HARMLESSLY VENOMOUS. Uses its venom to subdue prey, but is not dangerous to humans because a) they have an ineffective venom delivery mechanism, b) their mouths too small to gain purchase, and/or c) their venom is not adapted for causing physiological damage to mammals.
The Chihuahuan Nightsnake is characterized by smooth scales, a divided anal scale, and eyes that close to vertical slits when exposed to strong light. The latter character is present also in venomous snakes in Kansas, but unlike the Chihuahuan Nightsnake, they have a pit located between and slightly below the eye and nostril on each side of the head. The body and tail of this snake are gray or grayish yellow with 50- 70 dark brown blotches on the back. The head is gray or brown and the neck has three elongate large brown blotches. The sides of the body have 2- 3 rows of smaller brown spots which alternate with the blotches on the back. External sexual differences are not known.
Adults normally grow 360-410 mm (14-16 inches) in total length. The largest specimen from Kansas is a female (KU 193259) from Clark County with total length of 412 mm (163⁄16 inches) collected by John Tollefson, Martin Capron, and Chris Stammler on 29 May 1983. The maximum length throughout the range is 581 mm (227⁄8 inches) (Boundy, 1995; Powell et al., 2016).
Rundquist (2002) reported that specimens captured in his study ranged from 161-334 mm snout-vent length. Adult males (n=13; 201-285 mm snout-vent length; 33-61 mm total length; 4.5-15.0 g) were not as long or as heavy as adult females (n=13; 203-355 mm snout-vent length; 29-54 total length; 11.0-25.0 g), but had longer tail lengths.
Known from two isolated populations in the Red Hills, and is conspicuously absent from Meade and southeastern Seward counties.
This small snake is known from two disjunct populations in Kansas as follows: 1) northern Clark County in the vicinity of Clark State Fishing Lake and environs to the immediate south; and along outcroppings of the Dog Creek and Blaine formations in southeastern Comanche County, and western Barber County. Records from northwestern Oklahoma and southeastern Colorado indicate that this species may ultimately be found elsewhere in Kanas along the Cimarron River.
Hibbard (1937) found three specimens during mid-June in Clark County beneath rocks on southeast-facing hillside slopes and along a canyon rim.
Ray E. Ashton (pers. comm., 1974; Collins, 1993) found a single specimen in Barber County on 21 October under a small rock on the north-facing slope of a hill. The site was 200 yards from a stream, and air temperature exceeded 70°F. Collins (1982) found a specimen of this snake beneath a rock on a canyon slope in Comanche County on 11 May. Miller (1983) discovered a Chihuahuan Nightsnake and a Collared Lizard beneath the same flat rock along the rim of a canyon in Comanche County on 14 June. Miller (1987) found four of these snakes, two each from Comanche and Clark counties; they were taken, often after rainfall, inside the cracks of large gypsum rocks or beneath flat rocks between 3 May and 7 June at air temperatures of about 80°F.
Hibbard (1937) found four eggs in a female Chihuahuan Nightsnake from Clark County. Nothing is known of the breeding cycle of this species in Kansas. Presumably, mating occurs shortly after emergence from winter inactivity. Females probably produce one clutch of two to six eggs per summer. The eggs hatch within two months. Fitch (1970) suggested that this species may have a lengthy breeding season. Rundquist (2002) observed ovulating females as early as 13 May and found male-female pairs under cover objects between 1 May and 26 May but did not observe copulation. A male/female pair (MHP 8260/8261) was found by Travis W. Taggart and Curtis J. Schmidt on 7 April 2004 in central Barber County. Gravid individuals were discovered between 25 May and 9 June that contained 3-5 eggs (Collins, 1993).
The Chihuahuan Nightsnake feeds principally on small lizards. Miller (1987) reported this snake eating a Plains Black-headed Snake in Clark County. Rundquist (2002) found the following prey items in the gastrointestinal tracks of preserved specimens he examined: Aspidoscelis sexlineata, Sceloporus consobrinus, Phrynosoma cornutum, Plestiodon sp (obsoletus or obtusirostris), and Rena dissecta. Rundquist (2002) observed that this species was capable of immobilizing an Aspidoscelis sexlineata within 15 seconds of being bitten.
