Common Names in English:
Coast Horned Lizard
P. c. blainvillei is found in a wide variety of vegetation types including coastal sage scrub , annual grassland, chaparral , oak woodland, riparian woodland and coniferous forest (Klauber, 1939; Stebbins, 1954). In inland areas, this species is restricted to areas with pockets of open microhabitat , created by disturbance (e.g. , floods, fire, roads, grazed areas, fire breaks ) (Jennings and Hayes, 1994).
Horned lizards of the genus Phrynosoma are primarily ant-eating reptiles
whose dietary habits are well known (Montanucci, 1981; Pianka and
Parker, 1975; Powell and Russell, 1984; Rissing, 1981; Turner and
Medica, 1982). Up to 90% of the diet
of P. c.
) (Pianka and Parker,
1975), and this species does not appear to eat non-native
ants (Jennings and Hayes, 1994) that have replaced native ants in
much of southern California (Ward, 1987). Other slow moving insects,
such as beetles, flies, and caterpillars are consumed opportunistically
when encountered (Presch, 1969; Pianka and Parker, 1975). Whitford
and Bryant (1979) studied the predator
closely related Phrynosoma cornutum and determined some interesting
results which may apply to P. coronatum since they are so closely
related and share the same resource
. They found two ant species
to be the most important prey for P. cornutum: Pogonomyrmex desertorum
and Pogonomyrmex rugosus; P. californicus was also found to be a
prey item, however, because few colonies are active
during the summer
when horned lizards are active, it was considered a minor prey species.
They found that at a single stop, the maximum number of ants eaten
by P. cornutum per species was: 18 P. californicus, 29 P. rugosus,
and 25 P. desertorum. The dietary species composition of individual
horned lizards varied from one species to four and the total number
of ants ingested in a day varied from approximately 30 to >100
In addition, Whitford and Bryant (1979) found that the lizards feed most often on ants that were not associated with nest discs or foraging columns and took only a few ants at any one place. When active, P. rugosus was preferred over P. desertorum (based on a larger number taken), however they did not completely switch to P. rugosus. Because P. rugosus activity was found to be unreliable, alternate prey is expected to be utilized (Whitford & Bryant, 1979). Hatchling P. cornutum was found by Whitford & Bryant to feed exclusively on P. rugosus and P. desertorum, "taking an average of three harvester ants per bout and retreating to the shelter of a low shrub or grass where they remained for about 20-30 minutes before feeding again.”
In southern California, the male reproductive cycle begins during
mid to late March and ends in June as testes
decrease in size. Testes
become their maximum size during Spring
with sperminogenesis in progress
(Goldberg, 1983). Female P.
c. blainvillei are oviparous
of 6-17 eggs
between May and July each year (Stebbins, 1954; Howard, 1974; Goldberg,
appear in late July to early August, and require
2 - 3 years to reach reproductive age (Stebbins, 1954; Howard, 1974;
Pianka and Parker, 1975; Goldberg, 1983).
After reviewing the data (Stebbins, 1954; Pianka and Parker, 1975; Howard, 1974), Goldberg (1983) found a range of average clutch sizes from various studies ranging from 11 to 12.5 individuals. Goldberg (1983) also found that P. coronatum has the potential to produce multiple clutches during the Spring.
The daily diurnal
activity of P. c.
blainvillei is distinctive. As
reach >19oC (almost 15 degrees
temperatures of normal activity), just prior to sunrise, this taxon
from burial sites in the substrate into a position that allows
them to bask
in the first rays of the sun (Heath
, 1965; Hagar, 1992).
Heath (1962) found that two distinct
activity; (1) the lizards "may move upward in the sand
are exposed and remain in this position until warmed to their
activity levels; (2) alternately, they emerge completely and begin
in a fully exposed position.” He also found a similarity
times between two groups of P. coronatum and P. cornutum,
suggesting the operation of an endogenous or circadian rhythm
High site fidelity is often exhibited by P. c. blainvillei, as effective thermoregulation (optimum: 29-39 degrees Celsius) requires familiarity with their surroundings (Heath, 1965). Midday temperatures over 40oC are avoided as P. c. blainvillei bury themselves in the substrate, reemerging in the later afternoon to resume full activities (e.g. , feeding, territorial , and reproductive).
