A new study indicates previously unknown high altitude contests between two of America’s most sensational mammals — mountain goats and bighorn sheep — over access to minerals previously unavailable due to the past presence of glaciers which, now, are vanishing due to global warming.A new study indicates previously unknown high altitude contests between two of America’s most sensational mammals — mountain goats and bighorn sheep — over access to minerals previously unavailable due to the past presence of glaciers which, now, are vanishing due to global warming.