Musk-ox underlay fur - also known as 'quivat' - is one of the warmest natural substances on earth with 3 1/2 times the insulation value of goose down. At the turn of the century, this value led to musk-oxen being slaughtered to near extinction along Canada's and Alaska's Arctic coastal areas - mostly by European whaling ships. Only the musk-oxen that were less accessible to these hunting forays such as those residing on the higher Arctic Islands and in the deep mainland interior continued to survive. This photo was taken by and donated to this site by US photographer (the late) Bill Silliker Jr.; taken on a Great Canadian Wildlife Adventures expedition in Canada's Far North.