Greater short-horned LizardPhrynosoma hernandesi
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General Distribution: Extreme southern Alberta, Canada, to southern Durango, Mexico; western Nebraska (few historical records from western Kansas) to southeastern Oregon. Widest geographic distribution of any horned lizard.
Colorado Distribution: Greater Short-horned Lizards can be found throughout much of the eastern plains, Front Range, San Luis Valley, and West Slope (after Hammerson 1999, Shipley & Reading 2006, and Colorado Parks & Wildlife).
Conservation Status: Designated as a Non-game Species in Colorado. A Scientific Collection Permit from Colorado Parks & Wildlife is required to capture or handle this species (see State of Colorado regulations here). NatureServe rank: G5 (Globally Secure), S5 (State Secure). General threats to conservation include habitat loss and fragmentation, and vehicle traffic on and off road. This species is also vulnerable to illegal collection. If you find yourself with a horned lizard (e.g., your child brings one home), and you cannot immediately return it to the location of collection, please contact Colorado Parks & Wildlife. There is evidence that horned lizards are obligate hibernators, and do not survive long in captivity.
Diagnostic Features
Coloration / Markings
Size: Adults are sexually-dimorphic, with females in Weld County averaging about 64 mm (2.5 in) Snout-to-Vent Length (SVL), and males averaging about 55 mm (2.2 in) SVL (D. Martin, unpublished data). Neonates are typically 20-26 mm SVL, with mass around 1.0 g at birth, and sexes become dimorphic as they approach sexual maturity at 1 to 2 years of age. Maximum size listed by Hammerson (1999) is 150 mm Total Length; Degenhardt et al. (1996) list maximum size in New Mexico as 83 mm SVL for males and 98 mm SVL for females. Short-horned Lizards in the San Luis Valley are known to be smaller than those outside the Valley (see Lahti 2010).
Habitat: Short-horned Lizards range throughout short and mixed-grass prairies, pinõn-juniper, sagebrush, open conifer woodland, and mountain shrubland. They can be found at elevations up to around 3,353 m (11,000 ft), in sandy or otherwise well-drained soils and usually in areas with sparse vegetation.
Activity: Short-horned Lizards are primarily diurnal from April to September. They are not active when hibernating between October and March (see Mathies & Martin 2009 for more information on hibernation site selection in Weld County).
Reproduction: This is the only species of lizard in Colorado to give live birth, an adaptation for the relatively cool environments where this species resides. Sexual reproduction has been noted in March and April in Weld County (D. Martin & T. Mathies, personal observation), and in late April in Moffat County (D. Kovar & M. Olsen, personal observation). Neonates are born in early-to-mid-August in northeastern Colorado (D. Martin, unpublished data).
Feeding & Diet: Primarily insectivorous. In Weld County, Short-horned Lizards are known to feed on a variety of ant and beetle species, ground-dwelling bees, true bugs (Hemiptera), and other arthropods (D. Martin, unpublished data). Similar to other horned lizards, this species is a sit-and-wait predator.
Colorado Distribution: Greater Short-horned Lizards can be found throughout much of the eastern plains, Front Range, San Luis Valley, and West Slope (after Hammerson 1999, Shipley & Reading 2006, and Colorado Parks & Wildlife).
- BLUE = known historic occurrence.
- YELLOW = likely occurrence.
- GRAY = unlikely to occur.
Conservation Status: Designated as a Non-game Species in Colorado. A Scientific Collection Permit from Colorado Parks & Wildlife is required to capture or handle this species (see State of Colorado regulations here). NatureServe rank: G5 (Globally Secure), S5 (State Secure). General threats to conservation include habitat loss and fragmentation, and vehicle traffic on and off road. This species is also vulnerable to illegal collection. If you find yourself with a horned lizard (e.g., your child brings one home), and you cannot immediately return it to the location of collection, please contact Colorado Parks & Wildlife. There is evidence that horned lizards are obligate hibernators, and do not survive long in captivity.
