American Bullfrog - Lithobates catesbeianus
State Rank Reason (see State Rank above)
A conservation status rank is not applicable because this species is not a suitable target for conservation activities as a result of being exotic or introduced.
Deposited in a thin film, 1-2 eggs thick, containing from 3,000 to 47,840 eggs, and spread out over a large surface area (Howard 1983, McAuliffe 1978 as cited in Bury and Whelan 1985, Maxell et al. 2009). Each ovum is black above, whitish below, and is surrounded by a single jelly layer (Maxell et al. 2009). Ovum diameters are 1.2-1.7 mm, but, total egg diameters, including the jelly layer, are 6.4-10.4 mm (Livezey and Wright 1947).
Tadpoles that have a total length (TL) less than 25 mm are black with transverse gold bands on the dorsal side of the head and body and with a patch of gold ventrally (Altig 1970, Corkran and Thoms 2006). Larger tadpoles have body and tail musculature that are olive green to yellow base with flecks of yellow and numerous round black dots. Their tail fins are clear to yellow base with flecks of yellow and round dots and flecks of black. The ventral body surface of larger tadpoles is creamy white to bright yellow (Maxell et al. 2009). Larvae have a TL of 3–178 mm (up to 4.5 inches) (Corkran and Thoms 2006, Wright and Wright 1949).
JUVENILES AND ADULTS:
A fold of skin extends from the back of the eye, over the tympanum, down to the front leg. Mature males have tympanums twice the diameter of the eye, while mature females have tympanums about the same diameter as the eye (National Research Council, 1974). Dorsal base color varies based on size. Typically, smaller individuals are pale green to dark olive green with small dark spots, while larger individuals have dark mottling (Maxell et al. 2009). A series of black bands often extends across the legs. Ventral color is cream to bright yellow with gray to dark olive-green mottling usually present (Maxell et al. 2009). As sexual maturity approaches, the upper abdomen in males temporarily turns yellowish in color (Flores-Nava, 2005). Males are also slightly smaller than females and have darkly pigmented thumb pads in contrast to the more delicate streamlined thumb of the female (National Research Council, 1974). Snout-vent length (SVL) of 39-220 mm (up to 8 inches) and weighing up to 908 grams (Lutterschmidt et al. 1996, Thomas and Wogan 1999, Maxell et al. 2009). American Bullfrogs are not native to Montana.
Males advertise breeding and defend territories with a series of deep, bellowing calls that sound like "brrrruumm" (Werner et al. 2004). Calls can be heard up to 800 meters (approximately 2,625 feet) and may be confused with the 'booming' display flight of the Common Nighthawk (Chordeiles minor
) (Bryce Maxell, personal observation).
Adults of Northern Leopard Frog (Lithobates pipiens
) and Columbia Spotted Frog (Rana luteiventris
) have tympanums smaller than their eyes and have white stripes extending from the tip of their snout to their front leg. Both these species lack the fold of skin extending from the back of the eye, over the tympanum, down to the front leg (Maxell et al. 2009).
Northern Leopard Frog and Columbia Spotted Frog lay their eggs soon after snow melt in the spring and their egg masses are round or globular. Larvae of these two species are smaller, do not have a creamy yellow ventral color, and do not have round black dots on their dorsal surface and tail musculature. See sections on distribution to identify possible regions of co-occurrence for American Bullfrog, Columbia Spotted Frog, and Northern Leopard Frog.
Western Hemisphere Range
Native Range: Eastern United States to Minnesota and eastern Colorado south to Texas, but historically absent from the Cape Cod archipelago and associated islands off the east coast (Bury and Whelan 1985, Wiese 1990).
Introduced Range: From Washington, northern Idaho and Montana on the westslope of the Continental Divide in Colorado, New Mexico to Nevada, California and Arizona in the south.
Montana's Bitterroot River and Flathead River basin populations have been established since the 1960's (Black 1969b, 1969a, Werner and Reichel 1994, Reichel 1995b, Hendricks and Reichel 1996b, Werner et al. 1998a, Werner et al. 2004, Maxell et al. 2009), but the Yellowstone River populations have been a later introduction (2000's) with the epicenter being in Billings and expansion downstream (Sepulveda et al. 2015).
