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North Dakota's

Federally Listed Endangered, Threatened, and Candidate Species – 1995


Eastern Short-horned Lizard (Phrynosoma douglassii brevirostra)

GIF -- species photo gif--species map

Status: Former Candidate (Note: As of February 28, 1996, this species is no longer listed as a Candidate species. However, it remains a species of management concern.)

Historical Status:
The eastern short-horned lizard appears to have a historic distribution range similar to its present distribution range. Habitat loss and habitat fragmentation has lowered the numbers of the species.

Present Status:
The eastern short-horned lizard is found in the western counties of the Dakotas to northeastern Montana and adjacent Canada, south to eastern Colorado and extreme northeastern Utah. In Wyoming and Colorado the eastern short-horned lizard is no longer present in several large areas. The species is locally common in the semi-arid short grass plains of the extreme western portion of Nebraska. In North Dakota the eastern short-horned lizards have been found along the Little Missouri River and Knife River drainages in the counties of Williams, Divide, McKenzie, Golden Valley, Billings, Slope, Dunn, and Bowman.

Habitat:
The eastern short-horned lizard frequents shortgrass prairie, sagebrush, open rocky or sandy plains, and open pinon-juniper, pine-spruce, and spruce-fir forests. Typically, the species inhabits hot dry or semiarid regions, such as the shortgrass plains in rather rough terrain. The soils may be stony, sandy, or firm, but usually some fine loose soil is present. The species is often found under or around sagebrush plants.

Life History:
The eastern short-horned lizard is active during daylight hours from late spring to fall. The species spends a considerable amount of time basking in the sun, which is crucial for digestion. Eastern short-horned lizards will bury themselves in the soil on cloudy days and also to hibernate for the winter. The eastern short-horned lizard, when chased by a predator, stops and lowers its body flat to the ground to camouflage itself into the soil. A unique defense mechanism used by the species is its ability to squirt blood from the corners of its eyes. The eastern short-horned lizard has a reproductive style (ovoviviparous) different from most lizards. The species carries its young in a transparent membrane. In late July or August the membrane breaks open and 5 to 36 young are born. The diet of the species consists of a variety of ants, spiders, beetles, snails, grasshoppers, and sowbugs.

Aid to identification:
The eastern short-horned lizards are 2 1/2 to 5 inches long from snout to tip of tail. The body color is brown to gray. The eastern short-horned lizard has a flat, broad body and a short tail. Dark blotches are present on either side of the neck immediately behind the head. Two parallel rows of irregular dark blotches are located on the back. The species have pyramid shaped spines positioned in longitudinal rows along the back and short spiny temporal horns at the rear of its head. A single row of whitish lateral fringe soft spines separates the dorsal and ventral surfaces.

Reasons for decline:
Loss of habitat due to cropping, intensive grazing, and oil development has affected the species in the shortgrass prairie badlands of North Dakota and other western states. Aerial spraying of insecticides may have also affected insect populations, the main diet of eastern short-horned lizards.

Recommendations:
Notify a natural resource agency of any eastern short-horned lizard sightings.

Comments:
The eastern short-horned lizard is often called the "horny toad or prairie cookie" in local areas.

References:
The Amphibians and Reptiles of North Dakota, by G. C. Wheeler and J. Wheeler, 1966. Published by the University of North Dakota Press, Grand Forks, ND.
Handbook of Lizards, Lizards of the United States and Canada, by H. M. Smith, 1946. Published by Comstock Publishing Associates, Ithaca, New York.


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