Living with Wild Snakes
By Eric Roscoe
The Eastern, or Common Gartersnake (Thamnophis sirtalis) is one of Wisconsin’s most abundant and widespread snakes. These snakes are harmless to humans, and feed on small fish, amphibians, insects, earthworms, and other invertebrates.
Wisconsin currently has 21 different recognized species of snakes that, depending on the species and their ranges, can generally be found or encountered statewide. However, only 2 species in the state are venomous and medically significant to pets and people, the timber rattlesnake (Crotalus horridus) and eastern massasauga (Sistrurus catenatus). Both of these species, however, are quite restricted in range and habitat in the state, and are typically not likely to be encountered in many cases. Many other harmless, and nonvenomous snakes can often be found in and around homes, yards, gardens, sheds, barns, and other outbuildings, and other areas of property. Oftentimes, snakes and other animals are found in these areas due to several common factors, including the availability of suitable hibernacula on site (such as stone or concrete foundations, rock walls/piles, stairways, patios, and the like), as well as sufficient to abundant food sources and shelter/access to cover in the form of overgrowth of vegetation, artificial or natural debris, and other similar cover.
Generally, the vast majority of snakes and other reptiles and amphibians are harmless and very beneficial to have around due to the fact that many will naturally consume many different types of pest or nuisance species such as insects, rats, mice, and other rodents. If however, safety and/or preferences to not have these animals around is still a concern, there are ways of humanely deterring snakes and other herps (or herptiles) from your yard or property. These are several key aspects in doing so.
The Eastern Fox snake (Pantherophis vulpinus) is perhaps the most commonly seen and widespread “large snake” in Wisconsin. As with many harmless snakes in Wisconsin, they may rapidly vibrate their tails in dry debris to create a buzzing sound similar to a rattlesnake. They are also often called “Pine snakes” in Wisconsin and the Upper Midwest, and are harmless and beneficial to humans in that they consume rodents and other small animals.
Sealing/Eliminating the Hibernaculum
A hibernaculum can be any area of refuge that goes beneath the frostline and maintains relatively mild temperatures of at least 40-55 degrees during the winter in which many reptiles and amphibians may use or return to each year. Hibernaculums may include stone or concrete foundations, stairways, patios, rock walls, or other suitable structures. New homes or residential areas may also be built on top of, or disrupt/displace existing hibernaculums nearby. Sealing any visible cracks to any actual or potential hibernaculum sites is oftentimes one effective way of deterring unwanted snakes using tuck pointing, expandable caulking, or other repair techniques. If no cracks, gaps, or other openings can be readily located, an energy auditing company may be able to detect them using specialized equipment, although it should be remembered that snakes can and do fit through as small as ½” cracks. Sealing the cracks should also only be done during mid-summer, if possible. Doing so too early or late in the year risks sealing/trapping the snakes inside, leaving them unable to exit and potentially causing odor issues due to their deaths later on. Sealing the hibernaculum(s) during mid-summer serves as the greatest likelihood that the snakes using them have dispersed into the surrounding area for the summer.
If a snake or other reptile/amphibian is found in a basement or other area of the residence during the winter or very low temperatures, do not set or release it outside until temperatures have risen to at least 40-50 degrees during the day if possible. Releasing a reptile or amphibian outside during these times risks death to that animal. If possible, the best course of action is to simply leave the animal alone, and more than likely it will remain out of sight and then emerge and leave when the time comes.
The Eastern Milksnake (Lampropeltis triangulum) is another commonly encountered harmless snake in and around houses, especially with older stone foundations. As with many of Wisconsin’s harmless snakes, milk snakes will rapidly vibrate their tails when threatened, and can be brightly colored with red blotches as juveniles, but are excellent rodent controllers.
In most cases, reptiles and amphibians can be relocated a short distance away from where they were found with little to no ill effects to the animal if they are nonvenomous and can be safely handled or transported. Attempting to handle any venomous animals should only be done by experienced individuals with the knowledge and ability to do so. Wisconsin does have a rattlesnake hotline that can be contacted in order to arrange for safe and humane removal of these snakes. Alternatively, a venomous animal found on a property can be discouraged simply by spraying it with a garden hose (at appropriate settings) to encourage it to leave and move on. However, relocation should only be done within distances of ½ a mile to 1 mile in most cases. Many of these animals have specific home ranges (including their hibernacula and food sources, for example) in which they will attempt to return to, and which can spell a death sentence for the animal. Furthermore, relocating an animal too far away from where it was found increases the risks of potentially spreading pathogens or diseases from one population to another in which they may not have previously existed.
The Eastern Hognose snake (Heterodon platirhinos) is a short, thick bodied, medium sized snake that can be highly variable in color and pattern. These snakes have an excellent repertoire of defensive behaviors when encountered, which include hissing, spreading of the head and neck, mock-striking, and playing dead while regurgitating and defecating. These snakes, although fearsome looking, are harmless to humans and are mainly frog, toad, and other amphibian eaters.
Reduce or Eliminate Food and Habitat Availability
There are several different effective methods which may be utilized to reduce or eliminate your property’s attractiveness to rodents and other prey animals, and subsequently snakes that feed on them. If possible, place or set any bird or other wildlife feeders away from your home as much as possible (as dropped seeds will attract rodents). Also remove or clean up any overgrown grass, shrubs/bushes, or other vegetation from around the property, remove or set back brushpiles, gardens, woodpiles, debris piles, compost heaps, or other forms of old foundations/debris, as all of these provide favorable cover for both snakes and their food sources. Lastly, do not feed or attempt to feed any wild animals or wildlife. Doing so is against the law in most areas, and animals that are fed will often become habituated to people and handouts, often losing their natural fear or wariness of humans and becoming a nuisance and/or a danger to other pets and people, as well as jeopardizing the animal’s welfare.
