Newsgroups: rec.backcountry
\nFrom: eugene@amelia.nas.nasa.gov (Eugene N. Miya)
\nSubject: [l\/m 9\/2\/92] Snake bite: Distilled Wisdom (11\/28) XYZ
\nOrganization: NAS Program, NASA Ames Research Center, Moffett Field, CA
\nDate: Mon, 11 Jan 93 12:20:18 GMT
\nMessage-ID:
\nReply-To: hall@vice.ico.tek.com (Hal Lillywhite)
\nLines: 881<\/p>\n
Panel 11<\/p>\n
[These lines may not correspond in your news reader.]<\/p>\n
\t\tTABLE OF CONTENTS<\/p>\n
Summary . . . . . . . . . . . . . . . . . . Line 25<\/p>\n
Acknowledgments and References . . . . . . Line 74<\/p>\n
Various Snakes and their Effects . . . . . Line 193<\/p>\n
Venoms . . . . . . . . . . . . . . . . . . Line 237<\/p>\n
Four Special Cases . . . . . . . . . . . . Line 276<\/p>\n
Identification . . . . . . . . . . . . . . Line 344<\/p>\n
The “Three Nasties” . . . . . . . . . . . . Line 425
\n Eastern Diamondback . . . . . . . . . . Line 478
\n Western Diamondback . . . . . . . . . . Line 526
\n Mojave . . . . . . . . . . . . . . . . . Line 552<\/p>\n
Prevention . . . . . . . . . . . . . . . . Line 621<\/p>\n
Treatment . . . . . . . . . . . . . . . . . Line 690<\/p>\n
SUMMARY:<\/p>\n
Poisonous snake bite is a potentially serious accident. It can
\n lead to severe pain or other problems, occasionally even death.
\n However in North America it is not nearly as dangerous as most
\n believe. These snakes seldom bite humans and even when they do
\n such bites are seldom fatal. There is no need to allow fear of
\n snakes to ruin your enjoyment of the outdoors.<\/p>\n
Snakes will usually avoid you if you give them a chance. Try to
\n be sure they know you are comming, don’t reach into places they
\n might hide, be careful turning over rocks, boards etc. in snake
\n country. Leave snakes alone unless you are sure they are safe
\n (there is no simple rule to identify which are poisonous). This
\n also applies to dead snakes and detached heads – reflex bites are
\n just as dangerous as bites by a live snake.<\/p>\n
If someone is bitten:<\/p>\n
Clean and disinfect the wound.<\/p>\n
Transport to a hospital as quickly as reasonably possible.
\n Try to keep the patient quiet and resting. If necessary a
\n victim alone must walk to reach treatment but this should be
\n avoided if possible.<\/p>\n
Immobilize the area much as for a fracture. Use constricting
\n bands above and below the site but be certain they do not
\n interfere with blood circulation, they are only to slow down
\n the movement of lymphatic fluids just under the skin.
\n Alternatively, wrap entire area snugly with a cloth, elastic
\n bandage, etc again being careful not to interfere with blood
\n circulation.<\/p>\n
As best you can, identify the snake to aid in determining the
\n proper treatment. If you can do so safely, kill the snake and
\n take it with you to the hospital for definite identification.
\n (But don’t kill snakes which haven’t bitten anybody.)<\/p>\n
*DO NOT* cut into the wound area unless you are medically
\n trained to do so. You will probably do more damage than the
\n snake did. If you have a good syringe style suction device
\n and the snake is a pit viper, you may attempt to suck venom
\n out through the wound it went into, but do not let this delay
\n evacuation to a hospital.<\/p>\n
[End of Summary]<\/p>\n
ACKNOWLEDGEMENTS AND REFERENCES<\/p>\n
At the outset I would like to thank the following for their helpful
\ncomments and suggestions:<\/p>\n
loosemore-sandra@CS.YALE.EDU (Sandra Loosemore)
\nblazekm@a.cs.okstate.edu
\npholland@iastate.edu (Paul Hollander)
\nKLEINSCHMIDT@MCCLB0.MED.NYU.EDU (Jochen)<\/p>\n
A special thanks to:<\/p>\n
CWA@NAUVAX.UCC.NAU.EDU (Curt Anderson) for providing information I
\nwas not able to find in the library here.<\/p>\n
ed@titipu.meta.COM (Edward Reid) who put me into contact with Paul
\nMoler, a professional herpologist with the Florida Dept. of Game
\nand Freshwater Fish. <\/p>\n
And of course a big thanks to Dr. Moler who was very helpful in
\ncorrecting some errors and providing information.<\/p>\n
References – as long as this posting is, it only scratches the
\nsurface. The following sources will provide more information:<\/p>\n
_Medicine for Mountaineering_, (referred to as ‘MFM’ throughout this
\narticle) Third Edition 1985. James A. Wilkerson, M.D. ed. The
\nsnakebite section starts on p234. This book, published by the
\nMountaineers in Seattle, is probably the standard reference for
\nbackcountry medicine.<\/p>\n
_A Field Guide to Western Reptiles and Amphibians_, Robert C.
