''Crotalus'' is a
genus
Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...
of
venomous
Venom or zootoxin is a type of toxin produced by an animal that is actively delivered through a wound by means of a bite, sting, or similar action. The toxin is delivered through a specially evolved ''venom apparatus'', such as fangs or a sti ...
pit viper
The Crotalinae, commonly known as pit vipers,Mehrtens JM (1987). ''Living Snakes of the World in Color''. New York: Sterling Publishers. 480 pp. . crotaline snakes (from grc, κρόταλον ''krotalon'' castanet), or pit adders, are a subfa ...
s in the
family
Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...
Viperidae
The Viperidae (vipers) are a family of snakes found in most parts of the world, except for Antarctica, Australia, Hawaii, Madagascar, and various other isolated islands. They are venomous and have long (relative to non-vipers), hinged fangs tha ...
, known as
rattlesnake
Rattlesnakes are venomous snakes that form the genera ''Crotalus'' and ''Sistrurus'' of the subfamily Crotalinae (the pit vipers). All rattlesnakes are vipers. Rattlesnakes are predators that live in a wide array of habitats, hunting small anim ...
s or rattlers.
[ Wright AH, Wright AA (1957). ''Handbook of Snakes of the United States and Canada''. Ithaca and London: Comstock Publishing Associates (7th printing, 1985). 1,105 pp. (in 2 volumes). .] The genus is found only in the Americas from southern Canada to northern
Argentina
Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it the second-largest country in South America after Brazil, th ...
,
and member
species
In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...
are colloquially known as rattlesnakes. The
generic
Generic or generics may refer to:
In business
* Generic term, a common name used for a range or class of similar things not protected by trademark
* Generic brand, a brand for a product that does not have an associated brand or trademark, other ...
name ''Crotalus'' is derived from the Greek word ''krótalοn'', which means "rattle" or "castanet", and refers to the rattle on the end of the tail, which makes this group (genera ''Crotalus'' and ''
Sistrurus
:''Common names: ground rattlesnakes, pygmy rattlesnakes, massasaugas'' Wright AH, Wright AA (1957). ''Handbook of Snakes of the United States and Canada''. Ithaca and London: Comstock Publishing Associates, a Division of Cornell University Press ...
'') so distinctive.
[Campbell JA, Lamar WW (2004). ''The Venomous Reptiles of the Western Hemisphere''. Ithaca and London: Comstock Publishing Associates. 870 pp. 1,500 plates. .] Currently, 32
to 45 species are recognized as being valid.
Description
Members of the genus ''Crotalus'' range in size from only (''
C. intermedius'', ''
C. pricei''), to over (
eastern
Eastern may refer to:
Transportation
*China Eastern Airlines, a current Chinese airline based in Shanghai
*Eastern Air, former name of Zambia Skyways
*Eastern Air Lines, a defunct American airline that operated from 1926 to 1991
*Eastern Air Li ...
and
western diamondback rattlesnake
The western diamondback rattlesnake or Texas diamond-backWright AH, Wright AA. (1957). ''Handbook of Snakes''. Comstock Publishing Associates. (7th printing, 1985). . (''Crotalus atrox'') is a rattlesnake species and member of the viper family, ...
s).
In general, adult males are slightly larger than females. Compared to most snakes, they are heavy-bodied, although some African vipers are much thicker.
[ Klauber LM (1997). ''Rattlesnakes: Their Habitats, Life Histories, and Influence on Mankind. Second Edition''. (First published in 1956, 1972). Berkeley: University of California Press. .] Most forms are easily recognized by the characteristic rattle on the end of their tails, although a few island populations form exceptions to this rule: ''
C. catalinensis'' has lost its rattle entirely, ''
Crotalus lorenzoensis
:''Common names: San Lorenzo Island rattlesnake.''
''Crotalus lorenzoensis'' is a species of pitviper, a venomous snake in the subfamily Crotalinae of the family Viperidae. The species is endemic to San Lorenzo Sur Island, Mexico.
Description ...
'' usually has no rattle, and both ''
Crotalus ruber lucasensis
:''Common names: San Lucan diamond rattlesnake.Klauber LM. 1997. Rattlesnakes: Their Habitats, Life Histories, and Influence on Mankind. Second Edition. 2 volumes. Reprint, University of California Press, Berkeley. .''
''Crotalus ruber lucasensi ...
