Via PhysOrg:

… Ice patches are accumulations of annual snow that, until recently,
remained frozen all year. For millennia, caribou seeking relief from
summer heat and insects have made their way to ice patches where they
bed down until cooler temperatures prevail. Hunters noticed caribou
were, in effect, marooned on these ice islands and took advantage.

“I’m never surprised at the brilliance of ancient hunters anymore. I
feel stupid that we didn’t find this sooner,” says Andrews.

Ice patch archeology is a recent phenomenon that began in
Yukon. In 1997, sheep hunters discovered a 4,300-year-old dart shaft in
caribou dung that had become exposed as the ice receded…