From herding bison to reindeer, Australian Shepherds have always been highly valued for their versatility. Working bloodlines are selected for stamina, courage, and the natural ability to keep their charges on the move and together. Partnered with pastoralists in places like Finland, Sweden and even Alaska, Aussies now test their ability on reindeer. They and are being used to herd domestic caribou —just as they once drove herds of cattle — moving them from the mountains to the sea or from the tundra to the forests to graze on lichen (reindeer moss). Reindeer are fast and dogs are sometimes working in several feet of snow. Determination, strength, and endurance are traits necessary to tend migrating herds during their annual grazing cycles.
Traditional reindeer herders (human kind) such as the Jonnson family who live in Northern Sweden depend on upright, close-working stockdogs to drive their herd long distances of 300 kilometers (over 186 miles) between summer and winter grazing. Here is a link to video of Chippa — a really nice, long-tailed Aussie with good natural instinct owned by Silja Jonnson — working a herd of 2,000 animals after only two weeks of training:
http://www.youtube.com/watch?v=0zL0xcxYvVY
Here is another link to an article about how Australian Shepherds were used to work wild bison in Yellowstone National Park: