Anna Berington walks Stormy at left and Kristy Berington walks Blue Thursday in Takotna. The mushers are identical twins and the first sisters to run the Iditarod. (Marc Lester / Anchorage Daily News)

Kyle Hopkins in Takotna --

Nevermind the mountains. The toughest part of the 2012 Iditarod would be resisting the temptation to race at her rookie sister's side, Kristy Berington predicted before the start.

Turns out she’s not even trying. The identical twins spotted each other in the Skwentna checkpoint, just 66 miles into the race, and have been running together ever since.

“I recognized (Kristy) and I pulled over right away,” Anna Berington said early this morning. “We’ve just been going back and forth, taking turns leading the way.”

The 28-year-old Beringtons wrote similar run-and-rest schedules, meaning they sleep and race at roughly the same times. Even their dog teams are mirror images: A mix of puppies, 2-year-olds and veteran huskies.

The pair are the first twins and the first sisters to compete in the 975-mile race. They'll likely caravan all the way to Nome.

"It'd be hard not too at this point," Anna said.

Kristy Berington, left, and her sister Anna in Takotna. (Marc Lester / Anchorage Daily News)The Berington sisters parked next to each other in Takotna.