Why does the Democratic Party in the US use a donkey as a symbol when donkeys are traditionally thought of as foolish animals?

by i_post_gibberish

As a non-American it's always confused me why Republicans are represented by the traditionally wise elephant and Democrats by the traditionally stupid donkey in political cartoons and so on even when the cartoonist is pro-Democrat. Is it that Republicans got people to associate the parties with their respective animals so well that Democrats gave up on trying to change it and tried to "reclaim" the donkey instead?

ForExes

/u/coneballs15 briefly answered this recently here

MaesterBarth

So why are the Republicans Elephants?