North America's Rockies, a world class mountain chain with the greatest and fastest contrast both within and between seasons, are very demanding for wildlife. Prey species must chose between the safer heights or grazing near predators, like mountain goats facing cougar, wolves or bears. Mating and raising offspring must usually be timed in sync with the snow-free season and the abundant summer, when some migratory species pass bye like humming birds. The wolverine's scavenging however is most abundant is winter, when many carcasses are well-preserved. Even the sparse human population and tourists still needs some pioneering/competitive survival spirit and precise timing but is rewarded with invigorating vital adventure.