Don't let the cartoonish grin fool you; moose are among the most dangerous, regularly encountered animals in the world. They prefer to leave humans alone, but if disturbed or threatened they are known to respond by charging with aggression. They attack more people annually than bears do, and they are especially aggressive when defending a calf.
"The best practice around moose is to go away around a moose," Anchorage-area state wildlife biologist Jessy Coltrane, told the Huffington Post. "Assume every moose is a serial killer standing in the middle of the trail with a loaded gun."