What is the political symbolism behind the donkey and the elephant?

The Donkey of the Democratic Party can be tracked Back to Andrew Jackson’s 1828 presidential campaign, whose opponents called him an “ass.” Jackson took the picture and featured the donkey on his campaign posters. Years later, a political cartoonist named Thomas Nast helped popularize the donkey as a symbol for the entire Democratic Party.

Nast was also responsible for promoting the elephant as a symbol for the Republican Party. He first used it in an 1874 titled drawing “The Panic in the Third Term” with an elephant reading “The Republican Vote”. He continued to use the elephant as a symbol of the party, and other cartoonists followed his example and cemented the association.