Origin of the Democrat's donkey:
President Andrew Jackson was lampooned in political cartoons as "President Jackass," partly for ignoring a Supreme Court order and forcibly removing Native Americans from the American Southeast. A third of those Indians died on the forced march, which became known as the "Trail of Tears." For this, he was depicted with a human head on a donkey's body. Our first genocidal president liked it so much, he made it his party's symbol.
I'll be forever grateful unto him. Good choice and it's managed to apply all throughout the generations.