There are no predation records on the Chihuahuan Nightsnake in Kansas, though they are probably taken by larger mammals, birds, snakes, and arthropods.
First reported from Kansas by Brumwell (1936) in a set of privately printed maps. The first widely-published notice of this species from the state is by Hibbard (1937) based on specimens collected on the Stevenson Ranch (2 miles above Clark State Fishing Lake) in north-central Clark County. Two specimens were collected on 12 June 1936 (Claude W. Hibbard) and the other on 14 June 1936 (Joseph Tiehen). These are the earliest existing specimens known from Kansas.
Miller (1987) summarized the available information and added anecdotal distributional records and natural history information. Rundquist (2002) summarized all known information regarding the natural history and population status of this taxon in the state. Additionally, Rundquist (2002) contributed substantial new information on this seldom seen and little-known species. These data and his recommendations led to the down-listing of this species, from the state Threatened species list.
While this taxon is known from relatively few unique localities and actual observations, its rarity is undoubtedly more perceived than actual. The Kansas populations of Chihuahuan Nightsnakes have probably changed little over the past 50 years.
Based on a captive specimen, Snider and Bowler (1992) reported a maximum longevity for this species of nine years and three months.
References
Dugès, Alfredo. 1865. Du Liophis janii. Academie des Sciences et Lettres de Montpellier. Memoires de la Section des Sciences. 6:32–33.
Ortenburger, Arthur I. 1928. The whip snakes and racers: Genera Masticophis and Coluber. Memiors of the University of Michigan Museum (1):1-247.
Brumwell, Malcolm J. 1936. Distributional records of the reptilia and amphibians of Kansas. Privately printed. 22 pp.
Hibbard, Claude W. 1937. Hypsiglena ochrorhynchus in Kansas and additional notes on Leptotyphlops dulcis. Copeia 1937(1):74.
Ditmars, Raymond L. 1939. A Field Book of North American Snakes. Doubleday, Doran and Company, New York.
Schmidt, Karl Peterson and D. D. Davis. 1941. Field Book of Snakes of the United States and Canada. C.P. Putnam and Sons, New York. 365 pp.
Davenport, J. W. 1943. Field Book of the Snakes of Bexar County, Texas and Vicinity. Witte Memorial Museum, San Antonio, Texas.
Tanner, Wilmer W. 1944. A taxonomic study of the genus Hypsiglena. Great Basin Naturalist 5(3-4):25-92.
Smith, Hobart M. 1950. Handbook of Amphibians and Reptiles of Kansas. University of Kansas, Museum of Natural History, Miscellaneous Publication (2):336.
Schmidt, Karl P. 1953. A Check List of North American Amphibians and Reptiles. 6th Edition. University of Chicago Press, Chicago, Illinois. 280 pp.
Tanner, Wilmer W. 1954. Additional note on the genus Hypsiglena with a description of a new subspecies. Herpetologica 10:54-56.
Smith, Hobart M. 1956. Handbook of Amphibians and Reptiles of Kansas. Second edition. University of Kansas Museum of Natural History Miscellaneous Publication (9):1-356.
Loomis, Richard B. 1956. The chigger mites of Kansas (Acarina, Trombiculidae). University of Kansas Science Bulletin 37:1195-1443.
Conant, Roger. 1958. A Field Guide to Reptiles and Amphibians of Eastern North America. Houghton Mifflin Co, Boston.
Collins, H. H. 1959. Complete Field Guide to American Wildlife. Harper and Brothers, New York.
Cochran, Doris M. and Colman J. Goin. 1970. The New Field Book of Reptiles and Amphibians. Putnam's Sons, New York.
Fitch, Henry S. 1970. Reproductive cycles in lizards and snakes. University of Kansas Museum of Natural History Miscellaneous Publication (52):1-247.
Collins, Joseph T. 1974. Amphibians and Reptiles in Kansas. University of Kansas Museum of Natural History Public Education Series (1):283 pp.