Maximum elevation: 1,203 m (3,946 ft) in Flathead County (Werner et al. 2004).
For maps and other distributional information on non-native species see:
Nonindigenous Aquatic Species Database from the U.S. Geological Survey
Invasive Species Habitat Tool (INHABIT) from the U.S. Geological Survey
Invasive Species Compendium from the Centre for Agriculture and Bioscience International (CABI)
EDDMapS Species Information EDDMapS Species Information
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)
Adult and juvenile bullfrogs may migrate overland to find other suitable aquatic habitats, if their existing wetland or pond habitat dries or is undergoing desiccation.
American Bullfrogs are highly aquatic and appear to be mostly limited to warmer permanent water bodies with abundant emergent and/or aquatic vegetation (Giermakowski 1998, Maxell et al. 2009). American Bullfrogs are found in lakes, ponds, cattle tanks, bogs, oxbow wetlands and sluggish portions of streams and rivers. Individuals are rarely found more than a few meters from the edge of the water (Raney 1940, Maxell et al. 2009). So far, they seem to have been unable to invade colder waters and high elevations in Montana, but there is some evidence that they may be adapting to colder water beaver ponds at some localities (Nussbaum et al. 1983, Werner and Plummer 1995b). Adults and larvae overwinter in shallow standing or flowing permanent waters on the bottom’s surface (Stinner et al. 1994). Adults typically do not move more than a few hundred meters within a season and show strong homing abilities when displaced (McAtee 1921, Raney 1940, Durham and Bennett 1963, Currie and Bellis 1969). However, individuals have been known to move up to 2.8 km and have been found in temporary pools up to 1.6 km from permanent water (Ingram and Raney 1943, Willis et al. 1956, Hammerson 1999).
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
Recently Disturbed or Modified
Wetland and Riparian Systems
- Occasionally Associated with these Ecological Systems
Wetland and Riparian Systems
American Bullfrogs are voracious feeders and have been implicated in extirpations of native frogs and turtles and declines in waterfowl production. Tadpoles feed on a variety of algae and bacteria, are commonly coprophagous, and may feed on eggs and smaller tadpoles (Steinwascher 1978b, Ehrlich 1979, Kiesecker and Blaustein 1997b). Because of their herbivorous nature, larvae can have a significant impact upon benthic algae and have the potential to disturb aquatic community structure. Adults will eat anything smaller than themselves, including ducklings, fish, mice, frogs, small turtles, and may frequently cannibalize smaller individuals (Bury and Whelan 1985, Maxell et al. 2009). In Oklahoma, the diet in ponds was predominantly insects such as mostly Coleoptera, Orthoptera, Hemiptera (82% by weight) and crayfish (6% by weight). In streams the diet was mostly crayfish (73% by weight) and insects such as Coleoptera (25% by weight).
Found in lakes, ponds, cattle tanks, bogs, oxbow wetlands and sluggish portions of streams and rivers. American Bullfrogs may be affecting Northern Leopard Frog and Columbia Spotted Frog populations in the Bitterroot Valley. Suitable ponds are now occupied solely by American Bullfrogs. Tadpoles are commonly found with predatory fish because they are apparently not very palatable or nutritious (Lewis et al. 1961, Kirk 1964, Kruse and Francis 1977, Kats et al. 1988). Furthermore, tadpoles release chemicals that have been shown to inhibit reproduction in some fish (Boyd 1975).
Breeding takes place in warmer weather from late June through late August. Their loud, deep "jug o'rum" call can be heard from a considerable distance. Females deposit eggs in a thin layer on the surface of warmer waters and can produce 10,000 to 20,000 eggs. (Maxell et al. 2009). Eggs subsequently sink onto submerged vegetation and hatch in three to five days (Bury and Whelan 1985) Tadpoles transform to adults as quickly as 4 months in warmer climates and up to 3 years in colder locations. In colder climates, bullfrogs require year-round persistence of water for tadpoles to mature and over-winter.
