Several Iditarod dogs have tested positive for opioids after racing a thousand miles across Alaska. Only dogs from the first 20 teams are tested, and blood is drawn six hours after a team crosses the finish line. All of the dogs that tested positive were on one team, and the test showed someone fed the dogs the drug 15 hours earlier. It is unclear who gave the dogs drugs, and some people suspect sabotage. The governing body is strengthening doping rules for future years.