Great Plains Toad - Anaxyrus cognatus
State Rank Reason (see State Rank above)
Current trend is unknown due to a scarcity of observations, but long-term declines are possible due to declines in ephemeral waterbodies (bison wallows). Species faces threats from habitat loss including development of native habitat, and reduced availability of burrows due to black-tailed prairie dog declines.
- Details on Status Ranking and Review
Great Plains Toad (Anaxyrus cognatus) Conservation Status Review
Review Date = 05/03/2018
ScoreG - 200,000-2,500,000 km squared (about 80,000-1,000,000 square miles)
Comment233,208 square Kilometers from Natural Heritage Program range maps
ScoreA - Very Large Decline (decline of >90%, with <10% of population size, range extent, area occupied, and/or number or condition of occurrences remaining)
CommentHistoic data sugest that this species made extensive use of buffalo wallows for breeding which may indicate a substanital decline in available breeding habitat
ScoreU - Unknown. Short-term trend in population, range, area occupied, and number and condition of occurrences unknown.
CommentRecent calling surveys recorded few observations of this species.
ScoreB - Moderate and imminent threat. Threat is moderate to severe and imminent for a significant proportion (20-60%) of the population or area.
CommentLoss of habitat due to conversion of native prairie to agriculture. Loss of hibernacula/ burrow systems due to prairie dog declines. Water quality of breeding sites. Lack of knowledge to assess threats.
SeverityModerate - Major reduction of species population or long-term degradation or reduction of habitat in Montana, requiring 50-100 years for recovery.
ScopeModerate - 20-60% of total population or area affected
ImmediacyHigh - Threat is operational (happening now) or imminent (within a year).
ScoreC - Not Intrinsically Vulnerable. Species matures quickly, reproduces frequently, and/or has high fecundity such that populations recover quickly (< 5 years or 2 generations) from decreases in abundance; or species has high dispersal capability such that extirpated populations soon become reestablished through natural recolonization (unaided by humans).
CommentSpecies mature in 2-3 years, produce thousands of eggs with low survival
ScoreB - Narrow. Specialist. Specific habitat(s) or other abiotic and/or biotic factors (see above) are used or required by the Element, but these key requirements are common and within the generalized range of the species within the area of interest.
CommentPlains /xeric landscapes near drainages and waterbodies
Raw Conservation Status Score
3.5 + 0 (geographic distribution) + 0 (environmental specificity) + -0.5 (long-term trend) + -0.75 (threats) = 2.25
Laid communally in single or more rarely double strings containing 1,342 to 45,054 eggs (Bragg 1937a, Krupa 1994). Each ovum is black above, shaded progressively lighter to white below. There are two jelly layers surrounding each ovum, including the outer jelly layer that composes the string (Bragg 1937a). Ovum diameters are approximately 1.2-1.3 mm, but total egg diameters, including the two jelly layers are approximately 2.0 mm. The jelly string is constricted between eggs to approximately 1.7 mm (Bragg 1937a).
Mottled brown and gray dorsally with a light greenish-yellow and reddish iridescence ventrally (Bragg 1936). The dorsal tail fin is dendritically pigmented and highly arched while the ventral tail fin is of uniform width and transparent (Bragg 1936). The dorsal pattern of large, paired blotches appears before metamorphosis is complete. The upper mandible is highly arched and labial tooth rows are usually 2/3 with oral papillae restricted to the sides of the mouth. Eyes are located dorsally. Total length (TL) of 8-29 mm (Bragg 1936, Bragg 1940a).
JUVENILES AND ADULTS
The skin is covered with numerous small warts. Juveniles typically have reddish colored warts. A white stripe usually extends down the center of the back and large paired green to brown blotches are present dorsally. These blotches are outlined or separated by white bands. The ventral side is cream to white colored (Krupa 1990). Large parotid glands are present behind the eyes. The underside of the hind foot often has a sharp-edged tubercle and a smaller dark-tipped tubercle. Except for small metamorphs, a large bony plate or hard lump (boss) covers the snout from the tip to the front of the eyes. In addition, cranial crests are present behind the eyes and converge toward the boss on the snout to form a “V” between the eyes (Krupa 1990). Snout-vent length (SVL) of males is typically less than 95 mm and females can reach up to 115 mm (Bragg 1937b; Bragg 1940a; Krupa 1990). Males have dark, loose throat skin and a dark patch on the inner surface of the innermost digit of the forefeet during breeding. The vocal sac, when inflated, may extend beyond the front of the face.
The geographic range of Western Toad (Anaxyrus boreas
) does not overlap with the geographic range of Great Plains Toad and adult Western Toad lack cranial crests. If present in Montana, the Canadian Toad (Anaxyrus hemiophrys
) are probably limited to the extreme northeast corner of the state and adults either lack or have weakly developed cranial crests behind the eyes.
