The canine athletes are "the best-bred mutts in the world. There is no purebred dog suited for the task," she adds. "A Siberian is like having a little Volkswagen with pinstriped paint and mag wheels. It looks real cute, but it's slower than slow and not very personable - no work ethic, but suited for the environment, and anybody can drive them. But you can't win with a Volkswagen at the Indianapolis 500."

Plettner trains her dogs "to go really far with a lot of small breaks [to play with them and give them a snack] and then a giant break. I never drive them really, really hard for 10 hours. I'm kind of a believer in the long-run, long-rest theory." And she makes sure the breaks set her team's tails a-­wagging - literally. "I have a little thing I call the jolly routine. It's just all about making every dog wag his tail. If you feel really good about your job, you don't feel too bad if the boss has you work a couple hours' overtime," she says.

Still, it's Mackey's team that arrives first at Finger Lake, at 6:30 a.m. and after 45 miles of mushing. Eighty-one more teams, most with 16 dogs still running, will pull in throughout the day and into the evening. Races are won and lost at the checkpoints. Some mushers, anxious to find a pace that will serve both the dogs' needs and their own desire to finish well, constantly shift their run-rest strategies. "I judge the dogs on what they look like they're capable of doing that day," says Mackey. "Today I might be able to do a 100-mile run, and if tomorrow they look like they can only do 40, that's what I'll do."

During the early days of the race, it's not the getting ahead that matters much; it's all about helping the dogs settle in to the pace of the race. "The dogs are pretty amped up; they're excited," says Mackey. Some teams stop at Finger Lake to rest and fuel up. Others hand over their race logs for the obligatory vet check and blow on through.