\nStebbins, Houghton Mifflin, 1966. A good guide to snakes (and other
\nreptiles etc.) including descriptions, color illustrations and maps
\nof their ranges. Part of the Peterson Field Guide Series, sponsored
\nby the Audubon Society and National Wildlife Federation. Covers
\nonly the western U.S.<\/p>\n
_Rattlesnakes_, Laurence M. Klauber, University of California Press,
\n1982. This is a condensation of a 2 volume series on the same topic
\nwhich I have not seen. This book does not provide as much
\nidentification information as does Stebbins (but it does include
\nrange maps). It does provide a lot of interesting information about
\nall sorts of topics from the snake life cycle to collections of
\nfolklore and misinformation.<\/p>\n
I have not actually seen the following although others have
\nrecommended them:<\/p>\n
_The Audubon Society Field Guide to North American Reptiles and
\nAmphibians_ <\/p>\n
_Conant, R. 1975. A field Guide to Reptiles and Amphibians of
\nEastern and Central North America_, Houghton Mifflin Company;Boston.
\nCovers the eastern U.S. but there is also a western edition.<\/p>\n
Russell, Findlay E. 1983. _Snake Venom Poisoning_. Scholium International,
\n Great Neck, NY. (reprint with corrections of the 1980 edition.)<\/p>\n
INTRODUCTION:<\/p>\n
Snakebite is always a hot topic. In what follows I will attempt to
\ndescribe prevention and treatment of bites by poisonous snakes in
\nNorth America as well as the effects of such bites. Be aware that
\nwe are dealing with overreaction and hype here. Popular literature,
\nfolklore, movies etc. have greatly exaggerated both the probability
\nof snakebite and the likely outcome should it happen. We are much
\nless likely to get bitten than many would have us believe. Further-
\nmore snakebite, while serious, is not the death sentence often
\nimplied. Snakes (poisonous and otherwise) have excited a lot of
\naversion and superstition over the ages, resulting in unwarranted
\nfear, sometimes even panic. Aside from its adverse effect on the
\nenjoyment of life, this fear and panic can lead to:<\/p>\n
Improper treatment of those few cases which need treatment for
\n envenomation <\/p>\n
Dangerous overtreatment for bites in which envenomation does not
\n occur<\/p>\n
Worsening of outcome of snakebites due to panic, and <\/p>\n
Unnecessary and dangerous treatment of bites by non-poisonous
\n snakes. <\/p>\n
With a couple of exceptions listed below, snakebite in the U.S.
\nshould be treated conservatively. Even on those exceptions there is
\nno need to jump in with knives tournequets etc. to try to suck out
\nthe venom (particularly by mouth). However victims should be given
\nappropriate treatment and rapidly evacuated to medical facilities.<\/p>\n
“About no other medical subject has so much been written when
\n so little has been known!<\/p>\n
“Poisonous snake bites are unquestionably serious, potentially
\n deadly accidents. Nonetheless, the danger from a single bite
\n has been greatly exaggerated, particularly in the United States,
\n where an average of less than fifteen people die each year as
\n the result of bites by poisonous snakes. Less than one percent
\n of poisonous snake bites in this country are lethal. In other
\n parts of the world poisonous snakes are a more serious problem.
\n Many of the snakes in those areas have a much more toxic venom,
\n treatment is less successful, and sophisticated medical care is
\n less available.” (MFM p234)<\/p>\n
Of course severity will vary with species as well as with the
\nindividual snake – larger snakes of the same species tend to have
\nmore venom (possibly offset by the larger snake having learned to
\n“ration” its venom while a younger animal is more likely to inject
\nthe full load). However in North America we do not have the really
\nnasty varieties found in some parts of the world. There is no
\nreason to panic when someone is bitten by a snake. Even the “three
\nnasties” described below are not nearly as dangerous as the cobras,
\nblack mambas and death adders found in some parts of the world.<\/p>\n
THE VARIOUS SNAKES AND THEIR EFFECTS:<\/p>\n
According to MFM poisonous snakes in the US all belong to one of
\ntwo families:<\/p>\n
Crotalids (pit vipers):
\n copperhead
\n water moccasin or cottonmouth
\n various species of rattlesnake<\/p>\n
Elapids: only the coral snake (eastern and western versions)
\n lives in the U.S.<\/p>\n
Crotalids have the most efficient injection mechanism of any snake,
\nabout as good as a hypodermic syringe and needle. They are equipped
\nwith relatively long hollow fangs backed up by a system of injecting
\nvenom through those fangs. This gives them the ability to inject large
\nvolumes of venom quickly. Crotalid fangs can fold back into the mouth
\nso lack of visible fangs does not necessarily mean an unarmed snake.
\nMost crotalids have venom less toxic than that of coral snakes.
\nCrotalids, however are more dangerous because (a) they are more likely
\nto bite a human, (b) they can inject venom *much* more efficiently, and
\n(c) they are usually larger and have more venom to use. <\/p>\n
Elapids on the other hand have grooved fangs, a much less efficient
\ninjection mechanism. Generally they chew to get the venom into the
\nvictim. The size of coral snakes also limits them to biting fingers
\nor loose folds of skin. These snakes belong to the same family as
\nsome of the world’s nastiest critters: black mamba, death adder and
\ncobra. However the American coral snakes is about as mild as a
\npoisonous snake can be. It is not aggressive. – Children have
\nreportedly played with them for hours without being bitten. (No
\nrecord exists of how many parental heart attacks this has caused.)