Although overlap in habitat use exists, Woodhouse’s Toad (Anaxyrus woodhousii
) seem to be more commonly associated with sandy soils on floodplains while the Great Plains Toad is more commonly associated with heavier soils in upland habitats (Timken and Dunlap 1965). Eggs and larvae of Woodhouse’s and Great Plains Toad are very similar and may not be differentiable by even thoroughly trained herpetologists. However, Woodhouse's Toad tadpoles lack the strongly arched tail fin and eggs are enclosed in a single jelly layer. In addition, eggs and larvae of Woodhouse’s Toad are much more likely to be found in permanent or semi-permanent waters than those of Great Plains Toad (Bragg 1940a). Adult Woodhouse’s Toad lack the shield or ‘boss’ on the tip of the snout and have “L” shaped cranial crests between and behind each eye. Metamorph Woodhouse’s Toad lack the large paired dorsal blotches that are present on Great Plains Toad (Bragg 1937b).
Western Hemisphere Range
The Great Plains Toad is recognized as a distinct species. The range consists of the Great Plains from central Mexico to southeastern Alberta and in the desert southwest as far west as eastern California and as far north as southern Utah. Great Plains Toad can be found at elevations up to 2,440 m (8,000 ft) (Stebbins 2003, Goebel 1996). In Montana they have been sparsely documented across the plains east of Shelby, Great Falls, Lewiston, and Billings.
Maximum elevation: 1,319 m (4327 ft) Hensley Creek drainage, 20.3 km E of Warner Hill, N of Columbus in Stillwater County (Grover, Cole and Dell Despain MTNHP 2010).
Observations in Montana Natural Heritage Program Database
Number of Observations:
(Click on the following maps and charts to see full sized version)
Map Help and Descriptions
(Observations spanning multiple months or years are excluded from time charts)
No information is available specific to Montana. Elsewhere the species is known to migrate up to several hundred meters between breeding pools and nonbreeding terrestrial habitats.
Little specific information on the habitat of Great Plains Toad is available. The Great Plains Toad can be found in floodplain habitats but are more common in upland grasslands with harder packed soils (Bragg 1940a, Smith and Bragg 1949, Timken and Dunlap 1965). Great Plains Toads have been reported from sagebrush-grassland, rainwater pools in road ruts, in stream valleys, at small reservoirs and stock ponds, and around rural farms; breeding has been documented in small reservoirs and backwater sites along streams (Mosimann and Rabb 1952, Dood 1980, Hendricks 1999a, Hossack et al. 2003). When inactive, adults lie dormant in rodent or self-excavated burrows and under rocks and wood when terrestrial conditions are not favorable. When conditions are warmer and moist, they will emerge to feed (Bragg 1937a, Smith and Bragg 1949, Dimmitt and Ruibal 1980, Flowers and Graves 1994, 1995).
Ecological Systems Associated with this Species
- Details on Creation and Suggested Uses and Limitations
How Associations Were Made
We associated the use and habitat quality (common or occasional) of each of the 82 ecological systems mapped in Montana for
vertebrate animal species that regularly breed, overwinter, or migrate through the state by:
- Using personal observations and reviewing literature that summarize the breeding, overwintering, or migratory habitat requirements of each species (Dobkin 1992, Hart et al. 1998, Hutto and Young 1999, Maxell 2000, Foresman 2012, Adams 2003, and Werner et al. 2004);
- Evaluating structural characteristics and distribution of each ecological system relative to the species' range and habitat requirements;
- Examining the observation records for each species in the state-wide point observation database associated with each ecological system;
- Calculating the percentage of observations associated with each ecological system relative to the percent of Montana covered by each ecological system to get a measure of "observations versus availability of habitat".
Species that breed in Montana were only evaluated for breeding habitat use, species that only overwinter in Montana were only evaluated for overwintering habitat use, and species that only migrate through Montana were only evaluated for migratory habitat use.
In general, species were listed as associated with an ecological system if structural characteristics of used habitat documented in the literature were present in the ecological system or large numbers of point observations were associated with the ecological system.
However, species were not listed as associated with an ecological system if there was no support in the literature for use of structural characteristics in an ecological system, even if
point observations were associated with that system.
Common versus occasional association with an ecological system was assigned based on the degree to which the structural characteristics of an ecological system matched the preferred structural habitat characteristics for each species as represented in scientific literature.
The percentage of observations associated with each ecological system relative to the percent of Montana covered by each ecological system was also used to guide assignment of common versus occasional association.
If you have any questions or comments on species associations with ecological systems, please contact the Montana Natural Heritage Program's Senior Zoologist.
Suggested Uses and Limitations
Species associations with ecological systems should be used to generate potential lists of species that may occupy broader landscapes for the purposes of landscape-level planning.
These potential lists of species should not be used in place of documented occurrences of species (this information can be requested at: mtnhp.org/requests
) or systematic surveys for species and evaluations of habitat at a local site level by trained biologists.
Users of this information should be aware that the land cover data used to generate species associations is based on imagery from the late 1990s and early 2000s and was only intended to be used at broader landscape scales.
Land cover mapping accuracy is particularly problematic when the systems occur as small patches or where the land cover types have been altered over the past decade.
Thus, particular caution should be used when using the associations in assessments of smaller areas (e.g., evaluations of public land survey sections).
Finally, although a species may be associated with a particular ecological system within its known geographic range, portions of that ecological system may occur outside of the species' known geographic range.
- Adams, R.A. 2003. Bats of the Rocky Mountain West; natural history, ecology, and conservation. Boulder, CO: University Press of Colorado. 289 p.
- Dobkin, D. S. 1992. Neotropical migrant land birds in the Northern Rockies and Great Plains. USDA Forest Service, Northern Region. Publication No. R1-93-34. Missoula, MT.
