Aliy Zirkle drives her dog team during the 2014 Iditarod. Emily Schwing/NPR hide caption

itoggle caption Emily Schwing/NPR

Several female mushers in the Iditarod Trail Sled Dog Race are trying out new attire that allows them to skip bathroom stops. Here, a musher and his team pass fans at the ceremonial start of the race in Anchorage. Dan Joling/AP hide caption

itoggle caption Dan Joling/AP

Dallas Seavey holds his leaders, Diesel, left, and Guiness, after he arrived at the finish line to claim victory in the Iditarod Trail Sled Dog Race in Nome, Alaska, on Tuesday, March 13, 2012. Marc Lester/Anchorage Daily News/Landov hide caption

itoggle caption Marc Lester/Anchorage Daily News/Landov