'' and ''
Crotalus estebanensis
''Crotalus estebanensis'', commonly known as the San Esteban Island rattlesnake,Klauber LM. 1997. Rattlesnakes: Their Habitats, Life Histories, and Influence on Mankind. Second Edition. 2 volumes. Reprint, University of California Press, Berkeley ...
'' exhibit a tendency for rattle loss. The rattle may also be lacking in any species due to a congenital abnormality.
The rattle consists of a series of loosely interlocking hollow shells, each of which was at one point the scale covering the tip of the tail. In most other snakes, the tail tip, or terminal spine, is cone-shaped, hardly any thicker than the rest of the skin, and is shed along with it at each successive molt. In this case, however, the end scale, or "button", is much thicker and shaped like a bulb, with one or two annular constrictions to prevent it from falling off. Before each molt, a new button will have developed inside the last one and before the skin is shed off its body, the tip of new button shrinks, then loosening the shell of the previous one. This process continues so the succession of molts produces an appendage consisting of a number of interlocking segments that make an audible noise when vibrated. Since younger specimens may shed several times in a year at a frequency that depends on their environment and how much they eat, every time adding a new segment to the rattle, the number of segments is not just a function of the age of the snake. In theory, the rattle could become very long indeed, but in practice, the older segments tend to wear out and fall off. How quickly this happens depends on the snake's environment, but end segments tend to break off after the rattle becomes about six or seven segments long; finding specimens with as many as a dozen segments is common. In captive specimens, however, as many as 29 segments have been found.
[ Parker HW, Grandison AGC (1977). ''Snakes — a natural history. Second Edition''. London and Ithaca: British Museum (Natural History) and Cornell University Press. 108 pp. 16 plates. LCCCN 76-54625. (cloth), (paper).][Stidworthy J (1974). ''Snakes of the World''. New York: Grosset & Dunlap Inc. 160 pp. .]
Distribution and habitat
The genus ''Crotalus'' is found in the Americas from southern Canada to central Argentina.
Behavior
No species of ''Crotalus'' is considered aggressive; when threatened, most retreat quickly, but most species defend themselves readily when cornered.
There is no consensus in the available literature about how far rattlesnakes can strike, with estimates ranging from one-third to the entire body length of the rattlesnake. Strike distance depends not just on the snake’s size, but also on many other factors, including its species, the position of its body, and its degree of excitement. This is compounded by a further lack of consensus as to the location on the anchor coil of the snake from where a strike should be measured. They rarely strike further than half of their body length, and almost never more than three-fourths, but trusting such values is unwise if only because it is not feasible to accurately judge the length of a coiled snake.
Feeding
The diets of species of ''Crotalus'' generally consist of
vertebrate
Vertebrates () comprise all animal taxa within the subphylum Vertebrata () ( chordates with backbones), including all mammals, birds, reptiles, amphibians, and fish. Vertebrates represent the overwhelming majority of the phylum Chordata, ...
s, although many
invertebrate
Invertebrates are a paraphyletic group of animals that neither possess nor develop a vertebral column (commonly known as a ''backbone'' or ''spine''), derived from the notochord. This is a grouping including all animals apart from the chordate ...
species have also been consumed. Smaller species feed mainly on lizards, while larger species start by feeding on lizards as juveniles and then switch to preying mainly on mammals as adults. Prey items more frequently taken include rabbits, ground squirrels, tree squirrels, chipmunks, prairie dogs, gophers, and rats and mice, while those less frequently taken include birds, snakes, and amphibians.
Cannibalism
Cannibalism is the act of consuming another individual of the same species as food. Cannibalism is a common ecological interaction in the animal kingdom and has been recorded in more than 1,500 species. Human cannibalism is well documented, b ...
has been reported in a number of different species. Individuals that feed on rodents usually release their prey after a strike to avoid their teeth, and these snakes evidently can discriminate between trails left by prey that has or has not been envenomated.
Predators
For all species of ''Crotalus'', the most significant threats come from people, but they also face many natural enemies. These include other snakes, such as
kingsnake
Kingsnakes are Colubridae, colubrid New World members of the genus ''Lampropeltis'', which includes 26 species. Among these, about 45 subspecies are recognized. They are nonvenomous and ophiophagy, ophiophagous in diet.