- Foresman, K.R. 2012. Mammals of Montana. Second edition. Mountain Press Publishing, Missoula, Montana. 429 pp.
- Hart, M.M., W.A. Williams, P.C. Thornton, K.P. McLaughlin, C.M. Tobalske, B.A. Maxell, D.P. Hendricks, C.R. Peterson, and R.L. Redmond. 1998. Montana atlas of terrestrial vertebrates. Montana Cooperative Wildlife Research Unit, University of Montana, Missoula, MT. 1302 p.
- Hutto, R.L. and J.S. Young. 1999. Habitat relationships of landbirds in the Northern Region, USDA Forest Service, Rocky Mountain Research Station RMRS-GTR-32. 72 p.
- Maxell, B.A. 2000. Management of Montana's amphibians: a review of factors that may present a risk to population viability and accounts on the identification, distribution, taxonomy, habitat use, natural history, and the status and conservation of individual species. Report to U.S. Forest Service Region 1. Missoula, MT: Wildlife Biology Program, University of Montana. 161 p.
- Werner, J.K., B.A. Maxell, P. Hendricks, and D. Flath. 2004. Amphibians and reptiles of Montana. Missoula, MT: Mountain Press Publishing Company. 262 p.
- Commonly Associated with these Ecological Systems
Shrubland, Steppe and Savanna Systems
Sparse and Barren Systems
Wetland and Riparian Systems
- Occasionally Associated with these Ecological Systems
Forest and Woodland Systems
Human Land Use
Shrubland, Steppe and Savanna Systems
Wetland and Riparian Systems
Although food habits in Montana have not been studied, adult and juvenile Great Plains Toads are generally known to eat a variety of small terrestrial invertebrates, including spiders, moths, caterpillars, flies, beetles, termites, and ants (Bragg 1937a, Smith and Bragg 1949, Dimmitt and Ruibal 1980, Flowers and Graves 1994, 1995, Hammerson 1999). Great Plains Toads require 11 to 22 feedings per year to survive. In the playa wetlands of northwest Texas, carabid beetles were the most common food (Anderson et al. 1999). Larvae are herbivorous and detritivores and eat suspended matter, organic debris, algae, and plant tissue (Bragg 1940a).
Great Plains Toads are uncommon near human habitation (Black 1970d). They are mainly nocturnal (Bragg 1940a, Black 1970d). Eggs are wrapped around vegetation on the pond bottom and hatch in 2-3 days (Bragg 1937a, Bragg 1940a). Tadpoles metamorphose in 18 to 45 days (Bragg 1937b, Bragg 1940a, Krupa 1994). Post-metamorphic young may form aggregations (Graves 1993). Creusere and Whitford (1976) found individuals 1,600 meters from the nearest breeding site but is likely that they range farther than this. Population explosions and mass unidirectional migrations have been reported for local areas as well as regions as large as several thousand square miles in area (Bragg and Brooks 1958).
This species enters water only to breed after late spring and summer rains when minimum temperatures are above 12 °C (Bragg 1937a, Bragg 1940a, Krupa 1994). It breeds almost exclusively in clear and shallow temporary waters including rain pools, flooded areas, and ponds and reservoirs that fluctuate in size. Great Plains Toad appear to prefer breeding in stock tanks and roadside ponds rather than floodplains (Baxter and Stone 1985). Eggs and larvae develop in shallow water, usually clear or slightly turbid, but not muddy.
From information gathered in Oklahoma, breeding choruses usually last a few days but are of variable duration. They lasted up to 14 days in March but only 1 to 2 days in June (Krupa 1994). Clutch size was usually several thousand eggs that hatch in a few days. The larval period was short (as few as 18 days) in June and long (up to 49 days) in early spring. Pools rarely held water long enough for larvae to reach metamorphosis (Krupa 1994). Great Plains Toads are sexually mature in 2 to 5 years. The species commonly exhibits communal egg deposition (Krupa 1994).
In Montana, Great Plains toads have been documented breeding in temporary pools of flooded grasslands in May to July (Bragg 1940a, Black 1970d). Two of three females collected in north-central Montana on July 20 had well developed eggs (Mosimann and Rabb 1952).
The following was taken from the Status and Conservation section for the Great Plains Toad account in Maxell et al. 2009
In the past 150 years Great Plains Toads have only been documented at about 30 localities across the plains east of the Rocky Mountains and at the present time their status across this region is almost completely unknown. Risk factors relevant to the viability of populations of this species are likely to include grazing, use of pesticides and herbicides, nonindigenous species, road and trail development, on- and off-road vehicle use, development of water impoundments, habitat loss/fragmentation, and metapopulation impacts, all as described above. However, the lack of information on the distribution, status, habitat use, and basic biology of the species may currently represent the greatest risk to the viability of the species (i.e., the species could have undergone, or currently be undergoing, drastic declines but we lack any kind of baseline information that would allow us to make such a determination). Individual studies that specifically identify risk factors or other issues relevant to the conservation of the Great Plains Toad include the following. (1) Bragg (1937a) reports that all Great Plains Toad eggs in pools that were heavily contaminated with fecal material from cattle died while other eggs in nearby uncontaminated pools survived. (2) Several authors report that large numbers are killed on highways by motor vehicles (Bragg 1940a, Bragg and Brooks 1958, Hammerson 1999). Bragg and Brooks (1958) report a mean of 60 individuals per 30 linear feet of highway were killed on roads in North Dakota and Minnesota during a population explosion and mass migration event. (3) Hammerson (1999) notes that several populations have been extirpated due to residential and commercial development in Colorado. (4) Stuart (1995) found exotic American Bullfrogs (Lithobates catesbeianus
) preying on Great Plains Toads. (5) Great Plains Toads often occupy Prairie Dog (Cynomys
sp.) burrows and these burrows may serve as critical refugia for the species (Craig Knowles, Fauna West Wildlife Consultants, pers. comm.).
