Here are warnings for each dangerous U.S. animal or things that let you know that they are near by; Mountain lion: Warning signs. Bears: Warning signs, droppings, paw prints, marks on trees, and fresh diggings. Bees: Nests. Deer: Hoof prints. Rattle snakes: Shed skin, and rattling noise. Bison: Hoof marks. Gators: Warning signs. Sharks:Pectoral fins. Wolves: Paw prints and howling. Scorpions: No real warning signs. Fireants: Ant hills. When I mean warning signs, I mean posted signs that say there are dangerous animals near by. Like below.