Description
Kingsnakes ...
s (''Lampropeltis''), coachwhips (''
Masticophis
''Masticophis'' is a genus of colubrid snakes, commonly referred to as whip snakes or coachwhips, which are endemic to the Americas. Conant R (1975). ''A Field Guide to Reptiles and Amphibians of Eastern and Central North America, Second Edition ...
''), indigo snakes (''
Drymarchon
''Drymarchon'' is a genus of large nonvenomous colubrid snakes, commonly known as indigo snakes or cribos, found in the Southeastern United States, Central America, and South America. Reaching or more in length, they are among the world's larges ...
''), and racers (''
Coluber''); birds, such as hawks, eagles, owls, roadrunners, and ravens; and mammals, such as cats, coyotes, foxes, wildcats, badgers, skunks, and pigs. Certain species of birds frequently prey on these snakes, but this is not without risk. Two cases were reported in which dead hawks found near venomous snakes had suffered hemorrhage and gangrenous necrosis due to snakebite.
Reproduction
The genus ''Crotalus'' is
ovoviviparous
Ovoviviparity, ovovivipary, ovivipary, or aplacental viviparity is a term used as a "bridging" form of reproduction between egg-laying oviparous and live-bearing viviparous reproduction. Ovoviviparous animals possess embryos that develop insi ...
, giving birth to live young.
The basic lifecycle of many
Nearctic
The Nearctic realm is one of the eight biogeographic realms constituting the Earth's land surface.
The Nearctic realm covers most of North America, including Greenland, Central Florida, and the highlands of Mexico. The parts of North America t ...
species has been known for quite some time. Females at an age of 26 months undergo
vitellogenesis
Vitellogenesis is the process of yolk protein formation in the oocytes of non mammalian vertebrates during sexual maturation. The term ''vitellogenesis'' comes from the Latin ''vitellus'' ("egg yolk"). Yolk proteins, such as Lipovitellin and Phosv ...
as they enter their third
hibernation
Hibernation is a state of minimal activity and metabolic depression undergone by some animal species. Hibernation is a seasonal heterothermy characterized by low body-temperature, slow breathing and heart-rate, and low metabolic rate. It most ...
, mate the following spring, and give birth later in September or October.
Several variations to this basic cycle occur. In North America, the females of some species store sperm in their oviducts for at least eight months, and the males (all species of which undergo
spermatogenesis
Spermatogenesis is the process by which haploid spermatozoa develop from germ cells in the seminiferous tubules of the testis. This process starts with the mitotic division of the stem cells located close to the basement membrane of the tubule ...
during the summer) store sperm in the
vas deferens
The vas deferens or ductus deferens is part of the male reproductive system of many vertebrates. The ducts transport sperm from the epididymis to the ejaculatory ducts in anticipation of ejaculation. The vas deferens is a partially coiled tube ...
for at least a year. Thus, species that store sperm for a shorter duration mate in the spring and store sperm in the vas deferens, while those that do so for a longer duration mate in the fall and store sperm in the oviduct over the winter, after which fertilization occurs the following spring.
In addition, species that occur further north, where weather is colder during much of the year and the feeding and growing season is short, may reproduce only every other year or less. Those found in central and southern Mexico or the tropics have reproductive cycles that correspond mostly with the rainy season.
Venom
Two main
hemotoxic
Hemotoxins, haemotoxins or hematotoxins are toxins that destroy red blood cells, disrupt blood clotting, and/or cause organ degeneration and generalized tissue damage. The term ''hemotoxin'' is to some degree a misnomer since toxins that damage ...
effects are caused by rattlesnake venom. First, zinc-containing metalloproteases act upon capillary endothelial cells to cause platelet aggregation and hemorrhage.
Second, the platelet antagonist crotalin creates a severe bleeding effect as it binds to the surface proteins, blocking aggregation.
Neurotoxic
Neurotoxicity is a form of toxicity in which a biological, chemical, or physical agent produces an adverse effect on the structure or function of the central and/or peripheral nervous system. It occurs when exposure to a substance – specificall ...
effects may also be caused by rattlesnake venom. These effects vary by species, and within species by population.
Species
''*'') Not including the
nominate subspecies
In biological classification, subspecies is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (morphology), but that can successfully interbreed. Not all species ...
T)
Type species
In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specimen ...
See also
*
Snakebite
A snakebite is an injury caused by the bite of a snake, especially a venomous snake. A common sign of a bite from a venomous snake is the presence of two puncture wounds from the animal's fangs. Sometimes venom injection from the bite may occu ...