- Literature Cited AboveLegend: View Online Publication
- Anderson, A. M., D. A. Haukos, and J. T. Anderson. 1999. Diet composition of three anurans from the playa wetlands of northwest Texas. Copeia 1999:515-520.
- Baxter, G.T. and M.D. Stone. 1985. Amphibians and reptiles of Wyoming. Second edition. Wyoming Game and Fish Department. Cheyenne, WY. 137 p.
- Black, J.H. 1970d. Some aspects of the distribution, natural history and zoogeography of the toad genus Bufo in Montana. M.S. thesis. University of Montana, Missoula, MT. 70 p.
- Bragg, A. N. 1940a. Observations on the ecology and natural history of Anura. I. Habits, habitat and breeding of Bufo cognatus Say. American Naturalist 74: 322-349, 424-438.
- Bragg, A.N. 1936. Notes on the breeding habits, eggs and embryos of Bufo cognatus with a description of the tadpole. Copeia 1936: 14-20.
- Bragg, A.N. 1937a. A note on the metamorphosis of the tadpoles of Bufo cognatus. Copeia 1937: 227-228.
- Bragg, A.N. 1937b. Observations on Bufo cognatus with special references to breeding habits and eggs. American Midland Naturalist 18: 273-284.
- Bragg, A.N. and M. Brooks. 1958. Social behavior in juveniles of Bufo cognatus Say. Herpetologica 14: 141-147.
- Creusere, F.M. and W.G. Whitford. 1976. Ecological relationships in a desert anuran community. Herpetologica 32: 7-18.
- Dimmitt, M.A. and R. Ruibal. 1980. Exploitation of food resources by spadefoot toads (Scaphiopus). Copeia (4): 854-862.
- Dood, A.R. 1980. Terry Badlands nongame survey and inventory final report. Montana Department of Fish, Wildlife, and Parks and Bureau of Land Management, Helena, MT. 70 pp.
- Flowers, M.A. and B.M. Graves. 1994. Feeding ecology of juvenile great plains toad (Bufo cognatus) and woodhouse's toad (Bufo woudhousii). North Dakota Academy of Science Proceedings. 48: 22
- Flowers, M.A. and B.M. Graves. 1995. Prey selectivity and size-specific diet changes in Bufo cognatus and Bufo woudhousii during early postmetamorphic ontogeny. Journal of Herpetology 29(4): 608-612.
- Goebel, A.M. 1996. Systematics and conservation of bufonids in North America and in the Bufo boreas species group. Ph.D. Dissertation. University of Colorado, Boulder, CO. 274 p.
- Graves, R. J. 1993. Ecology and exploitation of crayfish (Pacifastacus leniusculus) in Noxon Rapids Reservoir, Montana. M.A. thesis. University of Montana, Missoula, MT. 88 p.
- Hammerson, G.A. 1999. Amphibians and reptiles in Colorado. University Press of Colorado & Colorado Division of Wildlife. Denver, CO. 484 p.
- Hendricks, P. 1999a. Amphibian and reptile survey of the Bureau of Land Management Miles City District, Montana. Montana Natural Heritage Program, Helena, MT. 80 p.
- Hossack, B., D. Pilliod, and S. Corn. 2003. Amphibian survey of Medicine Lake National Wildlife Complex: 2001-2002. USGS Northern Rocky Mountain Science Center, Aldo Leopold Wilderness Research Institute, Missoula, Montana. 19 p.
- Krupa, J.J. 1994. Breeding biology of the Great Plains toad in Oklahoma. Journal of Herpetology 28: 217-224.
- Maxell, B.A., P. Hendricks, M.T. Gates, and S. Lenard. 2009. Montana amphibian and reptile status assessment, literature review, and conservation plan, June 2009. Montana Natural Heritage Program. Helena, MT. 643 p.
- Mosimann, J.E. and G.B. Rabb. 1952. The herpetology of Tiber Reservoir Area, Montana. Copeia(1): 23-27.
- Smith, C.C. and A.N. Bragg. 1949. Observations on the ecology and natural history of Anura, VII. Food and feeding habits of the common species of toads in Oklahoma. Ecology 30(3): 333-349.
- Stebbins, R. C. 2003. A field guide to western reptiles and amphibians. 3rd Edition. Houghton Mifflin Company, Boston and New York. 533 p.
- Stuart, J.N. 1995. Anura: Rana catesbeiana (Bullfrog). Diet. Herpetological Review 26(1): 33.
