The Boxer is a medium to large, short-haired breed of dog, developed in Germany. The coat is smooth and tight-fitting; colors are fawn, brindled, or white, with or without white markings. Boxers are a bright, energetic and playful breed and tend to be very good with children. Their suspicion of strangers, alertness, agility, and strength make them formidable guard dogs. They sometimes appear at dog agility or dog obedience trials and flyball events. These strong and intelligent animals have also been used as service dogs, guide dogs for the blind, therapy dogs, police dogs in K9 units, and occasionally herding cattle or sheep.