Timber rattlesnake

The timber rattlesnake was one of the many reptile species originally described by Carl Linnaeus in the landmark 1758 10th edition of his Systema Naturae, and still bears its original name Crotalus horridus.{{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= 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}}

The subspecies C. h. atricaudatus (Latreille in Sonnini and Latreille, 1802), often referred to as the canebrake rattlesnake, is currently considered invalid.{{ITIS|id=174307|taxon=Crotalus horridus atricaudatus |access-date=13 March 2023}} Previously, it was recognized by Gloyd (1936) and Klauber (1936). Based on an analysis of geographic variation, Pisani et al. (1972) concluded no subspecies should be recognized. This was rejected by 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 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.

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. {{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 |pages=373 |doi=10.22621/cfn.v130i4.1936 |doi-access=free }}

Adults usually grow to total length of {{convert|91|–|152|cm|in|round=0.5|abbr=on}}. In Pennsylvania, the smallest size females that could produce viable eggs was {{convert|72.2|cm|in|abbr=on}}.Galligan, John H.; Dunson, William A. (1979). "Biology and status of timber rattlesnake (Crotalus horridus) populations in Pennsylvania". Biological Conservation 15 (1): 13–58. 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.[http://www.tpwd.state.tx.us/huntwild/wild/species/timberrattlesnake/ Timber Rattlesnake (Crotalus horridus)]. Tpwd.state.tx.us. Retrieved on 2013-01-05.Fitch, Henry S.; Pisani, George R.; Greene, Harry W.; Echelle, Alice F.; Zerwekh Michael (2004). "A field study of the timber rattlesnake in Leavenworth County, Kansas". Journal of Kansas Herpetology 11: 18-24.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.Clark, Rulon W. (2006). "Fixed Videography to Study Predation Behavior of an Ambush Foraging Snake, Crotalus horridus ". Copeia 2006 (2): 181–187. 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}}.{{cite book |author=Campbell JA |author-link=Jonathan A. Campbell |author2=Lamar WW|title=The Venomous Reptiles of the Western Hemisphere (2 volumes)|publisher=Comstock Publishing Associates|year=2004|isbn=0-8014-4141-2}} {{Page needed|date=May 2011}} Large specimens can reportedly weigh as much as {{convert|4.5|kg|lb|abbr=on}}.[http://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.

The dorsal scales are keeled{{cite book |author=Behler JL |author2=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.) 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).

File:C. Horridus.jpg, showing strongly keeled dorsal scales]]

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 and internasal scales, only a single canthal scale is present. Five to seven intersupraocular scales are seen. The number of prefoveal scales varies between two and eight. Usually, the first supralabial scale is in broad contact with the prenasal scale, although slightly to moderately separated along its posteroventral margin by the most anterior prefoveals.

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.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). Melanism is common, and some individuals are very dark, almost solid black.Schmidt KP, 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). The tails of C. horridus are black and can be described as 'velvety.'{{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}}

Timber rattlesnakes are present in the eastern United States from southern Minnesota and southern New Hampshire, south to East Texas and North Florida.Conant R, Collins JT (1998). Reptiles and Amphibians of Eastern/Central North America. New York: Houghton Mifflin. {{ISBN|0-395-90452-8}} 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.{{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}}

Its historic range includes southern Ontario and southern Quebec in Canada, but in May 2001, the Canadian Species at Risk Act listed it as extirpated in Canada.[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. A Canadian government sponsored recovery strategy is under study to support the reintroducing of this predator of many pests to its former Canadian habitat.{{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}}

Many were present in some of the thick forest areas of central and southeastern Iowa, mostly within the Mississippi, Skunk, 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, along Credit Island Park, in southern Scott County, and in the forested areas of southern 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, 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.

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 forests in rugged terrain. C. horridus can be found in a variety of terrestrial habitats including lowland cane thickets (thus the common name canebrake rattlesnake), high areas around swamps and river floodplains, hardwood and pine forests, mountainous areas, and rural habitats in farming areas. During the summer, gravid females seem to prefer open, rocky ledges where the temperatures are higher, while males and nongravid females tend to spend more time in cooler, denser woodland with more closed forest canopy.[http://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.

Female timber rattlers often bask in the sun before giving birth, in open rocky areas known as "basking knolls".{{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}}

During the winter, timber rattlesnakes brumate in dens and limestone crevices, often together with copperheads (Agkistrodon contortrix) and rat snakes (Pantherophis alleghaniensis, P. obsoletus, and P. spiloides). 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.{{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 }} Timber rattlesnakes occupying the same hibernaculum (especially juveniles and pregnant females{{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}}) have been reported to be more closely related to each other than to the rattlesnakes in neighboring dens;{{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}} studies have suggested this behavior may be related to juveniles’ ability to track chemical cues from relatives.{{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}} Timber rattlesnakes have also been found to leave dens multiple times in midwinter to briefly bask.{{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 |url=https://doi.org/10.1670/14-113 |issn=0022-1511|url-access=subscription }}

Males often mate farther away from winter hibernacula than females.{{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) |url=https://doi.org/10.1643/CH-08-121 |journal=Copeia |volume=2010 |issue=1 |pages=54–61 |doi=10.1643/CH-08-121 |s2cid=84279929 |issn=0045-8511|url-access=subscription }}

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. Macrogeographic differences were observed within the population and may have correlated resource levels influencing growth rates and additionally human encounters could influence survival.{{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 }}

The prey of the timber rattlesnake are mainly small mammals, in particular mice, rats, squirrels, and rabbits, but may include small birds, frogs, and other small animals.{{cite web | url=https://animaldiversity.org/accounts/Crotalus_horridus/ | title=Crotalus horridus (Timber rattlesnake (atricaudatus)) | website=Animal Diversity Web }} 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.Clark RW (2004). "Timber rattlesnakes (Crotalus horridus) use chemical cues to select ambush sites". Journal of Chemical Ecology 30 (3): 607–617.Reinert, Howard K. Reinert; Cundall, David; Bushar, Lauretta M. (1984). "Foraging behavior of the timber rattlesnake, Crotalus horridus ". Copeia 1984: 976–981. 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).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. 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.Goetz S.M. et al., 2016. 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 shrews (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 bobwhites, but also a surprising number of passerines.Clark RW (2002). '"Diet of the timber rattlesnake, Crotalus horridus ". Journal of Herpetology 36 (3): 494–499.

