Identification | Biology | Damage ID | Management | Handling
Overview of Damage Prevention and Control Methods
- Reduce sources of food including populations of rodents, fish, and invertebrates
- Keep vegetation closely mowed
- Remove bushes, shrubs, rocks, boards, firewood, and debris lying close to the ground
- Alter sites that provide habitat and protected basking locations
- Seal all openings ¼ inch and larger with mortar, 1/8-inch hardware cloth, sheet metal, Copper Stuff-Fit or Xcluder™
- Snake-proof fence
- Boundary made from lava rocks
- Not applicable
- Several repellents for snakes have been promoted but none have extensive research demonstrating effectiveness for real-world applications.
- None registered
- Shotguns and small-caliber rifles when health and safety are at risk
- Funnel traps with drift fences
- Pitfall traps with drift fences
- Glueboard traps
Other Control Methods
- A blow to the head or neck with a hoe or shovel
- Place piles of damp burlap bags or towels where snakes have been seen
- Use snake tongs and hooks carefully
- Install perches for raptors that capture snakes
Damage Prevention and Control Methods
Snakes can be controlled whenever they are active (e.g., in temperatures above 50°F). Non-venomous snakes are harmless and cause no damage. Spending money for control of non-venomous snakes is seldom justified. Most methods for the control of snakes are inexpensive, except for snake-proof fences. Time spent educating people about snakes is valuable.
The primary food sources of most snakes, especially larger ones, are birds, eggs of birds, and rodents such as rats, mice, and chipmunks. No program for control of rodent-eating snakes is complete without removing rodents and habitats for rodents. Put all possible sources of food for rodents in secure containers. Clean up food for pets after each feeding and store the food where it will be unavailable to rodents. Keep all vegetation closely mowed around buildings. Remove bushes, shrubs, rocks, boards, and debris lying close to the ground, as these provide cover for rodents and snakes. Alter landscape to reduce areas required for basking.
Snakes enter houses, barns and other buildings when conditions are suitable inside the buildings and means of entry are available. Snakes particularly are attracted to rodents and insects, and cool, damp, dark areas associated with out-buildings and basements. All openings ⅛-inch and larger should be sealed to exclude snakes. Since snakes do not gnaw or damage structures to gain entry, sealants and closures suitable to exclude mice will protect against snake entry. Secure openings as you would to exclude mice.
Check the corners of doors and windows, around water pipes, and entrances for utility lines. Holes in masonry foundations (poured concrete and concrete blocks, stones, or bricks) should be sealed to exclude snakes. Holes in wooden buildings can be sealed with sheet metal, Copper Stuf-Fit, Xcluder™, or ⅛-inch mesh hardware cloth. Secure weep vents with Xcluder™ cloth or weep vent screens. Consult the section on exclusion for additional information.
In some cases, homeowners may obtain peace of mind by constructing a snake-proof fence around their home or yard. A properly constructed, snake-proof fence will keep out all venomous snakes and most non-venomous snakes (some non-venomous snakes are good climbers). The cost of fencing a whole yard may be high, but it costs little to enclose a play area for children who are too young to recognize snakes that are dangerous.
A snake-proof fence should be made of heavy galvanized ¼-inch mesh hardware cloth that is 36 inches tall. Bury the lower edge 4 to 6 inches in the ground. The fence should be slanted outward from the bottom to the top at a 30o angle.
Place stakes for support inside the fence and make sure that gates are tightly fitted. Gates should swing inward because of the outward slope of the fence. A 36-inch, vertical fence with a 12-inch lip at the top, facing outside, and angled downward at a 30o angle also may work.
Side view of a drift fence to exclude snakes. Image by PCWD.
Holes under the fence should be firmly filled, with concrete if possible. Mow the vegetation just outside the fence, as snakes might use plants to climb over the fence. If necessary, support the fence with more and sturdier stakes and strong wire connected to the upper edge.
A boundary made of lava rocks may be as effective as a fence. The course texture of lava rock appears to divert many rodents and snakes, including pit vipers. Border an area with lava rock that is at least 12 inches in width to deter snakes from entering. Depending on the region, the width of the boundary can vary (i.e., large snake species may be able to find a way across). Boundaries of lava rock work well to exclude species that are climbing or arboreal. Lava rock is a common landscaping item and can aid in the exclusion of snakes while maintaining an aesthetic view in the yard.
Frightening devices are not applicable for the control of snakes.
Several repellents for the control of snakes are on the market. Research on the applications’ effectiveness is either lacking or inconsistent. Liquid Fence® Snake Repellent uses 2- to 3-foot bands of mint oil, sodium lauryl sulfate, thyme oil white, putrescent egg solids, and garlic oil to protect a perimeter. Currently, the active ingredients in Dr. T’sTM Snake-A-Way® Active include sulfur and naphthalene. It is registered for the control of rattlesnakes and checkered garter snakes, but apparently is not effective against most other species. Use band applications around the area to be protected.