- Timken, R.L. and D.G. Dunlap. 1965. Ecological distribution of the two species of Bufo in southeastern South Dakota. Proceedings of the South Dakota Academy of Sciences 44: 113-117.
- Additional ReferencesLegend: View Online Publication
Do you know of a citation we're missing?
- [PRESI] Powder River Eagle Studies Incorporated. 1998a. Big Sky Mine 1997 wildlife monitoring studies. Powder River Eagle Studies Incorporated. Gillete, WY.
- [PRESI] Powder River Eagle Studies Incorporated. 1998b. Spring Creek Mine 1997 wildlife monitoring studies. Powder River Eagle Studies Incorporated. Gillete, WY.
- [WESCO] Western Ecological Services Company. 1983a. Wildlife inventory of the Knowlton known recoverable coal resource area, Montana. Western Ecological Services Company, Novato, CA. 107 p.
- [WESCO] Western Ecological Services Company. 1983b. Wildlife inventory of the Southwest Circle known recoverable coal resource area, Montana. Western Ecological Services Company, Novato, CA. 131 p.
- Armentrout, D. and F.L. Rose. 1971. Some physiological responses to anoxia in the Great Plains toad (Bufo cognatus). Comparative Biochemistry and Physiology 38A(1): 447-455.
- Bieniak, A., and R. Watka. 1962. Vascularization of respiratory surfaces in Bufo cognatus Say and Bufo compactilis Wiegmann. Academy of Poland Science Services Science and Biology Bulletin 10: 9-12.
- Black, J.H. 1967a. Toads of Montana. Montana Wildlife 1967(Spring): 22-28.
- Black, J.H. 1971. The toad genus Bufo in Montana. Northwest Science 45: 156-162.
- Boundy, J. 1992a. Bufo cognatus (Great Plains toad). Herpetological Review 23(4) 122.
- Bragg, A.N. 1938a. Observations on the natural history of Bufo cognatus Say. Proceedings of the Oklahoma Academy of Science 19: 41-42.
- Bragg, A.N. 1939a. Possible hybridization of Bufo cognatus and B. w. woodhousii. Copeia 1939(3): 173.
- Bragg, A.N. 1950. Size range in adults of the toad Bufo cognatus. Copeia 1950(2): 153-154.
- Bragg, A.N. 1958. A melanistic tendency in the Great Plains toad (Bufo cognatus). Southwest Naturalist 3(1-4): 229-230.
- Bragg, A.N. and A.O. Weese. 1950. Observations on the ecology and natural history of Anura. XIV. Growth rates and age at sexual maturity of Bufo cognatus under natural conditions in central Oklahoma, p. 47-58. In researches on the amphibians of Oklaho
- Bragg, A.N. and C.C. Smith. 1942. Observations on the ecology and natural history of Anura. IX. Notes on breeding behavior in Oklahoma. Great Basin Naturalist 3: 33-50.
- Bragg, A.N. and J. Bresler. 1950. Viability of the eggs of Bufo cognatus. Proceedings of the Oklahoma Academy of Science 32: 13-14.
- Brown, L.E. and J.R. Pierce. 1967. Male-male interactions and chorusing intensities of the Great Plains toad, Bufo cognatus. Copeia 1967(1): 149-154.
- Brown, L.E. and M.A. Ewert. 1971. A natural hybrid between the toads Bufo hemiophrys and Bufo cognatus in Minnesota. Journal of Herpetology 5(1): 78-82.
- Brunson, R.B. 1955. Check list of the amphibians and reptiles of Montana. Proceedings of the Montana Academy of Sciences 15: 27-29.
- Carlsen, T. and R. Northrup. 1992. Canyon Ferry Wildlife Management Area Final Draft Management Plan. March 1992.
- Carlson, J. (Coordinator, Montana Animal Species of Concern Committee). 2003. Montana Animal Species of Concern January 2003. Helena, MT: Montana Natural Heritage Program and Montana Fish, Wildlife, and Parks. In Press. 12p.
- Cook, F.R. 1960. New localities for the plains spadefoot toad, tiger salamander, and the great plains toad in the Canadian prairies. Copeia 1960 (4): 363-364.
- Cooper, S.V., C. Jean, and P. Hendricks. 2001. Biological survey of a prairie landscape in Montana's glaciated plains. Report to the Bureau of Land Management. Montana Natural Heritage Program, Helena, MT. 24 pp. plus appendices.
- Cope, E. D. 1879. A contribution to the zoology of Montana. American Naturalist 13(7): 432-441.
- Cope, E.D. 1889. The Batrachia of North America. Bulletin of the U.S. National Museum 34: 1-525, figs. 1-119, pls. 1-86.
- Cornejo, D.O. 1986. Larval community structure in four species of non-riparian Sonoran Desert anurans. M.S. Thesis, University of Arizona. 176 p.
- Crother, B.I. (ed.) 2008. Scientific and standard English names of amphibians and reptiles of North America north of Mexico. SSAR Herpetological Circular No. 37:1-84.
- Econ, Inc. 1988. Wildlife monitoring report, 1987 field season, Big Sky Mine. March 1988. In Peabody Mining and Reclamation Plan Big Sky Mine Area B. Vol. 8, cont., Tab 10 - Wildlife Resources. Appendix 10-1, 1987 Annual Wildlife Report.
