Timber rattlesnake

{{Short description|Species of reptile}} {{Speciesbox | name = Timber rattlesnake | fossil_range = {{Fossil range|10.3|0}} [[Miocene]] – [[Neogene|Present]]<ref>{{cite journal |last1=Parmley |first1=Dennis |title=Hemphillian (Late Miocene) snakes from Nebraska, with comments on Arikareean through Blancan snakes of midcontinental North America |journal=Journal of Vertebrate Paleontology |date=1995 |volume=15 |issue=1 |pages=79–95 |doi=10.1080/02724634.1995.10011208 |bibcode=1995JVPal..15...79P |s2cid=129349031 |url=https://www.tandfonline.com/doi/abs/10.1080/02724634.1995.10011208|url-access=subscription }}</ref> | image = Timber Rattlesnake (Crotalus horridus) - Flickr - 2ndPeter.jpg| | image_caption = | status = LC | status_system = IUCN3.1 | status_ref = <ref name=IUCN>{{cite iucn |author=Hammerson, G.A. |author-link=species:Geoffrey A. Hammerson |year=2007 |title=''Crotalus horridus '' |article-number=e.T64318A12765920 |doi=10.2305/IUCN.UK.2007.RLTS.T64318A12765920.en |access-date=9 November 2022}}</ref> | status2 = G4 | status2_system = TNC | status2_ref = <ref>{{cite web|website=NatureServe Network Biodiversity Location Data accessed through NatureServe Explorer|author=NatureServe|title=''Crotalus horridus''|url=https://explorer.natureserve.org/Taxon/ELEMENT_GLOBAL.2.100455/Crotalus_horridus|publisher=NatureServe|location=Arlington, Virginia|date=2 June 2023|access-date=25 June 2023}}</ref> | genus = Crotalus | species = horridus | authority = [[Carl Linnaeus|Linnaeus]], [[10th edition of Systema Naturae|1758]] | range_map = Crotalus horridus range.png | range_map_caption = Timber rattlesnake range<ref>{{cite journal |last1=U.S. Geological Survey |title=Timber Rattlesnake (''Crotalus horridus'') rTIRAx_CONUS_2001v1 Range Map |journal=Gap Analysis Project |date=2017 |doi=10.5066/F7BR8R5P }}</ref> | synonyms = {{collapsible list|bullets=true | ''Crotalus horridus'' Linnaeus, 1758 | ''Crotalus boiquira'' [[Bernard Germain de Lacépède|Lacépède]], 1789 | ''Crotalus atricaudatus'' [[Pierre André Latreille|Latreille]] ''In'' [[Charles-Nicolas-Sigisbert Sonnini de Manoncourt|Sonnini]] & Latreille, 1801 | ''Crotalus zetazomae'' Brickell, 1805 | ''Crotalinus cyanurus'' [[Constantine Samuel Rafinesque|Rafinesque]], 1818 | ''Crotalus catesbaei'' Hemprich, 1820 | ''Crotalurus cyanurus'' – Rafinesque, 1820 | ''Caudisona horrida'' – Fleming, 1822 | ''Crotalus horidus'' [[John Edward Gray|Gray]], 1825 (''ex errore'') | ''Crotalus durissus'' var. ''concolor'' [[Giorgio Jan|Jan]], 1859 | ''Crotalus durissus'' var. ''melanurus'' Jan, 1859 | ''Crotalus durissus'' var. ''mexicana'' Jan, 1863 | ''Crotalus fasciatus'' Higgins, 1873 | ''Crotalus horridus'' var. ''atricaudatus'' – [[Samuel Garman|Garman]], 1884 | ''Crotalus horridus'' – [[George Albert Boulenger|Boulenger]], 1896 | ''Crotalus durissus cincolor'' Notestein, 1905 (''ex errore'') | ''Crotalus horridus horridus'' – [[Howard K. Gloyd|Gloyd]], 1935 | ''Crotalus horridus atricaudatus'' – Gloyd, 1935 | ''Crotalus horridus'' – [[:fr:Joseph T. Collins|Collins]] & Knight, 1980 }} | synonyms_ref = <ref name="McD99">[[species:Roy Wallace McDiarmid|McDiarmid RW]], [[Jonathan A. Campbell|Campbell JA]], [[species:T'Shaka A. Touré|Touré TA]] (1999). ''Snake Species of the World: A Taxonomic and Geographic Reference, Volume 1''. Washington, District of Columbia: Herpetologists' League. {{ISBN|1-893777-00-6}} (series). {{ISBN|1-893777-01-4}} (volume).</ref> }}

The '''timber rattlesnake''' ('''''Crotalus horridus'''''), also known [[Common name|commonly]] as the '''banded rattlesnake''', and the '''canebrake rattlesnake''' in [[southern United States]] <ref name="W&W57">[[Albert Hazen Wright|Wright AH]], [[species:Anna Allen Wright|Wright AA]] (1957). ''Handbook of Snakes of the United States and Canada''. Ithaca and London: Comstock Publishing Associates, a division of Cornell University Press. (7th printing, 1985). 1,105 pp. (in two volumes). {{ISBN|0-8014-0463-0}}. (''Crotalus horridus'', pp. 956–966.)</ref> is a [[species]] of [[Crotalinae|pit viper]] in the [[Family (taxonomy)|family]] [[Viperidae]]. The species is native to the eastern United States. Like all other pit vipers, it is [[Venomous snake|venomous]], with a very toxic bite.<ref>{{Cite journal|doi = 10.1186/1471-2164-14-394|title = The genesis of an exceptionally lethal venom in the timber rattlesnake (''Crotalus horridus'') revealed through comparative venom-gland transcriptomics|year = 2013|last1 = Rokyta|first1 = Darin R.|last2 = Wray|first2 = Kenneth P.|last3 = Margres|first3 = Mark J.|journal = BMC Genomics|volume = 14|page = 394|pmid = 23758969|pmc = 3701607 | doi-access=free }}</ref> Its venom is extremely potent, and both hemorrhagic and neurotoxic venom are present depending on population and location.<ref>Rokyta, D. R., Wray, K. P., McGivern, J. J., & Margres, M. J. (2015). The transcriptomic and proteomic basis for the evolution of a novel venom phenotype within the Timber Rattlesnake (Crotalus horridus). Toxicon, 98, 34-48.</ref><ref>{{Cite journal |last1=Rokyta |first1=Darin R |last2=Wray |first2=Kenneth P |last3=Margres |first3=Mark J |date=2013 |title=The genesis of an exceptionally lethal venom in the timber rattlesnake (Crotalus horridus) revealed through comparative venom-gland transcriptomics |journal=BMC Genomics |language=en |volume=14 |issue=1 |page=394 |doi=10.1186/1471-2164-14-394 |doi-access=free |pmid=23758969 |pmc=3701607 |issn=1471-2164}}</ref> ''C. horridus'' is the only [[rattlesnake]] species in most of the populous [[Northeastern United States]] and is second only to its relatives to the west, the [[Crotalus viridis|prairie rattlesnake]], as the most northerly distributed venomous snake in North America.<ref name="Con75">[[Roger Conant (herpetologist)|Conant R]] (1975). ''A Field Guide to Reptiles and Amphibians of Eastern and Central North America, Second Edition''. (First published in 1958). Boston: Houghton Mifflin Company. xviii + 429 pp. + Plates 1–48. {{ISBN|0-395-19979-4}} (hardcover), {{ISBN|0-395-19977-8}} (paperback). (''Crotalus horridus'', pp. 233–235 + Plate 35 + Map 178.)</ref><ref>Brown, William S. (1991). "Female Reproductive Ecology in a Northern Population of the Timber Rattlesnake, ''Crotalus horridus'' ". ''Herpetologica'' '''47''' (1): 101-115.</ref> There are no [[subspecies]] that are recognized as being valid.<ref name=NRDB/><ref name="ITIS">{{ITIS|id=174306|taxon=''Crotalus horridus ''|access-date=13 March 2023}}</ref>