Tollesturp's (1981) observations suggest that olfactory cues are important in Phrynosoma's daily activities, including courtship , feeding, sex recognition, and conspecific interactions . In addition, they were observed to apparently mark sites by partially extruding the cloaca and rubbing it back and forth on the substrate.
Contrary to Heath (1962), Whitford and Bryant (1979) did not observe activity in P. cornutum until approximately two hours after sunrise, and most feeding and other activity was confined to the morning hours. Typical morning activity observed by Whitford and Bryant involved "sitting for 30 seconds to several minutes, walking followed by elevated sitting, lasting from a few seconds to several minutes, terminated by a feeding bout or further walking, then resumption of elevated sitting.” They also found that a significant portion of the daily activity of P. cornutum involves shrub climbing and movement in the shrub canopy. Through the middle part of the day, the lizards positioned themselves in a shrub canopy where the ambient temps ranged from 35 to 40 degrees C. Their feeding corresponded with the peak activity patterns of harvester ants , between the hours of 0900 and 1100 (Whitford and Ettershank, 1975; Whitford, et. al., 1976). As expected, the bulk of thermoregulatory basking occurred in the early morning and late afternoon.
Survival: The defense that P. c. blainvillei most often uses against approaching predators is to depend on their cryptic appearance and simply lie motionless (Jennings and Hayes, 1994). Klauber (1939) documented change in body coloration to match the soil or sand on which they were found. Other methods used include hissing, inflating lungs to increase apparent size (Pianka and Parker, 1975; Munger, 1986; Sherbrooke, 1981), raising their horns by lowering their snout (Pianka and Parker, 1975; Sherbrooke, 1981), squirting blood from the corner of the eye (which seems to repel dogs and cats) (Presch, 1969; Pianka and Parker, 1975), tilting the body when irritated (Milne and Milne, 1950; Smith, 1946; Tollestrup, 1981), presenting a bristling of scales of the back while standing well up on the legs (Bryant, 1911), and running a short distance before flattening out or burrowing several centimeters under the ground (Presch, 1969). When P. coronatum flattens its body, it usually tucks its head down, exposing its horns, and often charges the enemy (Winton, 1916). An additional defense mechanism may be based on learned avoidance by predators suggested by reports of snakes dying while trying to swallow Phrynosoma which are well documented in the literature (Klauber, 1972; Milne and Milne, 1950; Van Denburgh, 1922; Vorhies, 1948; Wright and Wright, 1957).
The work conducted by Whitford and Bryant (1979) suggests that the coevolution of a foraging strategy in relation to the responses of their prey has allowed the horned lizard to survive with a potentially limited resource base .
Socio-Spatial Behavior: The literature contains conflicting data on the social behavior of P. coronatum. According to Carpenter (1967), the typical pattern of Iguanid courtship includes push-ups, head-bobs, a prancing strut, grasping of the female by the nape of the neck, and male mounting the female dorsally (Carpenter, 1967; Carpenter and Ferguson, 1977). Lynn (1965) found "no evidence of territoriality , no evidence of any type of social hierarchy, no evidence that the display (head-bob/push-up) is used in sex or species recognition, and no evidence that the display is used on courtship." Stamps (1977) speculates that horned lizards have only simplified displays and lack territorial defense. Contrary to these reports, Tollestrup (1981) found that P. coronatum utilizes a diverse repertoire of displays for species recognition, courtship and sex; including head-bob (a vertical motion of the head; (Lynn (1965) described this as "three (sometimes four) quick bobs , a bob with a quick upward movement and a slow downward movement, a slow bob); push-up (an extension of the forelimbs that raises the front part of the body); tail-curled-up (with all four limbs extended or the body pressed flat against the substrate, the tail is curled up over the body); and scratching (the two forelimbs are moved alternately with a scratching or pawing motion usually without the claws in contact with the substrate). Tollestrup (1981) observed that displays between males are usually performed from an elevated perch such as a gopher mound or cow dung, and are characterized by a frequency increase in head-bobs and push-ups, and by the use of the rocking display. One male would then run toward the other, each continuing to display. "Males presented their vents with their tails curled up over the back to other males and in each case, the male with the curled tail moved out of the area" (Tollestrup 1981). Tollestrup observed no biting or combat with the horns. Using a radiotelemetry study, Munger (1984) found that horned lizards utilize limited home ranges , occupying areas much smaller than they would if they moved randomly. His data further suggest that there is a reduction in home range overlap, and contrary to expectation, overlap between sexes tended to be less than overlap between individuals of the same sex (Munger, 1984). In Whitford and Bryant's 1979 study, the closely related P. cornutum moved an average of 46.8 meters per day (range = 9-91 m ). They also found that an individual horned lizard moved over a zigzag course during a day but rarely crossed its own trail .
