Snakes are in the order Squamata, are characterized by their lack of eyelids and external ears. Snakes feel vibrations traveling through the ground, which in turn sends a signal to the brain telling it that prey, or a predator is near.
Reticulated Python Barbados Threadsnake
The largest snake in the world is the Reticulated Python, Python reticulatus which can attain lengths of up to 25 feet, most people think it is the anaconda which is the heaviest snake getting up to 220 pounds. Leptotyphlops carlae or Barbados Threadsnake is the smallest species only getting 4 inches.
There are around 3,000 species of snakes worldwide and can be found on every continent except Antarctica; some even live in the Indian and Pacific Oceans called sea snakes.
Reticulated Python photo by Mariluna, licensed under CC BY-SA 3.0
Barbados Threadsnake photo by Blair Hedges, Penn State, Leptotyphlops carlae