Timber rattlesnake Article

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Timber rattlesnake
Canebrake rattlesnake (4531335952).jpg
At Jacksonville Zoo and Gardens
Scientific classification edit
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Squamata
Suborder: Serpentes
Family: Viperidae
Genus: Crotalus
C. horridus
Binomial name
Crotalus horridus
Crotalus horridus distribution.png
Synonyms [2]
  • Crotalus horridus
    Linnaeus, 1758
  • Crotalus boiquira
    Lacépède, 1789
  • Crotalus atricaudatus
    Latreille, 1801
    In Sonnini & Latreille, 1801
  • Crotalus zetazomae
    Brickell, 1805
  • Crotalinus cyanurus
    Rafinesque, 1818
  • Crotalus catesbaei
    Hemprich, 1820
  • Crotalurus cyanurus
    — Rafinesque, 1820
  • Caudisona horrida
    — Fleming, 1822
  • Crotalus horidus [sic]
    Gray, 1825
    (ex errore)
  • Crotalus durissus var. concolor
    Jan, 1859
  • Crotalus durissus var. melanurus
    Jan, 1859
  • Crotalus durissus var. mexicana
    Jan, 1863
  • Crotalus fasciatus
    Higgins, 1873
  • Crotalus horridus var. atricaudatus
    Garman, 1884
  • Crotalus horridus
    Boulenger, 1896
  • Crotalus durissus cincolor [sic]
    Notestein, 1905
    (ex errore)
  • Crotalus horridus horridus
    Gloyd, 1935
  • Crotalus horridus atricaudatus
    — Gloyd, 1935
  • Crotalus horridus
    Collins & Knight, 1980
Adult Crotalus horridus, Florida
Juvenile Crotalus horridus, Florida

The timber rattlesnake, canebrake rattlesnake or banded rattlesnake (Crotalus horridus), [3] is a species of venomous pit viper endemic to the eastern United States. This is the only rattlesnake species in most of the populous northeastern United States and is second only to the related prairie rattlesnake as the most northerly distributed venomous snake in North America. [4] [5] No subspecies are currently recognized. [6]


The subspecies C. h. atricaudatus ( Latreille in Sonnini and Latreille, 1802), often referred to as the canebrake rattlesnake, [3] is currently considered invalid. [7] Previously, it was recognized by Gloyd (1936) also Klauber (1936). Based on an analysis of geographic variation, Pisani et al. (1972) concluded no species 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 state it is not possible to tell them apart without having more information than usual, 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. [8]


Adults usually grow to total length of 92–152 cm (36–60 in). [4] In Pennsylvania, the smallest female that could produce viable young was found to be 72.2 cm (28.4 in). [9] Most adult timber rattlesnakes found measure less than 100 to 115 cm (39 to 45 in) in total length and weigh typically between 500 and 1,500 g (1.1 and 3.3 lb), often being towards the lower end of that weight range. [10] [11] [12] [13] The maximum reported total length is 189.2 cm (74.5 in). [14] Holt (1924) mentions a large specimen caught in Montgomery County, Alabama, which had a total length of 159 cm (62.5 in) and weighed 2.5 kg (5.5 lb). [8] Large specimens can reportedly weigh as much as 4.5 kg (9.9 lb). [15]

The dorsal scales are keeled [16] 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 higher than it is wide. In the internasal-prefrontal area, four to 22 scales are seen, including two 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, only a single canthal scale is present. Five to seven intersupraocular scales are noted. 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 reveals. [8]

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. [17] Melanism is common, and some individuals are very dark, almost solid black. [18]

Distribution and habitat

Found in the eastern United States from southern Minnesota and southern New Hampshire, south to East Texas and north Florida, [19] 115 rattlesnakes have been marked within Brown County State Park in Indiana, one of the only places where they can be found in the state. [20]

Its historic range includes southern Ontario and southern Quebec in Canada, [2] but in May 2001, the Canadian Species at Risk Act listed it as extirpated in Canada. [21] A Canadian government-sponsored recovery strategy is currently under study to support the reintroducing of this predator of many pests to its former Canadian habitat.

Although several experts disagree, many were found 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.[ citation needed]

In Pennsylvania, it is not found west of Chestnut Ridge, which is in the Laurel Highlands, nor is it found in the southeastern corner of the state. Thus, its range does not include the areas of Philadelphia and Pittsburgh, the two largest cities in Pennsylvania. [4]

C. horridus is extirpated in Maine and Rhode Island and is almost extirpated in New Hampshire.

In Massachusetts, the snakes are active from mid-May to mid-October. [22] Early settlers were afraid of the snake, as its population was widespread throughout the state. 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. [22] 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. [23]

Generally, this species is found in deciduous forests in rugged terrain. During the summer, gravid (pregnant) 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. [24]


Female timber rattlers often bask in the sun before giving birth, in open rocky areas known as "basking knolls". [25] During the winter, timber rattlesnakes brumate in dens, in limestone crevices, often together with copperheads and black rat snakes. [18] As with all snakes, they are ectothermic. As with most rattlesnakes females give birth to live young and typically this happens during the fall in private dens located in rocky fields; the family stays together until spring. In warmer weather timber rattlesnakes prefer to seek sunlight on rocky ridges or stone strewn areas to recharge themselves for the day ahead and seek prey in the underbrush. Though they do not enjoy it in particular, they are excellent swimmers and they undulate their bodies, moving similar to a crocodile in water but with their rattles easily seen sticking out of the water. They can and will take to water readily if they desire food, new territory, or a mate; like the larger eastern diamondback with which they share the Southern half of their range they have been recorded slithering on the beach and jumping into the surf for to swim in the sea, diving under the waves until the water is sound enough to carry them. [26]


Their prey is mainly small mammals, but may include small birds, frogs, bird eggs, and other small animals, including other snakes or the occasional house rat if they can find one. Although capable of consuming other rattlesnakes, the most common snake they prey upon are garter snakes. [24] 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. [27] [28] Timber rattlesnakes are known to use fallen logs or abandoned stone walls 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 tends to be caught when they come to the ground). [28] [29] 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 8 g (0.28 oz) and unable to attack subadult eastern cottontail rabbits (typically 500–1,000 g (1.1–2.2 lb), 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. [30]

Danger to Humans and Pets

Potentially, this is one of North America's most dangerous snakes, due to its long fangs, impressive size, and high venom yield. The snake is most deadly to adult males who become overconfident in their abilities or have imbibed too much alcohol and have badly impaired their judgment, according to 1997 statistics from one hospital in the USA. [31] Children must be taught to recognize this snake and mind where they step in rock strewn areas; they must be told to never touch or disturb it for any reason and slowly back away from it, since it takes less time for the venom to circulate through their bloodstream if bitten. Dogs should be taken to the veterinarian right away should a timber rattlesnake bite them as they are also susceptible to all types of rattlesnake venom.

However, despite all this, they have a very meek disposition and shall strike only if molested or frightened. [32] They have a long brumation period because their natural habitat is too cold for large portions of the year and thus they require rocky dens to stay warm in. Temperamentally, they are not like their kin West of the Mississippi River in the sense that those rattlesnakes do not have the luxury of having many places to hide except for burrows or dry sparse vegetation. Cousins to the timber rattlesnake like the Western diamondback have to be more aggressive to survive and have to stand their ground more often to avoid getting stepped on or eaten by raptors. A timber rattlesnake, by contrast, will sit there still, silent, hopeful it has not been seen, and have many options in terms of places to hide, up to and even including lakes and rivers to dive in. They prefer to flee rather than fight and are terrified of anything bigger than they are since they think that the bigger animal, man included, will try to eat them. If a timber rattlesnake knows it has been seen, it often performs a good deal of preliminary rattling and feinting before striking. [33]Even where abundant they are not easy to locate as they are extremely shy. 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. [3]


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. [34] 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. [32]

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. [32]

CroFab antivenom, while not specific for C. horridus, is used to treat envenomations from this species. [35] It is effective.


The timber rattlesnake was designated the state reptile of West Virginia in 2008. [36] 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..." [37]

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, [38] and treatment of their bites was poorly effective. The motto Nemo me impune lacesset (with the verb in the future tense) appears above a C. 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.