P. c. blainvillei emerges from hibernation in March, and becomes surface active in April through July, after which most adults estivate (summer hibernation) (Hagar, 1992). The adults reappear again briefly in late summer and return to overwintering sites between August and early October depending upon elevation (Klauber, 1939; Howard, 1974; Hagar, 1992).
- Whittaker & Margulis,1978
- C. Linnaeus, 1758
- (Hatschek, 1888) Cavalier-Smith, 1983
- Grobben, 1908
- (Haeckel, 1874) Cavalier-Smith, 1998
- Bateson, 1885
- Cuvier, 1812
- Jawed Vertebrates
- Goodrich, 1930
- Subclass: Diapsida ()
- Class: Reptilia () - Reptiles
- Superclass: Tetrapoda () - Goodrich, 1930
- Infraphylum: Gnathostomata () - auct. - Jawed Vertebrates
- Subphylum: Vertebrata () - Cuvier, 1812 - Vertebrates
- Phylum: Chordata () - Bateson, 1885 - Chordates
- Infrakingdom: Chordonia () - (Haeckel, 1874) Cavalier-Smith, 1998
- Branch: Deuterostomia () - Grobben, 1908
- Subkingdom: Bilateria () - (Hatschek, 1888) Cavalier-Smith, 1983
- Kingdom: Animalia () - C. Linnaeus, 1758 - animals
Agama coronatum Blainville • Phrynosoma blainvillii Gray • Phrynosoma coronatum blainvillii Gray • Phrynosoma frontalis Van Denburgh
Members of the genus Phrynosoma
ZipcodeZoo has pages for 27 species and subspecies in this genus:
P. asio (Giant Horned Lizard) · P. blainvillii (San Diego Horned Lizard) · P. braconnieri (Short-Tail Horned Lizard) · P. cerroense (Cedros Island Horned Lizard) · P. cornutum (Texas Horned Lizard) · P. coronatum (Blainville Horned Lizard) · P. coronatum blainvilli (Coast Horned Lizard) · P. coronatum blainvillii (Coast Horned Lizard) · P. coronatum frontale (California Horned Lizard) · P. ditmarsi (Rock Horned Lizard) · P. douglasii (Pygmy Horned Lizard) · P. douglasii douglasii (Pigmy Short-Horned Lizard) · P. douglassii (Eastern Short-Horned Lizard) · P. douglassii douglassii (Pigmy Short-Horned Lizard) · P. douglassii hernandesi (Mountain Short-Horned Lizard) · P. douglassii ornatissimum (Desert Short-Horned Lizard) · P. douglassii ornatum (Salt Lake Short-Horned Lizard) · P. hernandesi (Greater Short-Horned Lizards) · P. mcallii (Flat-Tailed Horned Lizard) · P. modestum (Round-Tailed Horned Lizard) · P. orbiculare (Mexican Horned Toad) · P. platyrhinos (Desert Horned Lizard) · P. platyrhinos calidiarum (Desert Horned Lizard) · P. platyrhinos platyrhinos (Desert Horned Lizard) · P. solare (Regal Horned Lizard) · P. taurus (Mexican Horned Lizard) · P. wigginsi (Gulf Coast Horned Lizard)
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- Baur, B. 1979. Pfledge und "Zucht" der Reisenkrotenechse, Phrynosoma asio (reptilia: Sauria: Iguanidae). Salamandra 15:1-12.
- Bruner, H.L. 1907. On the cephalic veins and sinuses of reptiles, with description of a mechanism for raising the venous blood pressure in the head. Amer. Jour. Anat., 7:1-117, 17 figs., 3 pls.
- Bryant, H. C. 1911. The horned lizards of California and Nevada of the genera Phrynosoma and Anota. Univer. California Publ. Zool. 9:1-84.
- Burleson G.L. 1942. The source of blood ejected from the eye by horned toads. Copeia 1942, No. 4. Dec 28. Pp. 246-248. Herpetologica. 1989. 45(2). Pp 208-216.