In Montana, American Bullfrogs breed during warm weather in late-June and July. Eggs hatch in about 4 or 5 days. The tadpole stage may last 2-3 years in Montana based on Bitterroot and Yellowstone River studies. American Bullfrogs reach sexual maturity in 4 to 5 years. Eggs were observed in western Montana in early July. Tadpoles were observed metamorphosing into juvenile frogs in early June (Maxell et al. 2009).
Current management for the Yellowstone River populations has been to try and eliminate as many populations as possible to prevent further spread. Not much management has taken place in the Bitterroot Valley where bullfrogs have virtually wiped out native amphibians from many of the low valley ponds and wetlands.Contact information for Aquatic Invasive Species personnel:Montana Fish, Wildlife, and Parks Aquatic Invasive Species staffMontana Department of Natural Resources and Conservation's Aquatic Invasive Species Grant ProgramMontana Invasive Species Council (MISC)Upper Columbia Conservation Commission (UC3)
The following was taken from the Status and Conservation section for the American Bullfrog account in Maxell et al. 2009
In Montana the American Bullfrog has been documented with an almost continuous distribution in the valley bottoms along the Bitterroot River downstream of Darby, the Clark Fork River downstream of Missoula, and the Flathead River downstream of Dixon (Hendricks and Reichel 1996b, Werner and Reichel 1996, Werner et al. 1998a). In addition, reproducing populations have been reported in Laurel, Billings and Fort Peck. Individual adults have been reported in Helena, Belgrade, near Silver City northwest of Helena, and near Lake Koocanusa near the Canadian border. The impetus for American Bullfrog introduction in the western United States and in Montana seems largely to be due to their use as a recreational hunting and food item, apparently, in some cases, as a result of native frogs having already declined because of human hunting and consumption (Bury and Whelan 1985, Jennings and Hayes 1985). Unfortunately, American Bullfrogs continue to be introduced into new sites from source populations in and outside of Montana (Bryce Maxell, pers. obs.) even though unauthorized introduction or transplantation of wildlife into the natural environment is prohibited by Montana law (Levell 1995, MCA 87-5-711). American Bullfrogs represent a major predation and competition threat to native amphibians and other vertebrate and invertebrate species. American Bullfrogs have been implicated in the declines of a number of amphibian species throughout the western United States and around the world (Dumas 1966, Black 1969b, Moyle 1973, Hammerson 1982, 1999, Bury and Whelan 1985, Hayes and Jennings 1988, Schwalbe and Rosen 1988, Kupferberg 1994, Lanoo et al. 1994, Arano et al. 1995, Rosen et al. 1995, Stebbins and Cohen 1995, Kupferberg 1997a, Lawler et al. 1999, however, see Hayes and Jennings 1986, and Corn 1994). All 3 life history stages of amphibians may be subject to direct predation by adults of the American Bullfrog (e.g., Korschgen and Baskett 1963, Carpenter and Morrison 1973, Bury and Whelan 1985, Clarkson and DeVos 1986, Werner et al. 1995). Additionally, both the eggs and larvae of native amphibians may be preyed upon by larvae of American Bullfrog (e.g., Ehrlich 1979, Kiesecker and Blaustein 1997b). Furthermore, egg, larval and adult amphibians are also likely to be indirectly affected by the threat of predation due to (1) adult avoidance of oviposition sites where predators are present (e.g., Resetarits and Wilbur 1989), (2) decreased larval foraging as a result of competition or staying in refuges to avoid predators (e.g., Kiesecker 1997, Kiesecker and Blaustein 1998), and (3) decreased adult foraging and growth rates as a result of avoiding areas with American Bullfrogs. Native amphibian larvae or adults may also be subject to chemically mediated interference competition (e.g., Petranka 1989a, Griffiths et al. 1993) or exploitative competition for resources (e.g., Kupferberg 1997a). Finally, native predators such as Gartersnakes (Thamnophis
