The following account is modified from Amphibian Declines: The Conservation Status of United States Species, edited by Michael Lannoo (©2005 by the Regents of the University of California), used with permission of University of California Press. The book is available from UC Press.

Rana blairi Mecham, Littlejohn, Oldham, Brown and Brown, 1973
Plains Leopard Frog

John A. Crawford¹
Lauren E. Brown²
Charles W. Painter³

1. Historical versus Current Distribution. Plains leopard frogs (Rana blairi) occur throughout much of the Great Plains and into the central Midwest (prairie peninsula). Their range extends eastward from central New Mexico, central Colorado, and Nebraska (excluding the panhandle) to central Indiana. The northern limit of this range occurs in southern South Dakota and central Iowa and extends south into northern Texas, excluding most of southern Missouri, Arkansas, and southeastern Oklahoma. Isolated population clusters occur in southern Illinois, New Mexico, and southeastern Arizona (L.E. Brown, 1992; L.E. Brown et al., 1993; Conant and Collins, 1998). In New Mexico, plains leopard frogs are found up to 2,130 m in altitude near Sierra Blanca, Lincoln County (Stebbins, 1985; Degenhardt et al., 1996). In Arizona, plains leopard frogs are isolated on the western side of the Chiricahua Mountains and adjoining Sulfer Springs Valley, where they have a range in altitude of 110–2,590 m (Stebbins, 1985). However, in Colorado, plains leopard frogs are found only below 1,828 m (Hammerson, 1982a, 1999). In Missouri, plains leopard frogs occur everywhere except the Ozark Plateau and in the extreme southeast (L.E. Brown, 1992; L.E. Brown et al., 1993; Johnson, 1997). In Indiana, Minton (2001) notes that their range is poorly known, but plains leopard frogs occur primarily along the western border of the state. Plains leopard frogs were first described in 1973, so earlier studies of "leopard frogs" (typically Rana pipiens) from sites within the range of plains leopard frogs (L.E. Brown, 1973b, 1992) may instead refer to R. blairi.

2. Historical versus Current Abundance. The decline and extirpation of populations (particularly in the west) has been documented by Christiansen and Bailey (1991), Frost and Bagnara (1977), Platz (1981), Hammerson (1982a,b), Frost (1983), Hayes and Jennings (1986), Clarkson and Rorabaugh (1989), Cousineau and Rogers (1991), and L.E. Brown (1992). Hammerson (1999) notes that plains leopard frogs remain widely distributed within their historical range in eastern Colorado, but in areas now occupied by American bullfrogs (R. catesbeiana), plains leopard frogs have become scarce.

3. Life History Features.

A. Breeding. Amplexus and reproduction are aquatic (Johnson, 1997).

i. Breeding migrations. Likely from upland (southern distribution) or overwintering (northern distribution) sites to seasonal, semi-permanent, or fishless permanent wetlands.

ii. Breeding habitat. A variety of aquatic habitats are used, including water-filled ditches, ponds, river sloughs, streams, temporary pools, marshes, wetlands, canyon pools, etc. (Stebbins, 1985; L.E. Brown, 1992; Degenhardt et al., 1996; Johnson, 1997). Breeding has been reported from February–October (L.E. Brown, 1992; Degenhardt et al., 1996).

B. Eggs.

i. Egg deposition sites. Eggs are usually attached to vegetation in shallow water (Frost and Bagnara, 1977; Hammerson, 1982a; Lynch, 1985; Degenhardt et al., 1996).

ii. Clutch size. Each female may produce a clutch of 4,000–6,500 eggs (Frost and Bagnara, 1977; Hammerson, 1982a; Lynch, 1985; Degenhardt et al., 1996; Johnson, 1997). Eggs are reported to hatch in “a few days” (Minton, 2001) to 3 wk (Collins, 1993).

C. Larvae/Metamorphosis.

i. Length of larval stage. Tadpoles usually metamorphose during mid summer; however, those tadpoles that hatch late in the breeding season may overwinter and transform the following spring (Gillis, 1975; Scott and Jennings, 1985; L.E. Brown, 1992; Degenhardt et al., 1996; Johnson, 1997). Late stage tadpoles were described by Korky (1978; see also Scott and Jennings, 1985).

ii. Larval requirements.

a. Food. Likely algivorous–omnivorous suspension feeders, similar to other species of tadpoles within the Rana pipiens complex.

b. Cover. Aquatic macrophytes in seasonal and semi-permanent wetlands provide cover.

iii. Larval polymorphisms. Unknown and unlikely.

iv. Features of metamorphosis. Tadpoles metamorphose at 27–30 mm SVL (Degenhardt et al., 1996; Johnson, 1997).

v. Post-metamorphic migrations. From breeding wetlands to upland feeding sites. Fitch (1958; see also Collins, 1993) recorded successive mass migrations of newly metamorphosed juveniles and adults leaving an upland pond in northeastern Kansas. He speculated that many die when they fail to find aquatic habitat during their movements.

D. Juvenile Habitat. Similar to adults. Lynch (1985; see also L.E. Brown, 1992) found juveniles and adults along streams during autumn.

E. Adult Habitat. Originally a prairie species, plains leopard frogs are now found primarily on grasslands, but can also be found in a variety of other habitats (e.g., oak, oak savanna, oak–pine forests; Stebbins, 1985; L.E. Brown, 1992). Plains leopard frogs are more drought and heat resistant than northern leopard frogs (Rana pipiens; Gillis, 1979; Stebbins, 1985; Minton, 2001). Adults are often associated with prairie potholes, pools in rocky canyons, livestock tanks, streams, and irrigation ditches (Stebbins, 1985; Degenhardt et al., 1996). Although considered by some parasitologists to be aquatic (Brooks, 1976b; see also L.E. Brown, 1992), during the summer, plains leopard frogs can be found some distance from water (Johnson, 1997). Brown and Morris (1990; see also L.E. Brown, 1992) noted that plains leopard frogs were never found in cultivated fields or in mature upland forests.