- Carpenter, C. 1962. Aggression and social structure of iguanid lizards. Pp. 87-105 In: W.W. Milstead (Ed.), Lizard Ecology: A symposium. Univ. Missouri Press, Columbia.
- Carpenter, C. 1967. Aggression and social structure of iguanid lizards. Pp. 87-105. IN:W.W. Milstead (Ed.), Lizard Ecology: A Symposium. Univ. Missouri Press, Columbia.
- Carpenter, C.C. and G.W. Ferguson. 1977. Variation and evolution of stereotyped behavior in reptiles. Pp. 335-554. In: C Gans and D.W. Tinkle (Ed.), Biology of the Reptilia. Vol 7. Academic Press, London.
- Goldberg, S.R. 1983. The reproduction of the coast horned lizard, Phrynosoma coronatum in Southern California. The Southwestern Naturalist. Vol 28, No. 4 Pp. 478-479.
- Grey (1946)- San Diego horned Lizard Phrynosoma coronatum blainvillei. In: Smith H.M. 1946. Handbook of Lizards. Pp. 293-295. Comstock Publ. Assoc., Ithaca, New York.
- Hagar, S. B. 1992. Surface activity, movement, and home range of the San Diego horned lizard, Phrynosoma coronatum blainvillei. Master’s Thesis, California State University, Fullerton.
- Hayes, M. P., and C. Guyer. 1981. The herpetofauna of Ballona. Pp. H1 - H80 In: R. W. Schreiber (editor), The biota of the Ballona region, Los Angeles County. Supplement I, Marina Del Rey/Ballona Local Coastal Plan, Los Angeles County Natural History Museum Foundation, Los Angeles, California.
- Heath, J. E. 1965. Temperature regulation and diurnal activity in horned lizards. Univ. California Publ. Zool. 64:97-136.
- Heath, J.E. 1962. Temperature-Independent morning Emergence in Lizards of the Genus Phrynosoma. Science. Vol 138. Pp. 891-892.
- Howard, C. W. 1974. Comparative reproductive ecology of horned lizards (genus Phrynosoma) in southwestern United States and northern Mexico. Journal of the Arizona Academy of Science 9(3):108-116.
- Jennings, M. R. 1988. Phrynosoma coronatum. Catalogue of American Amphibians and Reptiles:428.1-428.5.
- Jennings, M. R., and M. P. Hayes. 1994. Amphibian and reptile Species of Special Concern in California. Final report submitted to California Department of Fish and Game, Inland Fisheries Division, Rancho Cordova, California, under Contract 8023.
- Klauber, L. M. 1939. Studies of reptiles life in the arid southwest. Part I, Night collecting on the desert with ecological statistics; Part II, Speculations on protective coloration and protective reflectivity; Part III, Notes on some lizards of the southwestern United States. Bulletin of the Zoological Society of San Diego (14):1-100.
- Klauber, L. M. 1972. Rattlesnakes, Their Habits, Life Histories, and Influence on Mankind. Univ. Calif. Press, Berkeley and Los Angeles, California. Southwestern Naturalist 28(4):478-479.
- Lynn, R.T. 1965. A comparative study of display behaviour in Phrynosoma (Iguanidae). Southwest nat. 10:25-30.
- Milne, L.J. 1938. Mating of Phrynosoma coronatum. Copeia 1938:200-201.
- Milne, L.J., and M.J. Milne. 1950. Notes on the behaviour of horne toads. Amer. Midl. Nat. 44:720-741.
- Montanucci, R. R. 1968. Notes on the distribution and ecology of some lizards in the San Joaquin Valley, California. Herpetologica 24(4):316-320.
- Montanucci, R.R. 1981. Habitat separation between Phrynosoma douglassi and P. orbiculare (Lacertlia: Iguanidae) in Mexico. Copeia 1981:147-153.
- Montanucci, R.R. 1989. The relationship of morphology to diet in the horned lizard genus Phrynosoma. Herpetologica. 1989. 45(2), pp 208-216.
- Munger, J.C. 1984. Home Ranges of Horned Lizards (Phrynosoma): circumscribed or exclusive? Oecologica (Berlin) 62:351-360.
