REPTILIA (Reptiles) SERPENTES (Snakes) CROTALIDAE (Pit Vipers)

WESTERN DIAMOND-BACKED RATTLESNAKE
Crotalus atrox Baird & Girard 1853
krō-tă-ləs — ā-trŏx


Conservation Status:

State: None

Federal: None
NatureServe State: SNA - Not Applicable
NatureServe National: N5 - Secure
NatureServe Global: G5 - Secure
CITES: None

An adult Western Diamond-backed Rattlesnake from Ellsworth County. Image by Kassie Sheridan.
An adult Western Diamond-backed Rattlesnake from Ellsworth County, Kansas. Image © Rachel Roth.
An adult Western Diamond-backed Rattlesnake from Ellsworth County, Kansas. © Travis W. Taggart.
An adult Western Diamond-backed Rattlesnake observed in southern Barber County. © Keith Yearout, 2019.
An adult from Kanopolis State Park, Ellsworth, Co. Image © Suzanne L. Collins, CNAH.
An adult Western Diamond-backed Rattlesnake from Ellsworth County, Kansas. © Travis W. Taggart.
An adult Western Diamond-backed Rattlesnake from Ellsworth County, Kansas. Image © Lyndzee Rhine.

Description:
DANGEROUSLY VENOMOUS (a threat to life or limb): This large snake can be a brown, yellowish gray, pale blue-gray, or a pinkish ground color. The diamond shapes blotches down the length of its body are darker with pale white/cream edges. The tail is cream/white with well-defined contrasting jet-black rings. The head markings include a pale oblique band from nostril to upper labials and a similar but narrower band behind the eye.

Distribution:
Native populations approach Kansas just south of Comanche and Barber counties. In 2019 an adult was documented in southwest Barber County and several specimens have been recorded 3-8 miles to the south. It is likely a natural transient, if not established. Western Diamond-backed Rattlesnakes inhabit dry, rocky, shrub-covered terrain where they can conceal themselves inside rock crevices or mammal burrows. They should be expected among the gypsum deposits (Blaine Formation [Phanerozoic | Paleozoic | Permian]) in southeastern Kiowa, western Barber, and eastern Comanche counties.
The only known extant 'population' of these large serpents was introduced in the vicinity of Kanopolis State Park in Ellsworth County, where they have been found regularly since 1995.
(,   Museum Voucher) (,   Observation) (,   Literature Record) (,   iNat Record)
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  • Occurrence Summary:  
  • 35
    Records 
  • 17
    Museum Vouchers 
  • 18
    Other Observations 
Some county occurrences indicated below may be too imprecise to map above.
County Breakdown: County Name (# occurrences):
Barber (1); Cherokee (1); Comanche (1); Cowley (2); Crawford (1); Ellsworth (26); Kiowa (1); Lyon (1); Montgomery (1);

Natural History:
The Western Diamond-backed Rattlesnake reaches sexual maturity at three years of age. They mate in the spring following emergence from brumation. During courtship male rapidly flicks his tongue, and crawls in jerks on top of the female, which is passive.
Following copulation, the gestation period lasts for 5-6 months. Ten to 20 young are born in August and September. The young soon scatter in search of food and potential winter refuge.

