Rattlesnakes watch out...every year what may be the world's largest rattlesnake roundup takes place in Texas. See All National Geographic Videos video.nationalgeographic.com

bobcat vs rattlesnake

Competition for a mate is not as violent as you might think among these diamondback rattlesnakes. See All National Geographic Videos video.nationalgeographic.com

Check out Bear's Ten SCARY SURVIVAL moments: dsc.discovery.com When it comes to poisonous snakes, Bear takes no chances. And you shouldn't either.