August 2009 East Greenbush, N.Y. USA NikonD300 105mm w/ extension tube
Snakes use smell to track their prey. It smells by using its forked tongue to collect airborne particles then passing them to the Jacobson’s organ or the Vomeronasal organ in the mouth for examination. The fork in the tongue gives the snake a sort of directional sense of smell and taste simultaneously. The snake keeps its tongue constantly in motion, sampling particles from the air, ground, and water analyzing the chemicals found and determining the presence of prey or predators in its local environment.
Living snakes are found on every continent except Antarctica. Fifteen families are currently recognized comprising 456 genera and over 2,900 species. They range in size from the tiny, 10 cm long thread snake to pythons and anacondas of up to 7.6 m (25 ft) in length. The recently discovered fossil Titanoboa was 43 ft long. Snakes are thought to have evolved from either burrowing or aquatic lizards during the Cretaceous period. The diversity of modern snakes appeared during the Paleocene period.
Most species are non-venomous and those that have venom use it primarily to kill and subdue prey rather than for self-defense. (wiki)