==Taxonomy== The timber rattlesnake was one of the many [[Amphibia in the 10th edition of Systema Naturae|reptile species originally described]] by [[Carl Linnaeus]] in the landmark 1758 [[10th edition of Systema Naturae|10th edition]] of his ''[[Systema Naturae]]'', and still bears its original name ''Crotalus horridus''.<ref>{{cite book |last= Linnaeus |first=Carl |author-link= Carl Linnaeus |title= Systema Naturae per Regna Tria Naturae, Secundum Classes, Ordines, Genera, Species, cum Characteribus, Differentiis, Synonymis, Locis |publisher= (Laurentii Salvii) |location= [[Stockholm|Holmiae]] |volume= I |edition= 10th revised |language= la |year= 1758 |page= 214 |url= https://archie.org/stream/carolilinnaeisy00gesegoog#page/n223/mode/1up |via= The [[Internet Archive]]}}</ref>

The subspecies ''C. h. atricaudatus'' ([[Pierre André Latreille|Latreille]] ''in'' [[Charles-Nicolas-Sigisbert Sonnini de Manoncourt|Sonnini]] and Latreille, 1802), often referred to as the canebrake rattlesnake,<ref name="W&W57"/> is currently considered invalid.<ref name=NRDB/><ref name="ITIS-A">{{ITIS|id=174307|taxon=''Crotalus horridus atricaudatus ''|access-date=13 March 2023}}</ref> Previously, it was recognized by [[Howard K. Gloyd|Gloyd]] (1936) and [[Laurence Monroe Klauber|Klauber]] (1936). Based on an analysis of geographic variation, Pisani et al. (1972) concluded no subspecies should be recognized. This was rejected by [[Roger Conant (herpetologist)|Conant]] (1975), but followed by Collins and Knight (1980). Brown and Ernst (1986) found evidence for retaining the two subspecies, but stating them apart without having more information than usual is not possible, including adult size, color pattern, the number of [[Dorsal scales|dorsal scale]] rows, and the number of [[ventral scales]]. Dundee and Rossman (1989) recognized ''C. h. atricaudatus'', but others take a more neutral point of view.<ref name="C&L04"/>

The timber rattlesnake is one of 36 species in the genus ''Crotalus.'' This genus can be distinguished from ''Sistrurus'' by the small scales atop the head, rather than nine large scales found on ''Sistrurus.'' <ref>{{Cite journal |last=Cook |first=Francis R |date=2017-03-29 |title="Peterson Field Guide to Reptiles and Amphibians of Eastern and Central North America. Fourth Edition" by Robert Powell, Roger Conant, and Joseph T. Collins, 2016. [book review] |journal=The Canadian Field-Naturalist |volume=130 |issue=4 |page=373 |doi=10.22621/cfn.v130i4.1936 |doi-access=free }}</ref>

== Etymology == The name ''Crotalus'' is Latin for a rattle<ref name="Ernst and Ernst (2003)">Ernst, Carl H. and Evelyn M. Ernst. 2003. ''Snakes of the United States and Canada.'' Smithsonian Books. Washington D.C. xi, 668 pp. (see pages 563-564) {{ISBN|1-58834-019-8}}</ref> or, ''crŏtălisso'' to rattle or the sound of the castanet.<ref name="Lewis (1993)">Lewis, Charlton T. 1993. ''A Latin Dictionary, founded on Andrews' edition of Freund's Latin Dictionary, revised, enlarged, and in great part rewritten.'' Oxford University Press. Oxford. xiv, 2019 pp. (see page 484) {{ISBN|0-19-864201-6}}</ref> ''Horridus'' is Latin, meaning horrid or dreadful, presumably in reference to its potentially lethal venom. Although southern populations are generally no longer recognized as a valid subspecies, the name canebrake rattlesnake (''Crotalus horridus atricaudatus'') is occasionally still used and commonly encountered in older literature. ''Atricaudatus'' is Latin meaning black-tailed ({{Lang|la|atri}} = black, and {{Lang|la|caudatus}} = tailed).<ref name="Ernst and Ernst (2003)" />

==Description== Adults usually grow to total length of {{convert|91|–|152|cm|in|round=0.5|abbr=on}}.<ref name="Con75"/> In [[Pennsylvania]], the smallest size females that could produce viable eggs was {{convert|72.2|cm|in|abbr=on}}.<ref>Galligan, John H.; Dunson, William A. (1979). "Biology and status of timber rattlesnake (''Crotalus horridus'') populations in Pennsylvania". ''Biological Conservation'' '''15''' (1): 13–58.</ref> Most adult timber rattlesnakes found measure less than {{convert|115|cm|in|abbr=on}} in total length and weigh between {{convert|500|and|1500|g|lb|abbr=on}}, often being towards the lower end of that range.<ref>[http://www.tpwd.state.tx.us/huntwild/wild/species/timberrattlesnake/ Timber Rattlesnake (''Crotalus horridus'')]. Tpwd.state.tx.us. Retrieved on 2013-01-05.</ref><ref>[[Henry Sheldon Fitch|Fitch, Henry S.]]; Pisani, George R.; [[Harry W. Greene|Greene, Harry W.]]; [[species:Alice F. Echelle|Echelle, Alice F.]]; Zerwekh Michael (2004). "A field study of the timber rattlesnake in Leavenworth County, Kansas". ''Journal of Kansas Herpetology'' '''11''': 18-24.</ref><ref>Brown, William S.; Kéry, Marc; Hines, James E. Hines (2007). "Survival of timber rattlesnakes (''Crotalus horridus'') estimated by capture-recapture models in relation to age, sex, color morph, time, and birthplace". ''Copeia'' '''2007''' (3): 656-671.</ref><ref>Clark, Rulon W. (2006). "Fixed Videography to Study Predation Behavior of an Ambush Foraging Snake, ''Crotalus horridus'' ". ''Copeia'' '''2006''' (2): 181–187.</ref> The maximum reported total length is {{convert|189.2|cm|in|abbr=on}} (Klauber, 1956). Holt (1924) mentions a large specimen caught in [[Montgomery County, Alabama]], which had a total length of {{convert|159|cm|in|round=0.5|abbr=on}} and weighed {{convert|2.5|kg|lb|abbr=on}}.<ref name="C&L04">{{cite book |author=Campbell JA |author-link=Jonathan A. Campbell |author2=[[species:William W. Lamar|Lamar WW]]|title=The Venomous Reptiles of the Western Hemisphere (2 volumes)|publisher=Comstock Publishing Associates|year=2004|isbn=0-8014-4141-2|volume=2|pp=548-551}}</ref> Large specimens can reportedly weigh as much as {{convert|4.5|kg|lb|abbr=on}}.<ref>[https://www.seaworld.org/animal-info/animal-bytes/animalia/eumetazoa/coelomates/deuterostomes/chordata/craniata/reptilia/squamata/canebrake-rattlesnake.htm ANIMAL BYTES – Canebrake Rattlesnake]. Seaworld.org. Retrieved on 2013-01-05.</ref>