Platt, Dwight R., Joseph T. Collins, and Ray E. Ashton, Jr. 1974. Rare, endangered and extirpated species in Kansas. II. Amphibians and reptiles. Transactions of the Kansas Academy of Science 76(3):185-192.
Conant, Roger. 1975. A Field Guide to Reptiles and Amphibians of Eastern and Central North America. Houghton Mifflin Co, Boston.
Rundquist, Eric M. 1976. Field checklist (of) amphibians and reptiles of Kansas. Kansas Herpetological Society, Lawrence.
Ashton, Ray E., Jr., Stephen R. Edwards, and George R. Pisani. 1976. Endangered and threatened amphibians and reptiles in the United States. Herpetological Circulars (5):65.
Perry, Janice. 1977. Kansas herps needed. Kansas Herpetological Society Newsletter (18):2-3.
Grow, David. 1977. Clark County visited by the Society. Kansas Herpetological Society Newsletter (19):1-2.
Clarke, Robert F. 1980. Snakes in Kansas. Kansas School Naturalist 26(3):1-15.
Jenner, Janann. 1981. A zoogeographic study of the taxonomy of the Xenodontine Colubrid snakes. Dissertation. New York University, New York, New York. 354 pp.
Collins, Joseph T. 1982. Amphibians and Reptiles in Kansas. 2nd edition. University of Kansas Museum of Natural History Public Education Series (8).
Ballinger, Royce E. and John D. Lynch. 1983. How to Know the Amphibians and Reptiles. Wm. C. Brown,, Dubuque, Iowa.
Secor, Stephen M. and Charles C. Carpenter. 1984. Distribution maps of Oklahoma reptiles. Oklahoma Herpetological Society Special Publication (3):1-57.
Collins, Joseph T. 1984. New records of fishes, amphibians, and reptiles in Kansas for 1983. Kansas Herpetological Society Newsletter (56):15-26.
Collins, Joseph T. (Editor). 1985. Natural Kansas. University Press of Kansas, Lawrence.
Layher, William G., Ken L. Brunson, J.Schaefer, Marvin D. Schwilling, and R. D. Wood. 1986. Summary of nongame task force actions relative to developing three species lists: Species in Need of Conservation, Threatened, and Endangered. Kansas Fish and Game Commission, Pratt. 27 pp.
Miller, Larry L. 1987. An investigation of four rare snakes in south-central Kansas. Final Report. Kansas Wildlife and Parks Commission, Pratt. 24 pp.
Busby, William H. 1988. The Kansas Natural Heritage Program: Taking stock of Kansas' natural heritage. Kansas Herpetological Society Newsletter (71):9-12.
Simmons, John E. 1989. Endangered and threatened in Kansas. Kansas Herpetological Society Newsletter (75):4-5.
Lardie, Richard L. 1990. Kansas threatened species and protection of the Gypsum Hills habitat. Kansas Herpetological Society Newsletter (80):14-15.
Collins, Joseph T. 1990. Maximum size records for Kansas amphibians and reptiles. Kansas Herpetological Society Newsletter (81):13-17.
Conant, Roger and Joseph T. Collins. 1991. Peterson Field Guide to Reptiles and Amphibians of Eastern and Central North America. 3rd ed. Houghton Mifflin Company, Boston, Massachusetts.
Ball, Robert L. 1992. High plains serpents: Results of a long-term study in Texas County, Oklahoma and Morton County, Kansas. Kansas Herpetological Society Newsletter (88):16-17.
Rundquist, Eric M. 1992. Results of the KHS 1992 fall field trip. Kansas Herpetological Society Newsletter (90):4.
Collins, Joseph T. and Suzanne L. Collins. 1993. Amphibians and Reptiles in Kansas. Third Edition. University Press of Kansas, Lawrence, Lawrence. 397 pp.
Collins, Joseph T. and Rundquist, Eric M. 1993. Results of the fifth Kansas herp count held during April-June 1993 . Kansas Herpetological Society Newsletter (94):7-11.
