Although many may bite in selfdefense, their bite usually produces nothing more than harmless scratches. There are only five species of venomous snakes in all of Missouri and we describe them in a separate section of this pamphlet. Snakes are members of the Class Reptilia, a group that also includes turtles. Snakes and lizards are similar in many way, but there are some important differences. A clear nonmovable scale covers the eyes of all snakes, whereas most lizards have movable eyelids.
Most lizards have legs, but some are legless.
In addition, lizards have a pair of lungs, while most snakes have an elongated right lung and either no left lung or only a rudimentary one. Although snakes are legless, they are able to move about with ease. A snake backbone has from 200 to 400 vertebrae, depending on the species, which permits extreme flexibility. Snakes move forward by a sidetoside movement, or in a straight line by literally walking on their ribs. All snakes can swim.