— This article by Jerry Cates and Dana T., first published in May 2009, was last revised on 24 April 2016. © Bugsinthenews Vol. 10:05.
Dana wrote: “Jerry — I originally found your website several weeks ago, while trying to find out, on the Internet, how best to keep rat snakes out of my yard.
We live in an established subdivision, but our home backs up to a wilderness area. it is very common for rabbits, opossums, raccoons, and–yes–snakes, to come into our yard. We love most of the wildlife, but we are less happy about having snakes in our landscaping and on the porch.
You told me rat snakes don’t pose a risk to us or our children, and that made me feel better, but today I found this copperhead on my front porch. I think it is time to move our efforts to keep snakes out to a higher level. What do you suggest?”
Dana had sent photos of a Texas rat snake she found in her back yard several weeks back. We discussed the alternatives that she could try to keep snakes out of her yard, and I suggested she study the posting regarding snake exclusion, along with the discussion on snake repellents.
By following those suggestions, she would probably not be seeing too many snakes around. And–Oh, well–a rat snake, every once in a while, was nothing to worry about anyway.
Ideally, following the advice on the two pages linked to in the previous paragraph will produce a reasonably snake-free environment. But there are no guarantees, especially when Mother Nature gets involved.
The advice I give people like Dana about snake exclusion and snake repellents isn’t magical. It is possible to carry out all the suggestions on those pages, and still have snakes show up where they are not wanted. Of course, if that snake is venomous and someone gets too close or steps on it, they will probably get bitten. My worst nightmare is that someone will mistakenly believe that, by following the procedures mentioned on those pages, their snake worries are forever behind them. That’s one of the reasons those pages are peppered with so many cautions against such thinking.
Thankfully, Dana was not so foolish. She’d read those cautions and had heeded them. When she opened her front door, she first looked to see if anything was on the porch before stepping out. But notice this: the copperhead on her porch blended in well with the reddish coloration of the brickwork, and it wasn’t easy to see. Dana is a good observer, though, and she saw it right away.
Good for her. Had she stepped on this snake, it would surely have bitten her. And although it was only about 24 inches long, she had a 50/50 chance that its bite would have landed her in the hospital, with a very sore ankle and leg, facing a lengthy recuperation and enormous medical bills. And, of course, she had less than a 0.02% chance that the bite would have been fatal (no fatal copperhead bites have been recorded in the U.S. since the early 1980’s).
The various species of copperhead snakes found in the U.S. and Canada cause about 25% of the reported venomous snake bites (75% are rattlesnakes, with coral snakes and cottonmouths representing less than 1% each). According to statistics compiled by the Texas Department of State Health Services, about 7,000 people are bitten by venomous snakes each year in the U.S.
Fortunately, only 1 out of 500 (0.02%) of these bites is fatal, and roughly half of the time the bite is dry–that is, the snake does not inject venom when it bites (either because its venom lumens are empty, or because it intentionally chooses not to inject venom with the bite).
The moment I learned about the copperhead on Dana’s front porch, I made arrangements to physically visit her home, in Allen, Texas. Together, we looked over her yard to see exactly what extraordinary conditions existed there that encouraged so many snakes.
The first thing I noticed was a small snake (unidentified, as only a portion of it was glimpsed for a second or so) in the landscaping near her front door.
That landscaping was so thick that it was impossible to find the snake once it disappeared in the vegetation, without damaging the botanicals in the process. Dana studied it for a moment, then said “Well, Jerry, I guess the first order of business is to do something to thin out my personal botanical garden.” Enough said.
No, maybe not enough said. The fact is, whenever the landscaping around your home is so thick and lush that it provides excellent habitat for rodents and their look-alikes (rabbits, raccoons, opossums, and so on), it will generally become home for some if not all of those animals at one time or another.
And when that happens, look out. Snakes are a’comin! You can count on it.
That’s what snakes do: cohabit locales with rodents and their look-alikes.
Now, you might not think of opossums and raccoons as rodent look-alikes, and if you have trouble with that I understand. You forget, obviously, that litters of both those animals look quite rodent-like, and it’s the babies that attract the snakes.
We also found rabbit holes in several locations, all surrounded by thick botanicals, in Dana’s yard. One of these had copious amounts of rabbit fur around the entrance, where a rabbit had recently been killed and devoured, most likely by a snake.
Where rabbits breed, mice and rats also will be found. Baiting regularly for rodents, and filling in rabbit holes with gravel and rocks, are important adjuncts to any snake exclusion program, particularly while lush vegetation remains an important part of the picture.
That’s fine for the short term, but let’s face it, the long term is what really counts.
And constantly baiting lush vegetation with even small amounts of rodent bait is a recipe for–well–disasters of all kinds. Some baits are relatively safe, but others are not so safe.
Some day you may unwittingly pick a bait in the latter camp, and if you don’t use tamper-resistent bait stations (which aren’t really as tamper-resistant as they claim, and in any case produce high-humidity environments and have other characteristics that make them way less than ideal under even the best of circumstances) your or your neighbor’s dog or cat will get a belly full of something that it should not have eaten, with predictable and–sigh–very unhappy results.
