Their main sense organ, then, is their tongue. Unlike humans, a snake's tongue is not used for swallowing. Having no legs or feet, they cannot dig holes, but can occupy dens made by small mammals like ground squirrels and chipmunks. They are extremely important predators, eating a variety of insects, grubs, worms, amphibians, and rodents. The 28 species of Iowa snakes range from the tiny and uncommon 7-inch western worm snake to the common bullsnake which can be over five feet long.
Timber rattlesnakes are common only in some very localized areas.
All other poisonous snakes are either exceedingly rare or absent in Iowa. Keeping your foundation and siding in good repair will keep not only snakes from entering your house uninvited, but also mice and insects. Cleaning up hiding places like boards or piles of junk in the yard will limit available habitat for snakes. On the other hand, providing constructed well pits or other hibernacula below ground is an excellent way to attract these important predators to your property, if you so desire. Snakes are a fascinating part of Iowa's wildlife diversity.