By 4000 BC the climate was warmer than it has ever been since the Ice Age. This likely was because of the great amount of melt water evaporating and adding water vapor to the air, causing a greenhouse effect. The Early Archaic tradition is sometimes known as the Late Paleo-Indian. The changes at this point were still very gradual. As the megafauna moved north, smaller mammals, such as deer, elk, and bison, became the major food source. Hunting was augmented by fishing and plant gathering.
The people living in Wisconsin at this time were known as the Boreal Archaic group. They had woodworking tools made of ground stone, such as the adze, gouge and grooved axe. The adze (an axe with an inward-turning blade) was a tool that allowed them the ability to make a dugout canoe. They used the lanceolate spear-points and as well as a side notched point.
It is during the Archaic, possibly during the Early Archaic time period, that the atlatl (A throwing device usually consisting of a stick fitted with a thong or socket to steady the butt of a spear or dart and extend the length it travels.) was first used. Weights on the atlatl were called bannerstones, and often were shaped like butterflies or bow ties. They developed woodworking skills with the ax and the celt (A common prehistoric tool of stone or metal, shaped like a chisel or ax head.).
Later groups of the Boreal Archaic were also known as the Old Copper Group because they made many of their tools and weapons of copper. The Old Copper Culture is indigenous to Wisconsin, but some of the copper artifacts have been found in other locations indicating a trade network existed.
Copper was available to this group, possible from a vein of ninety-nine percent pure copper discovered in the Lake Superior basin and in the form of nuggets in glacial outwash gravel beds. Copper is common in the area now known as Michigan's Upper Peninsula. The Great Lakes Archaic Indians were the first in North America to experiment with working metal. They learned how to both hot and cold hammer the copper, giving them the ability to make a variety of tools, projectile points, fishhooks and even jewelry.