The [[dorsal scales]] are [[keeled scales|keeled]]<ref name="B&K79">{{cite book |author=[[John L. Behler|Behler JL]] |author2=[[species:Frederic Wayne King|King FW]]|year=1979 |title=The Audubon Society Field Guide to North American Reptiles and Amphibians|publisher=New York: Alfred A. Knopf. 743 pp.|isbn=0-394-50824-6|url=https://archive.org/details/audubonsocietyfi00behl}} (''Crotalus horridus'', pp. 688–689 + Plates 619, 620, 653.)</ref> and arranged in 21–26 scale rows at midbody (usually 25 rows in the southern part of its geographic range, and 23 rows in the northern part). The [[ventral scales]] number 158–177 in males and 163–183 in females. Males have 20–30 [[subcaudal scales]], while females have 15–26. The [[rostral scale]] is normally a little taller than it is wide. In the internasal-prefrontal area there are 4–22 scales that include 2 large, triangular [[internasal scales]] that border the rostral, followed by two large, quadrangular [[prefrontal scales]] (anterior canthals) that may contact each other along the midline, or may be separated by many small scales. Between the [[Supraocular scales|supraocular]] and internasal scales, only a single canthal scale is present. Five to seven [[Interorbital scales|intersupraocular scales]] are seen. The number of prefoveal scales varies between two and eight. Usually, the first [[Supralabial scales|supralabial scale]] is in broad contact with the [[Nasal scale|prenasal scale]], although slightly to moderately separated along its posteroventral margin by the most anterior prefoveals.<ref name="C&L04"/>

[[Dorsum (anatomy)|Dorsally]], they have a pattern of dark brown or black crossbands on a yellowish-brown or grayish background. The crossbands have irregular zig-zag edges, and may be V- or M-shaped. Often a rust-colored vertebral stripe is present. Ventrally, they are yellowish, uniform, or marked with black.<ref>[[George Albert Boulenger|Boulenger GA]] (1896). ''Catalogue of the Snakes in the British Museum (Natural History), Volume III., Containing the ... Viperidæ''. London: Trustees of the British Museum (Natural History). (Taylor and Francis, printers). xiv + 727 pp. + Plates I–XXV. (''Crotalus horridus'', pp. 578–580).</ref> [[Melanism]] is common, and some individuals are very dark, almost solid black.<ref name="S&D41">[[Karl Patterson Schmidt|Schmidt KP]], [[D. Dwight Davis|Davis DD]] (1941). ''Field Book of Snakes of the United States and Canada''. New York: G.P. Putnam's Sons. 365 pp. (''Crotalus horridus horridus'', pp. 301–302 + Plate 33; ''Crotalus horridus atricaudatus'', p. 302).</ref> The tails of ''C. horridus'' are black and can be described as 'velvety.'<ref name=":0">{{Cite web |title=Species Profile: Canebrake / Timber Rattlesnake (Crotalus horridus) {{!}} SREL Herpetology |url=https://srelherp.uga.edu/snakes/crohor.htm |access-date=2023-04-25 |website=srelherp.uga.edu}}</ref>

<gallery mode="packed" heights="140px" caption="Four color variations of timber rattlesnakes (''Crotalus horridus'') from one [[Missouri]] county"> File:Timber Rattlesnake (Crotalus horridus) (15357864974).jpg|Timber rattlesnakes, [[in situ]] File:Timber Rattlesnake (Crotalus horridus) (26532488745).jpg|Timber rattlesnakes, in situ File:Timber Rattlesnake (Crotalus horridus) (31140366037).jpg|Timber rattlesnakes, in situ File:Timber Rattlesnake (Crotalus horridus) - Flickr - 2ndPeter (3).jpg|Timber rattlesnakes, in situ </gallery>

==Distribution and habitat== [[File:Viperidae- Crotalus horridus (Timber Rattlesnake) - 36427425226.jpg|thumb|Populations from cooler regions like northern latitudes or high elevations, are often darker like this one from [[Connecticut]].]] [[File:Timber Rattlesnake (dark coloration).JPG|thumb|A [[melanistic]] individual from Pennsylvania]] Timber rattlesnakes are present in the eastern United States from southern [[Minnesota]] and southern [[New Hampshire]], south to [[East Texas]] and [[North Florida]].<ref>Conant R, [[Joseph T. Collins|Collins JT]] (1998). ''Reptiles and Amphibians of Eastern/Central North America''. New York: Houghton Mifflin. {{ISBN|0-395-90452-8}}</ref> One hundred and fifteen rattlesnakes have been marked within [[Brown County State Park]] in [[Indiana]], one of the few places where they can be found in the state.<ref>{{cite web|url=https://www.in.gov/dnr/parklake/files/sp-Timber_brown-RattlesnakesFAQ2.pdf|title=The Timber Rattlesnake (''Crotalus horridus'') in Brown County State Park|publisher=[[Indiana Department of Natural Resources]]|access-date=August 8, 2017}}</ref>