- Edwards, J.R., J.L. Jenkins, and D.L. Swanson. 2004. Seasonal effects of dehydration on glucose mobilization in freeze-tolerant chorus frogs (Pseudaris triseriata) and free-tolerant toads (Bufo woodhousii and B. cognatus). Journal of Experimental Zoolo
- Ewert, M.A. 1969. Seasonal movements of the toads Bufo americanus and Bufo cognatus in northwestern Minnesota. Ph.D. dissertation. University of Minnesota. 193 pp.
- Fjell, Alan K., 1986, Peabody Coal Company Big Sky Mine, Rosebud County, MT. Wildlife monitoring report: 1985 field season. March 1986.
- Fjell, Alan K., and Brian R. Mahan, compilers., 1984, Peabody Coal Company Big Sky Mine, Rosebud County, MT. Wildlife monitoring report: 1983 field season. February 1984.
- Fjell, Alan K., and Brian R. Mahan., 1983, Peabody Coal Company Big Sky Mine, Rosebud County, MT. Wildlife monitoring report: 1982 field season. May 1983.
- Fjell, Alan K., and Brian R. Mahan., 1985, Peabody Coal Company Big Sky Mine, Rosebud County, MT. Wildlife monitoring report: 1984 field season. February 1985.
- Fjell, Alan K., and Brian R. Mahan., 1987, Big Sky Mine, Rosebud County, MT. Wildlife monitoring report: 1986 field season. April 1987.
- Flath, D.L. 2002. Reptile and amphibian surveys in the Madison-Missouri River Corridor, Montana. Annual Progress Report. 14pp.
- Flowers, M.A. and B.M. Graves. 1997. Juvenile toads avoid chemical cues from snake predators. Animal Behaviour 53(3): 641-646.
- Gates, M.T. 2005. Amphibian and reptile baseline survey: CX field study area Bighorn County, Montana. Report to Billings and Miles City Field Offices of Bureau of Land Management. Maxim Technologies, Billings, MT. 28pp + Appendices.
- Goldberg, S.R. and C.R. Bursey. 1991. Helminths of three toads, Bufo alvarius, Bufo cognatus (Bufonidae), and Scaphiopus couchii (Pelobatidae), from southern Arizona (USA). Journal of the Helminthological Society of Washington 58(1): 142-146.
- Goldberg, S.R., C.R. Bursey and I. Ramos. 1995. The component parasite community of three sympatric toad species, Bufo cognatus, Bufo debilis (Bufonidae), and Spea multiplicata (Pelobatidae) from New Mexico. Journal of the Helminthological Society of W
- Graves, B.M., C.H. Summers, and K.L. Olmstead. 1993. Sensory mediation of aggregation among postmetamorphic Bufo cognatus. Journal of Herpetology 27(3) 315-319.
- Gray, M.J., D.L. Miller, and L.M. Smith. 2005. Coelomic response and signal range of implant transmitters in Bufo cognatus. Herpetological Review 36(3):285-288.
- Hanauska-Brown, L., B.A. Maxell, A. Petersen, and S. Story. 2014. Diversity Monitoring in Montana 2008-2010 Final Report. Montana Fish, Wildlife & Parks. Helena, MT. 78 pp.
- Harvey, L.A. 1992. A skeletochronologic analysis of a high altitude population of Bufo cognatus. Bios 62(3/4): 232.
- Hayden, F.V. 1862. On the geology and natural history of the upper Missouri. Transactions of the American Philosophical Society New Series 12(1): 1-218
- Hendricks, P. and J.D. Reichel. 1996b. Preliminary amphibian and reptile survey of the Ashland District, Custer National Forest: 1995. Montana Natural Heritage Program, Helena, MT. 79 p.
- Hendricks, P. and J.D. Reichel. 1998. Amphibian and reptile survey on Montana refuges: 1996. Montana Natural Heritage Program, Helena, MT. 19 p.
- Holycross, A.T. and K.B. Malmos. 1992a. Bufo cognatus (Great Plains toad). Herpetological Review 23(1) 1992: 24.
- Jense, G.K. and R.L. Linder. 1970. Food habits of badgers in eastern South Dakota. Proceedings of the South Dakota Academy of Science 49: 37-41.
- Johnson, K.H., G.L. Kurz, R.A. Olson and T.D. Whitson. 1994. Bufo cognatus (Great Plains toad). Herpetological Review 25(2): 74.
- Johnson, W.E. and C.R. Propper. 1993. Effects of temperature and dehydration on feeding behavior of the Great Plains toad, Bufo cognatus. American Zoologist 33(5): 86A.
- Kilgore, D.L., Jr. 1969. An ecological study of the swift fox (Vulpes velox) in the Oklahoma panhandle. American Midland Naturalist 83(2): 512-534.
- Killebrew, F.C., K.B. Blair, H.M. Smith and D. Chiszar. 1995. Bufo cognatus (Great Plains toad). Herpetological Review 26(3): 151.
- Krupa, J.J. 1986. Multiple egg clutch production in the Great Plains toad. Prairie Naturalist 18: 151-152.
- Krupa, J.J. 1988a. Fertilization efficiency in the Great Plains toad (Bufo cognatus). Copeia 1988(3) 800-802.
