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NONPOISONOUS

SNAKES

Frightening

Not applicable.

Repellents

Several snake repellents have been

promoted, but none are consistently

effective.

Toxicants

None are registered.

Fumigants

None are registered.

Trapping

A funnel trap with drift fences can be

used.

Shooting

Nonpoisonous snakes are protected by

law in most states and indiscriminate

killing is illegal. Shooting or clubbing

is effective, however, where it is

allowed, with p ermission from the

state wildlife agency.

James L. Byford

Professor and Dean

School of Agriculture and

Home Economics

The University of Tennessee, Martin

Martin, Tennessee 38238

Damage Prevention and

Control Methods

Exclusion

Seal all openings (1/4 inch [0.6 cm]

and larger) with mortar, 1/8-inch

(0.3-cm) hardware cloth, sheet

metal, or steel wool.

A snake-proof fence can be used to

exclude snakes.

Habitat Modification

Reduce rodent populations.

Keep all vegetation closely mowed;

remove bushes, shrubs, rocks,

boards, firewood, and debris lying

close to the ground, especially

around buildings.

Alter all sites that provide cool, damp,

dark habitat for snakes.

Fig. 1. Bullsnake (gopher snake), Pituophis

melanoleucus

Other Methods

Remove snakes from inside buildings

by placing piles of damp burlap

bags or towels in areas where

snakes have been seen. After snakes

have been attracted, remove the

bags and snake(s) from the

building.

Glue boards can be used to capture

snakes found inside houses or other

buildings. Once caught, the snake

and board can be taken outside. The

snake can be released unharmed by

pouring vegetable oil on it (the oil

counteracts the adhesive).

Since nonpoisonous snakes are

completely harmless, control

programs for them are not necessary.

Learn how to distingu ish between

poisonous and nonpoisonous snakes

in your area.

PREVENTION AND CONTROL OF WILDLIFE DAMAGE — 1994

Coop erat ive Extension Division

Institute of Agriculture and Natural Resources

University of Nebraska - Lincoln

United States Department of Agriculture

Animal and Plant Health Inspection Service

Animal Damage Control

Great Plains Agricultural Council

Wildlife Committee

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Identification

Of the many kinds of snakes found in

the United States, only the following

are harmful: rattlesnakes, c opper-

heads, cottonmouths, coral snakes,

and sea snakes. The latter group lives

only in the oceans. All poisonous

snakes, except coral snakes and sea

snakes, belong in a group called pit

vipers. There are three ways to distin-

guish between pit vipers and

nonpoisonous snakes in the United

States:

(1) All pit vipers have a deep pit on

each side of the head, midway

between the eye and the nostril.

Nonpoisonous snakes do not have

these pits.

(2) On the underside of the tail of

pit vipers, scales go all the way

across in one row (except on the

very tip of the tail, which may have

two rows in some cases). On the

underside of the tail of all non-

poisonous snakes, scales are in two

rows all the way from the vent of

the snake to the tip of the tail (Fig.

2). The shed skin of a snake shows

the same characteristics.

(3) The pupil of pit vipers is verti-

cally elliptical (egg-shaped). In very

bright light, the pup il may be

almost a vertical line, due to

extreme contraction to shut out

light. The pupil of nonpoisonous

snakes is perfectly round (Fig. 3).

The poisonous coral snake is ringed

with red, yellow, and black, with red

and yellow rings touching. Non-

poisonous mimics of the coral snake

(such as the scarlet king snake) have

red and yellow rings, separated by

black rings. A helpful saying to memo-

rize is: “Red on yellow, kill a fellow;

red on black, friend of Jack.”

Range

Some sp ecies of nonpoisonous snakes

occur throughout several states, but

the majority have only limited ranges.

N onpoisonous

Poisonous

Fig. 2. Nonpoisonous snakes have two rows o f scales between the vent and the tip of the tail, while

poisonous snakes have only one row.

Habitat

Snakes are not very mobile, and even

though some are fairly adaptable, most

have specific habitat requirements.

Some live underground (these are

mostly small in size), and some have

eyes shielded by scales of the head.