After treating her yard with a commercial snake repellent, I followed that up with an essential-plant-oil based granular habitat modifier, leaving her enough of the latter to enable replenishing it in the yard several times. She immediately took steps to have the landscaping thinned out so rabbits and snakes no longer had places to hide, and I baited the yard with a commercial rodent bait (and she promised to replenish the bait regularly over the rest of the year). And that was the end of her snake problems for 2009. She never saw another snake all year long…
Early in the spring of 2010, I supplied her with another batch of essential-plant-oil granular habitat modifier, so she could keep that part of the program going. An inspection of her yard revealed that the landscaping was now thin enough to prevent harboring snakes and rodents in most places. She plans to thin out the vegetation where it is now a bit too thick.
Several rabbit holes were also found, which Dana plans to have filled with gravel. We baited the yard again with rodent bait, and will continue monitoring things. Hopefully, she won’t see any snakes in 2010, but–of course–Mother Nature is, if anything, unpredictable.
Related Links on BugsInTheNews:
- North American Snake Markings & Coloration Guide.
- Ophidian Dentition — Snake Teeth & Fangs — Morphology & Specialization
- Snake Anatomy, Physiology, and Taxonomy.
- Snake Exclusion — How to Snake-proof your Yard and Home.
- Snake Repellents — How, and How Well, do They Work?
- Snakebite First Aid.
- Snakes, Rodents, & Droughts.
- What is Meant by “A Reasonably Snake-Free Environment”?
- Southern Copperhead (Agkistrodon contortrix contortrix); Dana T., Allen, Texas–05.02.09
- Broad-Banded Copperhead (Agkistrodon contortrix laticinctus): Steve B., Round Rock TX–2 July 2009
- Cottonmouths & Copperheads in Travis and Harris Counties, Texas — June to August, 2010
- Western Cottonmouth (Agkistrodon piscivorus leucostoma, Troost 1836); Tammy D., Santa Fe, TX — 28 Aug 2011
- Western Cottonmouth (Agkistrodon piscivorus leucostoma, Troost 1836) juvenile snakebite; Margaret Archer, Manvel, TX — 5 Sep 2011
- Western Diamond-backed Rattlesnake (Crotalus atrox, Baird & Girard, 1853), Cedar Creek, TX — 22 Oct 2010
References to Scientific Articles, Books, and Papers:
- Arikan, Hüseyin et al. 2008. Electrophoretic characterisation of the venom samples obtained from various Anatolian snakes(Serpentes: Colubridae, Viperidae, Elapidae). N.W. J. Zool. Vol. 4, No. 1, pp.16-28.
- Birchard, Geoffrey F., et al., 1984. Foetal-Maternal Blood Respiratory Properties of an Ovoviviparous Snake; the Cottonmouth, Agkistrodon piscivorus. J. exp. Biol. 108, 247-25
- Chao, Betty H., et al. 1989. Agkistrodon piscivorus piscivorus platelet aggregation inhibitor: A potent inhibitor of platelet activation. Proc. Natl. Acad. Sci. USA Vol. 86, pp. 8050-8054
- Chippaux, J. P., et al. 1991. Snake Venom Variability: Methods of study, results, and Interpretation. Toxicon Vol. 29, No. I I , pp. 1279-1303.
- Conant, Roger, and Joseph T. Collins, 1998. Reptiles and Amphibians — Eastern/Central North America, Third Ed. Peterson Field Guides. Houghton Mifflin Co.
- Cundall, David. 2009. Viper Fangs: Functional Limitations of Extreme Teeth. Physiological and Biochemical Zoology 82(1):63–79.
- Deufel, Alexandra, and David Cundall. 2004.Functional plasticity of the venom delivery system in snakes with a focus on the poststrike prey release behavior. Zoologischer Anzeiger 245 (2006) 249–267
- Grachevca, Elena, et al., 2010. Molecular Basis for Infrared Detection by Snakes. Nature, 15 April 2010.
- Greene, Harry W., 1997. Snakes: the Evolution of Mystery in Nature. University of California Press.
- Schulz, Klaus-Dieter, 1996. A Monograph of the Colubrid Snakes of the Genus Elaphe Fitzinger. Koeltz Scientific Books.
- Tennant, Alan,1998. A Field Guide to Texas Snakes, Second Ed. Gulf Publishing.
- Weinstein, Scott A., et al. 1994.Reptile Venom Glands — Form, Function, and Future. Handbook of Venoms and Toxins of Reptiles. CRC Press.
- Werler, John E., and James R. Dixon, 2000. Texas Snakes. University of Texas Press.
- World Health Organization. 2002. Management of Snakebite and Research. WHO SEA-RES-2.
- Zaidan, Frederick III, 2002. Variation in cottonmouth (Agkistrodon piscivorus leucostoma) resting metabolic rates. Comparative Biochemistry and Physiology Part A 134 (2003) 511–523
- Zamudio, Kelly R., et al., 2000. Fang tip spread, puncture distance, and suction for snake bite. Toxicon 38 (2000) 723 – 728
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