Following the some of the same secret routes utilized by drug smugglers, stealthy predators are making their way into the United States from Mexico. According to the New York Times, male jaguars have crossed the border from Mexico in recent years. As yet there's no evidence that jaguars have been breeding in the U.S. If there were, this could complicate border control policy insofar as areas along the border could be declared critical habitat for the animal -- a move some environmentalist groups already urge. According to the story, one group has already filed suit on the issue, so the question may get resolved in federal court.