Now Where Did I Put That Dog Snap?

Dog boxes, hay, harnesses.
A Cantwell dog musher checks the stuff on his sled. 
Dog mushing (or "dog driving," as it's called in Alaska) is a very popular pastime. It grew organically out of the culture of the northcountry. After the great Ice Age, which ended around 10,000 years ago, various pre-Ice Age mammals that could have conceivably been domesticated -- such as camels and horses -- died out in North America. The only domesticated animal in all of Alaska that remained behind was the dog. Native Americans were very attached to their dogs, which they enjoyed as pets, and which served to carry things around.

Later, dogs were used to pull sleds. During the Gold Rush in the 1890's, northern sled dogs became famous, especially after Jack London, a young Californian, came north and wrote several best-selling novels about sled dogs, including "The Call Of The Wild."