Why are a donkey and an elephant the symbols of the Democratic and Republican Parties?

The donkey and the elephant are widely recognized symbols of the U.S. Democratic and Republican Parties. But what do animals have to do with politics, and how do cartoons fit in?

When the Democratic Party gathers for its 2008 convention in Denver, Colo., a donkey named Mordecai will give new meaning to the term "political animal." Mordecai is slated to be the first official live mascot in the… » Full Story on HowStuffWorks