And on the fourth day of the 2012 Iditarod, they rested.

Led by Ally Zirkle, the lead group of mushers plowed through the McGrath checkpoint late Tuesday night -- Zirkle stayed four minutes, just long enough to accept her award for being the first to reach the checkpoint -- before moving on to Takotna, the site where many will take their mandatory 24-hour rest.

Zirkle pulled into the small town known for its fresh pies at 3:30 a.m. EST early Wednesday morning and was quickly joined by John Baker, Mitch Seavey, Jeff King, Dallas Seavey, Ray Redington, Jr., Paul Gebhardt and Hugh Neff, all of whom arrived in McGrath within three hours of the race leader.

But not everyone made the 18-mile run from McGrath to Takotna. Four-time champion Lance Mackey, who arrived with two dogs in his sled, opted to take his 24-hour layover in McGrath, citing the health of his team as the main reason why:

The four-time champion told Iditarod Insider that he'd take his 24-hour layover at the checkpoint, a choice none of the other frontrunners made.

"I race my team first and my competition second," he said. "I've always said I'm not gonna win the Iditarod at the expense of my team."

And still others bypassed the layover altogether, with Martin Buser and son Rohn tearing through Takotna to take the lead ... kinda:

Martin arrived at 8:31 a.m. and left one minute later, a move that gives him the Iditarod lead.

But it comes with a big fat asterisk. [...]

The Busers still need to take their 24-hour layovers, so their status as race leaders doesn't mean much.

Once those taking their 24-hour layovers pull out of Takotna, they'll run the 23 miles to Ophir, a ghost town, before turning north and making their way for the Yukon River.

Coverage of the 2012 Iditarod can be found on the official website. With a subscription, one can track riders by way of GPS and watch video from the various checkpoints. For continued updates throughout the race, keep with this StoryStream.