species) that are dependent on larval or adult amphibians as a food source may also be impacted as a result of the loss of native amphibian larvae and the presence of larger American Bullfrog tadpoles and adults that they are unable to efficiently forage on (e.g., Kupferberg 1994). In addition to impacts on native amphibians, American Bullfrogs are known to prey on a variety of invertebrates (Carpenter and Morrison 1973) and vertebrates including young waterfowl, passerine birds, warm and cold water fishes, crayfish, snails, shrews, mice, bats, turtles, muskrat (Ondatra zibethicus
), lizards, young alligators, Gartersnakes, Prairie Rattlesnake (Crotalus viridis
), and a variety of plant matter (Korschgen and Moyle 1955, Lewis 1962, Korschgen and Baskett 1963, Black 1969b, Tyler and Hoestenbach 1979, Bury and Whelan 1985, Clarkson and DeVos 1986, Schwalbe and Rosen 1988, Stuart 1995, Crayon 1998). The current impact of American Bullfrogs on the native herpetofauna in Montana is not fully known. Black (1969b) reported that bullfrogs seemed to be having a negative impact on Northern Leopard Frog and Columbia Spotted Frog populations in the Bitterroot Valley with the disappearance of some Northern Leopard Frog populations apparently occurring at that time. However, Northern Leopard Frog populations have now been extirpated from virtually all of their former range in western Montana, so it is unlikely that American Bullfrogs were responsible for their declines unless they acted as a vector for disease. Native Long-toed Salamanders (Ambystoma macrodactylum
), Columbia Spotted Frogs, Pacific Treefrogs (Pseudacris regilla
), Painted Turtles (Chrysemys picta
), and western Terrestrial Gartersnake (Thamnophis elegans
) and Common Gartersnake (Thamnophis sirtalis
) appear not to have suffered widespread extirpation as a result of American Bullfrog introduction and many of these species are known to have breeding populations that are syntopic with breeding populations of American Bullfrogs at a few localities were fish have not been introduced in Ravalli and Sanders Counties (Werner and Plummer 1995b, Bryce Maxell, pers. obs.). Corn and Hendricks (1998) found several invertebrates in the stomachs of 21 American Bullfrogs at Lee Metcalf National Wildlife Refuge, and found only one vertebrate, an unidentified fish. Thus, while American Bullfrogs may be responsible for local declines or extirpations from isolated breeding sites, they do not appear to have caused widespread declines of the native amphibians. However, this does not mean that they are currently having no impact or will not cause extirpations of amphibians, invertebrates, or other vertebrates as they become more widespread.
Threats or Limiting Factors
Desiccation or drying of the wetland habitats before tadpoles metamorphose to adults is the limiting factor to bullfrogs. Based on a study in western Washington, conservation of ephemeral wetlands will halt range expansions of bullfrogs. Permanently inundated wetlands and man-made ponds are more likely to house the non-indigenous amphibian.
- Literature Cited AboveLegend: View Online Publication
- Altig, R. 1970. A key to the tadpoles of the continental United States and Canada. Herpetologica 26: 180-207.
- Arano, B., G. Llorente, M. Garcia-Paris, and P. Herrero. 1995. Species translocation menaces Iberian waterfrogs. Conservation Biology 9(1): 196-198.
- Black, J.H. 1969a. The frog genus Rana in Montana. Northwest Science 43(4): 191-195.
- Black, J.H. 1969b. Yes--there are bullfrogs in Montana. Montana Outdoors 1969: 4.
- Boyd, S.H. 1975. Inhibition of fish reproduction by Rana catesbeiana larvae. Physiological Zoology 48: 225-234.
- Bury, R.B. and J.A. Whelan. 1985. Ecology and management of the bullfrog. U.S. Department of the Interior, Fish and Wildlife Service/Resource Publication 155: 23pp.
- Carpenter, H.L. and E.O. Morrison. 1973. Feeding behavior of the bullfrog, Rana catesbeiana, in north central Texas. Bios 44: 188-193.
- Clarkson, R.W. and J.C. DeVos, Jr. 1986. The bullfrog, Rana catesbeiana Shaw, in the lower Colorado River, Arizona, California. Journal of Herpetology 20: 42-49.
- Corkran, C.C. and C. Thoms. 2006. Amphibians of Oregon, Washington, and British Columbia. 2nd Edition. