Quote Originally Posted by frankykeno
I know from doing some reading that their tongues are so sensitive that one fork can pick up more scent than the other fork and tell them if a rodent they are tracking went right or left.
Cool huh? They also have pit organs that give them infrared vision at night. You'll notice BP's (especially juveniles) can often miss their prey when striking... try feeding them at night with a black light. They tend to have much better aim .

As for the original question... technically yes they can "sniff". Snakes actually have TWO olfactory glands. The primary gland is absorbed through the nasal opening and into the primary olfactory gland. When they flick their tongue, they absorb odor particles, which is transfered to the Jacobson's organs (in the roof of the mouth) which is than processed by a different, smaller olfactory gland.

When hunting during the day, they use the combination of olfactory glands to judge distance and direction (like Jo mentioned), and during the night they add in the infrared vision for a much more accurate (and usually more successful) hunt.