Dogs are domesticated mammals, not natural wild animals. They were originally bred from wolves. They have been bred by humans for a long time and were the first animals ever to be domesticated. There are different studies that suggest that this happened between 15.000 and 100.000 years before our time. The dingo is also a dog, but many dingos have become wild animals again and live independently of humans in the range where they occur (parts of Australia).
Today, some are used as pets, others are used to help humans do their work. They are a popular pet because they are usually playful, friendly, loyal, and listen to humans. Thirty million dogs in the United States are registered as pets. They eat both meat and vegetables, often mixed together and sold in stores as dog food. Dogs often have jobs, including police dogs, army, assistance, fire messenger, hunting, herding, or rescue
Different dog breeds have different lifespans. In general, smaller dogs live longer than bigger ones. The size and the breed of the dog change how long the dog lives, on average. Breeds such as the Dachshund usually live for fifteen years, Chihuahuas can reach age twenty. The Great Dane, on the other hand, has an average lifespan of six to eight years; some Great Danes have lived for ten years