NON-POISONOUS SNAKES

Identification
Of the many kinds of snakes found in the United States, only the following are harmful: rattlesnakes, copperheads, 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 distinguish 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 nonpoisonous snakes, scales are in two rows all the way from the vent of the snake to the tip of the tail. The shed skin of a snake shows the same characteristics.

(3) The pupil of pit vipers is vertically elliptical (egg-shaped). In very bright light, the pupil may be almost a vertical line, due to extreme contraction to shut out light. The pupil of nonpoisonous snakes is perfectly round.

The poisonous coral snake is ringed with red, yellow, and black, with red and yellow rings touching. Nonpoisonous mimics of the coral snake (such as the scarlet king snake) have red and yellow rings, separated by black rings. A helpful saying to memorize is: “Red on yellow, kill a fellow; red on black, friend of Jack.”

Range
Some species of nonpoisonous snakes occur throughout several states, but the majority have only limited ranges.

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 primarily 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 following are areas around the home that seem to be attractive to snakes: firewood stacked directly on the ground; old lumber piles; junk piles; flower beds with heavy mulch; gardens; unkempt basements; shrubbery growing 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 different species eat many different kinds of food. Rat snakes eat primarily rodents (such as rats, mice, and chipmunks), 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 salamanders. 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, which helps them smell. Gaseous particles 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 ligament 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 hibernate 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 occasionally 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.

Nonpoisonous snakes have two rows of scales between the vent and the tip of the tail, while poisonous snakes have only one row.

Damage and Damage Identification
A nonpoisonous snake bite has no venom and can do no more harm than frighten the victim. After being bitten several thousand times by nonpoisonous snakes, the author and his students have never suffered any adverse reaction, and no treatment was ever used. The only harm nonpoisonous snakes can cause is frightening 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.

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 nonpoisonous snakes is justified. Most methods to remove snakes are inexpensive, except for the snake-proof fence, which can be quite expensive.

Legal Status
In most states, snakes are considered non-game wildlife and are protected by state law unless they are about to cause personal or property damage. Therefore, snakes should not be indiscriminately killed. Some species are listed on federal and/or state threatened and endangered species lists.


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.

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 permission from the state wildlife agency.

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 distinguish between poisonous and nonpoisonous snakes in your area.




ACKNOWLEDGEMENTS
The above information was adapted from PREVENTION AND CONTROL OF WILDLIFE DAMAGE with permission of the editors, Scott E. Hygnstrom, Robert M. Timm, and Gary E. Larson (Cooperative 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).