\nThe venom is relatively potent, however, and treatment should be given
\nfor bites which do occur. Coral snake bites make up less than 2% of
\nall U.S. snake bites. There are no known fatalities from coral snake
\nbites since the development of the _Micrurus fulvius_ antivenom. <\/p>\n
The western coral snake is even less dangerous. It is smaller yet
\nand would have a hard time biting a person even if inclined to do
\nso. The rare bites which do occur should be treated the same as
\nother coral snake bites.<\/p>\n
VENOMS:<\/p>\n
Snake venom usually contains two types of poison: <\/p>\n
Hemolytic toxins which attack the walls of blood vessels, and<\/p>\n
Neurotoxins which attack the nerves.<\/p>\n
Hemolytic toxin attacks blood vessel walls, allows serum to escape
\ninto the surrounding tissues and causes clotting within the vessels.
\nThe result is severe swelling, pain, and discoloration at the site.
\nIn the few cases where hemolytic toxins cause death the actual cause
\nis likely to be shock. The effects of hemolytic toxin are immediate
\nand primarily localized. Symptoms will be obvious.<\/p>\n
Neurotoxins produce much less obvious immediate symptoms, at times
\nfooling the victim into believing envenomation has not occurred.
\nHowever symptoms can appear later. Neurotoxins produce much less
\nlocal reaction than do hemolytic toxins. However they can affect
\nnerves quite removed from the site of the bite. In extreme cases they
\ncan cause respiratory arrest although this is uncommon with most North
\nAmerican snakes. However respiratory distress without actual arrest
\nis likely to occur in neurotoxin victims. Less severe symptoms from
\nneurotoxins include tingling or prickly feelings and eyelid paralysis.<\/p>\n
All snake venom probably has some of each kind of toxin. However in
\ngeneral the pit vipers have a higher fraction of hemolytic toxin
\nwhile elapids have more neurotoxin. (The Mojave rattlesnake, a pit
\nviper, is an exception. See below.)<\/p>\n
The potency of venom will vary, with species, with time of year and
\nwith geographic area. Furthermore the typical snake mouth is no
\ncleaner than a human’s – they tend to have a lot of microbial
\ncontamination. It is common for a snake to bite without injecting
\nvenom, especially in larger animals. However the microbial
\ncontaminants will always be present and should always be treated.
\n(Such contamination seems to be much less of a problem in bites by
\nnon-venomous snakes, probably because they do not penetrate deeply.)<\/p>\n
FOUR SPECIAL CASES:<\/p>\n
Four varieties deserve special mention: the copperhead because a
\nsingle bite is not very dangerous, and the diamondback (eastern and
\nwestern) and Mojave rattlesnakes because they are dangerous: <\/p>\n
The copperhead has probably the mildest venom of any poisonous
\nsnake in the U.S. Adults bitten by a single copperhead usually
\nneed only supportive therapy and good cleansing and disinfection
\nof the wound. A study of 400 victims of copperhead bites found
\nonly 2 deaths, both the result of simultaneous bites by 3 or more
\nsnakes. I would treat a copperhead bite pretty much as any other
\npit viper bite, but would be able to reassure the patient a bit
\nmore and would not be as concerned if medical help were not
\nreadily available. This not to say that a copperhead bite won’t
\nhurt, it will. These bites are still serious but are unlikely to be
\nlife threatening.<\/p>\n
The diamondbacks, on the other hand, are potentially deadly. Both
\nthe eastern and western versions are huge, the western species
\ncompensating for its slightly smaller size with a more potent venom.
\nMFM lists the eastern diamondback as an aggressive snake and claims
\nit is responsible for more human deaths than any other U.S. snake.
\nOthers dispute this. Paul Moler claims it is not particularly
\naggressive and quotes some numbers which indicate that it is unlikely
\nto lead in killing people. I am inclined to believe Dr. Moler who
\nlives and works in the habitat of the eastern diamondback. I
\nsuspect this snake’s impressive size and defense displays have given
\nit an exaggerated reputation. Its western cousin is almost
\ncertainly more aggressive and at least as well equipped to ruin
\nyour day.<\/p>\n
The Mojave rattler is quite dangerous in spite of its size. This
\nlittle rascal (little compared to the diamondbacks anyway) is armed
\nwith a very potent venom, high in neurotoxins. Initial reaction is
\nusually mild with severe symptoms comming 12 to 16 hours after the
\nbite. The early symptoms can easily fool you into believing there
\nis no problem. By the time severe symptoms appear the best time for
\ntreatment will have passed. (This one also has a couple of close
\nrelatives south of the border, the Mexican west coast rattler and
\nthe South American tropical rattlesnake, also known as cascabel or
\nneotropical rattlesnake. They provide problems at least equal to
\nthose of the Mojave version.)<\/p>\n
Bites from either diamondback or the Mojave rattler should be
\n*aggressively* treated. This does not mean cutting unless you meet
\nall the conditions for it described below. However do treat such
\nbites with any appropriate suction device you have, try to immobilize
\nthe venom and the affected area, and do your level best to evacuate
\nthe victim quickly to medical facilities.<\/p>\n
There is of course a wide variety of poisonous snakes throughout the
\nworld. I can’t discuss them here. They are generally confined to
\nwarmer climates in places such as Australia, Africa, the Indian
\nSubcontinent and Southeast Asia. (There are some exceptions such as
\nthe European viper which ranges up to the Arctic Circle but is not
\nas dangerous as some of the snakes inhabiting warmer climates). If
\nyou plan to engage in wilderness activities in these areas you might
\nlook up something about the snakes there before you go, or post a
\nrequest and maybe somebody familiar with the area of interest can
\nanswer. Many of these areas are inhabited by snakes *much* more
\ndangerous than those native to the North America. MFM does have
\nsome information on other areas as well as a list of central medical
\nfacilities which can provide more information. If you are not