- Krupa, J.J. 1988b. Mate choice and mate location tactics in the Great Plains toad (Bufo cognatus). Ph.D. Dissertation, University of Oklahoma. 102 p.
- Krupa, J.J. 1989. Alternative mating tactics in the Great Plains toad. Animal Behaviour 37(6): 1035-1043.
- Krupa, J.J. 1990a. Advertisement call variation in the Great Plains toad. Copeia 1990: 884-886.
- Krupa, J.J. 1990b. Bufo cognatus Say. Great Plains Toad. Catalogue of American Amphibians and Reptiles 457.1-457.8.
- Krupa, J.J. 1990c. Advertisement call variation in the Great Plains toad. Copeia. 1990(3). 884-886.
- Krupa, J.J. 1995b. How likely is male mate choice among anurans? Behaviour 132(9-10): 643-664.
- Leary, C.J., T.S. Jessop, A.M. Garcia, and R. Knapp. 2004. Steroid hormone profiles and relative body condition of calling and satelittle toads: implications for proximate regulation behavior in anurans. Behavioral Ecology 15(2):313-320.
- Livo, L.J. 1990a. Bufo cognatus (Great Plains toad). Microhabitat selection. Herpetological Review 21(3): 58.
- Logier, E.B.S. 1931. Bufo cognatus cognatus from Alberta. Canadian Field Naturalist 45: 90.
- Lomolino, M.V. and G.A. Smith. 2004. Terrestrial vertebrate communities at black-tailed prairie dog (Cynomys ludovicianus) towns. Biological Conservation 115(1):89-100.
- Long, D.R. 1987b. Reproductive and lipid patterns of a semiarid-adapted anuran, Bufo cognatus. Texas Journal of Science 39(1): 3-14.
- Martin, P.R. 1980b. Terrestrial wildlife inventory in selected coal areas of Montana. Montana Department of Fish, Wildlife and Parks and Bureau of Land Management, Helena, MT. 84 p.
- Martin, P.R., K. Dubois and H.B. Youmans. 1981. Terrestrial wildlife inventory in selected coal areas, Powder River resources area final report. Montana Department of Fish, Wildlife and Parks and Bureau of Land Management, Helena, MT. No. YA-553-CTO- 24. 288 p.
- Maxell, B. A. 2000. Management of Montana's amphibians: a review of factors that may present a risk to population viability and accounts on the identification, distribution, taxonomy, habitat use, natural history, and the status and conservation of individual species. Report to USFS Region 1, Order Number 43-0343-0-0224. University of Montana, Wildlife Biology Program. Missoula, MT. 161 p.
- Maxell, B.A., J.K. Werner, P. Hendricks, and D.L. Flath. 2003. Herpetology in Montana: a history, status summary, checklists, dichotomous keys, accounts for native, potentially native, and exotic species, and indexed bibliography. Society for Northwestern Vertebrate Biology, Northwest Fauna Number 5. Olympia, WA. 135 p.
- McAllister, C.T. and S.E. Trauth. 1995. New host records for Myxidium serotinum (Protozoa: Myxosporea) from North American amphibians. Journal of Parasitology 81(3): 485-488.
- McEneaney, T. and J. Jensen. 1974. The reptiles and amphibians of the Charles M. Russell National Wildlife Range - 1974. Charles M. Russell National Wildlife Refuge. Lewistown, MT. 3 p.
- Moore, J.E. 1953. Additional records of the toad Bufo cognatus in Alberta. Copeia 1953: 180-181.
- Mulcahy, D.G., M.R. Cummer, J.R. Mendelson III, B.L. Williams, and P.C. Ustach. 2002. Status and distribution of two species of Bufo in the Northeastern Bonneville Basin of Idaho and Utah. Herpetological Review 33(4):287-289.
- Paulson, B.K. and V.H. Hutchison. 1987. Blood changes in Bufo cognatus following acute heat stress. Comparative Biochemistry and Physiology A Comparative Physiology 87(2): 461-466.
- Powder River Eagle Studies, Inc., Gillette, WY., 1996, Spring Creek Mine 1995 Wildlife Monitoring Studies. Spring Creek Coal Company 1995-1996 Mining Annual Report. Vol. I, App. I. May 1996.
- Powder River Eagle Studies, Inc., Gillette, WY., 1997, Spring Creek Mine 1996 Wildlife Monitoring Studies. February 1997.
- Powder River Eagle Studies, Inc., Gillette, WY., 1999, Spring Creek Mine 1998 Wildlife Monitoring. March 1999.
- Preston, W.B. 1986. The Great Plains toad, Bufo cognatus, an addition to the herpetofauna of Manitoba (Canada). Canadian Field Naturalist 100(1): 119-120.
- Propper, C.R. and W.E. Johnson. 1994. Angiotensin II induces water absorption behavior in two species of desert anurans. Hormones and Behavior 28(1): 41-52.
- Reichel, J. and D. Flath. 1995. Identification of Montana's amphibians and reptiles. Montana Outdoors 26(3):15-34.
- Reichel, J.D. 1995b. Preliminary amphibian and reptile survey of the Sioux District of the Custer National Forest: 1994. Montana Natural Heritage Program, Helena, MT. 75 p.
- Roedel, M.D. and P. Hendricks. 1998a. Amphibian and reptile survey on the Bureau of Land Management Lewistown District: 1995-1998. Montana Natural Heritage Program, Helena, MT. 53 p.
