Missouri's Constrictors

You don't have to travel to a tropical country or visit a large zoo to see snakes that tighten coils of their body around their prey until it is dead. Of the 46 kinds of snakes native to Missouri, seven are considered true constrictors.

When we think of constrictors, we tend to think of those huge boa constrictors featured in movies or at zoos, but not all constrictor species are large snakes. Missouri’s red milk snake, for example, averages only 20 inches long.

Other Missouri constrictors include the black rat snake, the western fox snake, the Great Plains rat snake, the bullsnake, the prairie kingsnake and the speckled kingsnake.

Missouri’s constrictor snakes are all members of the “non-venomous” family, Colubridae. They mainly eat rodents, birds and bird eggs, but kingsnakes also eat lizards and other species of snakes.

Constrictors don’t crush their victims. Instead, they kill prey by suffocating it. For example, when a black rat snake grabs a deer mouse in its mouth, it rapidly wraps two or three coils of its body around the mouse and holds on, tightening whenever it can. This prevents the struggling deer mouse from breathing, and it quickly succumbs.

There is much value to a snake in the ability to kill its prey before devouring it. It not only secures the prey, but it reduces the victim’s ability to hurt or damage the snake.

Snakes that don’t have this ability, such as water snakes or garter snakes, capture frogs, fish and rodents and hang on with their sharp, recurved teeth and start swallowing. Before it dies, however, large prey can inflict a lot of damage on a snake or, as often happens, the prey’s struggles could free it.

It’s important to know that constriction is for killing prey rather than for defense. Missouri’s constrictor snakes bite to defend themselves, but the bite is nonvenomous and usually little more than a scratch. These snakes also try to defend themselves by emitting a strong, musky odor from glands at the base of their tail. All of our constrictors vibrate their tail when alarmed as another defense measure.

Constrictors don’t always use their suffocating grip to subdue prey. A good example occurs when fox snakes or prairie kingsnakes come across a litter of baby deer mice or nestling birds. Because the victims aren’t able to get away or to inflict damage, the snakes usually just swallow them alive.

Like most species of native wildlife, Missouri’s constrictors