\nfamiliar with the snakes in an area, assume they are dangerous
\n(especially in warm climates).<\/p>\n
IDENTIFICATION:<\/p>\n
*********************************************************************
\n* Rule One: If in doubt about whether a snake is poisonous or not, *
\n* >leave it alone<. There is no reliable rule to distinguish which *
\n* snakes are poisonous and which are not. Characteristics vary *
\n* greatly depending on locale and occasional individuals have *
\n* atypical coloration or pattern. *
\n*********************************************************************<\/p>\n
It is useful to be able to identify the poisonous varieties of
\nsnake. However it is not always easy. Coral snakes are probably
\nthe easiest to properly identify, they are small (usually no more
\nthan about 30 inches long, sometimes up to 40 inches), thin and
\nbrightly colored with small heads. They can be distinguished from
\nthe nonvenomous king snake and other harmless species by the presence
\nof adjacent red and yellow bands while king snakes have adjacent red
\nand black bands:<\/p>\n
Red touch yellow – kill a fellow
\n Red touch black – venom lack.<\/p>\n
Another mnemonic is to think of a traffic light. If red is adjacent
\nto yellow, stop!<\/p>\n
Pit vipers are a bit more difficult. Of course the presence of
\nrattles tells you that you are dealing with a poisonous snake, but
\nabsence thereof gives no assurance to the contrary. Copperheads and
\ncottonmouths have no rattles and even rattlers sometimes loose their
\nrattles. The presence of fangs indicates a venomous snake, but
\nthey may be folded back in the mouth and difficult to detect, or
\nthey may be broken off. The easiest indicator (but one which needs
\npractice, maybe in a zoo) is the characteristic heavy body and
\ntriangular head of the pit viper. While some non-poisonous snakes
\nalso have these characteristics it is better to treat a snake with
\ncaution unless you absolutely know it is safe.<\/p>\n
You may also look for the pit after which the pit viper is named.
\nThis will be between the eye and nostril, one on each side of the
\nhead (of course on the other hand you may not want to look that
\nclosely.) The other sure indicator, although not terribly useful
\nfor obvious reasons, is the scales behind the anal plate. Pit
\nvipers have a row of single scales reaching across the underside of
\ntheir bodies behind the anus while most other snakes have a double
\nrow of scales, joining in about the middle. This last information
\nis probably only useful to identify a dead snake, I certainly
\nwouldn't want to pick up a live one to look at its underscales, at
\nleast until I know it is not poisonous.<\/p>\n
Some older references suggest checking the pupils of the snake's
\neyes for identification. Pit vipers will have vertical slit pupils.
\nIf it has round pupils it is not a pit viper. Perhaps, but I'm not
\nanxious to get that close to a snake if I think it might be
\nvenomous.<\/p>\n
One good indicator of the type of snake is the location. Snakes
\ndon't wander far from home and tend to have a limited range and not
\nsurvive outside the conditions they prefer. Except in the rare case
\nof an escaped pet you will not find them in areas far removed from
\ntheir normal range. You simply won't find a Mojave rattler in Ohio
\nor an eastern diamondback in Colorado. Several of the books listed
\nabove describe the ranges for various species, usually with maps. <\/p>\n
Body markings are rarely sufficient for identification by the
\ninexperienced. It takes a *lot* of practice to learn to distinguish
\nbetween various species, some of which are quite similar externally.
\nFurthermore, individuals of the same species can have varying shades
\nof color, making such identification even more difficult. It is
\ngood to be familiar with what the dangerous snakes look like, but be
\nsure you can be accurate or treat all snakes with caution. See the
\nreferences listed above for pictures and other help in identifica-
\ntion. If you are concerned about venomous snakes, get a book on
\nherpetology and study it. Visit zoos, talk with specialists etc.
\nI assure you that you will not become an expert by reading usenet.<\/p>\n
Again, the best rule is, if there is any chance that the snake is
\npoisonous, leave it alone! Getting close enough to identify pits or
\nscales is dangerous. You might then be able to also examine the
\nfang marks on your body!<\/p>\n
THE "THREE NASTIES:"<\/p>\n
These three species all have the venom to make you pay *dearly*
\nshould you upset them. However different sources give different
\nassessments of the disposition of the eastern diamondback and Mojave
\nrattler. Some list them as short tempered and quick to strike
\nhumans while others say that they are not very aggressive. There is,
\nhowever, general agreement that all three pack a nasty wallop if
\nthey do bite. It is useful to know if you are in their range and be
\nable to recognize them in order to get proper treatment should
\nsomeone get bitten. Their bites are not sure death but are more
\nlikely to cause death than other North American venomous snakes.<\/p>\n
While a major distinguishing feature of both diamondbacks (at least
\nin the adult snake) is their size, this may be an unreliable indicator.
\nEven experts have a difficult time estimating the size of a live snake,
\na problem compounded when a novice unexpectedly encounters one. Size
\nestimates are typically quite generous to say the least. If the snake
\nis dead and can be measured you can get useful information. Most of
\nthe danger of a diamondback comes from its size and quantity of
\nvenom anyway. It won't make much difference if it is a juvenile
\ndiamondback or an adult of some other species (except the Mojave).<\/p>\n
If you can safely kill a snake which has bitten someone, do so. You
\ncan then measure the length and take the snake with you to the hospital
\nfor expert identification. Be careful to avoid reflex bites – either
\nfrom an intact dead snake or from a detached head. I do not advocate
\nkilling a snake unless it has actually bitten a person.<\/p>\n
You will notice some discrepancies in the following descriptions.
