Party Animals: How American politicians got their fursonas
Early next month, Americans will vote for various political offices, including President of the United States, the U.S.'s head of state. This is usually considered a pretty big deal in America, and even the world in general, as America still manages to wield a lot of political, economic and even cultural power on the world stage, despite itself. Some of the idiosyncrasies of the American political system may be a bit opaque to non-Americans (no, we don't really understand what the Electoral College is supposed to accomplish anymore, either). One aspect that seems to be uniquely American is the strong identification of American political parties with certain animals.
A brief history of American political parties
American politics has been been dominated by two parties, the Democrats and the Republicans, and every President since the 1860s has belonged to one or the other. At a local level, "third party" candidates and non-aligned "independent" candidates are more likely to gain office, but the two party system still is mostly followed even at the local level. George Washington, the first American president, is the only one not officially associated with a party, and even then, despite his personal misgivings about political parties, many historians agree he probably would have been a member of the Federalists if they'd coalesced early enough.
The Federalists can be considered the first American political party, rivals of the Democratic-Republican party. They were not very effective rivals, however, and the Democratic-Republican party is usually seen as the real "ur-party" from which the modern Democrats and Republicans split off. The first Democratic president was Andrew Jackson, who formed the Democratic party when he split from the Democratic-Republicans. The anti-Jackson wing of the former Democratic-Republican party formed the Whig party (taking its unusual name from the British Whig party), which didn't last long, partially due to the issue of slavery which was better addressed by the new Republican party, and partially because all their elected presidents kept dying on them. Despite the Republican party's "Grand Ol' Party" nickname, it's actually the younger of the two parties. Abraham Lincoln was the first Republican president, and the main two parties in American politics have been the Democrats and the Republicans ever since (though it should be noted that neither party has been static, and Jackson and Lincoln would probably both be bewildered by their political antecedents).
The Democratic Donkey
The first of the two major American parties to gain an animal symbol was, appropriately enough, the first party to coalesce. Unlike it's political rivals, however, the Democrats have never formally adopted an animal mascot, and the reason for this is actually fairly obvious if you stop to think about it. Nobody wants to be the jackass.
The donkey was used to symbolize the Democratic party from the very beginning, though not by the Democrats. Political rivals of Andrew Jackson were literally calling him a jackass by using the animal to symbolize him. However, this backfired a bit, as Jackson began to use the donkey to represent himself, partially to basically just troll his rivals, but partially because it was argued that, despite it's lowly place in society, the donkey was actually a very useful animal, and was used by Jackson and his supporters to show his appeal to the "common man". Additionally, whether or not you consider the donkey's fabled "stubbornness" to be a plus or a minus, Jackson himself was famously stubborn, so it fit him.
However, once Jackson left the presidency, the donkey actually faded from use by the Democrats. It was brought back into the limelight by the cartoonist Thomas Nast, who frequently used animal symbolism in his political cartoons, especially taking inspiration from Aesop's fables. He was apparently completely unaware of the Jackson/jackass connection, though his use of the animal was the same as Jackson's rivals. It should be noted that Nast, though on the Republican's side, usually only used to the donkey to symbolize the negative aspects of the Democrats. When showing the Democratic party in a more neutral light, he usually showed the party as a fox. This is probably inspired from Aesop, and especially the fable of the "The Ass in the Lion's Skin", where the fox figures out that the "lion" everyone is afraid of is really just a jackass after all. A tiger was also occasionally used.
The Republican elephant
The Republican party, unlike the Democrats, have adopted the elephant as their official symbol. Their animal of choice is also derived from the political cartoons of Thomas Nast. As a Republican supporter, it makes sense his choice to represent the Republicans wasn't an obvious insult. However, in its original context, the elephant wasn't much more flattering to the Republicans than the donkey was to the Democrats. In the first cartoon associating the Republicans with an elephant, the elephant in question is seen as basically well-meaning (it's trying to fix things), but still kind of stupid (it's about to fall in a hole).
There doesn't seem to be any particular reason Nast chose the elephant to represent the "Republican vote". Possibly in the original cartoon, which used the above-mentioned "ass in lion's skin" imagery, the elephant was chosen because it was an animal that wouldn't be frightened by a lion, real or fake. It could also have been chosen to represent an animal that seemed unstoppable (as the Republicans did at the time). Whatever reason, the elephant became Nast, and then the nation's, go-to symbol for the Republican party.
Third parties: moose and porcupine
For American parties represented by animals that are actually native to America, you have to look to the third parties.
Though third parties have not had a particularly successful time in American politics, a few have managed to stick around and effect the two major parties in sometimes very big ways. One of the most successful was Theodore Roosevelt's Progressive (or Bull Moose) party. The party was formed when former president Theodore Roosevelt ran against incumbent Republican president William Howard Taft for the Republican nomination. Roosevelt barely lost the nomination, declared himself "fit as a bull moose", and started up his own party. He went on to soundly thrash Taft in the general election (the only time a member of a third party has beaten one of the two main parties since they became the defaults), though the Democrat Woodrow Wilson won the election in the end.
More recently, the Libertarian party, after briefly flirting with the idea of a penguin mascot, has decided the porcupine is the animal that best represents them. The Libertarians have never really been the subject of political cartoons like the two main parties, but their reasons for picking the porcupine seem to follow the slightly self-deprecating reasons as the Democrats' and Republicans' animal mascots. The porcupine, like the Libertarian party, is mostly harmless.