Dogs are a domesticated descendent of the wild wolf. Unlike cats, dogs have been initially bred as workers but quickly also became great companions to humans. The strength, speed, intelligence, and versatility of dogs have meant that they have been used for a variety of roles throughout human settlement, including pulling sleighs, herding sheeps, search and rescue, hunting, aiding handicapped people, and sniffing for illegal drugs.
Domesticated dogs are highly receptive to human voice and hand movement. Unlike wolves, they can be trained to be well behaved and responsive to human commands. Among many skills, dogs can learn to bark on command, walk along a path, eat and rest at designated locations, and fetch. This intelligence and trainability means they can make great pets for families and little children, especially with breeds such as the labrador or maltese.
Some dog breeds still inherit a large degree of their wild and hunting ancestry. Dog breeds such as the Staffordshire Terrier, Cattle Dog, Rottweiler, and Pit Bull should be treated with extreme care and be leashed at all times in public. These types of dogs are responsible for hundreds of human injuries world wide and even the most tame of these breds will at times snap into a wild frenzy.