\nWhile all authorities agree that the eastern diamondback is our
\nlargest rattler, the guidebooks list a greater length for the
\nwestern version. I attribute this to the fact that the descriptions
\ncome from different books. Probably one author is more conservative
\nthan the other. Either diamondback can be impressive – they are
\nknown to swallow cottontail rabbits whole! (And there are less
\nreliable reports that they do the same with jackrabbits.)<\/p>\n
Different authors also do not agree on which is the most dangerous,
\nsome claiming this "honor" for the eastern diamondback, some for the
\nwestern version. The eastern version is larger and has more venom
\nbut its western cousin has a more potent venom. In my opinion the
\nMojave rattlesnake is also a good candidate for the most dangerous
\nsnake in the U.S. – its very potent venom with the delayed action
\nmake it a real danger. I'm not sure it matters much, I would not
\nwant to be bitten by any of the three. My (partially educated)
\nopinion is that the western diamondback is the most dangerous since
\nit is probably the most likely to bite a person. Next would be the
\nMojave, less likely to bite but likely to administer a *nasty* dose
\nof venom. The eastern diamondback would be third, probably no more
\nlikely to bite than a Mojave and a less severe (but still quite
\ndangerous) venom load.<\/p>\n
EASTERN DIAMONDBACK (Crotalus adamanteus)<\/p>\n
(Thanks to Curt for emailing this since I couldn't find the books
\nreferenced in our library.)<\/p>\n
According to Conant's Reptiles & Amphibians of Eastern\/Central U.S.,
\n"33-72"; record 96"(!). An ominously impressive snake to meet in the
\nfield. The diamonds, dark brown or black in color, are strongly
\noutlined by a row of cream-colored or yellowish scales. Ground color
\nolive, brown, or almost black. Pattern and colors vivid in freshly
\nshed specimens; dull and quite dark in those preparing to shed. Only
\nrattler within its range with 2 prominent light lines on face and
\nvertical light lines on snout. <\/p>\n
At home in the palmetto flatwoods and dry pinelands of the South.
\nOccasionally ventures into salt water, swimming to outlying Keys off
\nthe Florida coast. Some snakes will permit close approach without
\nmaking a sound, whereas others, completely concealed in palmettos or
\nother vegetation, will rattle when dogs or persons are 20 or 30 feet
\naway. Many stand their ground, but when hard pressed they back away,
\nrattling vigorously but still facing the intruder. Frequently they
\ntake refuge in burrows of gopher tortoises, in holes beneath stumps,
\netc. Rabbits, rodents, and birds are eaten.<\/p>\n
Range: Coastal lowlands from se. N.Carolina to extr. E. Louisiana;
\nall of Florida, including the Keys."<\/p>\n
According to Audubon's herp guide (not very good for identification of
\nunknowns, but has good info and pictures):<\/p>\n
"Our largest rattler. Heavy-bodied with large head sharply distinct
\nfrom neck. Back patterned with dark diamonds with light centers and
\nprominently bordered by a row of cream to yellow scales. Prominent
\nlight diagonal lines on side of head. Vertical light lines on snout.
\nScales keeled, in 27-29 rows."<\/p>\n
\tRange and habitat same as above, but get this,<\/p>\n
"Give it a wide berth; most dangerous snake in North America! Venom
\nhighly destructive to blood tissue. Stumpholes, gopher tortoise burrows,
\nand dense patches of saw palmetto often serve as retreats. Their
\nnumbers have been substantially reduced by extensive land development
\nand by rattlesnake hunters. Eats rabbits, squirrels, birds"\t<\/p>\n
(The following descriptions, Mojave and western diamondback, taken from
\nStebbins's book)<\/p>\n
WESTERN DIAMONDBACK RATTLESNAKE (Crotalus atrox)<\/p>\n
Identification: 30-89 inches. The largest western rattlesnake.
\nAbove: gray, brown or pink with brown diamond or hexagonal blotches
\non the back and fainter smaller blotches on the sides. Markings
\noften indefinite and peppered with small dark spots, giving an
\noverall speckled or dusty appearance. Tail set off from the rest of
\nthe body by broad black and white rings, about equal in width; hence
\nsometimes called the "coontail" rattler. A light diagonal stripe
\nbehind the eye intersects the upper lip well in front of the corner
\nof the mouth. Young: 9-14 inches, markings more distinct than in
\nadult.<\/p>\n
Frequents a variety of habitats in arid and semiarid regions from
\nthe plains into the mountains – desert, grassland, brushland,
\nwoodland, rank growth of river bottoms, rocky canyons, and lower
\nmountain slopes. Crepuscular and nocturnal, but also abroad in
\ndaytime. Perhaps the most dangerous North American serpent, often
\nholding ground and boldly defending itself when disturbed.
