The world’s only Key deer, the smallest subspecies of the white-tailed deer, are found in piney and marshy wetlands bordered by the Atlantic Ocean and Gulf of Mexico on the Florida Keys. The world’s only Key deer, the smallest subspecies of the white-tailed deer, are found in piney and marshy wetlands bordered by the Atlantic Ocean and Gulf of Mexico on the Florida Keys. Plants & Animals Ecology Phys.org – latest science and technology news stories