Fitch, Henry S. 1993. Relative abundance of snakes in Kansas. Transactions of the Kansas Academy of Science 96(3/4):213-224.
Rundquist, Eric M. 1994. Results of the sixth annual KHS herp counts held 1 April-31 May 1994. Kansas Herpetological Society Newsletter (97):5-14.
Collins, Joseph T., Suzanne L. Collins, Jerry Horak, Daniel Mulhern, William H. Busby, Craig C. Freeman, and G. Wallace. 1995. An Illustrated Guide to Endangered or Threatened Species in Kansas. University Press of Kansas, Lawrence.
Rundquist, Eric M. 1996. Results of the eighth annual KHS herp counts Held 1 April-31 May 1996. Kansas Herpetological Society Newsletter (104):6-17.
Rakestraw, J. 1996. Spring herp counts: A Kansas tradition. Reptile & Amphibian Magazine (March-April):75-80.
Rundquist, Eric M. 1997. Results of the ninth annual KHS herp counts held 1 April-31 May 1997. Kansas Herpetological Society Newsletter (108):12-17.
Rundquist, Eric M. 1997. KHS Spring Field Trips. Kansas Herpetological Society Newsletter (108):3.
Conant, Roger and Joseph T. Collins. 1998. Peterson Field Guide to Reptiles and Amphibians of Eastern and Central North America. 3rd ed, expanded. Houghton Mifflin Company, Boston, Massachusetts.
Powell, Robert, Joseph T Collins, and Errol D Hooper Jr. 1998. A Key to Amphibians & Reptiles of the Continental United States and Canada. Univ Press of Kansas, Lawrence, Kansas. 131 pp.
Rundquist, Eric M. 1999. Kansas Herpetological Society herp counts: A 10 year summary and evaluation. Kansas Herpetological Society Newsletter (115):42962.
Bartlett, Richard D. and Alan Tennant. 2000. Snakes of North America: Western Region.
. Gulf Publishing Company, Houston, Texas.
Rundquist, Eric M. 2000. 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.
Rundquist, Eric M. 2001. Results of the thirteenth annual KHS herp counts for 2001, held 1 April-30 June. Kansas Herpetological Society Newsletter (125):13-16.
Kingsbury, Bruce and Joanna Gibson. 2002. Habitat Management Guidelines for Amphibians and Reptiles of the Midwest. Publication of Partners in Amphibian and Reptile Conservation, Address not given. 152 pp.
Rundquist, Eric M. 2002. A collection of communications from Eric M. Rundquist in reference to the herpetofauna of the Alexander Ranch, Barber County, Kansas, 1991-2002 and including a summary of observations on the "Nightsnake", Hypsiglena torquata. Kansas Department of Wildlife and Parks, Pratt. 20 pp.
Rundquist, Eric M. 2002. Natural history of the Night Snake, Hypsiglena torquata, in Kansas. Journal of Kansas Herpetology (4):16-20.
Ernst, Carl H. and E. M. Ernst. 2003. Snakes of the United States and Canada. Smithsonian Institution Press, Washington, D. C. 668 pp.
Brunson, Ken. 2005. Kansas species in need of conservation (SINC). Kansas Department of Wildlife and Parks, Pratt, Kansas. 71 pp.
Bartlett, Richard D. and Patricia P. Bartlett. 2006. Guide and Reference to the Snakes of Eastern and Central North America (North of Mexico). University Press of Florida, Gainesville.
Collins, Joseph T. and Suzanne L. Collins. 2006. A Pocket Guide to Kansas Snakes. 1st ed. Great Plains Nature Center, Wichita, Kansas.
Taggart, Travis W. 2006. Distribution and status of Kansas herpetofauna in need of information. State Wildlife Grant T7. Kansas Department of Wildlife and Parks, Pratt. vii + 106 pp.
Mulcahy, Daniel G. 2008. Phylogeography and species boundaries of the western North American Nightsnake (Hypsiglena torquata): Revisiting the subspecies concept. Molecular Phylogenetics and Evolution 46:1095-1115.
