POISONOUS SNAKES AND SNAKEBITE IN NEBRASKA
Ron J. Johnson, Extension Wildlife Specialist
Nebraska has four kinds of poisonous snakes -- the prairie rattlesnake, timber rattlesnake, western massasauga (a small rattlesnake), and copperhead. The prairie rattlesnake is found in the western two-thirds of Nebraska and the other three in the southeastern corner. The poisonous coral snake and the cottonmouth or "water moccasin" do not occur in Nebraska.

Many Nebraskans enjoy outdoor recreational activities such as hiking, hunting, fishing, and camping, and farmers and ranchers often check fields by walking. Some understanding of poisonous snakes allows enjoyment of outdoor activities without undue fear of snakes.

This NebGuide provides information about Nebraska's poisonous snakes, some guidelines for avoiding snakebite, and suggestions on what to do in case of snakebite. Another NebGuide on snakes, "Controlling Snake Problems Around Homes," is also available.

Recognizing Poisonous Snakes

Knowing how to identify poisonous snakes, especially the kinds found in areas where you might go, is a good first step in avoiding them. Consider purchasing a good field guide and consulting books in libraries to help sharpen your skills. You can also use the Kwik-Key guide to Nebraska Snakes. Another good way to learn about snakes and how to identify them is to view them at local zoos and nature centers. Here are some features that may help you recognize Nebraska's four poisonous snakes.

At a distance, be alert for ...

1) A blotched or banded body pattern. Several nonpoisonous snakes are also blotched or banded, but all snakes in Nebraska that have lengthwise stripes are nonpoisonous. Although the timber rattlesnake may have a single rusty stripe down the center of the back, it is clearly a blotched snake much different from striped garter snakes.

2) A triangular head distinctly wider than the neck. However, several other snakes, including garter snakes, hognose snakes, and bullsnakes may also display this characteristic, especially when alarmed.

3) A warning rattle - a buzz or dry whirring sound. Rattlesnakes usually, but not always, sound a warning rattle when nearby. The presence of rattles or a "button" (first rattle) at the end of the tail also serve as identifying features. Some nonpoisonous snakes, including bullsnakes and rat snakes, vibrate their tails rapidly when alarmed; in dry vegetation this may sound like a warning rattle.

On dead or caged snakes ... (CAUTION: even dead snakes can bite by reflex)

4) In daylight, Elliptical (cat-like) eye pupils (the black center portion of the eye) (Fig. 1). Nebraska's nonpoisonous snakes have round eye pupils. Eye pupil shape (elliptical or round) may be visible from a distance on live snakes observed in good light.

5) A small pit on each side of the head between and slightly below the eye and nostril (Fig. 1). This small pit, which looks somewhat like another nostril, is heat sensitive and helps the snake locate warm-bodied prey such as mice. Snakes with this pit are called pit vipers and all of Nebraska's poisonous snakes are in this group. In fact, the only snake in the United States that is poisonous but not a pit viper is the coral snake, found far south of Nebraska in the southern states.

6) Scales on the underside of the tail that go all the way across in a single row (Fig. 1), except for the very tip, which may have two rows. On nonpoisonous snakes, these scales are in two rows from the vent all the way to the end of the tail. This characteristic also shows on shed snake skins.