Others, such as green snakes, live pri-

marily in trees. One group spends its

entire life in the oceans. In general,

snakes like cool, damp, dark areas

where they can find food. The follow-

ing are areas around the home that

seem to be attractive to snakes: fire-

wood stacked directly on the ground;

old lumber piles; junk piles; flower

beds with heavy mulch; gardens;

unkempt basements; shrubbery grow-

ing against foundations; barn lofts—

especially where stored feed attracts

rodents; attics in houses where there is

a rodent or bat problem; stream banks;

pond banks where there are boards,

innertubes, tires, planks, and other

items lying on the bank; unmowed

lawns; and abandoned lots and fields.

Food Habits

All snakes are predators, and the dif-

ferent species eat many different kinds

of food. Rat snakes eat primarily

rodents (such as rats, mice, and chip-

munks), bird eggs, and baby birds.

King snakes eat other snakes, as well

as rodents, young birds, and bird eggs.

Some snakes, such as green snakes, eat

primarily insects. Some small snakes,

such as earth snakes and worm snakes,

eat earthworms, slugs, and salaman-

ders. Water snakes eat primarily frogs,

fish, and tadpoles.

General Biology,

Reproduction, and

Behavior

Snakes are specialized animals, having

elongated bodies and no legs. They

have no ears, externally or internally,

and no eyelids, except for a protective

window beneath which the eye moves.

The organs of the body are elongated.

Snakes have a long, forked tongue,

Round pupil

Nostril

Fig. 3. Nonpoisonous snakes have a round eye pupil and have no pit between the eye and the nostril.

F-17

which helps them smell. Gaseous par-

ticles from odors are picked up by the

tongue and inserted into the two-holed

organ, called the Jacobson’s Organ, at

the roof of the mouth.

The two halves of the lower jaw are

not fused, but are connected by a liga-

ment to each other. They are also

loosely connected so the snake can

swallow food much larger than its

head. Because snakes are cold-blooded

and not very active, one meal may last

them several weeks. Also, because

they are cold-blooded, they may hiber-

nate during cold weather months or

aestivate during hot summer months

when the climate is severe. In either

case, they consume little or no food

during these times. Some snakes lay

eggs, some hatch their eggs inside the

body, and some give live birth. The

young of copperheads, rattlesnakes,

and cottonmouths are born alive.

Nonpoisonous snakes are harmless to

humans. In most cases, a snake will

crawl away when approached if it feels

it can reach cover safely. No snakes

charge or attack people, with the

exception of the racers, which occa-

sionally bluff by advancing toward an

intruder. Racers will retreat rapidly,

however, if challenged. Snakes react

only when cornered. Different species

react in different ways, playing dead

by turning over on the back, hissing,

opening the mouth in a menacing

manner, coiling, and striking and

biting if necessary.

Damage and Damage

Identification

A nonp oisonous snake bite has no

venom and can do no more harm than

frighten the victim. After being bitten

several thousand times by non-

poisonous snakes, the author and his

students have never suffered any

adverse reaction, and no treatment

was ever used. The only harm non-

poisonous snakes can cause is frighten-

ing people who are not familiar with

them. A bite from a poisonous snake,

however, causes an almost immediate

reaction—swelling, tissue turning a

dark blue-black, a tingling sensation,

and nausea. If none of these is

observed or felt, the bite was from a

nonpoisonous snake. Also, bites from

one of the pit vipers (copperheads,

rattlesnakes, and cottonmouths) will

reveal two fang marks, in addition to

teeth marks. All snakes have teeth;

only pit vipers have fangs. North

American pit vipers have only two

rows of teeth on top and two on the

bottom, whereas nonpoisonous snakes

have four on top and four on the

bottom.

Legal Status

In most states, snakes are considered

nongame wildlife and are protected by

state law unless they are about to

cause personal or property damage.

Therefore, snakes should not be indis-

criminately killed. Some species are

listed on federal and/or state threat-

ened and endangered species lists.

Damage Prevention and

Control Methods

Exclusion

Snakes enter houses, barns and other

buildings when habitat conditions are

suitable inside the buildings. They are

particularly attracted to rodents and

insects as well as cool, damp, dark

areas often associated with buildings.