Occurrence Activity:
White dates indicate there is at least a single recorded occurrence on that date. The darker blue a date is, the greater the relative number of observations for that date.
Remarks:
The status of this introduced taxon in Kansas has been discussed by Hall and Smith (1947), Smith (1950, 1956), Collins (1974, 1982, 1993), Fitch (1984), Riedel (1995, 1996), Rundquist (2000), Matlack and Rehmeier (2002), and Hutto and Taggart (2016).
This large rattlesnake is well-documented in Woods and Alfalfa counties in Oklahoma, just across from Barber and Comanche counties in Kansas. Suitable habitat for the Western Diamond-backed Rattlesnake does exist in southeastern Kiowa, western Barber, and eastern Comanche counties in Kansas. Reports of individuals are known from within 10 miles (Webb, 1970) and 0.75 miles (Hall and Smith, 1947) of Kansas in Woods County, Oklahoma. A juvenile was discovered three miles south of the Barber, Comanche, Woods county line in 2020 (Meg and Travis Taggart pers comm.)
There are three independent documented reports of Western Diamond-backed Rattlesnakes recently; in Kiowa (2016), Barber (2019), and Comanche (2021) counties.
All other reported occurrences (Cowley, Lyon, Cherokee, and Crawford counties) are considered releases or waifs.
Since 1991, at least 21 different specimens of this taxon have been observed and/or collected in the Horsethief/Buffalo Tracks Canyon area at Kanopolis State Park in Ellsworth County. This is almost certainly an introduced population (not relictual); there is no evidence that it is reproducing, however if not, the presence of 2-year old size classes would indicate that illegal releases may be ongoing.
Ongoing phylogeographic studies may shed light on the origin(s) of the population, and mark-recapture studies are needed to determine if the population is reproducing on its own. However, it may be unwise to rerelease any snakes captured for this purpose.
At least one individual has been bitten by a Western Diamond-backed Rattlesnake from the Kanopolis State Park population (Runduist, 1999), however, the bite occurred in a controlled laboratory setting at the University of Kansas, and not in the Park.
On 14 and 25 October 2017, two Western Diamond-backed Rattlesnakes were discovered near Coffeyville. Subsequent investigations revealed they had escaped from a resident's garage (Dufoe, 2017).