Weaver, Robert E. 2008. Distribution, abundance, and habitat associations of the Night Snake (Hypsiglena torquata) in Washington State. Northwestern Naturalist 89(3):164-170.
Collins, Joseph T. and Suzanne L. Collins. 2009. A Pocket Guide to Kansas Snakes. 2nd ed. Great Plains Nature Center, Wichita, Kansas.
Collins, Joseph T., Suzanne L. Collins, and Travis W. Taggart. 2010. Amphibians, Reptiles, and Turtles of Kansas. Eagle Mountain Publishing., Provo, Utah. 400 pp.
Mulcahy, Daniel G.,Thomas H. Beckstead, and Jack W. Sites. 2011. Molecular systematics of the Leptodeirini (Colubroidea: Dipsadidae) revisited: Species-tree analyses and multi-locus data. Copeia 2011(3):407-417.
Rohweder, Megan R. 2012. Spatial conservation prioritization of Kansas for terrestrial vertebrates. Thesis. Fort Hays State University, Hays, Kansas. 151 pp.
Powell, Robert, Joseph T Collins, and Errol D Hooper Jr. 2012. Key to the Herpetofauna of the Continental United States and Canada: Second Edition, Revised and Updated. Univ Press of Kansas, Lawrence, Kansas. 152 pp.
Taggart, Travis W. 2014. Results of the 2014 KHS Spring Field Trip to Barber County. Collinsorum 3(2-4):11.
Taggart, Travis W. 2014. Recent scientific and standard English name changes effecting the Kansas herpetofauna. Collinsorum 3(2-4):9-10.
Rohweder, Megan R. 2015. Kansas Wildlife Action Plan. Ecological Services Section, Kansas Department of Wildlife, Parks and Tourism in cooperation with the Kansas Biological Survey. 176 pp.
Powell, Robert, Roger Conant, and Joseph T. Collins. 2016. Peterson Field Guide to Reptiles and Amphibians of Eastern and Central North America. Houghton Mifflin Harcourt, Boston. 494 pp.
Taggart, Travis W. 2016. Spring 2016 KHS field trip to Clark County was a soggy success. Collinsorum 5(2-3):2-3.
Taggart, Travis W. 2016. Results of the KHS ‘Fall’ field trip to Barber County. Collinsorum 5(2-3):6-7.
Myers, Edward A., Michael J. Hickerson, and Frank T. Burbrink. 2016. Asynchronous diversification of snakes in the North American warm deserts. Journal of Biogeography 44(2):1-14.
Lee, Justin L., Adrian Thompson, and Daniel G. Mulcahy. 2016. Relationships between numbers of vertebrae, scale counts, and body size, with implications for taxonomy in Nightsnakes (Genus: Hypsiglena). Journal of Herpetology 50(4):616-620.
Crother, Brian I. (editor). 2017. Scientific and Standard English Names of Amphibians and Reptiles of North America North of Mexico, with Comments Regarding Confidence in Our Understanding. Eighth edition. Herpetological Circulars (43):1-102.
Taggart, Travis W. 2017. Herp Count: Clark County State Lake. Collinsorum 6(2-3):9.
Powell, Robert, Joseph T Collins, and Errol D Hooper Jr. 2019. Key to the Herpetofauna of the Continental United States and Canada. Third Edition. Univ Press of Kansas, Lawrence, Kansas. 192 pp.
Myers, Eward A. and Daniel G. Mulcahy. 2020. Six additional mitochondrial genomes for North American nightsnakes (Dipsadidae: Hypsiglena) and a novel gene feature for advanced snakes. Mitochondrial DNA Part B Resources 5(3):3056-3058.
Riedle, J. Daren. 2020. Revisiting Kansas Herpetological Society field trip and Herp Count data:
Distributional patterns and trend data of Kansas amphibians and reptiles. Collinsorum 9(1):7-16.
Russell, Elisabeth. 2023. Habitat associations and fine-scale movements of the Red-spotted Toad (Anaxyrus punctatus) in Kansas and the efficacy of remote telemetry for monitoring small-scale movements. Thesis. Fort Hays State University, Hays, Kansas. 81 pp.