A recent encyclopedia entry about dogs cites multiple research papers done by scientists at veterinary schools. According to the article, Labrador retrievers come in two specific breeds: English and American. The English breed is described as stocky and heavy, while the American breed is described as tall and lanky. The article describes current scientific research as showing that males of both breeds usually weigh about 29-41 kg (65-90 lb), and females weigh 25-32 kg (55-70 lb). Coat colors for both breeds come in solid black, yellow, or chocolate. All labs have strong tails and webbed feet, which help them swim. Devon would like to use this information to determine if his new dog is an English or American Labrador retriever.