Bibliography:
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1853 Baird, Spencer F. and Charles Girard. Catalogue of North American Reptiles in the Museum of the Smithsonian Institution. Part 1. Serpents. Smithsonian Miscellaneous Collections 2(5):xvi + 172
Contains the original descriptions of Crotalus atrox, Lampropeltis gentilis, Pantherophis emoryi, Rhinocheilus lecontei, Tantilla gracilis, Regina grahamii, Thamnophis elegans, Thamnophis marcianus, Thamnophis radix, and Virginia valeriae.
1947 Hall, Henry H. and Hobart M. Smith Selected records of reptiles and amphibians from southeastern Kansas Transactions of the Kansas Academy of Science 49(4):447-454
Report on certain Kansas specimens housed in the collection at what is now Pittsburg State University. Included are several species of dubious status today, including Cryptobranchus alleganiensis from the Neosho and Spring rivers (the only specimens from those significant drainages ever documented), Ambystoma maculatum from just north of Pittsburg, Crawford County, Heterodon nasicus from Crawford County, Opheodrys vernalis from Crawford County, Sonora episcopa from Crawford County, Agkistrodon piscivorus from Cherokee County, Crotalus atrox from Crawford County, and Crotalus viridis from Crawford County. They report several significant range extensions including Kinosternon flavescens from Turkey Creek in southeast Cherokee County, Graptemys geographica from just north of Pittsburg, Crotaphytus collaris from near Columbus, Cherokee County, Sceloporus consobrinus from just north of Pittsburg, Phrynosoma cornutum from Cherokee and Crawford counties, Heterodon platirhinos from Cherokee and Crawford counties, Haldea striatula from Crawford County, Sistrurus tergeminus from Crawford County, and a 402 lb Macrochelys temminckii in Cherokee County from just east of Chetopa (Labette County). They allude to the potential for Anaxyrus fowleri to occur in southeast Kansas and for native populations of Crotalus atrox in south central Kansas (in part from the disclosure that John R. Breukelman [then of ESU] had obtained three specimens in Woods County Oklahoma, 3/4 of a mile south of the Kansas line). None of the specimens the paper was based on, exist today.
1950 Smith, Hobart M. Handbook of Amphibians and Reptiles of Kansas. University of Kansas, Museum of Natural History, Miscellaneous Publication (2):336
The first modern herpetology of Kansas. Includes locality dot maps within individual species accounts. Reports 96 species from Kansas (table and text say 97 on p. 10) and 13 "probable but unverified" species and subspecies.
1956 Smith, Hobart M. Handbook of Amphibians and Reptiles of Kansas. Second edition. University of Kansas Museum of Natural History Miscellaneous Publication (9):1-356
Hobart M. Smith's updated second edition of his first (1950) modern herpetology of Kansas. Includes locality dot maps within individual species accounts. Reports 96 species from Kansas (table says 97 on p. 10; text says 98 on p. 10) and 11 "probable but unverified" species and subspecies. The second edition has updated taxonomy, added Plestiodon laticeps, and removed Eurycea tynerensis.
1959 Prophet, Carl W. An outline for conservation teaching in Kansas. Kansas School Naturalist 5(3):16
1974 Collins, Joseph T. Amphibians and Reptiles in Kansas University of Kansas Museum of Natural History Public Education Series (1):283 pp
Joseph T. Collins first Kansas herpetology. <Need to get species total and principal differences with previous 'version' (= Smith 1956)>
1974 Perry, Janice. KHS members take trip to southwest Kansas. Kansas Herpetological Society Newsletter (3):2-3
Account of a search for Crotalus atrox and other species discovered in Comanche County.
1974 Platt, Dwight R., Joseph T. Collins, and Ray E. Ashton, Jr. Rare, endangered and extirpated species in Kansas. II. Amphibians and reptiles. Transactions of the Kansas Academy of Science 76(3):185-192
The initial initiative to determine population and conservation status of Kansas' amphibians and reptiles based on our understanding at the time. A lot has changed regarding our increased knowledge on all the listed species.
1976 Ashton, Ray E., Jr., Stephen R. Edwards, and George R. Pisani. Endangered and threatened amphibians and reptiles in the United States. Herpetological Circulars (5):65
1978 Capron, Marty. Four county collecting raid: A south central Kansas herping saga. Kansas Herpetological Society Newsletter (26):9-12
1978 Harris, Herbert S. and Robert S. Simmons. A preliminary account of the rattlesnakes with descriptions of four new subspecies. Bulletin of the Maryland Herpetological Society 14():105-211
1979 Gray, Peter and Eddie Stegall. A field trip to the Red Hills. Kansas Herpetological Society Newsletter (29):6-8
1982 Collins, Joseph T. Amphibians and Reptiles in Kansas. 2nd edition. University of Kansas Museum of Natural History Public Education Series (8):
Joseph T. Collins second Kansas herpetology. <Need to get species total and principal differences with previous 'version' (= Collins 1974)>