Diagnostic Features
- Dorso-ventrally flattened body and tail.
- Short spines on head, body, and tail relative to Texas Horned Lizard.
- Head spines blunt compared to other horned lizards in Colorado.
- One row of lateral fringe scales.
- Males of all age-classes have enlarged post-anal scales relative to females. Adult males have rust-colored femoral pores.
- No mid-dorsal stripe (P. cornutum has a white mid-dorsal stripe; P. modestum does not have a mid-dorsal stripe).
Coloration / Markings
- Varied, typically matching general color of area soil and with a series of dark, irregular blotches on the dorsum.
- No mid-dorsal stripe.
- Both sexes and all age-classes are similarly patterned.
- Individuals in southwestern Colorado tend to be more reddish. Individuals in sandier soils tend to have increased white spotting on the dorsal surface (see photos for examples).
Size: Adults are sexually-dimorphic, with females in Weld County averaging about 64 mm (2.5 in) Snout-to-Vent Length (SVL), and males averaging about 55 mm (2.2 in) SVL (D. Martin, unpublished data). Neonates are typically 20-26 mm SVL, with mass around 1.0 g at birth, and sexes become dimorphic as they approach sexual maturity at 1 to 2 years of age. Maximum size listed by Hammerson (1999) is 150 mm Total Length; Degenhardt et al. (1996) list maximum size in New Mexico as 83 mm SVL for males and 98 mm SVL for females. Short-horned Lizards in the San Luis Valley are known to be smaller than those outside the Valley (see Lahti 2010).
Habitat: Short-horned Lizards range throughout short and mixed-grass prairies, pinõn-juniper, sagebrush, open conifer woodland, and mountain shrubland. They can be found at elevations up to around 3,353 m (11,000 ft), in sandy or otherwise well-drained soils and usually in areas with sparse vegetation.
Activity: Short-horned Lizards are primarily diurnal from April to September. They are not active when hibernating between October and March (see Mathies & Martin 2009 for more information on hibernation site selection in Weld County).
Reproduction: This is the only species of lizard in Colorado to give live birth, an adaptation for the relatively cool environments where this species resides. Sexual reproduction has been noted in March and April in Weld County (D. Martin & T. Mathies, personal observation), and in late April in Moffat County (D. Kovar & M. Olsen, personal observation). Neonates are born in early-to-mid-August in northeastern Colorado (D. Martin, unpublished data).
Feeding & Diet: Primarily insectivorous. In Weld County, Short-horned Lizards are known to feed on a variety of ant and beetle species, ground-dwelling bees, true bugs (Hemiptera), and other arthropods (D. Martin, unpublished data). Similar to other horned lizards, this species is a sit-and-wait predator.
Defenses from Predation: Short-horned lizards primarily use cryptic behavior and coloration as a defense against predation. When discovered, they may flee for cover or stand their ground. They will readily inflate their lungs to appear larger or more difficult for a predator to swallow. In some cases, they will eject blood from their orbital sinus (the corner of the eye), effectively squirting blood at a predator.
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Cited & Additional Resources
Colorado Parks and Wildlife. Short-horned Lizard. Natural Diversity Information Source. http://ndis.nrel.colostate.edu/wildlifespx.asp?SpCode=030208 [accessed Nov. 2013].
Degenhardt, W. G., C. W. Painter, and A. H. Price. 1996. Amphibians and reptiles of New Mexico. University of New Mexico Press, Albuquerque, New Mexico. 431 pp.
Hammerson, G. A. 1999. Amphibians and reptiles in Colorado. 2nd ed. University Press of Colorado, Boulder, Colorado. 484 pp.
Hodges, W. L. 2009. Greater Short-horned Lizard. Pages 178–181 in L. L. C. Jones and R. E. Lovich, eds. Lizards of the American Southwest. Rio Nuevo Publishers, Tucson, Arizona. 567 pp.
