Even though there are only a few dangerous snake species in the continental United States and Canada, these slithering creatures still inspire an ancient and instinctive fear among outdoorsmen and women. Yet this fear of snakes often spills over as a prejudice against harmless snake species. Severe bleeding can also occur, as the snake’s venom contains toxins that keep the blood from clotting. Gram for gram, the venom is the second worst rattlesnake venom in the U.S., containing numerous neurotoxins and myotoxins. This highly venomous snake species is one of the largest native snakes in North America.