Sled Dogs
How Prospectors Travel
http://en.wikipedia.org/wiki/Sled_dog

On a Christmas Day we were mushing our way over the Dawson trail.

Talk of your cold! through the parka's fold it stabbed like a driven nail.

If our eyes we'd close, then the lashes froze till sometimes we couldn't see;

It wasn't much fun, but the only one to whimper was Sam McGee.