Serpent mounds may very well have been produced in various parts of the northern hemisphere by the Picts. The Picts were a branch of the seafaring Israelite tribe of Dan. Traces of these people can be found all over western Europe, the British Isles and North America. Their identifying ensign was the image of a serpent. The Danites were well known for marking their territory with symbols and naming their territory after their father. Look at a map of western Europe, the Isles and North America and you will find many cities, towns, counties and even a country containing the telltale name of Dan. It may be written dan, din, den, dun, or don.
The Picts practiced a form of Paganism. They were dark skinned (ranging from red to almost black) and decorated their bodies with paint and feathers. Many historians believe that the northern and eastern American Indians descended from the Pictish tribes.