References
Further reading
*
*
*
Coues E (1875). "Synopsis of the Reptiles and Batrachians of Arizona; with Critical and Field Notes, and an Extensive Synonymy". pp. 585–633
09 ''In'':
Wheeler GM (1875). ''Report Upon Geographical and Geological Explorations and Surveys West of the One Hundredth Meridian. Volume V. Zoology: Reports Upon the Zoological Collections Obtained from Portions of Nevada, Utah, California, Colorado, New Mexico, and Arizona, During the Years 1871, 1872, 1873, and 1874''. Washington, District of Columbia: United States Government Printing Office.
*
Fitzinger L (1843). ''Systema Reptilium. Fasciculus Primus. Amblyglossae''. Vienna: Braumüller et Seidel. 106 pp. + indices
9 (in Latin).
*
Gloyd HK (1940). "The Rattlesnakes, Genera ''Sistrurus'' and ''Crotalus''. A Study in Zoogeography and Evolution". ''Special Publ. Chicago Acad. Sci.'' (4): 1-266, 10 figures, 31 plates.
*
*
Houttuyn, M (1764). ''Natuurlyke historie of uitvoerige beschryving der dieren, planten en mineraalen, volgens het samenstel van den Heer Linnæus. Met naauwkeurige afbeeldingen. Eerste deels, zesde stuk. Dieren van beiderley leven''. Amsterdam. 558 pp.
90 (in Dutch).
*Hubbs, Brian; O'Connor, Brendan (2012). ''A Guide to the Rattlesnakes and other Venomous Serpents of the United States''. Tempe, Arizona: Tricolor Books. 129 pp. .
*
*
*
*Klauber LM (1971). "Classification, distribution and biology of the venomous snakes of northern Mexico, the United States and Canada: ''Crotalus'' and ''Sistrurus'' ". pp. 115–156. ''In'': Bucherl W, Buckley E (1971). ''Venomous animals and their venoms, vol. 2. Venomous vertebrates''. New York: Academic Press.
*Klauber LM (1972). ''Rattlesnakes: Their habits, Life Histories, and Influence on Mankind''. Second edition. 2 Volumes. Berkeley, California: University of California Press.
*
Laurenti JN (1768). ''Specimen medicum, exhibens synopsin reptilium emendatum cum experimentis circa venena et antidota reptilium austriacorum''. Vienna: Joan. Thom. Nob. de Trattern. 214 pp. + Plates I-V
2 (in Latin).
*
Linnaeus C (1758). ''Systema naturae per regna tria naturae secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Tomus I. Editio Decima, Reformata''
Tenth Revised Edition, Volume 1
Tenth may refer to:
Numbers
* 10th, the ordinal form of the number ten
* One tenth, , or 0.1, a fraction, one part of a unit divided equally into ten parts.
** the SI prefix deci-
** tithe, a one-tenth part of something
* 1/10 of any unit of me ...
Stockholm. 824 pp.
14 (in Latin).
*
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.
38+ Plates 1-47. .
*
Rafinesque CS (1815). ''Analyse de la nature ou tableau de l'univers et des corps organisés''. Palermo: Jean Barravecchia. 224 pp. (Herpetology section) pp. 73–78
7 (in French).
*Rafinesque CS (1820). "Annals of Nature, or Annual Synopsys of New Genera and Species of Animals and Plants Discovered in North America". ''Lexington'' (22): 1-16
*Reuss T (1930). "''Glasnik Zemaljskog Muzeja u Bosni I Hercegovini'' ". ''Sveska za Prirodne Nauke'' 42: 57-114
0, 88 (in Bosnian).
*
Schmidt KP, Davis DD (1941). ''Field Book of Snakes of the United States and Canada''. New York: G.P. Putnam's Sons. 365 pp.
90-293
9 (nine) is the natural number following and preceding .
Evolution of the Arabic digit
In the beginning, various Indians wrote a digit 9 similar in shape to the modern closing question mark without the bottom dot. The Kshatrapa, Andhra and ...
*
Wagler J (1830). ''Natürliches system der amphibien, mit vorangehender classification der Säugthiere und Vögel. Ein Beitrag zur vergleichenden Zoologie''. Munich, Stuttgart and Tübingen: J.G. Cotta. vi + 354 pp. + one plate
76 (in German and Latin).
{{Authority control
Snake genera
Taxa named by Carl Linnaeus