Missouri's Constrictors

By Tom R. Johnson | May 14, 2010
From Missouri Conservationist: Dec 2006

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 play a role in the natural system of checks-and-balances. Their ability to locate and consume nests of destructive rats and mice before the young grow up to damage buildings, crops, stored grain and other foods makes these snakes important controllers of rodents.

If you come across one of Missouri’s constrictors, give it a wide berth and the respect it deserves as a valuable component of Missouri’s wildlife.

Black rat Snake

Great Plains Rat Snake

Western Fox Snake


Prairie Kingsnake

Speckled Kingsnake

Red Milk Snake

Black Rat Snake (Elaphe obsoleta)

Missourians often call them “black snakes,” but the name for this species is black rat snake. These are shiny black snakes with white on the upper lip, chin and neck. Some may have faint dark-brown blotches. You can usually see some white and sometimes red between the scales. The belly is mottled with gray or checkered with black markings.

Young black rat snakes (first two years after hatching) are light gray with dark-brown or black markings.

Length may range from 42 to 72 inches, making the black rat snake one of Missouri’s largest snakes. This species is well-known for its ability to climb trees. They are found statewide and live in a variety of habitats, including rocky wooded hillsides, wooded riverbanks, in or near farm buildings and in large brush piles.

Great Plains Rat Snake (Elaphe emoryi)

Great Plains rat snakes have a light gray background color that is covered with black-edged, brown blotches. There is a dark brown stripe between the eyes that extends along the sides of the head onto the neck. The belly is white with bold, squarish, black markings in a checkerboard pattern. This species ranges from 30 to 58 inches in length.

Great Plains rat snakes are found throughout the Missouri Ozarks and into western and northwestern parts of the state. They are commonly found on rocky, sparsely wooded hillsides, in or near abandoned farm buildings and in the vicinity of caves. Rodents are an important food, but this species is also known to eat bats.

Western Fox Snake (Elaphe vulpina)

This close relative of the black rat snake has a tan or greenish-tan background color, and its body is covered with numerous dark-brown blotches. Its head often has an orange cast to it, which has caused some folks to misidentify fox snakes as copperheads. The belly is normally yellow and has distinct black, checkered markings. Western fox snakes are from 36 to 54 inches long.

Their name likely comes from the strong musky odor, similar to the smell of a fox, that they emit when defending themselves.

The fox snake is not a common snake in Missouri and has been added to the list of endangered species. It is found in northeast and northwest parts of the state, mostly around the edges of large natural marshes.

Bullsnake (Pituophis catenifer sayi)

This tan or cream-colored snake has numerous large brown or black blotches. Its tail appears to be banded, and its belly is yellowish with small dark-brown or black markings along the sides.

This is Missouri’s largest species of snake, with adults ranging from 50 to 82 inches long. Bullsnakes will try to deter predators or threats by vibrating their tail and producing a loud hiss.

Bullsnakes are found in northern and western Missouri and are absent from the southeastern third of the state. They are commonly considered a prairie species, but this species also inhabits open woodlands of the Ozarks.

Prairie Kingsnake (Lampropeltis calligaster calligaster)

This species has a background color of tannish-gray or greenish-gray covered by blotches and saddles of brown or reddish-brown. The top of its head usually has a backward-pointing arrowhead-shaped marking. Its belly is yellow with rectangular brown markings. Hatchling prairie kingsnakes are light gray with dark-brown markings and look very much like baby black rat snakes. The length of this species is from 30 to 42 inches.

The reddish-brown markings of some prairie kingsnakes sometimes causes the misidentification of these snakes as copperheads.

The prairie kingsnake occurs statewide. It is usually found in grasslands, old fields, along the edge of woods and near farm buildings.

Speckled Kingsnake (Lampropeltis getulus holbrooki)

Often called the “salt-and-pepper snake,” this handsome species is generally black, but each scale on its back and sides has a white or yellow spot, causing it to look speckled. Its belly is light yellow and covered with a pattern of irregular black markings. Length is from 36 to 48 inches. Their diet includes lizards, snakes—including venomous species—and rodents.

Speckled kingsnakes are common statewide. They live in a variety of habitats, including prairies, forest edges, rocky, sparsely wooded hillsides and farmlands.

Red Milk Snake (Lampropeltis triangulum syspila)

This is Missouri’s smallest constrictor and one of the most colorful snakes in the state. Its background color is white or light gray, and its body is covered with red or orange markings bordered with black. It has a white belly that is strongly checkered with black. Its length ranges from 18 to 24 inches.

Red milk snakes are found statewide. They spend most of their time under rocks on open rocky hillsides. They can be confused with and somewhat resemble the venomous coral snake, but that species is not present in Missouri.

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