make it easier to live with people have not developed as strong characteristics of cats.
People often assume that because cats are not like dogs, they are not sociable animals. However, they are in fact sociable animals, just not in the same way as dogs. For at least 10,000 years, cats and people have experienced mutual benefits. Cats keep the population of rats and mice under control, whereas people provide places where a cat might find shelter, food and other cats.