Conservation status

This species is classified as least concern on the IUCN Red List (assessed in 2007). [1] 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. [39]

The timber rattlesnake is listed as endangered in New Jersey, Vermont, Massachusetts [40] (along with the copperhead viper), Virginia, New Hampshire, Indiana, [41] and Ohio, and it is threatened in New York, Connecticut, Illinois, Minnesota, and Texas.[ citation needed]

Timber rattlesnakes have already been extirpated in Maine, Rhode Island, and Ontario and only one population remains in New Hampshire. They are protected in many of the Appalachian states, but their populations continue to decline. [42]

See also


  1. ^ a b "The IUCN Red List of Threatened Species". IUCN Red List of Threatened Species. Retrieved 2018-10-27.
  2. ^ a b McDiarmid RW, Campbell JA, Touré T (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).
  3. ^ a b c Wright AH, Wright AA (1957). Handbook of Snakes of the United States and Canada. Ithaca and London: Comstock Publishing Associates. (7th printing, 1985). ISBN  0-8014-0463-0. (Crotalus horridus, pp. 956–966).
  4. ^ a b c 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. Boston. ISBN  0-395-19979-4. (Crotalus horridus, pp. 233–235 + Plate 35 + Map 178).
  5. ^ Brown WS (1991). "Female reproductive ecology in a northern population of the timber rattlesnake, Crotalus horridus ". Herpetologica 47 (1): 101-115.
  6. ^ "Crotalus horridus ". Integrated Taxonomic Information System. Retrieved 8 February 2007.
  7. ^ "Crotalus horridus atricaudatus ". Integrated Taxonomic Information System. Retrieved 27 September 2006.
  8. ^ a b c Campbell JA, Lamar WW (2004). The Venomous Reptiles of the Western Hemisphere (2 volumes). Comstock Publishing Associates. ISBN  0-8014-4141-2.CS1 maint: Uses authors parameter ( link)[ page needed]
  9. ^ Galligan JH, Dunson WA (1979) "Biology and status of timber rattlesnake (Crotalus horridus) populations in Pennsylvania". Biological Conservation 15 (1): 13-58.
  10. ^ Timber Rattlesnake (Crotalus horridus). Tpwd.state.tx.us. Retrieved on 2013-01-05.
  11. ^ Fitch HS, Pisani GR, Greene HW (2004). "A FIELD STUDY OF THE TIMBER RATTLESNAKE lN LEAVENWORTH COUNTY, KANSAS". Journal of Kansas Herpetology (1): 18.
  12. ^ Brown WS, Kéry M, Hines JE (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.
  13. ^ Clark RW (2006). "Fixed videography to study predation behavior of an ambush foraging snake, Crotalus horridus ". Copeia 2006 (2): 181-187.
  14. ^ (Klauber, 1956).
  15. ^ ANIMAL BYTES – Canebrake Rattlesnake. Seaworld.org. Retrieved on 2013-01-05.
  16. ^ Behler JL, King FW (1979). The Audubon Society Field Guide to North American Reptiles and Amphibians. New York: Alfred A. Knopf. 743 pp. ISBN  0-394-50824-6.CS1 maint: Uses authors parameter ( link) (Crotalus horridus, pp. 688-689 + Plates 619, 620, 653.)
  17. ^ 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).
  18. ^ a b 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).
  19. ^ Conant, Roger; Collins, Joseph T. (1998). Reptiles and Amphibians of Eastern/Central North America. New York: Houghton Mifflin. ISBN  0-395-90452-8
  20. ^ "The Timber Rattlesnake (Crotalus horridus) in Brown County State Park" (PDF). Indiana Department of Natural Resources. Retrieved August 8, 2017.
  21. ^ Crotalus horridus at Species at Risk Public Registry. Accessed 23 June 2008.
  22. ^ a b "Timber Rattlesnake: Crotalus Horridus " (PDF). Massachusetts Division of Fisheries and Wildlife.
  23. ^ "Timber Rattlesnake". Snakes of Massachusetts.
  24. ^ a b Timber Rattlesnake Fact Sheet at NY State Dept. of Environmental Conservation. Accessed 8 February 2007.
  25. ^ Furman, Jon (2007). Timber rattlesnakes in Vermont and New York: biology, history, and the fate of an endangered species. UPNE. p. 133. ISBN  978-1-58465-656-2.
  26. ^ "Here's another thing to worry about in the ocean: This huge rattlesnake". newsobserver. Retrieved 2019-01-26.
  27. ^ Clark RW (2004). "Timber rattlesnakes (Crotalus horridus) use chemical cues to select ambush sites". Journal of Chemical Ecology 30 (3): 607-617.
  28. ^ a b Reinert HK, Cundall D, Bushar LM (1984). "Foraging behavior of the timber rattlesnake, Crotalus horridus ". Copeia 1984 (4): 976-981.
  29. ^ Platt SG, Hawkes AW, Rainwater TR (2001). '"Diet of the canebrake rattlesnake (Crotalus horridus atricaudatus): An additional record and review". Texas Journal of Science 53 (2): 115-120.
  30. ^ Clark RW (2002). "Diet of the timber rattlesnake, Crotalus horridus ". Journal of Herpetology 36 (3): 494-499.
  31. ^ "Hubris & the Serpent: The Truth About Rattlesnake Bite Victims". Territory Supply. 2017-12-24. Retrieved 2019-01-26.
  32. ^ a b c 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.
  33. ^ United States Navy (1991). Poisonous Snakes of the World. New York: United States Government / Dover Publications Inc. 203 pp. ISBN  0-486-26629-X.
  34. ^ "Snake Venoms and the Neuromuscular Junction: Spontaneous Activity". Medscape.com. 2004-08-16. Retrieved 2014-07-29.
  35. ^ "MAVIN 2013-05-14, Crotalus horridus horridus ". Toxinfo.org. Retrieved 2014-07-29.
  36. ^ "Senate concurrent resolution 28 (bill status 2008 regular session)". West Virginia Legislature. Retrieved February 22, 2011.
  37. ^ "Senate concurrent resolution no. 28". 1st session of the 80th legislature. West Virginia Legislature. 2008. Retrieved February 25, 2011.
  38. ^ Bryson, Bill (2004). A Short History of Nearly Everything. New York: Broadway Books. p. 81.
  39. ^ 2001 Categories & Criteria (version 3.1) at the IUCN Red List. Accessed 13 September 2007.
  40. ^ "Massachusetts List of Endangered, Threatened and Special Concern Speci". Mass.gov. Retrieved 2014-07-29.
  41. ^ Indiana Legislative Services Agency (2011), "312 IAC 9-5-4: Endangered species of reptiles and amphibians", Indiana Administrative Code, retrieved 28 April 2012
  42. ^ "Timber Rattlesnake". Orianne Society. Archived from the original on 26 October 2015. Retrieved 6 August 2015.

