The wild ancestors of all dogs were hunters. Wolves and other wild relatives of the dog still hunt in packs for their food. Dogs have retained the urge to be with the pack. This is why they do not like to be left alone for long. Some breeds of dogs still retain the hunting instinct.
Dogs exist in a wide range of sizes, colors, and temperaments.
Some, such as the Doberman pinscher and the German shepherd, serve as alert and aggressive watchdogs. Others, such as the beagle and the cocker spaniel, are playful family pets, even though they were bred for hunting. Still others, such as the collie and the Welsh corgi, can herd farm or range animals. Each of the dogs just mentioned is a purebred. Dogs have been with humans since prehistoric times.