Which animal is the symbol of the democratic party in the US?

The donkey is the unofficial symbol of the Democratic party. and is used most often to represent it. (For why - see related question below : "Why is the donkey the symbol of the Democratic party").

The rooster is the only symbol ever recognized officially by the Democrats, although there is some question as to whether or not it was adopted on a regional or national level. The rooster still appears on many state ballots and may date to the 1840 "Log Cabin & Hard Cider" presidential election.