Moose are one of the more dangerous animals you might encounter in North America. According to the Alaska Department of Fish and Game, moose can become ornery and aggressive "when they are hungry, tired of walking in deep snow, or harassed by people, dogs and traffic." So they're basically like people. Very large people with horns.
Normally, moose don't take their aggression out on people, though. They tend to fight one another. The American Museum of Natural History has immortalized this tendency in a diorama depicting two bull moose duking it out. Here's a video (the first in a new series from PBS called "Diorama"), in which Ross MacPhee, curator of the mammals collection, explains why moose are so pugnacious:
Most of the time, male moose fight over females or territory (which they hope is full of females). And it turns out that the point isn't actually for one moose to gore the other moose with his antlers. It's to push harder and show that he's stronger. Whoever can move the other one out of the way wins.
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