Nebraska's Poisonous Snakes
click to enlarge
Prairie rattlesnake (Crotalus viridis). As the name indicates, this rattlesnake lives in grassland areas of the Great Plains including the western two-thirds of Nebraska (Fig. 2). They are moderate in size, about 35-45 inches long, and olive, greenish-gray, or greenish-brown in color with brownish blotches down the back. The blotches, outlined with a thin white line, become more narrow crossbands on the tail. The head has two light slanting lines, with the top line above the corner of the mouth. Young are born in late summer to early fall, are about 8 to 12 inches long, and number from 4 to 20 in a litter. Prairie rattlesnakes prefer habitats such as prairies, pastures, prairie dog towns, and rock outcroppings. In winter, they den together in sites that don't freeze such as deep rock crevices or burrows of other animals. Their food is mostly small mammals such as small rabbits, kangaroo rats, young prairie dogs, and other rodents. Young eat mice and lizards. Prairie rattlesnakes are often active in the daytime.
click to enlarge
Timber rattlesnake (Crotalus horridus). The timber rattlesnake is a species of the eastern United States but its range extends into the wooded areas of southeastern Nebraska (Fig. 3). Adults are fairly large, commonly 45 to 55 inches long, and heavy-bodied. Their color is yellowish brown to dark brown or gray, with dark blotches down the back that become crossbands toward the tail. The blotches are somewhat jagged or "V"-shaped and have yellowish edges. There may be a single reddish stripe down the middle of the back. The head is usually unmarked and the tail, in adults, is black, giving rise to the name "velvet-tail rattler." Young are born in late summer to early fall, are about 10 to 14 inches long and number from 5 to 20 in a litter. Timber rattlesnakes prefer forested areas with rock outcroppings or rock ledges but may venture into adjacent sites. Rocky ledges with southern exposures are favorite sunning spots in spring and fall, a place not to climb unless you can see where you'll place your hands. Such rocky areas also provide den sites where they hibernate in groups, sometimes with other kinds of snakes. Timber rattlesnakes eat mostly rodents and other small animals that are common in second-growth woodlands. They may be active at night or during the day, in part depending on when the temperature is most suitable. Timber rattlesnakes are generally mild-mannered and prefer to avoid people. They may try to retreat when approached or lie motionless, depending on natural camouflage for concealment.
click to enlarge
Western massasauga (Sistrurus catenatus). This is a small rattlesnake, about 20 to 30 inches long, with dark, somewhat round, blotches down the back and other smaller and less distinct blotches on the sides (Fig.4). The ground color is light gray or tan-gray and the belly light with brown or black mottling. The head has nine large scales on top, unlike other rattlesnakes that have many small scales on top of the head. Young are born in mid to late summer, are about 7 to 9 inches long at birth, and number from 2 to 19 in a litter. Massasaugas are found in prairie or grassland areas often in marshy sites or on rock outcroppings where these are available. The name massasauga is a Native American term meaning "swamp dweller," referring to its use of marshy or wet habitat areas. Massasaugas eat mostly small rodents and shrews, plus some frogs, lizards, birds, and other small snakes. When approached, these snakes may remain silent and try to retreat, but if aroused or picked up, they bite quite readily.
click to enlarge
Copperhead (Agkistrodon contortrix). Copperheads are stout-bodied snakes, appropriately named because of the coppery top of the head. In Nebraska, they are known to occur only in southern Gage and Richardson Counties, but they may also occur along the Missouri River bluffs south of the Platte River (Fig. 5). They are copper to tan or chestnut in color with darker chestnut or reddish-brown "hourglass" shaped crossbands. The dark bands are narrow in the middle of the back and wider on the sides, thus the hourglass shape. The belly has variable gray to black markings. Young are born in late summer to early fall, about 8 to 10 inches long and from 2 to 15 in a litter. Young have a yellow-tipped tail, which, when twitched is thought to lure small food items such as insects within range. Copperheads prefer wooded areas with rocky outcrops, but use a variety of other habitats such as abandoned sawdust or wood piles, abandoned farm buildings, and grassy areas with rotting logs or debris for cover. In fall, they gather to hibernate, often on rocky forested hillsides with southern or eastern exposures. Their winter den is sometimes shared with other kinds of snakes. Copperheads eat mostly mice but also take lizards, frogs, large caterpillars, and cicadas. They are generally active at night and often lie quietly sunning in the daytime. Because they blend in well with the background, hikers in copperhead country should be alert for them lying along trail edges. Copperheads are generally quiet snakes and prefer to avoid people. They may lie motionless or try to retreat, but if threatened, they often vibrate the tail rapidly and strike vigorously. The bite, although poisonous, is almost never fatal.