1985 Capron, Marty. A western diamondback rattlesnake released in Sumner County, Kansas. Kansas Herpetological Society Newsletter (59):5-6
Report on a specimen of Crotalus atrox discovered near Belle Plain, Sumner County, Kansas.
1985 Capron, Marty. Thunder snakes, blow vipers, and others. Kansas Herpetological Society Newsletter (60):9-10
1990 Lardie, Richard L. Kansas threatened species and protection of the Gypsum Hills habitat. Kansas Herpetological Society Newsletter (80):14-15
1991 Conant, Roger and Joseph T. Collins. Peterson Field Guide to Reptiles and Amphibians of Eastern and Central North America. 3rd ed. Houghton Mifflin Company, Boston, Massachusetts. pp.
1993 Collins, Joseph T. and Suzanne L. Collins. Amphibians and Reptiles in Kansas. Third Edition. University Press of Kansas, Lawrence, Lawrence. 397pp.
Joseph T. Collins third Kansas herpetology. <Need to get species total and principal differences with previous 'version' (= Collins 1982)>
1993 Fitch, Henry S. and George R. Pisani. Life history traits of the Western Diamondback Rattlesnake (Crotalus atrox) studied from roundup samples in Oklahoma. Occasional Papers of the Museum of Natural History, The University of Kansas (156):1-24
1995 Riedle, J. Daren. A report on the occurrence of the Western Diamondback Rattlesnake Crotalus atrox in Kansas Kansas Department of Wildlife and Parks, Pratt. 7pp.
1995 Rundquist, Eric M. Editor's note. Kansas Herpetological Society Newsletter (102):3
1996 Miller, Larry L. Results of the KHS 1995 fall field trip. Kansas Herpetological Society Newsletter (103):3
1996 Riedle, J. Daren. Some Occurrences of the Western Diamondback Rattlesnake (Crotalus atrox) in Kansas Kansas Herpetological Society Newsletter (105):18-19
1997 Mosher, Tom. Another Western Diamondback Rattlesnake in Kansas. Kansas Herpetological Society Newsletter (108):19
Report of a large Crotalus atrox found recently hit on a road in northern Lyon County.
1998 Conant, Roger and Joseph T. Collins. Peterson Field Guide to Reptiles and Amphibians of Eastern and Central North America. 3rd ed, expanded. Houghton Mifflin Company, Boston, Massachusetts. pp.
1999 Rundquist, Eric M. KHS Business, Editor's Note. Kansas Herpetological Society Newsletter (116):3
First reported bite on a human from a Western Diamond-backed Rattlesnake collected in Kansas.
1999 Rundquist, Eric M. KHS spring field trip. Kansas Herpetological Society Newsletter (116):3
2000 Fitch, Henry S. Population structure and biomass of some common snakes in central North America. Scientific Papers of the Natural History Museum University of Kansas (17):1-7
2000 Rundquist, Eric M. Results of the eleventh and twelfth annual KHS herpetofaunal counts for 1999-2000, held 1 April-31 May. Kansas Herpetological Society Newsletter (122):11-16
2002 Kingsbury, Bruce and Joanna Gibson. Habitat Management Guidelines for Amphibians and Reptiles of the Midwest. Publication of Partners in Amphibian and Reptile Conservation, Address not given. 152pp.
2002 Matlack, Raymond S. and Ryan L. Rehmeier. Status of the Western Diamondback Rattlesnake (Crotalus atrox) in Kansas Southwestern Naturalist 47(2):312-313
2003 Taggart, Travis W. Dangerous Diamondbacks in Kansas. Journal of Kansas Herpetology (8):18
2006 Taggart, Travis W. Distribution and status of Kansas herpetofauna in need of information. State Wildlife Grant T7. Kansas Department of Wildlife and Parks, Pratt. vii + 106pp.
2010 Collins, Joseph T., Suzanne L. Collins, and Travis W. Taggart. Amphibians, Reptiles, and Turtles of Kansas Eagle Mountain Publishing., Provo, Utah. 400pp.
Joseph T. Collins fourth Kansas herpetology. <Need to get species total and principal differences with previous 'version' (= Collins 1993)>
2016 Powell, Robert, Roger Conant, and Joseph T. Collins. Peterson Field Guide to Reptiles and Amphibians of Eastern and Central North America. Houghton Mifflin Harcourt, Boston. 494pp.
2017 Hutto, Paxson and Travis W. Taggart Recent sightings of the Western Diamond-backed Rattlesnake at Kanopolis State Park, Ellsworth County, Kansas. Collinsorum 6(1):13
2017 Taggart, Travis W. The KHS Fall Field Trip to be held at Kanopolis State Park. Collinsorum 6(2-3):3
2017 Dufoe, Jennifer. Rattlesnake discovered in Coffeyville area. Coffeyville Journal 129(86):2,3
Report of an escaped 63" Western Diamond-backed Rattlesnake discovered at a residence near the Coffeyville Animal Shelter, in Coffeyville, Montgomery County.
2021 Holding, Matthew L., Jason L. Strickland, Rhett M. Rautsaw, Erich P. Hofmann, Andrew J. Mason, Michael P. Hogan, Gunnar S. Nystrom, Schyler A. Ellsworth, Timothy J. Colston, Miguel Borja, Gamaliel Castaneda-Gaytan, Christoph I. Grunwald , Jason M. Jones, Luciana A. Freitas-de-Sousa, Vincent Louis Viala, Mark J. Margres, Erika Hingst-Zaher, Inacio L. M. Junqueira-de-Azevedo, Ana M. Moura-da-Silvaf, Felipe G. Grazziotin, H. Lisle Gibbs, Darin R. Rokyta, and Christopher L. Parkinson. Phylogenetically diverse diets favor more complex venoms in North American pitvipers. Proceedings of the Academy of Natural Sciences of the United States of America. 118(17):10
Account Last Updated:
12/16/2021 9:42:56 AM