All openings 1/4 inch (0.6 cm) and

larger should be sealed to exclude

snakes. Check the corners of doors and

windows, as well as around water

pipe and electrical service entrances.

Holes in masonry foundations (poured

concrete and concrete blocks or bricks)

should be sealed with mortar to

exclude snakes. Holes in wooden

buildings can be sealed with fine mesh

(1/8-inch [0.3-cm]) hardware cloth or

sheet metal.

In some cases, the homeowner may get

peace of mind by constructing a snake-

proof fence arou nd the home or yard

(Fig. 4). A properly constructed snake-

proof fence will keep out all poisonous

snakes and most harmless snakes

(some nonpoisonous snakes are fairly

good climbers). The cost of fencing a

whole yard may be high, but it costs

little to enclose a play space for chil-

dren too young to recognize danger-

ous snakes. The following design is

taken from information from the US

Fish and Wildlife Service.

The fence should be made of heavy

galvanized hardware cloth, 36 inches

(91 cm) wide with a 1/4-inch (0.6-cm)

mesh. The lower edge should be bur-

ied 6 inches (15 cm) in the ground, and

the fence should be slanted outward

from the bottom to the top at a 30

o

angle (Fig. 5). Place supporting stakes

inside the fence and make sure that

any gate is tightly fitted. Gates should

swing inward because of the outward

slope of the fence. A 36-inch (91-cm)

vertical fence with a 12-inch (30-cm) lip

at the top, facing outside and angled

downward at a 30

o

angle would prob-

ably work as well. Any opening under

the fence should be firmly filled—con-

crete is preferable. Mow all vegetation

just outside the fence, for snakes might

Fig. 4. Though fairly expensive, a properly constructed snake-proof fence can keep snakes from en-

tering a given area.

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Toxicants

None are registered.

Fumigants

There are no legal fumigants to kill

snakes. Moreover, because most

snakes do not burrow, using fumi-

gants in underground burrows is not a

feasible method of control. In the past,

pest control operators have completely

encased houses with plastic and fumi-

gated at tremendous expense to the

homeowner (several thousand dol-

lars). This is not a reasonable control

method for nonpoisonous snakes since

the animals being killed are completely

harmless.

Trapping

One method reported by researchers

to catch snakes involves a funnel trap

with drift fences constructed of 1/4-

inch or 1/2-inch (0.6- or 1.3-cm) mesh

hardware cloth erected 2 feet (0.6 m)

high and 25 feet (7.5 m) long. Posts for

drift fences should be on the back side

of the fence. These fences guide ani-

mals into the funnel end of the trap

(Fig. 6).

One type of funnel trap can be made

by rolling a 3 x 4-foot (0.9 x 1.2-m)

piece of 1/4-inch (0.6-cm) mesh hard-

ware cloth into a cylinder about 1 foot

(0.3 m) in diameter and 4 feet (1.2 m)

long. An entrance funnel can be made

similarly and fitted into one end of the

cylinder. Close the other end of the

cylinder with hardware cloth and

attach the drift fence. To catch the ani-

mal from either direction, put another

funnel at the other end of the trap and

another drift fence facing the op posite

direction.

Shooting

Nonpoisonous snakes are protected by

law in most states, and indiscriminate

killing is illegal. Shooting or clubbing is

extremely effective in states where it is

allowed and will soon eliminate the

snake pop ulation. Permission may be

required from the local state wildlife

agency.

Other Methods

It is not difficult to remove snakes

from inside a house or other buildings.

Place piles of damp burlap bags or

towels in areas where snakes have

been seen or are likely to be found.

Cover each pile with a dry burlap bag

or towel to slow evaporation. Snakes

are attracted to damp, cool, dark areas

such as these piles. After the bags or

towels have been out for a couple of

weeks, completely remove them with

a large scoop shovel during the middle

of the day when snakes are likely to be

inside or underneath.

Glue boards have proven to be useful

for trapping snakes in or under build-

ings. Sec urely tack several rodent glue

traps (or use bulk glue) to a plywood

board approximately 24 x 16 inches

use these plants to help climb over the

fence. If children tend to crush the

fence, it must be supported by more

and sturdier stakes and by strong wire

connected to its upper edge.