\nLive-bearing.<\/p>\n
Range: SE California to E Oklahoma and E Texas, south to Isthmus of
\nTehauantepec. Old records for central Arkansas and Trinidad, Las
\nAnimas Co., Colorado. Sea level to 7000 feet.<\/p>\n
MOJAVE RATTLESNAKE (Crotalus scutulatus)<\/p>\n
Identification: 24-51 inches. Well-defined, light-edged dark gray to
\nbrown diamonds, ovals, hexagons down middle of back; light scales of
\npattern usually entirely light-colored. Ground color greenish gray,
\nolive green, brownish, or yellowish. A white to yellowish stripe
\nextends from behind the eye to a point behind the corner of the mouth
\nexcept at extreme southern end of range. Tail with contrasting light
\nand dark rings; dark rings narrower than light rings. Enlarged scales
\non snout and between the supraoculars.<\/p>\n
Chiefly inhabits upland desert and lower mountain slopes, but ranges
\nto about sea level near the mouth of the Colorado river and to high
\nelevations in the Sierra Madre Occidental. Habitats vary–barren
\ndesert, grassland, open juniper woodland, and scrubland. This rattler
\nseems to be most common in areas of scattered scrubby growth such as
\ncreosote bush and mesquite. Not common in broken rocky terrain or
\nwhere vegetation is dense. Eats kangaroo rats and other rodents; and
\nprobably other reptiles. AN EXTREMELY DANGEROUS SNAKE–EXCITABLE AND
\nWITH HIGHLY POTENT VENOM.<\/p>\n
Range–S. Nevada to Puebla, near southern edge of Mexican Plateau;
\nwestern edge of Mojave Desert, Calif. to extreme w. Tex. From near sea
\nlevel to around 8300 feet.<\/p>\n
In case of a bite it may be important to distinguish between the
\ndiamondback and the Mojave. The ranges of the species overlap and
\nif you are in the area of overlap you may not know which was the
\nculprit. The distinction is important in the case of a bite with
\nlittle or no local reaction. In a diamondback bite this indicates
\nthat envenomation did not occur. However if a Mojave was the
\nculprit no such assumption can be made and systemic reaction may
\noccur 12-16 hours later. The two species are very similar in
\nappearance. The relative width of light and dark tail bands may
\nbe the best way to distinguish between the two. If uncertain,
\nassume the snake was a Mojave and treat accordingly.<\/p>\n
Other similar snakes include the speckled and western rattlesnakes
\n(there are several sub-species of the speckled). Their ranges also
\noverlap those of the Mojave and diamondback. Similar problems
\nexist – that is for all except the Mojave lack of local reaction
\nindicates no envenomation. Again, unless you can positively
\nidentify the snake as not a Mojave, assume that any bite was
\nadministered by the Mojave if in its range.<\/p>\n
Mojave venom can be up to 20 times the as potent as diamondback venom
\nalthough quantity will typically be about 1\/6 that of a diamondback.
\nSpecific references to Mojave and its unusual venom are:<\/p>\n
_The Venomous Reptiles of Arizona_, (Arizona Game and Fish) pp55-56<\/p>\n
_Journal of Herpetology_, Vol 23 no. 2, pp 131ff (1989)<\/p>\n
_Herpetologica_, vol 47 No. 1 (March 1992) pp 54ff<\/p>\n
One other note on the Mojave: There is a central Arizona version
\nwhich can be considered a subspecies. As far as I know, nobody has
\nyet found any differences between it and its more widely distributed
\ncousins except that its venom is very similar to the diamondback
\nvenom. This of course makes it less dangerous than the standard
\nversion. There are also "hybrids" which have components from both
\nvenom types. Hybrids present the particular danger of a local
\nreaction which may fool victims and medical personnel into believing
\nthe culprit was a diamondback until the systemic reaction due to
\nneurotoxin sets in later. Even experts can't tell the difference
\nbetween different varieties of Mojave except by analyzing the venom.
\nObviously all Mojave (or suspected Mojave) bites should be treated
\nfor the worst case.<\/p>\n
PREVENTION:<\/p>\n
Obviously the best prevention is to avoid getting bitten. This is
\nfacilitated by the fact that humans are not the natural prey of any
\nvenomous snake. We are a bit large for them to swallow whole and
\nthey have no means of chopping us up into bite size pieces. Nearly
\nall snakebites in humans are the result of a snake defending itself
\nwhen it feels threatened. In general snakes are shy and will simply
\nleave if you give them a chance. The basic rule is to be sure the
\nsnake knows you are coming. Walk heavily, they probably sense
\nground vibrations better than sound. If they sense your presence
\nthey will almost always leave before you even know they are there.
\n(This may not apply in other parts of the world. Some of the more
\npotent snakes may protect their territory as well as their bodies.)<\/p>\n
If you do unexpectedly confront a snake, stay calm, back away and
\ndo nothing to threaten it. (This assumes of course that the
\nsurprise didn't cause you to jump well beyond the snake's reach.
\nIt's amazing what the human body can do in such circumstances.)<\/p>\n
Don't run around barefoot in snake country, especially after dark.
\nDuring warm weather snakes will be most active at night and will
\ndefend themselves if stepped on or if you walk too close and they
\nsense danger. MFM lists going barefoot and gathering firewood after
\ndark as two of the more common activities leading to snakebite.
