An adult Chihuahuan Nightsnake from Clark County. Image by Lisa Wehrly.
An adult Chihuahuan Night Snake from Clark County, Kansas. © Lisa Wehrly.
An adult Chihuahuan Night Snake from Barber County, Kansas. © Lisa Wehrly. iNat #90464858.
An adult Chihuahuan Nightsnake from Barber County, Kansas. Image by Jacob Basler.
REPTILIA (Reptiles) SQUAMATA (PART) (Snakes) DIPSADIDAE (Harmless Rear-Fanged Snakes)

Chihuahuan Nightsnake
Hypsiglena jani (Dugès 1865)
hĭp-sĭ-glē-nă — jăn-ī


Conservation Status:

State: Kansas Species in Need of Conservation (SINC)

Federal: None
NatureServe State: S2 - Imperiled
NatureServe National: N5 - Secure
NatureServe Global: G5 - Secure
CITES: None
Diagnosis:
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.

Distribution:
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.
(,   Museum Voucher) (,   Observation) (,   Literature Record) (,   iNat Record), (  Fossil)
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Full range depicted by light shaded red area. Export Google Earth (.kml)
  • Occurrence Summary:  
  • 75
    Records 
  • 61
    Museum Vouchers 
  • 14
    Other Observations 
Some county occurrences indicated below may be too imprecise to map above.
County Breakdown: County Name (# occurrences):
Barber (36); Clark (28); Comanche (11);

Fossil History:
Not known from Kansas.

Natural History:
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.

Occurrence Activity:
Number of Unique Obervations (=days): 50; Range: 06 Jan to 22 Oct
Remarks:
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.