Its historic range includes southern [[Ontario]] and southern [[Quebec]] in [[Canada]],<ref name="McD99"/> but in May 2001, the Canadian [[Species at Risk Act]] listed it as [[Local extinction|extirpated]] in Canada.<ref name="SaRPR">[http://www.sararegistry.gc.ca/species/speciesDetails_e.cfm?sid=682 ''Crotalus horridus''] {{Webarchive|url=https://web.archive.org/web/20160401115327/http://www.sararegistry.gc.ca/species/speciesDetails_e.cfm?sid=682 |date=2016-04-01 }} at [http://www.sararegistry.gc.ca/ Species at Risk Public Registry] {{Webarchive|url=https://web.archive.org/web/20161224121952/http://www.sararegistry.gc.ca/ |date=2016-12-24 }}. Accessed 23 June 2008.</ref> A Canadian government sponsored recovery strategy is under study to support the reintroducing of this predator of many pests to its former Canadian habitat.<ref>{{cite web|author1=Campbell, Craig |author2=Weller, Wayne |author2-link=species:Wayne F. Weller |url=https://www.canada.ca/en/environment-climate-change/services/species-risk-public-registry/recovery-strategies/timber-rattlesnake-2010.html |title=Timber rattlesnake (''Crotalus horridus''): recovery strategy 2010 |publisher=Canada.ca |date=2 December 2009|access-date=2022-03-20}}</ref>

Many were present in some of the thick forest areas of central and southeastern [[Iowa]], mostly within the [[Mississippi River|Mississippi]], [[Skunk River (Iowa)|Skunk]], [[Iowa River|Iowa]], and [[Des Moines River]] valleys, in several places in these areas; bites from timber rattlesnakes have been widespread, especially in a localized area of [[Geode State Park]], in southeastern [[Henry County, Iowa|Henry County]], along Credit Island Park, in southern [[Scott County, Iowa|Scott County]], and in the forested areas of southern [[Clinton County, Iowa|Clinton County]]. The museum at Amana Colony, Iowa, asserts that one founding family lost their firstborn, a daughter, at the age of three, due to a rattlesnake bite she received while playing on a woodpile in the 19th century.{{Citation needed|date=April 2023}}

In Pennsylvania, it is not present west of [[Chestnut Ridge (Laurel Highlands)|Chestnut Ridge]], which is in the [[Laurel Highlands]], nor is it present in the urban areas of the southeastern corner of the state. Thus, its range does not include [[Philadelphia]] and [[Pittsburgh]], the two largest cities in Pennsylvania.<ref name="Con75"/>

''C. horridus'' is extirpated from [[Michigan]], [[Delaware]], [[Maine]] and [[Rhode Island]], and is considered close to extirpation in New Hampshire.

Generally, this species is found in [[deciduous forest]]s in rugged terrain. ''C. horridus'' can be found in a variety of terrestrial habitats including lowland [[canebrake|cane thicket]]s (thus the [[common name]] canebrake rattlesnake), high areas around swamps and river [[floodplain]]s, [[hardwood]] and [[pine]] forests, mountainous areas, and rural habitats in [[Agricultural land|farming area]]s.<ref name=":0" /> During the summer, [[wiktionary:gravid|gravid]] females seem to prefer open, rocky [[wiktionary:ledge|ledge]]s where the temperatures are higher, while males and nongravid females tend to spend more time in cooler, denser woodland with more closed [[forest canopy]].<ref name="NYSDEC">[https://www.dec.ny.gov/animals/7147.html Timber Rattlesnake Fact Sheet] at [http://www.dec.state.ny.us/ NY State Dept. of Environmental Conservation]. Accessed 8 February 2007.</ref>

==Behavior== Female timber rattlers often bask in the sun before giving birth, in open rocky areas known as "basking knolls".<ref>{{cite book|author=Furman, Jon|title=Timber Rattlesnakes in Vermont and New York: Biology, History, and the Fate of an Endangered Species|location=Lebanon, New Hampshire|publisher=University Press of New England|year=2007|isbn=978-1-58465-656-2|url=https://books.google.com/books?id=S5bM83jWl9YC&pg=PA133|page=133}}</ref>

During the winter, timber rattlesnakes [[Brumation|brumate]] in dens and limestone crevices, often together with copperheads (''[[Agkistrodon contortrix]]'') and rat snakes (''[[Pantherophis alleghaniensis]]'', ''[[Pantherophis obsoletus|P. obsoletus]]'', and ''[[Pantherophis spiloides|P. spiloides]]'').<ref name="S&D41"/> Timber rattlesnakes exhibit high levels of [[philopatry]] to their natural hibernaculum, which means that they are likely to return to the same hibernaculum, or communal wintering den, each year.<ref name=":1">{{Cite journal |last1=Clark |first1=Rulon W. |last2=Marchand |first2=Michael N. |last3=Clifford |first3=Brendan J. |last4=Stechert |first4=Randy |last5=Stephens |first5=Sierra |date=2011-02-01 |title=Decline of an isolated timber rattlesnake (''Crotalus horridus'') population: Interactions between climate change, disease, and loss of genetic diversity |url=https://www.sciencedirect.com/science/article/pii/S0006320710004969 |journal=Biological Conservation |language=en |volume=144 |issue=2 |pages=886–891 |doi=10.1016/j.biocon.2010.12.001 |bibcode=2011BCons.144..886C |issn=0006-3207|url-access=subscription }}</ref> Timber rattlesnakes occupying the same hibernaculum (especially juveniles and pregnant females<ref>{{cite journal |last1=Clark |first1=Rulon W. |last2=Brown |first2=William S. |last3=Stechert |first3=Randy |last4=Greene |first4=Harry W. |title=Cryptic sociality in rattlesnakes (''Crotalus horridus'') detected by kinship analysis |journal=Biology Letters |date=23 August 2012 |volume=8 |issue=4 |pages=523–525 |doi=10.1098/rsbl.2011.1217 |pmid=22357940 |pmc=3391446 |issn=1744-9561}}</ref>) have been reported to be more closely related to each other than to the rattlesnakes in neighboring dens;<ref>{{cite journal |last1=Clark |first1=Rulon W. |title=Kin recognition in rattlesnakes |journal=Proceedings of the Royal Society of London. Series B: Biological Sciences |date=7 May 2004 |volume=271 |issue=Suppl. 4 |pages=S243–S245 |doi=10.1098/rsbl.2004.0162 |pmid=15252996 |pmc=1810029 |url=https://www.researchgate.net/publication/8456518 |access-date=14 February 2024}}</ref> studies have suggested this behavior may be related to juveniles' ability to track chemical cues from relatives.<ref>{{cite journal |last1=Cobb |first1=Vincent A. |last2=Green |first2=J. Jeffrey |last3=Worrall |first3=Timothy |last4=Pruett |first4=Jake |last5=Glorioso |first5=Brad |title=Initial Den Location Behavior in a Litter of Neonate ''Crotalus horridus'' (Timber Rattlesnakes) |journal=Southeastern Naturalist |date=December 2005 |volume=4 |issue=4 |pages=723–730 |doi=10.1656/1528-7092(2005)004[0723:IDLBIA]2.0.CO;2 |s2cid=85611741 |url=https://www.researchgate.net/publication/228501878}}</ref> Timber rattlesnakes have also been found to leave dens multiple times in midwinter to briefly bask.<ref>{{cite journal |last1=Nordberg |first1=Eric J. |last2=Cobb |first2=Vincent A. |title=Midwinter Emergence in Hibernating Timber Rattlesnakes (''Crotalus horridus'') |journal=Journal of Herpetology |date=June 2016 |volume=50 |issue=2 |pages=203–208 |doi=10.1670/14-113 |issn=0022-1511}}</ref>