Further reading

  • Brown CW, Ernst CH (1986). "A study of variation in eastern timber rattlesnakes, Crotalus horridus Linnae (Serpentes, Viperidae)". Brimleyana 12: 57–74.
  • Brown, William S. (July 1987). "Hidden Life of the Timber Rattler". National Geographic. Vol. 172 no. 1. pp. 128–138. ISSN  0027-9358. OCLC  643483454.
  • Cist C (1845). The Cincinnati Miscellany or Antiquities of the West. vol. 1. Cincinnati. 272 pp.
  • Collins JT, Knight JL (1980). "Crotalus horridus Linnaeus. Timber rattlesnake". Catalogue of American Amphibians and Reptiles. 253.1 – 253.2.
  • Conant, Roger; Bridges, William (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. 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.
  • Holt EG (1924). "Additional records for the Alabama herpetological catalogue". Copeia 1924 (136): 100–101.
  • Klauber LM (1936). "Key to the rattlesnakes with summary of characteristics". Trans. San Diego Soc. Nat. Hist. 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, diferentiis, synonymis, locis. Editio Decima, Reformata [Tenth Edition, Revised]. Stockholm: L. Salvius. 824 pp. (Crotalus horridus, new species, p. 214).
  • Morris, Percy A. (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).
  • Pisani GR, Collins JT, Edwards SR (1972). "A re-evaluation of the subspecies of Crotalus horridus ". Trans. Kansas Acad. Sci. 75: 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).
  • Zim HS, Smith HM (1956). Reptiles and Amphibians: A Guide to Familiar American Species: A Golden Nature Guide. New York: Simon and Schuster. 160 pp. (Crotalus horridus, pp. 111-112, 156).

External links