Habitat Modification

The primary food of most snakes,

especially the larger ones, is birds, bird

eggs, and rodents such as rats, mice,

and chipmunks. No control program

for rodent-eating snakes is ever com-

plete without removing rodents and

rodent habitats. Put all possible

sources of rodent food in secure con-

tainers. Be sure to keep all dog or cat

food cleaned up after each feeding and

make the stored food unavailable to

the rodents. Keep all vegetation closely

mowed around bu ildings. Remove

bushes, shrubs, rocks, boards, and de-

bris of any kind lying close to the

ground, as these provide cover for

both rodents and snakes. Refer to the

chapters on rodents for more informa-

tion on their control.

Frightening

Not applicable.

Repellents

Several repellents have been used in

the past, but none has been consis-

tently effective. Currently Dr. T’s

TM

Snake-A-Way® is registered for the

control of rattlesnakes and the check-

ered garter snake, but is apparently

not effective against most species of

snakes. Active ingredients include sul-

fur and naphthalene. Band applica-

tions around the area to be protected

are recommended.

Fig. 5. Side view of a drift fence to exclude

snakes.

Fig. 6. A funnel trap with a drift fence is o ne way to catch snakes.

30

o

(Stakes inside)

Fence

4 to 6"

Underground

Drift fence

Funnel

Funnel

Drift fence

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(61 x 41 cm) to make a glue patch at

least 7 x 12 inches (15 to 30 cm). Place

the board against a wall where snakes

are likely to travel. Snakes become

stuck when they try to cross the board.

Do not place the board near any object

(pipes or beams) that the snake can use

for leverage in attempting to free itself.

A hole drilled through the plywood

board will allow removal of the board

and the entrapped snake with a long

stick or hooked pole. Animals trapped

in the glue can be removed with the

aid of vegetable oil, which counteracts

the adhesive.

Do not use glue boards outdoors or in

any location where they are likely to

catch pets or nontarget wildlife. The

glue can be quite messy and is hard to

remove from animals.

Economics of Damage and

Control

As mentioned earlier, nonpoisonous

snakes are completely harmless and

cause no damage, except occasionally

frightening people. Therefore, no

expense toward control of non-

poisonous snakes is justified. Most

methods to remove snakes are inex-

pensive, except for the snake-proof

fence, which can be quite expensive.

Acknowledgments

Appreciation is expressed to the US Fish and

Wildlife Service for some of the information

presented in this chapter, particularly the design

of the snake-proof fence.

Figures 1 through 3 by Emily Oseas Routman.

Figures 4 through 6 by Jill Sack Johnson.

For Additional

Information

Boys, F. E. 1959. Poisono us amphibians and

reptiles. C. C. Thomas Co., Springfield,

Illino is. 149 pp.

Conant, R. 1975. A field guide to reptiles and

amphibians of eastern and central North

America. Houghton Mifflin Co., Boston.

429 pp.

Ditmars, R. L. 1939. A field book of North

American snakes. Doubleday, Doran, and

Co., New York. 305 pp.

Ditmars, R. L. 1966. Snakes o f the world.

Macmillan Co., New York, 207 pp.

Huheey, J. E., and A. Stupka. 1967. Amphibians

and reptiles of the Great Smokey Mountains

National Park. Univ. Tennessee Press,

Knoxville. 98 pp.

Lamburn, J. B. C. 1964. Snake lore. Doubleday

and Co., New York. 152 pp.

Leviton, A. E. 1971. Reptiles and amphibians of

North Americ a. Doubleday and Co., New

York. 250 pp.

Parker, H. W. 1977. Snakes — a natural history.

Cornell Univ. Press, 124 pp.

Schlauch, F. C. 1976. City snakes, suburban

salamanders. Nat. Hist. 85:46-53.

Schmidt, K. P., and D. D. David. 1941. Field

book of snakes of the United States and

Canada. G. P. Putnam’s Sons. New York.

365 pp.

Simon, H. 1973. Snakes: the facts and the

folklore. Viking Press, New York. 128 pp.

Stidworthy, J. 1972. Snakes of the world. Bantam

Books, Inc., 159 pp.

Editors

Scott E. Hygnstrom

Robert M. Timm

Gary E. Larson

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