Adult Bed bugs are 5mm long. Before feeding they are a flattened oval shape and light brown, but become rounder and darker after feeding. They come out at night and are attracted to the warmth of our bodies and carbon dioxide in our breath. They are usually found in bedrooms and hide in cracks and crevices during the day time. The most common shelter of Bed bugs is in the seams of mattresses, in crevices in the bed frame, behind furniture surrounding the bed (especially the headboard) or where the wall meets the floor. A more established infestation is associated with dark or black staining of the mattress from Bed bug excreta. An established infestation will also be associated with an unpleasant scent secreted by bed bugs.