by Steve Thibeault There was a time when a bivvy referred to a military encampment, usually without too much protection or shelter. This camp was composed of a ramshackle collection of tents or makeshift shelters. Today, the bivvy bag has evolved into a solo or ultralight camping adventure accessory. Its function is to keep the user dry and warm by protecting a sleeping bag and it can help to raise the body temperature by up to 10 degrees. For someone who is inclined to travel off into the w