Ultimate Viper National Geographic Explorer : Season 2007 Episode 15
CNBC 2h 00m
Aired: November 21st, 2007 @ 8:00 PM EST on CNBC
Vipers have been evolving their way to the top of the reptile heap for millions of years. Their venom is lethal and they can strike with precision in complete darkness. Now, some vipers may be evolving into even deadlier forms. Did humans help?