\nGoing barefoot not only exposes you but also makes your footsteps
\nquieter so you are less likely to be felt. You could invest in a
\npair of "snakeproof" boots but any high top leather boot is probably
\nadequate. Long pants will also help since the snake has difficulty
\ndistinguishing between clothing and you. Venom injected into a
\nfold of your clothing won't hurt you much.<\/p>\n
Remember that snakes like to hide under rocks, logs, brush etc. to
\nprotect themselves from sun or cold. Be *very* careful in snake
\ncountry about moving such objects or reaching into anywhere a snake
\nmight hide, or even walking by them. They might well perceive your
\nactions as aggressive and defend themselves. This is probably the
\nmost dangerous situation since there may be more than one snake in
\nthe same place and, taken by surprise, they will strike without
\nwarning. Furthermore they will be more likely to bite your
\nunprotected hand, not a leg or foot protected by clothing.<\/p>\n
Rock climbers should be careful in snake country. Snakes like to
\nsun themselves on ledges and it can be a real eye-opener to poke
\nyour head up and stare one in the eyes. And while you won't find
\nthem in the middle of a 5.12 face you may find them in cracks near
\nledges etc. Remember, the mice and rats which inhabit many cliff
\nareas mean food to a snake and so attract them.<\/p>\n
It is also a good idea to protect yourself while sleeping. Snakes
\nwon't come looking to bite you, but when the temperature starts
\nto drop they often do look for a warm place to spend the night.
\nThat sleeping bag with you inside can be very attractive. Use
\ninsect netting or something else to keep them out (unless you
\nrelish the thought of waking up to find a snake in bed with you).
\nThere is a bit of controversy about if they will actually crawl into
\nbed with you, but I would want to take precautions. Also check the
\nsleeping bag before you get in to be sure it isn't already
\noccupied. The same goes for your boots in the morning.<\/p>\n
Be careful entering old buildings such as mining cabins. They make
\nnice homes for snakes.<\/p>\n
Obviously you should not handle or tease poisonous snakes. Less
\nobvious is the danger of handling them when they are dead. A reflex
\nstrike from a dead snake can be just as dangerous as a bite by a
\nlive one. This also applies to detached heads of dead snakes.<\/p>\n
TREATMENT:<\/p>\n
Now, what about treatment? What do you do if you or a member of
\nyour party becomes one of the unfortunate few to actually get
\nbitten?<\/p>\n
The first thing is to remain calm. Remember, snake bite is *not*
\nusually deadly in spite of all the hype about it. Even without
\ntreatment you will almost certainly recover. If you can identify
\nthe snake do so. It is better if you can safely take it with you to
\nthe hospital to be sure of getting the right anti-venom. However
\ndo not risk more bites to do so. Remember the first rule of rescue:
\nDo not create any more victims or risk further injuring the current
\nvictim.<\/p>\n
Treat for microbial infection. Bacteria which cause tetanus and gas
\ngangrene have been isolated from the mouths of poisonous snakes.
\nCleanse the wound and if possible disinfect with Betadyne or other
\neffective antiseptic. Cleansing and disinfecting the wound is the
\nsingle most effective treatment you can give in the field. The
\nvictim should also be sure his tetanus vaccine is up to date.<\/p>\n
Definitive treatment requires a physician who will administer anti-
\nvenom as well as other treatment. Most antivenom is made with horse
\nserum so try to find out if the patient has any allergy to it and if
\nso be sure the doctor is informed of that fact. Keep the patient as
\nquiet as possible and evacuate quickly to medical facilities.<\/p>\n
A word about the Mojave: Most of the snakes of this species have a
\nvenom high in neurotoxin as described above. This is particularly
\ndifficult to treat, both in the field and in a medical facility.
\nThe standard antivenom is less effective against it than against
\nvenoms with a higher percentage of hemolytic toxins. It is
\nespecially important to start treatment quickly for a Mojave bite.
\nThe bitten limb must be immobilized and spread of the venom slowed
\nas much as possible. This is one case where it would be worth an
\nextra effort to remove the venom if the conditions below can be met.
\nAlso be extra diligent to in transporting the victim quickly to a
\nhospital. Be prepared to provide breathing assistance.<\/p>\n
A victim alone should try to evacuate himself to medical facilities,
\neven if this includes walking. Obviously he should do no more
\nexercise than absolutely necessary. <\/p>\n
If the victim is accompanied by only one other person that person
\nshould do as much treatment as can be done quickly, then go for help.