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.{{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 |url=https://doi.org/10.1007/s00265-005-0032-9 |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|url-access=subscription }}

Potentially, this is one of North America's most dangerous snakes, due to its long fangs, impressive size, and high venom yield. This is to some degree offset by its relatively mild dispositionNorris 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}}. and long brumation period. Before striking, they often perform a good deal of preliminary rattling and feinting.US Navy (1991). Poisonous Snakes of the World. New York: US Government / Dover Publications Inc. 203 pp. {{ISBN|0-486-26629-X}}. 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.

Considerable geographic and 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 neurotoxic, and is found in various parts of the southern range. One effect of the toxin can be generalized myokymia.{{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}} Type B is hemorrhagic and 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.

The neurotoxic component of the type A venom is referred to as canebrake toxin, and is a 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 fibrinogen-clotting enzyme that can produce defibrination syndrome, and a bradykinin-releasing enzyme.

CroFab antivenom, while not specific for C. horridus, is used to treat envenomations from this species.{{cite web|url=http://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}}

File:Gadsden flag.svg

The timber rattlesnake was designated the state reptile of West Virginia in 2008.{{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}} 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..."{{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}}

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,Bryson, Bill (2004). A Short History of Nearly Everything. New York: Broadway Books. p. 81. and treatment of their bites was poorly effective. The motto Nemo me impune lacesset (with the verb in the future tense) appears above a Crotalus horridus on a 1778 $20 bill from 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, individualism, and small government.{{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}}{{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 }}

This species is classified as least concern on the IUCN Red List (assessed in 2007). 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.{{Redlist CC2001|date=13 September|year=2007}}

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.{{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 |pages=394 |doi=10.1186/1471-2164-14-394 |doi-access=free |pmid=23758969 |issn=1471-2164|pmc=3701607 }} The timber rattlesnake is listed as endangered in New Jersey,{{Cite web |title=Timber Rattlesnake Conservation |url=https://dep.nj.gov/njfw/conservation/timber-rattlesnake-conservation/ |website=New Jersey Fish and Wildlife}} Ohio, Vermont, Connecticut, Massachusetts,{{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}} Virginia,{{Cite web |title=Snakes |url=https://dwr.virginia.gov/wildlife/nuisance/snakes/ |access-date=2024-12-18 |website=dwr.virginia.gov |language=en}} Indiana,{{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/}}{{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}} and New Hampshire.{{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}} The species is listed as threatened in Illinois{{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}} and New York{{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}}{{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}}

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

In Massachusetts, the snakes are active from mid-May to mid-October.{{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}} Early settlers were afraid of the snake, as its population was widespread throughout the state. The town of 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.{{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}} In 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.{{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}} Since that time their habitat has been reduced to the Blue Hills south of Boston, the Berkshires in Western Massachusetts, and parts of the Connecticut River Valley, notably in the area of the Holyoke Range. 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.{{cite web |title=Timber Rattlesnake |url=http://www.masnakes.org/snakes/timber_rattle/ |website=Snakes of Massachusetts}} In September 2021, a five-foot long timber rattlesnake was recorded on video on a trail in the Blue Hills Reservation.{{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}}

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.{{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|url-status=dead}} 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.

• Snakebite

{{Reflist|35em|refs=

{{NRDB species |genus=Crotalus |species=horridus |access-date=13 March 2023}}

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• Brown, Christopher W.; 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|pages=128–138|volume=172|issue=1|date=July 1987|issn=0027-9358|oclc=643483454}}
• Cist C (1845). The Cincinnati Miscellany or Antiquities of the West. vol. 1. Cincinnati. 272 pp.
• Collins, Joseph T.; Knight. James L. (1980). "Crotalus horridus Linnaeus. Timber rattlesnake". Catalogue of American Amphibians and Reptiles. 253.1 – 253.2.
• Conant R, 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 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).
• Gloyd HK (1936). "The cane-brake rattlesnake". Copeia 1935 (4): 175–178.
• Goetz, Scott M.; Petersen, Christopher E.; Rose, Robert K.; Kleopfer, John D.; 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.
• Holt EG (1924). "Additional records for the Alabama herpetological catalogue". Copeia 1924: 100–101.
• Hubbs B, 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).
• 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.
• 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).
• 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).
• 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).
• Netting MG, 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.; Edwards, Stephen R. (1972). "A re-evaluation of the subspecies of Crotalus horridus{{-"}}. Transactions of the Kansas Academy of Science 75 (3): 255–263.
• Powell R, 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).
• Schmidt KP (1953). A Check List of North American Amphibians and Reptiles, Sixth Edition. Chicago: American Society of Ichthyologists and Herpetologists. 280 pp.
• Smith HM, 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).

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{{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.
• [http://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.

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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:Taxa named by Carl Linnaeus