The Birnirk people used many of the same hunting methods and technology as Punuk and Old Bering Sea, but there was no art. There is very little evidence of tool or weapon decoration. The little art that was present in the Birnirk stage was limited to spiral and concentric motifs on clay pots with bone paddles. They did use sledges, of the same basic design as were later used with dog teams. Birnirk people were sea-mammal hunters who engaged in fishing and whaling. Birnirk houses were square shaped, with walls constructed of horizontal logs and single or double posts in each corner. Sleeping areas were at the back of the dwelling and were either built up or at floor level. No interior hearths were found in the house ruins, although heavily encrusted and fire-blackened pottery vessel fragments suggest extensive use of open fires.