From this story on the Discovery Channel's web site:
A treasure trove of ancient weapons has emerged from melting ice patches in the Canadian Arctic, revealing hunting strategies thousands of years old. The weapons, which include a 2,400-year-old spear throwing tools, a 1000-year-old ground squirrel snare, and bows and arrows dating back 850 years, have been found high in the remote Mackenzie Mountains, a region where Mountain Boreal caribou abound in the summer months. Dotted with ice patches resulting from accumulation of annual snow that, until recently, remained frozen all year, the mountains have been the caribous' shelter for millennia. Seeking relief from the heat and annoying bugs, the animals huddle on the ice patches, becoming an easy target for hunters who recognized this behavior millennia ago.