Four-time and defending champion Dallas Seavey mushes during the ceremonial start of the Iditarod Trail Sled Dog Race in Anchorage, Alaska, on March 4. Seavey has faced recent accusations of doping, which he denies, and animal cruelty, which local officials say is not supported by evidence.

Four-time and defending champion Dallas Seavey mushes during the ceremonial start of the Iditarod Trail Sled Dog Race in Anchorage, Alaska, on March 4. Seavey has faced recent accusations of doping, which he denies, and animal cruelty, which local officials say is not supported by evidence. Michael Dinneen/AP …
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