Males often mate farther away from winter hibernacula than females.<ref>{{Cite journal |last=Anderson |first=Corey Devin |date=2010-02-26 |title=Effects of Movement and Mating Patterns on Gene Flow among Overwintering Hibernacula of the Timber Rattlesnake (''Crotalus horridus'') |journal=Copeia |volume=2010 |issue=1 |pages=54–61 |doi=10.1643/CH-08-121 |s2cid=84279929 |issn=0045-8511}}</ref>

===Reproduction=== [[File:Timber Rattlesnake (Crotalus horridus), Colorado Co., TX, 2016.jpg|thumb|A juvenile from east Texas]] A lifetime reproduction study of a population in the Adirondack Mountains of New York found that the first reproduction occurs at a mean age of 9.6 years. The mean length of reproductive cycles is 4.2 years, the mean reproductive life span is 9.6 years, and the average fecundity is 7.7 offspring per litter. Nonviable offspring were found in 20% of the field litters. Most females only reproduced once in a lifetime. Macrogeographic differences were observed within the population and may have correlated resource levels influencing growth rates and additionally human encounters could influence survival.<ref>{{Cite journal |last=Brown |first=William S. |date=December 2016 |title=Lifetime reproduction in a northern metapopulation of timber rattlesnakes (''Crotalus horridus'') |journal=Herpetologica |volume=72 |issue=4 |pages=331–342 |doi=10.1655/Herpetologica-D-16-00019.1 |s2cid=88757784 |doi-access=free }}</ref>

===Diet=== [[File:TimberRattler W Prey.JPG|thumb|A timber rattlesnake eating a rabbit (''[[Sylvilagus]]'')]] The prey of the timber rattlesnake are mainly small [[mammal]]s, in particular [[mice]], [[rat]]s, [[squirrel]]s, and [[rabbit]]s, but may include small [[bird]]s, [[frog]]s, and other small animals.<ref name="NYSDEC" /><ref name="animaldiversity.org">{{cite web | url=https://animaldiversity.org/accounts/Crotalus_horridus/ | title=Crotalus horridus (Timber rattlesnake (atricaudatus)) | website=[[Animal Diversity Web]] }}</ref> Like most rattlesnakes, timber rattlesnakes are known to use chemical cues to find sites to ambush their prey and often strike their prey and track them until they can be consumed.<ref>Clark RW (2004). "Timber rattlesnakes (''Crotalus horridus'') use chemical cues to select ambush sites". ''Journal of Chemical Ecology'' '''30''' (3): 607–617.</ref><ref name="Reinert, H. K. 1984">Reinert, Howard K. Reinert; Cundall, David; Bushar, Lauretta M. (1984). "Foraging behavior of the timber rattlesnake, ''Crotalus horridus'' ". ''Copeia'' '''1984''': 976–981.</ref> Timber rattlesnakes are known to use fallen logs as a waiting site for prey to pass by, giving them an elevated perch from which to effectively strike their prey, which is almost entirely terrestrial rather than arboreal (even arboreal prey such as squirrels tend to be caught when they come to the ground).<ref name="Reinert, H. K. 1984"/><ref>Platt, Steven G.; Hawkes, Anthony W.; Rainwater, Thomas R. (2001). "Diet of the canebrake rattlesnake (''Crotalus horridus atricaudatus''): An additional record and review". ''Texas Journal of Science'' '''53''' (2): 115–120.</ref> If the arboreal prey (squirrels) are in the trees, it was found that the snake might indicate vertical tree posture, meaning it leans up against a tree looking at the squirrel and waiting for it to come down.<ref>Goetz S.M. et al., 2016.</ref> The primary foods by genera of timber rattlesnakes were as follows: ''[[Peromyscus]]'' (33.3%), ''[[Microtus]]'' (10.9%), ''[[Tamias]]'' (qv) (10.6%), ''[[Sylvilagus]]'' (10.4%), ''[[Sigmodon]]'' (5.3%) and ''[[Sciurus]]'' (4.2%). Based on examination of the snout-to-vent length, juvenile timber rattlesnakes were found to differ slightly in dietary preferences from adult rattlesnakes, being more likely to consume smaller prey such as [[shrew]]s (averaging {{convert|8|g|oz|abbr=on}} and unable to attack subadult [[eastern cottontail]] rabbits (averaging {{convert|500|-|1000|g|lb|abbr=on}} but ''Peromyscus'' was the number one prey item for both young and adult rattlesnakes. Several birds, although always secondary to mammals, are also known to be hunted, mainly ground-dwelling species such as [[Northern bobwhite|bobwhite]]s, but also a surprising number of [[passerine]]s.<ref>Clark RW (2002). '"Diet of the timber rattlesnake, ''Crotalus horridus'' ". ''Journal of Herpetology'' '''36''' (3): 494–499.</ref>

Prey sometimes exhibit anti-snake displays like tail-flagging, but timber rattlesnakes show no immediate or overt response to these displays. There is no rattling, striking, or other defensive behavior in response to prey anti-snake displays.<ref>{{Cite journal |last=Clark |first=Rulon W. |date=2005-12-01 |title=Pursuit-deterrent communication between prey animals and timber rattlesnakes (''Crotalus horridus''): the response of snakes to harassment displays |journal=Behavioral Ecology and Sociobiology |language=en |volume=59 |issue=2 |pages=258–261 |doi=10.1007/s00265-005-0032-9 |bibcode=2005BEcoS..59..258C |s2cid=12089360 |issn=1432-0762}}</ref>

===Venom=== [[File:Timber Rattlesnake (Crotalus horridus) - Flickr - 2ndPeter (1).jpg|thumb|Timber rattlesnake (''Crotalus horridus'') from Missouri]] Potentially, this is one of North America's most dangerous snakes, due to its long fangs, impressive size, and high [[Venomous snake|venom]] yield. This is to some degree offset by its relatively mild disposition<ref name="Nor-C&L04">Norris R (2004). "Venom Poisoning in North American Reptiles". ''In'' Campbell JA, Lamar WW (2004). ''The Venomous Reptiles of the Western Hemisphere''. Ithaca and London: Comstock Publishing Associates. 870 pp., 1,500 plates. {{ISBN|0-8014-4141-2}}.</ref> and long brumation period. Before striking, they often perform a good deal of preliminary rattling and feinting.<ref name="USN91">US Navy (1991). ''Poisonous Snakes of the World''. New York: US Government / Dover Publications Inc. 203 pp. {{ISBN|0-486-26629-X}}.</ref> Cist (1845) described how he lived in western Pennsylvania for many years, and the species was quite common there, but in all that time, he heard of only a single death resulting from its bite.<ref name="W&W57"/>

A timber rattlesnake will always make the effort to retreat from perceived danger before deciding to attack, and if left undisturbed poses nearly no threat to the humans who encounter them. Educating people about the shy and skittish behavior of timber rattlesnakes is an easy way to save lives, as they will only attack if they are cornered. The easiest way to keep oneself safe in areas with known and suspected dens of rattlesnakes is simply to avoid rockshelters they prefer to den in, and especially to not attempt to enter the den, as this is a perfect opportunity for the rattlesnake to act defensively. The remote and wooded habitat of these snakes makes emergency medical care difficult or even impossible with the rapid progression of venom-induced incapacitation, and thus it is critical knowledge for human safety to not disturb the denning rattlesnakes in the rare chance of encountering one unexpectedly.