\nLarger groups should send someone for help while others stay to
\nprovide as much treatment as they can, or start to evacuate the patient
\nif possible. The object is to get the victim to a medical facility
\nquickly with as little rough handling or movement on his part as
\npossible. Helicopter evacuation is preferred but even having an
\nambulance at the trailhead is a great help.<\/p>\n
Try to slow the spread of the venom. Use constricting bands above
\nand below the site of the bite. These should *not* be tight enough
\nto cut off circulation, all you want to do is slow down the movement
\nof the fluids under the skin. Keep watching these bands, they should
\nnot be on a swollen area and you may have to move them as swelling
\nincreases. To re-iterate: *Do*not*cut*off*circulation*. <\/p>\n
A more recent development for immobilizing the venom is to wrap the
\narea snugly with fabric and immobilize the limb with a splint. Any
\ntype of fabric, including elastic bandages, works well. Just be
\nsure it is not tight enough to cut off blood circulation and watch
\nfor swelling which might make it too tight.<\/p>\n
The bitten limb should be immobilized, especially if bitten by an
\nelapid such as a coral snake. Treat it like a fracture.<\/p>\n
You will not be able to remove very much of the venom, almost none
\nin an elapid bite where the chewing will have dispersed it. However,
\nyou should try if *all* of the following criteria are met:<\/p>\n
1. You can start venom removal within 10 minutes (thereafter it
\ntends to be so dispersed that you will not likely be very
\neffective)<\/p>\n
2. You have appropriate suction devices to remove it. This means a
\nsyringe style suction device, the rubber suction cups often sold in
\n"snake-bite kits" do not develop enough suction to do the job. It
\nis not necessary to cut the wound to suck out venom, it went in
\nthrough the fang marks and can come out the same way. In my opinion
\nyou should not try to suck it out with your mouth. That is not likely
\nto be effective, risks venom getting into your blood via an open sore,
\nand most importantly is likely to further contaminate the wound. If
\nyou lack an appropriate suction device, forget it.<\/p>\n
3. The bite was inflicted by a pit viper.<\/p>\n
If you do try to remove the venom, place the suction device over the
\nfang marks. They may not always be obvious if the snake has bitten
\nhard enough to leave marks from other teeth also. Be aware that you
\nare not going to get out much of the venom. Removal of 5 to 15%
\nwould be about all you can expect. The sooner after the bite you
\nstart the more effective you will be, the venom disperses quickly.<\/p>\n
There is some controversy over the idea of cutting into the flesh
\naround the fang marks. While this can facilitate removal of venom
\nit is also very dangerous. Unless you really know what you are
\ndoing you may do more damage than the snake did. Muscles, nerves,
\nand blood vessels may all be in the area and you can damage them,
\nsometimes permanently. Most classes I have attended do not
\nrecommend cutting. MFM recommends it under certain conditions,
\nnamely:<\/p>\n
1. The "surgeon" knows enough to avoid cutting anything vital. In
\nmy mind this eliminates most of us, including myself, from doing
\nthis cutting. The cuts need to be quite deep, about an eighth to a
\nquarter of an inch, and I don't think most of us remember enough
\nanatomy to do that safely, especially during the tense times which
\naccompany a snake bite.<\/p>\n
2. The culprit is positively identified as a pit viper. (Antivenom
\nis the only effective treatment for elapid bites, including the
\ncoral snake.)<\/p>\n
3. The victim is 3 hours or more from the nearest medical facility
\nand incision and suction will not delay evacuation.<\/p>\n
Keep in mind that MFM is aimed at a readership which includes some
\nhighly trained medical people, physicians etc. It may make sense
\nfor them to perform some procedures which most of us should not even
\nthink about attempting. You will do no damage with an appropriate
\nattempt to suck venom out of the same wound it went in. However you
\ncan do a *lot* of damage when you start cutting. Leave the surgery
\nto those trained and licensed to do it.<\/p>\n
(MFM mentions cold therapy only to *strongly* advise against its use.
\nIt is *not* effective and, particularly in the case of a pit viper
\nbite, will impede recovery. Cold will restrict circulation already
\ncompromised by the damage to blood vessels. Furthermore, the body's
\nprinciple detoxifying mechanism appears to be the action of
\nantibodies against the venom. Lowering of the temperature retards
\naccess of antibodies to the toxins. Cold therapy apparently was
\nproposed on the assumption that the venom is an emzyme. In fact
\nmost are peptides which cooling does not inactivate.)<\/p>\n
How about a "snake-bite kit?" Obviously you want to be prepared for
\nemergencies which are likely to happen but I don't think that
\nnecessarily means buying a kit and carrying it all the time. Except
\nfor a suction device you should already be carrying everything you
\nneed in your standard first aid kit. Snakebite is so rare that I
\ndon't think I would even bother with a suction device unless a bite
\nby one of the "three nasties" is a reasonable probability. Items
\nwhich ought to be in your first aid kit and are useful in case of
\nsnake bite are:<\/p>\n
1. A good antiseptic (eg. Betadyne) to cleanse the bite.<\/p>\n
2. Elastic bandage or gauze ("cling") to use in making constricting
\nbands or wrapping the area to immobilize the venom.<\/p>\n
3. Splinting materials to immobilize the limb bitten.<\/p>\n
(Written by Hal Lillywhite. Last update: 2 September 1992)<\/p>\n
TABLE OF CONTENTS of this chain:<\/p>\n
11\/ Snake bite
\n12\/ Netiquette
\n13\/ Questions on conditions and travel
\n14\/ Dedication to Aldo Leopold
\n15\/ Leopold’s lot.
\n16\/ Morbid backcountry\/memorial
\n17\/ Information about bears
\n18\/ Poison ivy, frequently ask, under question
\n19\/ Lyme disease, frequently ask, under question
\n20\/ “Telling questions” backcountry Turing test
\n21\/ AMS
\n22\/ Words from Foreman and Hayduke
\n23\/ A bit of song (like camp songs)
\n24\/ What is natural?
\n25\/ A romantic notion of high-tech employment
\n26\/ Other news groups of related interest, networking
\n27\/ Films\/cinema references
\n28\/ References (written)
\n1\/ DISCLAIMER
\n2\/ Ethics
\n3\/ Learning I
\n4\/ learning II (lists, “Ten Essentials,” Chouinard comments)
\n5\/ Summary of past topics
\n6\/ Non-wisdom: fire-arms topic circular discussion
\n7\/ Phone \/ address lists
\n8\/ Fletcher’s Law of Inverse Appreciation and advice
\n9\/ Water Filter wisdom
\n10\/ Words from Rachel Carson<\/p>\n
END.<\/p>\n