- Rogers, J.S. 1972. Discriminant function analysis of morphological relationships within the Bufo cognatus species group. Copeia 1972(2): 381-383.
- Rogers, J.S. 1973a. Biochemical and morphological analysis of potential introgression between Bufo cognatus and Bufo speciosus. American Midland Naturalist 90(1): 127-142.
- Rogers, J.S. 1973b. Protein polymorphism, genic heterozygositya nd divergence in the toads Bufo cognatus and B. speciosus. Copeia 1973(2): 322-330.
- Rogers, K.L. and L. Harvey. 1994. A skeletochronological assessment of fossil and recent Bufo cognatus from south-central Colorado. Journal of Herpetology 28: 133-140.
- Rubial, R. 1962. The adaptive value of bladder water in the toad, Bufo cognatus. Physiological Zoology 35(3): 218-223.
- Russell, A. P. and A. M. Bauer. 1993. The amphibians and reptiles of Alberta. University of Calgary Press. Calgary, Alberta. 264 p.
- Say, T. 1823. In James, Stephen H. Long's Expedition of the Rocky Mountains. 1819-1820. Volume 2, p. 190.
- Schmid, W.D. 1965. High temperature tolerance of Bufo hemiophrys and Bufo cognatus. Ecology 46(4): 559-560.
- Scow, K.L. 1980. Terrestrial wildlife survey American Colloid study area Phillips County, Montana. Western Technology and Engineering, Inc., Helena, MT.
- Sievert, L. 1991. Thermoregulatory behaviour in the toads Bufo marinus and Bufo cognatus. Journal of Thermal Biology 16(5): 309-312.
- Smith, H.M. 1946. The tadpoles of Bufo cognatus Say. University of Kansas Publications Museum of Natural History 1(3): 93-96.
- Smith, H.M., G.A. Hammerson, D. Chiszar and C. Ramotnik. 1993a. Bufo cognatus (Great Plains toad). Herpetological Review 24(4) 152-153.
- Sullivan, B.K. 1982a. Male mating behavior in the Great Plains toad (Bufo cognatus). Animal Behavior 30: 939-940.
- Sullivan, B.K. 1983a. Sexual selection and mating system variation in the Great Plains toad (Bufo cognatus Say) and woodhouse’s toad (Bufo woodhousei australis Shannon and Lowe). Ph.D. Dissertation, Arizona State University. 138 pp.
- Sullivan, B.K. 1983b. Sexual selection in the Great Plains toad (Bufo cognatus). Behaviour 84(3-4): 258-264.
- Sullivan, B.K. 1985. Sexual selection and mating system variation in anuran amphibians of the Arizona-Sonoran desert. Great Basin Naturalist 45(4): 688-696.
- Sullivan, B.K. 1990. Natural hybrid between the Great Plains toad (Bufo cognatus) and the red-spotted toad (Bufo punctatus) from central Arizona. Great Basin Naturalist 50(4) 1990: 371-372.
- Tester, J.R., A. Parker, and D.B. Siniff. 1965. Experimental studies of habitat preference and thermoregulation of Bufo americanus, B. hemiophrys, and B. cognatus. Journal of the Minnesota Academy of Sciences 33: 27-32.
- Thompson, L.S. 1981. Circle West wildlife monitoring study: Third annual report. Technical report No. 8. Montana Department of Natural Resources and Conservation. Helena, Montana.
- Thompson, L.S. 1982. Circle West Wildlife Monitoring Study. Fourth annual report. Technical report 10. Montana Department of Natural Resources and Conservation, Helena, Montana.
- Tihen, J.A. 1959. An interesting vertebral anomaly in a toad, Bufo cognatus. Herpetologica 15(1): 29-30.
- Tuegal, M. 2004. Skunk predation on the Great Plains toad (Buco cognatus). Sonoran Herpetologist 17(12):118.
- Vitt, L.J., J.P. Caldwell, and D.B. Shepard. 2005. Inventory of amphibians and reptiles in the Billings Field Office Region, Montana. Sam Noble Oklahoma Museum of Natural History and Department of Zoology, University of Oklahoma, Norman, OK. 33 pp.
- Waage, Bruce C., 1995, Western Energy Company Rosebud Mine, Colstrip, Montana:1994 Annual Wildlife Monitoring Report; December 1, 1993 - November 30, 1994. February 27, 1995.
- Waage, Bruce C., 1996, Western Energy Company Rosebud Mine, Colstrip, Montana: 1995 Annual Wildlife Monitoring Report; December 1, 1994 - November 30, 1995. February 28, 1996.
- Werner, J.K., B.A. Maxell, P. Hendricks and D.L. Flath. 2004. Amphibians and Reptiles of Montana. Mountain Press Publishing Company: Missoula, MT. 262 pp.
- Wheeler, G.C. and J. Wheeler. 1966. The amphibians and reptiles of North Dakota. University of North Dakota, Grand Forks, ND. 104 pp.
- Zweifel, R.G. 1968b. Reproductive biology of anurans of the arid southwest, with emphasis on adaptation of embryos to temperature. Bulletin of the American Museum of Natural History 140(1): 1-64.
- Additional Sources of Information Related to "Amphibians"