- Munger, J.C. 1984. Home ranges of horned lizards (Phrynosoma): circumscribed and exclusive? Oecologia (Berlin) (1984) 62:351-360.
- Pianka, E. R., and W. S. Parker. 1975. Ecology of horned lizards: A review with special reference to Phrynosoma platyrhinos. Copeia 1975(1):141-162.
- Powell, G.L. and A. P. Russel. 1984. The diet of the eastern short horned lizard (Phrynosoma douglassi brevirostre) in Alberta, and its relationship to sexual size dimorphism. Can. J. Sci. 62:428-440.
- Presh, W. 1969. Evolutionary osteology and relationships of the horned lizard genus Phrynosoma (family Iguanidae). Copeia 1969:250-275.
- Reeve, W. L. 1952. Taxonomy and distribution of the horned lizard genus Phrynosoma. University of Kansas Science Bulletin 34(14):817-960.
- Rissing, S.W. 1981. Prey preferences in the desert horned lizard: Influence of prey foraging method and aggressive behavior. Ecology 6: 1031-1040.
- Schoenherr, A.A.1976. The Herptofauna of the San Gabriel Mountains Los Angeles, California Including Distribution and Biogeography. Special Publication of the Southwestern Herpetologist's Society, February 1, 1976.
- Sherbrooke, W.C. 1981. Horned Lizards: Unique reptiles of western North America. Southwest Parks and Monuments Assoc. Globe, Arizona.
- Smith, H.M. 1946. Handbook of lizards. Comstock Publ. Co., Ithaca New York.
- Stamps, J.A. 1977. Social behavior and spacing patterns in lizards. Pp. 265-334. IN: C.Gans and D.W. Tinkle (Eds.), Biology of the Reptilia. Vol. 7. Academic Press, London.
- Stebbins, R. C. 1954. Amphibians and reptiles of western North America. McGraw-Hill Book Company, New York, New York.
- Tollestrup, K. 1981. The social behavior and displays of two species of horned lizards, Phrynosoma platyrhinos and Phrynosoma coronatum. Herpetelogica 37(3):130-141.
- Turner, F.B. and P.A. Medica. 1982. The distribution and abundance of the flat-tailed horned lizard (Phrynosoma mcallii). Copeia 1982:815-823.
- Van Denburgh, J. 1922. The reptiles of Western North America; an account of the species known to inhabit California, Oregon, Washington, Idaho, Utah, Nevada, Arizona, British Columbia, Sonora, and Lower California. Volume I. Lizards. Occasional Papers of the Academy of Sciences (10):1-611.
- Vorhies, C.T. 1948. Food items of rattlesnakes. Copeia 1948:302-303.
- Ward, P. S. 1987. Distribution of the introduced Argentine ant (Iridomyrmex humulis) in natural habitats of the lower Sacramento Valley and its effects on the indigenous ant fauna. Higardia 55(2):1-16.
- Whitford, W.G., P. Johnson, and J. Ramirez. 1976. Comparative ecology of the harvester ant Pogonomyrmex barbatus (F. Smith) and Pogonomyrmex rugosus (Emery). Insectes Sociaux. 23:117-132.
- Whitford, W.G., and G. Ettershank. 1975. Factors affecting foraging activity in Chihuahuan desert harvester ants. Environmental Entomology. 4:689-696.
- Whitford, W.G., and M. Bryant. 1979. Behavior of a predator and its prey: the horned lizard (Phrynosoma cornutum) and harvester ants (Pogonomyrmex spp.). Ecology. 60(4):686-694.
- Winton, W.M. 1916. Habits and behaviour of the Texas horned toad, Phrynosoma coronatum. Copeia 1916:81-84.
- Wood, S.F. 1936. Courting behaviour of some western lizards. Copeia 1936:177.
- Wright A.H. and A.A. Wright. 1957. Handbook of snakes. Comstock Publ. Assoc., Ithaca, New York.
- Brands, S.J. (comp.) 1989-present. The Taxonomicon. Universal Taxonomic Services, Zwaag, The Netherlands. Accessed February 5, 2012.
- Global Biodiversity Information Facility. Accessed October 11, 2007. http://www.gbif.org Mediated distribution data from provider.
- Integrated Hardwood Range Management Program, Understanding the Plants and Animals of Western Riverside County MSHCP University of California, Berkeley and Center for Conservation Biology, University of California, Riverside.