Bibliography:
1865 Dugès, Alfredo. Du Liophis janii.  Academie des Sciences et Lettres de Montpellier. Memoires de la Section des Sciences. 6():32–33
Contains the original description of Hypsiglena jani.
1928 Ortenburger, Arthur I. The whip snakes and racers: Genera Masticophis and Coluber. Memiors of the University of Michigan Museum (1):1-247
1936 Brumwell, Malcolm J. Distributional records of the reptilia and amphibians of Kansas. Privately printed, . 22pp.
County dot maps of the Kansas herpetofauna. This work has been attributed to have been written around 1933, but that may be in error. 
Hypsiglena jani was not known from Kansas until Claude W. Hibbard collected three specimens on the Stevenson Ranch in north-central Clark County (above Clark State Lake) during June 1936 (Hibbard, 1937). Brumwell plotted this locality, which leads me to believe that the 1936 would have been the earliest date this manuscript could have been written.
1937 Hibbard, Claude W. Hypsiglena ochrorhynchus in Kansas and additional notes on Leptotyphlops dulcis. Copeia 1937(1):74
1939 Ditmars, Raymond L. A Field Book of North American Snakes. Doubleday, Doran and Company, New York. pp.
1941 Schmidt, Karl Peterson and D. D. Davis. Field Book of Snakes of the United States and Canada. C.P. Putnam and Sons, New York. 365pp.
1943 Davenport, J. W. Field Book of the Snakes of Bexar County, Texas and Vicinity. Witte Memorial Museum, San Antonio, Texas. pp.
1944 Tanner, Wilmer W. A taxonomic study of the genus Hypsiglena. Great Basin Naturalist 5(3-4):25-92
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.
1953 Schmidt, Karl P. A Check List of North American Amphibians and Reptiles. 6th Edition. University of Chicago Press, Chicago, Illinois. 280pp.
Schmidt's first edition of his standardized checklist to North American amphibians and reptiles. Includes several specific references to Kansas in the range descriptions.
1954 Tanner, Wilmer W. Additional note on the genus Hypsiglena with a description of a new subspecies. Herpetologica 10():54-56
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.
1956 Loomis, Richard B. The chigger mites of Kansas (Acarina, Trombiculidae). University of Kansas Science Bulletin 37():1195-1443
Examined 2,628 Kansas reptiles of 48 species consisting of 27 turtles of 4 species, 1,736 lizards of 12 species and 892 snakes of 32 species for chiggers. Eleven species of chiggers were recovered from reptiles.
For amphibians, 1188 individuals of 21 species were examined. Five species of chigger mite were recovered from amphibians.
1958 Conant, Roger. A Field Guide to Reptiles and Amphibians of Eastern North America. Houghton Mifflin Co, Boston. pp.
1959 Collins, H. H. Complete Field Guide to American Wildlife. Harper and Brothers, New York. pp.
1970 Cochran, Doris M. and Colman J. Goin. The New Field Book of Reptiles and Amphibians. Putnam's Sons, New York. pp.
1970 Fitch, Henry S. Reproductive cycles in lizards and snakes. University of Kansas Museum of Natural History Miscellaneous Publication (52):1-247
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 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.
1975 Conant, Roger. A Field Guide to Reptiles and Amphibians of Eastern and Central North America. Houghton Mifflin Co, Boston. pp.
1976 Rundquist, Eric M. Field checklist (of) amphibians and reptiles of Kansas. Kansas Herpetological Society, Lawrence. pp.
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
1977 Perry, Janice. Kansas herps needed. Kansas Herpetological Society Newsletter (18):2-3
List of Kansas amphibians and reptiles desired for the SSAR/HL meeting to be held 7-13 August 1977.
1977 Grow, David. Clark County visited by the Society. Kansas Herpetological Society Newsletter (19):1-2
1980 Clarke, Robert F. Snakes in Kansas. Kansas School Naturalist 26(3):1-15
1981 Jenner, Janann. A zoogeographic study of the taxonomy of the Xenodontine Colubrid snakes Dissertation. New York University, New York, New York. 354pp.
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)>
1983 Ballinger, Royce E. and John D. Lynch. How to Know the Amphibians and Reptiles. Wm. C. Brown,, Dubuque, Iowa. pp.
1984 Secor, Stephen M. and Charles C. Carpenter. Distribution maps of Oklahoma reptiles. Oklahoma Herpetological Society Special Publication (3):1-57
1984 Collins, Joseph T. New records of fishes, amphibians, and reptiles in Kansas for 1983. Kansas Herpetological Society Newsletter (56):15-26
Invalidated the specimens of Thamnophis sirtalis from Hamilton County (reidentified as T. cyrtopsis; KU 2088) and Wallace County mapped in Collins, 1982.
1985 Collins, Joseph T. (Editor) Natural Kansas. University Press of Kansas, Lawrence. pp.
1986 Layher, William G., Ken L. Brunson, J.Schaefer, Marvin D. Schwilling, and R. D. Wood. 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. 27pp.
1987 Miller, Larry L. An investigation of four rare snakes in south-central Kansas. Final Report. Kansas Wildlife and Parks Commission, Pratt. 24pp.
1988 Busby, William H. The Kansas Natural Heritage Program: Taking stock of Kansas' natural heritage. Kansas Herpetological Society Newsletter (71):9-12
1989 Simmons, John E. Endangered and threatened in Kansas. Kansas Herpetological Society Newsletter (75):4-5
1990 Lardie, Richard L. Kansas threatened species and protection of the Gypsum Hills habitat. Kansas Herpetological Society Newsletter (80):14-15
1990 Collins, Joseph T. Maximum size records for Kansas amphibians and reptiles. Kansas Herpetological Society Newsletter (81):13-17
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.
1992 Ball, Robert L. High plains serpents: Results of a long-term study in Texas County, Oklahoma and Morton County, Kansas Kansas Herpetological Society Newsletter (88):16-17
1992 Rundquist, Eric M. Results of the KHS 1992 fall field trip. Kansas Herpetological Society Newsletter (90):4
