Great Plains Toad - Anaxyrus cognatus
The skin of adult Great Plains Toads is covered with numerous small warts; cranial crests are prominent, and diverge posteriorly from a hard lump (boss) on top of the snout. The parotoid glands posterior to the eyes are elongated. The back exhibits a somewhat symmetrical pattern of large, light-edged dark spots or patches. The underside of the hind foot often has a sharp-edged tubercle and a smaller dark-tipped tubercle. Females can reach 11.4 centimeters snout-vent length (SVL); males are usually less than 9.5 centimeters SVL. 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 breeding call is a long continuous trill or pulsating ringing sound.
Juveniles have reddish warts. Tadpoles are initially blackish on the dorsum with light or gold flecking, then become paler and mottled brown; the dorsal pattern of large, paired blotches appears before metamorphosis is complete. The eyes are dorsal, and the dorsal fin is highly arched with some black dentritic lines. The upper mandible is highly arched, and labial tooth rows are usually 2/3, with oral papillae restricted to the sides of the mouth. Total length ranges from 25 to 35 millimeters. Eggs are black above, white below, and about 1.2 to 1.3 millimeters in diameter, usually in a single row in long strings of two-layered jelly that is constricted between individual eggs.
Boreal Toad (Bufo boreas) lacks cranial crests and is found only in mountainous parts of Montana. On Woodhouse's Toad (Bufo woodhousii), the cranial crests are parallel between the eyes, forming two back-to-back L shapes (not convergent between the eyes in a V), and do not merge on the snout in a bony lump or boss. Both Boreal and Woodhouse's Toads lack the symmetrical black-green spots with light halos on on the back and sides . Boreal Toad tadpoles are dark to black on the back, lack any gold flecking, and are found only in mountainous parts of the state. Woodhouse's Toad tadpoles lack the strongly arched tail fin. Woodhouse's Toad eggs are enclosed in a single jelly layer; Boreal Toad eggs are in strings that are not pinched between eggs, and are present only in the mountainous parts of the state.
Western Hemisphere Range
Summary of Observations Submitted for Montana
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. It has 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 1999, Hossack et al. 2003).
Information gathered from other locations indicates that when inactive, the Great Plains Toad is found in burrows and under rocks or wood. During the active season, it occupies burrows during the day that are quite shallow. This species enters water only to breed. It breeds in rain pools, flooded areas, and ponds and reservoirs that fluctuate in size, and appears to prefer 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.
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 (high, medium, or low) 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 2001, 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 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 associated as using 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 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.
High, medium, and low habitat quality was assigned based on the degree to which the structural characteristics of an ecological system matched the preferred structural habitat characteristics for each species in the 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 assignments of habitat quality.
If you have any questions or comments on species associations with ecological systems, please contact Bryce Maxell at email@example.com
or (406) 444-3655.
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: http://mtnhp.org/requests/default.asp
) 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. 2001. The wild mammals of Montana. Special Publication No. 12. Lawrence, KS: The American Society of Mammalogists. 278 p.
- 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
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 arthropods, including spiders, moths, caterpillars, flies, beetles, termites, and ants (Dimmitt and Ruibal 1980, Hammerson 1999), and 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 eat suspended matter, organic debris, algae, and plant tissue.
Great Plains Toads are uncommon near human habitation (Black 1970). They are mainly nocturnal (Bragg 1940, Black 1970). Post-metamorphic young may form aggregations (Graves 1993).
Great Plains Toads breed only after rain in clear, shallow, temporary pools of flooded grasslands, probably May to July in Montana (Bragg 1940, Black 1970). Two of three females collected in north-central Montana on July 20 had well developed eggs (Mosimann and Rabb 1952).
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).
No special management needs are currently recognized. However, at permanent and semi-permanent water bodies (reservoirs and stock ponds) where breeding has been observed, portions of the shoreline with emergent vegetation could be fenced to create enclosures that protect breeding adults, eggs, and tadpoles from trampling and the removal of emergent cover by livestock. Another option would be the creation of ponds designed for use by prairie amphibians as breeding sites, with the perimeter surrounded by fencing to prevent access by livestock. Game fish should not be introduced to any of these ponds.
- 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. 1970. 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. 1940. 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.
- 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.
- 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. 1999. 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.
- Mosimann, J.E. and G.B. Rabb. 1952. The herpetology of Tiber Reservoir Area, Montana. Copeia(1): 23-27.
- 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. 1940. Observations on the ecology and natural history of Anura. I. Habits, habitat and breeding of Bufo cognatus say. Amer. Nat. 74:322-438.
- 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. 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.
- Bragg, A.N. and M. Brooks. 1958. Social behavior in juveniles of Bufo cognatus Say. Herpetologica 14: 141-147.
- 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, Tom, and Rick 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. 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.
- Creusere, F.M. and W.G. Whitford. 1976. Ecological relationships in a desert anuran community. Herpetologica 32: 7-18.
- 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., Helena, MT., 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. 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.
- 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. 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.
- Harvey, L.A. 1992. A skeletochronologic analysis of a high altitude population of Bufo cognatus. Bios 62(3/4): 232.
- Hayden, F.V. 1863. On the geology and natural history of the upper Missouri. Transactions of the American Philosophical Society New Series 12(1): 1-218 (pages 177-178).
- Hendricks, P. 1999. Amphibian and reptile surveys on Montana refuges: 1998-1999. Montana Natural Heritage Program, Helena, MT. 22pp.
- Hendricks, P. and J. D. Reichel. 1996. 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. Factors influencing advertisement calls of the Great Plains toad. Copeia (in press).
- 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. 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. 1995. 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. 1998. 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, 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.
- 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.
- 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.
- 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. and P.S. Nichols. 1982. Circle West wildlife monitoring study; fourth annual report for period March 1, 1981 - May 31, 1982. Circle West Technical Report No. 10. Montana Department of Natural Resources and Conservation, Helena, MT.
- Tihen, J.A. 1959. An interesting vertebral anomaly in a toad, Bufo cognatus. Herpetologica 15(1): 29-30.
- 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.
- 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.