Lahti, M. The status of dwarfed populations of Short-horned Lizards and Great Plains Toads in the San Luis Valley, Colorado. 2010. Dissertation, Utah State University. 201 pp.
Martin, D. 2009. Guide to the Horned Lizards of Colorado (brochure, 2nd ed.). Colorado Parks & Wildlife.
Martin, D. 2006. The Blood-squirting Short-horned Lizard. Pages 35-37 in Colorado Outdoors. Colorado Parks & Wildlife, Denver, Colorado.
Mathies, T., and D. J. Martin. 2008. Overwintering site selection by Short-horned Lizards in northeastern Colorado. Journal of Herpetology 42:163–171.
Sherbrooke, W. C. 2003. Introduction to the horned lizards of North America. University of California Press, Berkeley and Los Angeles, California. 191 pp.
Shipley, B.K., and R. P. Reading. 2006. A comparison of herpetofauna and small mammal diversity on black-tailed prairie dog (Cynomys ludovicianus) colonies and non-colonized grasslands in Colorado. Journal of Arid Environments 66: 27-41.
Colorado Parks and Wildlife. Short-horned Lizard. Natural Diversity Information Source. http://ndis.nrel.colostate.edu/wildlifespx.asp?SpCode=030208 [accessed Nov. 2013].
Degenhardt, W. G., C. W. Painter, and A. H. Price. 1996. Amphibians and reptiles of New Mexico. University of New Mexico Press, Albuquerque, New Mexico. 431 pp.
Hammerson, G. A. 1999. Amphibians and reptiles in Colorado. 2nd ed. University Press of Colorado, Boulder, Colorado. 484 pp.
Hodges, W. L. 2009. Greater Short-horned Lizard. Pages 178–181 in L. L. C. Jones and R. E. Lovich, eds. Lizards of the American Southwest. Rio Nuevo Publishers, Tucson, Arizona. 567 pp.
Lahti, M. The status of dwarfed populations of Short-horned Lizards and Great Plains Toads in the San Luis Valley, Colorado. 2010. Dissertation, Utah State University. 201 pp.
Martin, D. 2009. Guide to the Horned Lizards of Colorado (brochure, 2nd ed.). Colorado Parks & Wildlife.
Martin, D. 2006. The Blood-squirting Short-horned Lizard. Pages 35-37 in Colorado Outdoors. Colorado Parks & Wildlife, Denver, Colorado.
Mathies, T., and D. J. Martin. 2008. Overwintering site selection by Short-horned Lizards in northeastern Colorado. Journal of Herpetology 42:163–171.
Sherbrooke, W. C. 2003. Introduction to the horned lizards of North America. University of California Press, Berkeley and Los Angeles, California. 191 pp.
Shipley, B.K., and R. P. Reading. 2006. A comparison of herpetofauna and small mammal diversity on black-tailed prairie dog (Cynomys ludovicianus) colonies and non-colonized grasslands in Colorado. Journal of Arid Environments 66: 27-41.
Account compiled by: Danny Martin and Tom Mathies
Reviewed by: Ben Fisher (text) and Lauren Livo (map)
Last updated: 4/14/2022 by Rémi Pattyn
Suggested Citation
Colorado Partners in Amphibian and Reptile Conservation. 2013. Species account for Short-horned Lizard (Phrynosoma hernandesi). Compiled by Danny Martin and Tom Mathies. http://www.coparc.org/colorado-lizards---short-horned-lizard.html [accessed date here].
Reviewed by: Ben Fisher (text) and Lauren Livo (map)
Last updated: 4/14/2022 by Rémi Pattyn
Suggested Citation
Colorado Partners in Amphibian and Reptile Conservation. 2013. Species account for Short-horned Lizard (Phrynosoma hernandesi). Compiled by Danny Martin and Tom Mathies. http://www.coparc.org/colorado-lizards---short-horned-lizard.html [accessed date here].