We went to the start of the UP 200 sled dog race here in Marquette. We go every year, but this year the temperature was actually pretty warm (in the 20s), compared to last year's negative temp.
Those poor dogs in the bottom picture were back-up dogs, so they weren't being run. I think they were sad about being left out. Once they're harnessed, the dogs go crazy because they just want to RUN! They anchor the sleds down because the dogs are just pulling like crazy. I took some video (not too good because it's from my still camera)
here.