they were created by a cartoonist Thomas Nast in Harper's Weekly in 1874. They were just adopted as the party's logo in respect to Nast and his work, so the animals kinda just stuck to the partys.
Thomas Nast? I didnt know that. He's also the guy who first drew Santa as we know him today
yep, and over time santa transformed with society.
Wow, nast has a taste for the past :D