Other species of reptiles and amphibians can oftentimes be very difficult to exclude completely, particularly if they are ubiquitous in an area or are associated with larger nearby ponds or other wetlands nearby. If, for whatever reason their removal or exclusion is desired, keeping bushes, grass, and other vegetation well-trimmed and insect food availability reduced as much as possible by using safe, environmentally friendly pesticides or other chemicals are perhaps the few limited options.
If you live in the western or southwestern regions of Wisconsin, you may see a Gray, or Midland Ratsnake (Pantherophis spiloides). These large snakes are excellent climbers, and can be found in trees, birdhouses, and the rafters of barns, garages, and other outbuildings. Elsewhere in the U.S., rat snakes tend to be one of the most commonly encountered “large snakes” in and around homes, but are harmless to humans and are excellent rodent controllers. They are a protected wild animal species in WI.
Perimeter fencing can also be used to deter unwanted snakes, although its practicality and effectiveness may vary depending on the size of one’s yard or property and it can still be difficult to exclude snakes as most snakes can climb or burrow over or under them, or can fit through gaps and openings in them. Aside from perhaps smooth, impervious concrete walls or barriers, fencing is one of the lesser effective ways of deterring snakes in general.
Commercial or Store Products
Products such as Snake-A-Away, Snake Stopper, moth balls, and other powders, pellets, or sprays that are commonly available at many hardware and garden centers have been shown to be largely ineffective at repelling snakes. These products may have been tested in areas of less ventilation, but are much less effective if used outdoors or in most well ventilated areas. Also realize that the off-label use of some products, such as mothballs, is in violation of state and federal laws and are considered pesticides regulated by the United States Environmental Protection Agency (EPA) and state Department of Agriculture and Consumer Services or similar agencies. Mothballs are not legal for the purpose of snake repellants. Furthermore, some mothball products, or ingredients thereof, may be outright unlawful and imported without any evaluation or oversight. Whenever possible, do not use glue traps to capture or remove unwanted snakes, as these products are inhumane for any animals caught in them, and can lead to a slow suffering or death. Animals caught in glue traps, however, can often be safely removed by gradually using a non-sticking cooking oil or spray on and around them and then cleaned off (if the animal is nonvenomous and safe to touch or handle).
The DeKay’s Brownsnake (Storeria dekayi) is a small, harmless snake that is widespread over Wisconsin, and may be found in garages, gardens, and backyards. They are a small species seldom exceeding 12″, and feed on slugs, earthworms, and other small soft bodied insects and invertebrates, but certainly may bluff to make themselves appear larger than they are. The Red bellied snake (Storeria occipitomaculata) is a similar, related small species that has a bright reddish-orange belly and is also common in the state.
Can I Just Keep It?
This depends on several factors, including what species the animal(s) are, their legal statuses/levels of protection, whether it is legal to do so, and other things. Generally, laws and regulations pertaining to the keeping or possession of native species will vary by state, and more information can be sought by contacting your state’s department of natural resources or fish & game/wildlife departments. Generally speaking, though, many species of native herps can be difficult to keep in captivity and will not always make suitable pets. In addition, keeping the animal will likely not solve the problem of deterring them since there are likely to be more in the area that will locate and refill that particular niche.
The Minnesota and Wisconsin Departments of Natural Resources (DNR) have additional tips and information on dealing with unwanted snakes that can be viewed here: http://www.dnr.state.mn.us/livingwith_wildlife/snakes/deterring.html http://dnr.wi.gov/files/PDF/pubs/er/ER0670.pdf
A Note on Venomous Snakes in Wisconsin
Is it likely that I will have a venomous snake on my property in Wisconsin? One of the very frequent concerns of gardeners and homeowners is whether the snakes they will encounter will be venomous or not. In Wisconsin, there are 21 species of snakes, the vast majority of which are nonvenomous and harmless to humans. Only two species, the timber rattlesnake (Crotalus horridus) and the eastern massasauga (Sistrurus catenatus), or swamp rattlesnake, are venomous. Neither of these species are common or widespread in Wisconsin, with the timber rattlesnake occupying the steep, rugged and remote bluffs and valleys of western and southwestern Wisconsin, and the eastern massasauga occupying only a very small number of isolated swamps and adjacent uplands of west-central and perhaps southeastern Wisconsin. The eastern massasuga in particular, is one of Wisconsin’s most endangered reptiles, and have experienced population declines of 90% or more from their historic levels, and as such, are almost never likely to be seen in or around homes.
Only in a small number of localities in the extreme western tier of the state are rattlesnakes commonly encountered by people in adjacent areas to bluffs after the snakes emerge from their dens and disperse in the late spring and summer. If one has a confirmed venomous snake in these, or other areas of the state, it is firstly important to never attempt to capture, harass, or kill the venomous snake as doing so greatly increases the risks of being bitten or envenomated. In many cases, these snakes may be encountered transiently as they are dispersing for the summer from their rocky bluff dens. Some emerging bodies of advice and research show that lightly spraying the snake with a garden hose (but not on full blast as to not injure the snake) can encourage them to move on elsewhere. Likewise, a Rattlesnake removal and relocation hotline provided by the Wisconsin Department of Natural Resources (WI-DNR) and other experienced public and private organizations and individuals is another available resource and alternative to killing snakes. In these cases, snakes are located, removed, and relocated no more than 1 mile from where they were captured to ensure they will still survive. Many snakes, both venomous and nonvenomous, will instinctually use and return to the same denning locations in the spring and fall of each year, and if they are removed from these areas too great of distances, they’re overall likelihood of survival is greatly diminished.