Republicans have their elephants. Democrats have their donkeys. Progressives in Vermont have their moose. The symbol comes from way back in the day of the old Bull Moose Party of Teddy Roosevelt.
The interesting thing is that, although the Progressive Party has never been the powerhouse the Republican and Democratic parties have been, it's the only political party with a symbol animal that is actually American. The donkey and the elephant are from the Old World. This shirt, like the progressive moose, is made in America, under the environmental and labor laws of the USA. No sweatshop labor here. It's a truly progressive shirt for Vermont Progressives.