F. Home Range Size. Unknown.

G. Territories. Unknown.

H. Aestivation/Avoiding Dessication. Unknown. However, when subjected to desiccating conditions, plains leopard frogs will assume a water conservation position of legs tucked into the body and ventral surface pressed against the substrate (Gillis, 1979).

I. Seasonal Migrations. May be more pronounced in the northeastern portion of their range, where breeding ponds may differ and be some distance from overwintering ponds, and moist conditions allow foraging away from open water (Collins, 1993). Collins (1993) also noted that after summer rains, both adults and juveniles traveled long distances from the breeding site.

J. Torpor (Hibernation). Plains leopard frogs overwinter in the mud and dead leaves in ponds and streams (L.E. Brown, 1992; Collins, 1993; Johnson, 1997). They are active under the ice (Black et al., 1976; see also L.E. Brown, 1992) and on land during the winter (Collins, 1993).

K. Interspecific Associations/Exclusions. Plains leopard frogs coexist with Chiricahua leopard frogs (R. chiricahuensis) and their range overlaps with Rio Grande leopard frogs (R. berlandieri; Stebbins, 1985). In central Texas, plains leopard frogs hybridize with Rio Grande leopard frogs (Platz, 1981; Stebbins, 1985). Plains leopard frogs can overlap with northern leopard frogs in the northern part of their range and southern leopard frogs (R. sphenocephala) in the southern part of their range (Conant and Collins, 1998). Hybridization with both species may occur, but this normally is caused by habitat disturbance and alteration due to human activity (Hammerson, 1982a; L.E. Brown, 1992; Collins, 1993; Johnson, 1997; Minton, 2001).

L. Age/Size at Reproductive Maturity. Adults range from 51–111 mm SVL, with western animals being larger (Minton, 2001). In Indiana, males range from 47.0–61.7 mm, and females from 50.5–59.3 mm (Minton, 2001).

M. Longevity. Unknown.

N. Feeding Behavior. Feed on a variety of insects, spiders, annelids, snails, and other invertebrates (Hammerson, 1982a; L.E. Brown, 1992; Degenhardt et al., 1996; Johnson, 1997). Collins (1993) states that plains leopard frogs feed primarily on nonaquatic insects. Examination of stomach contents of Kansas specimens revealed beetles, grasshoppers, crickets, worms, and aquatic snails (Collins, 1993). Plains leopard frogs have also eaten bats (Creel, 1963; Degenhardt et al., 1996).

O. Predators. Predatory fishes (Kruse and Francis, 1977), American bullfrogs (Kruse and Francis, 1977; Smith, 1977; Ehrlich, 1979; Hammerson, 1982b; Hammerson, 1999), and snakes including western terrestrial garter snakes (Thamnophis elegans) and black-necked garter snakes (T. cyrtopsis; Hammerson, 1982a, 1999). Avian predators include Mississippi kites (Ictina mississippiensis; Robinson, 1957) and perhaps burrowing owls (Athene cunicularia; Parmley and Tyler, 1978). Mammalian predators include blacktail prairie dogs (Cyonomys ludovicianus; Parmley and Tyler, 1978; L.E. Brown, 1992), raccoons, opossums, and skunks (Collins, 1993).

P. Anti-Predator Mechanisms. When frightened, plains leopard frogs will leap away from, rather than towards, water (Frost and Bagnara, 1977). When captured by a predator, plains leopard frogs often emit a loud distress call (Degenhardt et al., 1996). Breeding in seasonal and semi-permanent wetlands reduces the risk of American bullfrog predation (Hammerson, 1999).

Q. Diseases. Unreported.

R. Parasites. Platyhelminths (Brooks, 1976b) and cephalogonimid trematodes (Brooks and Welch, 1976).

4. Conservation. Plains leopard frogs are generally widespread and abundant throughout most of their range, (Conant and Collins, 1998). Isolated populations occur in southern Illinois, New Mexico, and southeastern Arizona (L.E. Brown, 1992; L.E. Brown et al., 1993; Conant and Collins, 1998). Arizona has legally Protected plain leopard frogs, which means a permit is required to collect and/or possess these animals (Levell, 1997).

The decline and extirpation of populations has been documented by a number of researchers (e.g., Frost and Bagnara, 1977; Platz, 1981; Hammerson, 1982a,b; Frost, 1983; Hayes and Jennings, 1986; Clarkson and Rorabaugh, 1989; Christiansen and Bailey, 1991; Cousineau and Rogers, 1991; L.E. Brown, 1992). Hammerson (1999) noted that in areas in Colorado now occupied by American bullfrogs, plains leopard frogs have become scarce. Brown and Morris (1990; see also L.E. Brown, 1992) never found plains leopard frogs in cultivated fields, and the conversion of the Midwest prairies to agriculture has most likely most likely led to a decline in plains leopard frog populations.

¹John A. Crawford
Division of Biological Sciences
University of Missouri
105 Tucker Hall
Columbia, Missouri 65211-7400
jac7vc@mizzou.edu

²Lauren E. Brown
Department of Biological Sciences
Illinois State University
Campus Box 4120
Normal, Illinois 61790-4120

³Charles W. Painter
Endangered Species Program
New Mexico Department of Game and Fish
P.O. Box 25112
Santa Fe, New Mexico 87504
cpainter@state.nm.us

Citation: AmphibiaWeb. 2024. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 24 Nov 2024.

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