Considerable geographic and [[Ontogeny|ontogenetic]] variation occurs regarding the toxicity of the venom, which can be said for many rattlesnake species. Four venom patterns have been described for this species: Type A is largely [[Neurotoxin|neurotoxic]], and is found in various parts of the southern range. One effect of the toxin can be generalized [[myokymia]].<ref>{{cite web|url=http://www.medscape.com/viewarticle/487281_5 |title=Snake Venoms and the Neuromuscular Junction: Spontaneous Activity |publisher=Medscape.com |date=2004-08-16 |access-date=2014-07-29}}</ref> Type B is [[Bleeding|hemorrhagic]] and [[Proteolysis|proteolytic]], and is found consistently in the north and in parts of the southeast. Type A + B is found in areas where the aforementioned types apparently intergrade in southwestern [[Arkansas]] and northern [[Louisiana]]. Type C venom has none of the above components and is relatively weak.<ref name="Nor-C&L04"/>

The neurotoxic component of the type A venom is referred to as canebrake toxin, and is a [[Phospholipase A2|phospholipase A2]]. It is analogous to the neurotoxins found in the venoms of several other rattlesnake species, and when present, contributes significantly to the overall toxicity. Other components found in the venom include a small basic [[peptide]] that works as a [[myotoxin]], a [[fibrin]]ogen-clotting [[enzyme]] that can produce [[Disseminated intravascular coagulation|defibrination syndrome]], and a [[bradykinin]]-releasing enzyme.<ref name="Nor-C&L04"/>

[[CroFab]] [[antivenom]], while not specific for ''C. horridus'', is used to treat envenomations from this species.<ref name="MAVIN">{{cite web|url=https://www.toxinfo.org/antivenoms/indication/CROTALUS_HORRIDUS_HORRIDUS.html |title=MAVIN 2013-05-14, ''Crotalus horridus horridus ''|publisher=Toxinfo.org |access-date=2014-07-29}}</ref>

==Symbol== [[File:Gadsden flag.svg|thumb|The Gadsden flag depicting a timber rattlesnake]] The timber rattlesnake was designated the [[state reptile]] of West Virginia in 2008.<ref name="West Virginia">{{cite web | url = http://www.legis.state.wv.us/Bill_Status/Resolution_History.cfm?year=2008&sessiontype=RS&input4=28&billtype=cr&houseorig=s&btype=res | title = Senate concurrent resolution 28 (bill status 2008 regular session) | access-date = February 22, 2011 | publisher = West Virginia Legislature}}</ref> That state's legislature praised "...a proud contribution by the eighth grade class at [[Romney Middle School]], from West Virginia's oldest county, in West Virginia's oldest town, to have been instrumental in making the timber rattlesnake the state reptile..."<ref name="WV resolution">{{cite web|title=Senate concurrent resolution no. 28|url=http://www.legis.state.wv.us/Bill_Status/resolution.cfm?billdoc=scr28%20amended.htm&yr=2008&sesstype=RS&i=28|work=1st session of the 80th legislature|publisher=West Virginia Legislature|access-date=February 25, 2011|year=2008}}</ref>

This snake became a prominent symbol of American anger and resolve during the [[American Revolution]] due to its fearsome reputation. In the 18th century, European-trained doctors and scientists had little firsthand experience with or information on timber rattlesnakes,<ref>[[Bill Bryson|Bryson, Bill]] (2004). ''A Short History of Nearly Everything''. New York: Broadway Books. p. 81.</ref> and treatment of their bites was poorly effective. The motto ''[[Nemo me impune lacessit|Nemo me impune lacesset]]'' (with the verb in the [[future tense]]) appears above a ''Crotalus horridus'' on a 1778 $20 bill from [[Georgia (U.S. state)|Georgia]] as an early example of the colonial use of the coiled rattlesnake symbol, which later became famous on the [[Gadsden flag]], a flag that has been used by advocates of [[Libertarianism in the United States|libertarianism]], [[individualism]], and [[Libertarian conservatism|small government]].<ref>{{Cite web |last=Conversation |first=The |date=2021-01-08 |title=Yellow Gadsden Flag Carries a Long and Shifting History |url=https://www.snopes.com/news/2021/01/08/yellow-gadsden-flag-carries-a-long-and-shifting-history/ |access-date=2023-12-08 |website=Snopes |language=en}}</ref><ref>{{Cite web |title=A Florida license plate has reopened the debate over the 'Don't tread on me' flag |website=[[NPR]] |date=10 August 2022 |url=https://www.npr.org/2022/08/10/1116523396/florida-dont-tread-on-me-license-plate-ron-desantis |last1=Neuman |first1=Scott }}</ref>

==Conservation status== [[File:Timber Rattlesnake (Crotalus horridus) - Flickr - 2ndPeter (2).jpg|thumb|Timber Rattlesnake (''Crotalus horridus'')]] This species is classified as least concern on the [[IUCN Red List]] (assessed in 2007).<ref name=IUCN/> Species are listed as such due to their wide distribution, presumed large population, or because they are unlikely to be declining fast enough to qualify for listing in a more threatened category.<ref name="ICUN-31">{{Redlist CC2001|date=13 September|year=2007}}</ref>

