The timber, prairie and Massasauga rattlesnakes can all be found in Iowa and are generally considered to be the only poisonous snakes native to the state. Rarely, copperheads can be found in localized areas in south-eastern Iowa.
The prairie rattlesnake is found in select areas of northern Iowa where it can reach lengths of 45 inches with the largest specimen recorded at 57 inches. They are normally tan, mottled brown and muddy green and can be identified by their triangular head and large tan rattle on the end of their tail. They normally hibernate in groups throughout the winter before venturing above ground in April or May. The snake's main diet consists of small mammals, amphibians, birds and bird's eggs.
The Massasauga rattlesnake is slightly smaller than the prairie rattlesnake generally only attaining a maximum length of 30 inches. The longest one ever recorded was 39 inches. This snake is normally brown or gray with white or yellow stripes that extend from its head to its neck with additional stripes running along its cheek and jaw-line.
Copperheads are generally the same size as the Massasauga rattlesnakes. However, Copperheads are characterized by a dull-orange color with dark bands that encircle their bodies. Although they lack a rattle, their bright coloring makes them distinctive.