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 Collins, Joseph T. and Rundquist, Eric M. Results of the fifth Kansas herp count held during April-June 1993 . Kansas Herpetological Society Newsletter (94):7-11
1993 Fitch, Henry S. Relative abundance of snakes in Kansas. Transactions of the Kansas Academy of Science 96(3/4):213-224
1994 Rundquist, Eric M. Results of the sixth annual KHS herp counts held 1 April-31 May 1994. Kansas Herpetological Society Newsletter (97):5-14
See, 1994 Rundquist, Eric M. Additions and corrections [to the results of the sixth annual KHS herp counts held 1 April-31 May 1994]. Kansas Herpetological Society Newsletter (98):4.
1995 Collins, Joseph T., Suzanne L. Collins, Jerry Horak, Daniel Mulhern, William H. Busby, Craig C. Freeman, and G. Wallace. An Illustrated Guide to Endangered or Threatened Species in Kansas. University Press of Kansas, Lawrence. pp.
1996 Rundquist, Eric M. Results of the eighth annual KHS herp counts Held 1 April-31 May 1996. Kansas Herpetological Society Newsletter (104):6-17
1996 Rakestraw, J. Spring herp counts: A Kansas tradition. Reptile & Amphibian Magazine (March-April):75-80
1997 Rundquist, Eric M. Results of the ninth annual KHS herp counts held 1 April-31 May 1997. Kansas Herpetological Society Newsletter (108):12-17
1997 Rundquist, Eric M. KHS Spring Field Trips. Kansas Herpetological Society Newsletter (108):3
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.
1998 Powell, Robert, Joseph T Collins, and Errol D Hooper Jr. A Key to Amphibians & Reptiles of the Continental United States and Canada. Univ Press of Kansas, Lawrence, Kansas. 131pp.
1999 Rundquist, Eric M. Kansas Herpetological Society herp counts: A 10 year summary and evaluation. Kansas Herpetological Society Newsletter (115):42962
2000 Bartlett, Richard D. and Alan Tennant. Snakes of North America: Western Region. . Gulf Publishing Company, Houston, Texas. pp.
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
2001 Rundquist, Eric M. Results of the thirteenth annual KHS herp counts for 2001, held 1 April-30 June. Kansas Herpetological Society Newsletter (125):13-16
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 Rundquist, Eric M. 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. 20pp.
2002 Rundquist, Eric M. Natural history of the Night Snake, Hypsiglena torquata, in Kansas. Journal of Kansas Herpetology (4):16-20
2003 Ernst, Carl H. and E. M. Ernst. Snakes of the United States and Canada. Smithsonian Institution Press, Washington, D. C. pp.
2005 Brunson, Ken. Kansas species in need of conservation (SINC). Kansas Department of Wildlife and Parks, Pratt, Kansas. 71pp.
2006 Bartlett, Richard D. and Patricia P. Bartlett. Guide and Reference to the Snakes of Eastern and Central North America (North of Mexico). University Press of Florida, Gainesville. pp.
2006 Collins, Joseph T. and Suzanne L. Collins. A Pocket Guide to Kansas Snakes. 1st ed. Great Plains Nature Center, Wichita, Kansas. pp.
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.
2008 Mulcahy, Daniel G. Phylogeography and species boundaries of the western North American Nightsnake (Hypsiglena torquata): Revisiting the subspecies concept Molecular Phylogenetics and Evolution 46():1095-1115
2008 Weaver, Robert E. Distribution, abundance, and habitat associations of the Night Snake (Hypsiglena torquata) in Washington State. Northwestern Naturalist 89(3):164-170
2009 Collins, Joseph T. and Suzanne L. Collins. A Pocket Guide to Kansas Snakes. 2nd ed. Great Plains Nature Center, Wichita, Kansas. pp.
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)>
2011 Mulcahy, Daniel G.,Thomas H. Beckstead, and Jack W. Sites. Molecular systematics of the Leptodeirini (Colubroidea: Dipsadidae) revisited: Species-tree analyses and multi-locus data. Copeia 2011(3):407-417
2012 Rohweder, Megan R. Spatial conservation prioritization of Kansas for terrestrial vertebrates. Thesis. Fort Hays State University, Hays, Kansas. 151pp.
2012 Powell, Robert, Joseph T Collins, and Errol D Hooper Jr. Key to the Herpetofauna of the Continental United States and Canada: Second Edition, Revised and Updated. Univ Press of Kansas, Lawrence, Kansas. 152pp.
2014 Taggart, Travis W. Results of the 2014 KHS Spring Field Trip to Barber County Collinsorum 3(2-4):11
2014 Taggart, Travis W. Recent scientific and standard English name changes effecting the Kansas herpetofauna. Collinsorum 3(2-4):9-10
2015 Rohweder, Megan R. Kansas Wildlife Action Plan. Ecological Services Section, Kansas Department of Wildlife, Parks and Tourism in cooperation with the Kansas Biological Survey. 176pp.
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.
2016 Taggart, Travis W. Spring 2016 KHS field trip to Clark County was a soggy success. Collinsorum 5(2-3):2-3
2016 Taggart, Travis W. Results of the KHS ‘Fall’ field trip to Barber County. Collinsorum 5(2-3):6-7
2016 Myers, Edward A., Michael J. Hickerson, and Frank T. Burbrink. Asynchronous diversification of snakes in the North American warm deserts. Journal of Biogeography 44(2):1-14
2016 Lee, Justin L., Adrian Thompson and Daniel G. Mulcahy. 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
2016 Lee, Justin L., Adrian Thompson, and Daniel G. Mulcahy 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
2017 Crother, Brian I. (editor) 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
2017 Taggart, Travis W. Herp Count: Clark County State Lake. Collinsorum 6(2-3):9
2019 Powell, Robert, Joseph T Collins, and Errol D Hooper Jr. Key to the Herpetofauna of the Continental United States and Canada. Third Edition. Univ Press of Kansas, Lawrence, Kansas. 192pp.
2020 Myers, Eward A. and Daniel G. Mulcahy. 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
2020 Riedle, J. Daren. 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
2023 Russell, Elisabeth 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. 81pp.
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Travis W. Taggart © 1999-2024 — w/ Sternberg Museum of Natural History, Fort Hays State University