''Crotalus horridus'' has been extirpated from many areas, particularly in the northern part of its range, and is classified as endangered in six states and threatened in five others.<ref>{{Cite journal |last1=Rokyta |first1=Darin R |last2=Wray |first2=Kenneth P |last3=Margres |first3=Mark J |date=2013 |title=The genesis of an exceptionally lethal venom in the timber rattlesnake (Crotalus horridus) revealed through comparative venom-gland transcriptomics |journal=BMC Genomics |language=en |volume=14 |issue=1 |page=394 |doi=10.1186/1471-2164-14-394 |doi-access=free |pmid=23758969 |issn=1471-2164|pmc=3701607 }}</ref> The timber rattlesnake is listed as endangered in New Jersey,<ref>{{Cite web |title=Timber Rattlesnake Conservation |url=https://dep.nj.gov/njfw/conservation/timber-rattlesnake-conservation/ |website=New Jersey Fish and Wildlife}}</ref> Ohio, Vermont, Connecticut, [[Massachusetts]],<ref>{{cite web|url=https://www.mass.gov/info-details/list-of-endangered-threatened-and-special-concern-species#reptiles |title=Massachusetts List of Endangered, Threatened and Special Concern Species |publisher=Mass.gov |access-date=2014-07-29}}</ref> Virginia,<ref>{{Cite web |title=Snakes |url=https://dwr.virginia.gov/wildlife/nuisance/snakes/ |access-date=2024-12-18 |website=dwr.virginia.gov |language=en}}</ref> Indiana,<ref name=312iac>{{citation|author=Indiana Legislative Services Agency|year=2011|title=312 IAC 9-5-4: Endangered species of reptiles and amphibians|work=Indiana Administrative Code|access-date=28 April 2012|url=http://www.in.gov/legislative/iac/}}</ref><ref>{{citation|title=The Timber Rattlesnake (Crotalus horridus) in Brown County State Park|publisher=Indiana Department of Natural Resources|url=https://www.in.gov/dnr/state-parks/files/sp-Timber_brown-RattlesnakesFAQ2.pdf}}</ref> and New Hampshire.<ref>{{Cite web |title=Timber Rattlesnake |url=https://www.wildlife.nh.gov/wildlife-and-habitat/species-occurring-nh/timber-rattlesnake |website=New Hampshire Fish and Game Department}}</ref> The species is listed as threatened in Illinois<ref>{{Cite web |title=timber rattlesnake |url=https://dnr.illinois.gov/education/wildaboutpages/wildaboutsnakes/wasnfamilycrotalidae/wasntimberrattlesnake.html |access-date=2024-12-18 |website=dnr.illinois.gov |language=en}}</ref> and [[New York (state)|New York]]<ref>{{citation |title=Species Status Assessment |year=2013 |url=https://www.dec.ny.gov/docs/wildlife_pdf/sgcntimberrattlesnak.pdf |publisher=New York State Department of Environmental Conservation}}</ref><ref>{{Cite web |title=Timber Rattlesnake - NYSDEC |url=https://dec.ny.gov/nature/animals-fish-plants/timber-rattlesnake |access-date=2024-12-18 |website=dec.ny.gov |language=en}}</ref>

In New York, timber rattlesnakes are "extirpated at 26% of historically known dens, and nearly extirpated at another 5%".<ref>Stechert, in Tyning, 1992.</ref> Brown (1984, 1988) suggested denning populations in New York have been reduced by 50–75% of their historical numbers.

In Massachusetts, the snakes are active from mid-May to mid-October.<ref name="mass.gov">{{cite web |title=Timber Rattlesnake: ''Crotalus horridus '' |url=http://www.mass.gov/eea/docs/dfg/nhesp/species-and-conservation/nhfacts/crotalus-horridus.pdf |website=Massachusetts Division of Fisheries and Wildlife}}</ref> Early settlers were afraid of the snake, as its population was widespread throughout the state. The town of [[Westborough, Massachusetts|Westborough]] paid 13 men two shillings per day to rid a local hill of snakes in 1680. The hill had so many rattlesnakes, it was named "Boston Hill" because the number of snakes killed rivaled the population of the young city of Boston.<ref>{{cite book |author=DeForest, Heman Packard |url=https://books.google.com/books?id=eyQsrKYGoh4C&q=snake&pg=RA1-PA459 |title=The History of Westborough Massachusetts, Part. 1 |year=1891 |pages=31–32 |access-date=October 8, 2021}}</ref> In [[Milford, Massachusetts|Milford]], men would hunt the rattlesnakes between May and early June. According to [[Adin Ballou]], when he arrived in town in 1824, snakes were still abundant, and by 1881 they were still reported in some areas of town.<ref>{{cite web |author=Ballou, Adin |author-link=Adin Ballou |date=1882 |title=History of the town of Milford, Worcester County, Massachusetts, from its first settlement to 1881 |url=https://archive.org/stream/historyoftownofm01ball/historyoftownofm01ball_djvu.txt |access-date=December 31, 2021 |publisher=Boston-Franklin Press: Rand, Avery, & Co. |pages=26–27}}</ref> Since that time their habitat has been reduced to the [[Blue Hills Reservation|Blue Hills]] south of [[Boston]], [[the Berkshires]] in [[Western Massachusetts]], and parts of the [[Connecticut River|Connecticut River Valley]], notably in the area of the [[Holyoke Range]].<ref name="mass.gov" /> The snake is so rare in the state that it is rarely encountered by people and is considered endangered, making it illegal to harass, kill, collect, or possess.<ref>{{cite web |title=Timber Rattlesnake |url=http://www.masnakes.org/snakes/timber_rattle/ |website=Snakes of Massachusetts}}</ref> In September 2021, a five-foot-long timber rattlesnake was recorded on video on a trail in the Blue Hills Reservation.<ref name="WBZ4">{{cite web |date=September 15, 2021 |title=Hiker Spots Rare Five-Foot Timber Rattlesnake In Blue Hills Reservation |url=https://boston.cbslocal.com/2021/09/15/timber-rattlesnake-blue-hills-hiker-video/ |access-date=September 17, 2021 |website=WBZ 4 CBS Boston}}</ref>

Timber rattlesnakes have already been extirpated in Maine and Rhode Island and only one population remains in New Hampshire. They are protected in many of the Appalachian states, but their populations continue to decline.<ref>{{cite web|title=Timber Rattlesnake|url=http://www.oriannesociety.org/timber-rattlesnake|publisher=Orianne Society|access-date=6 August 2015|archive-url=https://archive.today/20151026114451/http://www.oriannesociety.org/timber-rattlesnake|archive-date=26 October 2015}}</ref> While ''C. horridus'' was historically abundant throughout [[New England]], there has been a recent decline in the last known population in New Hampshire that is heading toward extinction because of genetic isolation, inbreeding, and stochastic weather events that render the population susceptible to opportunistic pathogens.<ref name=":1" />

<gallery mode="packed" heights="120px" caption="Closeup of the heads of four ''Crotalus horridus''"> File:Crotalus horridus atricaudatus Genève 24102014 1.jpg|The pit between the eye and nostril is sensitive to infrared radiation for locating prey. File:Crotalus horridus Stanton 1 (cropped).jpg|Frontal view of the head of a melanistic timber rattlesnake from Pennsylvania File:CHorridus (cropped).jpg|A black headed timber rattlesnake from West Virginia File:Canebrake Rattlesnake.jpg|An unusual redheaded canebrake rattlesnake from north Florida </gallery>

==See also== * [[Snakebite]]

==References== {{Reflist|35em|refs= <ref name=NRDB>{{NRDB species |genus=Crotalus |species=horridus |access-date=13 March 2023}}</ref> }}

