India, July 19 -- Snakes. They're scaly, cold-blooded, fascinating creatures. They smell with their tongue, and some have thermal vision. They also "hear" by sensing vibration, and swallow their prey whole. Despite these characteristics, however, you shouldn't be scared if you happen upon one while exploring one of America's national parks.

But if you do have a fear of snakes (known as ophidiophobia), you should know there are some national parks that are well-known among snake experts (known as herpetologists) as having an abundance of reptile life.

"The part of the U.S. where we probably have the most venomous snake species is the southwest, particularly the desert," Dr. John C. Maerz, a Dennis and Sarah Carey distinguished professo...