No toxicants are registered for the control of snakes. The use of fumigants in underground burrows is not a feasible method of control because most snakes do not burrow.
Shooting seldom is necessary for controlling snakes. Shooting should only be employed when human health and safety is at risk, such as with a venomous snake. When shooting, it is essential to consider ricochet and flying debris that may be dislodged by the bullet or shot. Shooting is not cost-effective for control.
Catch snakes with a funnel trap and drift fences constructed of ¼- or ½-inch mesh hardware cloth erected 2 feet high and 25 feet long. Two-foot high aluminum flashing is effective, also. Install posts for drift fences on the back side of the fences. The fences guide snakes into the funnel end of the trap.
One type of funnel trap can be made by rolling a 3- x 4-foot piece of ¼-inch mesh hardware cloth into a cylinder about 1 foot in diameter and 4 feet long. An entrance funnel can be made with hardware cloth attached to the drift fence. To catch a snake from either direction, put another funnel at the other end of the trap and another drift fence facing the opposite direction.
Drift fences can be combined with pit-traps. Construct the drift as instructed above and dig a hole on each end of the fence and on each side. Holes should be at least deep enough to hold a 5-gallon plastic pail. Pit traps may not be legal in your area. Additionally, due to the risk of injury to those who may step in the holes, only use them where the risk of human or pet traffic is low.
Glueboards are useful for trapping snakes outside, inside, and under buildings. Securely tack several rodent glue traps to a plywood board 24 x 16 inches in size to make a glue patch at least 7 x 12 inches in size. Do not use glueboards where they are likely to catch non-targets. The glue is messy and very difficult to remove from mammals and birds.
Place a glueboard against a wall where snakes are likely to travel. Snakes get stuck when they try to cross the board. Do not place a board near objects (pipes or beams) that the snake can use for leverage when attempting to free itself. If a venomous snake is captured, use snake tongs to move the trapped snake. Animals trapped in the glue can be removed with the aid of vegetable oil, which counteracts the adhesive. If live removal is desired, check traps frequently.
Several professionally manufactured glueboards for snakes are available, such as CahabaTM and SnakeGuard®. Both traps can be used inside buildings, but the CahabaTM is better able to withstand conditions outside of structures. One advantage with professionally manufactured traps have over rat-sized glueboards is that the captured snake is hidden from the view of the public.
Other Control Methods
Killing is seldom necessary to control snakes, but common snakes can be killed with a blow to the head or neck with a hoe or shovel.
The following discussion is a guide to conducting a search for snakes inside a structure. The principles can be applied to outdoor situations, but it is not recommended to search for snakes outdoors. First, determine where the snake was last seen. In cool basements, look for places that are warm, moist, and provide cover for the snake. Water heaters, gas appliances, and refrigerators are warm all of the time and provide excellent habitat for snakes.
Set glueboard traps if the snake is found within a reasonable amount of time. Have the client secure rooms by wedging towels underneath doors, an action that also may help reduce human stress. If a snake is seen, grab it by hand (only if non-venomous) or with snake tongs after asking bystanders to leave the area. Snakes usuall strike in self-defense and bite when grabbed.
To remove snakes from inside buildings, place piles of damp burlap bags or towels in areas where snakes have been seen or are likely to be found, such as near sources of heat or hiding places. Cover each pile with a dry burlap bag or towel to slow evaporation. During periods of warm weather, snakes are attracted to damp, cool, dark areas. After the bags or towels have been out for a couple of days, check for a snake underneath and remove the whole works with a large scoop shovel.
Snakes require specific handling techniques. When grabbing a snake by the head, be sure to support the body with your second hand to reduce the likelihood of spinal injury to the animal as it struggles. When using snake tongs, be careful not to break the back of the snake. Hooks are safer for snakes, but the pistol-grip function of tongs gives a great deal of control to the user. Do not squeeze too hard to avoid crushing the animal. Practice using snake tongs with a boiled egg. Use of expanded-jaw tongs will help distribute the pressure and provide a greater margin of safety for the snake.
Place non-venomous snakes in a pillow case and tie off the end, making sure that the snake is not present in the end where you are tying. If you have captured a venomous snake, place it in a 5-gallon pail or large plastic trash bin. Place the lid on the container and safely remove the snake from the area. Place snakes that have been captured in a cool area between 40° and 75°F and dispose of them according to state law. Keep all snakes out of direct sunlight.
Perches for raptors may encourage the presence of predators that prey on snakes. However, it is unlikely that predators will substantially reduce populations of snakes.