==Further reading== {{Refbegin}} *Brown, Christopher W.; [[Carl H. Ernst|Ernst, Carl H.]] (1986). "A Study of Variation in Eastern Timber Rattlesnakes, ''Crotalus horridus'' Linnae (Serpentes, Viperidae)". ''Brimleyana'' '''12''': 57–74. *{{cite magazine|title=Hidden Life of the Timber Rattler|first=William S.|last=Brown|magazine=[[National Geographic (magazine)|National Geographic]]|pages=128–138|volume=172|issue=1|date=July 1987|issn=0027-9358|oclc=643483454}} *[[Charles Cist (editor)|Cist C]] (1845). ''The Cincinnati Miscellany or Antiquities of the West''. vol. 1. Cincinnati. 272 pp. *[[Joseph T. Collins|Collins, Joseph T.]]; Knight. James L. (1980). "''Crotalus horridus'' Linnaeus. Timber rattlesnake". ''Catalogue of American Amphibians and Reptiles''. 253.1 – 253.2. *[[Roger Conant (herpetologist)|Conant R]], [[species:William Bridges|Bridges W]] (1939). ''What Snake Is That? A Field Guide to the Snakes of the United States East of the Rocky Mountains''. (with 108 drawings by [[species:Edmond V. Malnate|Edmond Malnate]]). New York and London: D. Appleton-Century Company. Frontispiece map + viii + 163 pp. + Plates A–C, 1–32. (''Crotalus h. horridus'', pp. 149–151 + Plate 31, figures 88A & 89; ''C. h. atricaudatus'', pp. 151–152 + Plate 31, figures 88B & 88C). *[[Howard K. Gloyd|Gloyd HK]] (1936). "The cane-brake rattlesnake". ''Copeia'' '''1935''' (4): 175–178. *Goetz, Scott M.; Petersen, Christopher E.; Rose, Robert K.; Kleopfer, John D.; [[species:Alan H. Savitzky|Savitzky, Alan H.]] (2016). "Diet and Foraging Behavior of Timber Rattlesnakes, ''Crotalus horridus'', in Eastern Virginia". ''Journal of Herpetology'' '''50''' (4): 520–526. https://doi.org/10.1670/15-086. *[[species:Ernest G. Holt|Holt EG]] (1924). "Additional records for the Alabama herpetological catalogue". ''Copeia'' '''1924''': 100–101. *[[species:Brian Hubbs|Hubbs B]], [[species:Brendan O'Connor|O'Connor B]] (2001). ''A Guide to Rattlesnakes and other Venomous Serpents of the United States''. Tempe, Arizona: Tricolor Books. 129 pp. {{ISBN|978-0-9754641-3-7}}. (''Crotalus horridus'', pp. 68–71). *[[Laurence Monroe Klauber|Klauber LM]] (1936). "Key to the rattlesnakes with summary of characteristics". ''Transactions of the San Diego Society of Natural History'' '''8''' (2): 185–176. *Klauber LM (1956). ''Rattlesnakes: Their Habitats, Life Histories, and Influence on Mankind''. 2 volumes. Berkeley: University of California Press. 1,476 pp. *[[Carl Linnaeus|Linnaeus C]] (1758). ''Systema naturæ per regna tria naturæ, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Tomus I. Editio Decima, Reformata'' [Volume I, Tenth Edition, Revised]. Stockholm: L. Salvius. (''Crotalus horridus'', new species, p. 214). (in Latin). *[[species:Clarence John McCoy|McCoy CJ]] (1980). ''Identification Guide to Pennsylvania Snakes''. (Design and illustrations by Michael Antonoplos). Pittsburgh, Pennsylvania: [[Carnegie Museum of Natural History]]. 12 pp. (''Crotalus horridus'', pp. 10–11). *[[species:Percy A. Morris|Morris PA]] (1948). ''Boy's Book of Snakes: How to Recognize and Understand Them''. (A volume of the Humanizing Science Series, edited by [[Jaques Cattell]]). New York: Ronald Press. viii + 185 pp. (''Crotalus h. horridus'', pp. 94–97, 181; ''C. h. atricaudatus'', pp. 98, 181). *[[M. Graham Netting|Netting MG]], [[Neil D. Richmond|Richmond ND]] (editors) (1970). ''Pennsylvania Reptiles and Amphibians''. Third Edition, Fifth Printing. (Photographs by Hal H. Harrison). Harrisburg, Pennsylvania: Pennsylvania Fish Commission. 24 pp. (''Crotalus horridus'', pp. 7–8 + front cover painting by Ned Smith). *Pisani, George R.; Collins, Joseph T.; [[species:Stephen R. Edwards|Edwards, Stephen R.]] (1972). "A re-evaluation of the subspecies of ''Crotalus horridus''{{-"}}. ''Transactions of the Kansas Academy of Science'' '''75''' (3): 255–263. *[[Robert Powell (herpetologist)|Powell R]], [[Roger Conant (herpetologist)|Conant R]], Collins JT (2016). ''Peterson Field Guide to Reptiles and Amphibians of Eastern and Central North America, Fourth Edition''. Boston and New York: Houghton Mifflin Harcourt. xiv + 494 pp., 47 plates, 207 figures. {{ISBN|978-0-544-12997-9}}. (''Crotalus horridus'', pp. 440–441 + Plate 46 + Figure 168 on p. 356). *[[Karl Patterson Schmidt|Schmidt KP]] (1953). ''A Check List of North American Amphibians and Reptiles, Sixth Edition''. Chicago: American Society of Ichthyologists and Herpetologists. 280 pp. *[[Hobart Muir Smith|Smith HM]], [[species:Edmund Darrell Brodie Jr.|Brodie ED Jr]] (1982). ''Reptiles of North America: A Guide to Field Identification''. New York: Golden Press. 240 pp. {{ISBN|0-307-13666-3}} (paperback), {{ISBN|0-307-47009-1}} (hardcover). (''Crotalus horridus'', pp. 206–207). {{Refend}}

==External links== {{Commons category|Crotalus horridus}} * [https://web.archive.org/web/20071230080055/http://www.venomousreptiles.org/articles/345 Account of severe ''C. horridus'' envenomation] at [https://web.archive.org/web/20080409033049/http://www.venomousreptiles.org/ venomousreptiles.org]. Accessed 12 December 2007. * [https://www.kingsnake.com/louisiana/species_canebrake.htm Snakes of Louisiana] at [http://www.kingsnake.com/ Kingsnake.com]. Accessed 7 August 2007. * [https://www.iowaherps.com/species/crotalus_horridus Timber rattlesnake] at Reptiles and Amphibians of Iowa.

[[Category:Crotalus|horridus]] [[Category:Snakes of North America]] [[Category:Reptiles of Canada]] [[Category:Reptiles of the United States]] [[Category:Fauna of the Eastern United States]] [[Category:Symbols of West Virginia]] [[Category:Reptiles described in 1758]] [[Category:Animal taxa named by Carl Linnaeus]] [[Category:Least concern biota of the United States]]