Dog power has been used for thousands of years and, in the Arctic, it has survived practically unchallenged until the present, whereas in temperate and tropical areas other animals have taken the place of dogs in helping humans move about. Nowadays dogs are still used for transportation in several areas, but there is also a boom in the recreational use of dogs as tractors, and not only for pulling sleds. Wikipedia links: Dog sled, Sled dog, Sirius Dog Sled Patrol, Will Steger (homepage). Help make this podcast sound better with a donation to the MARIO MICROPHONE FUND.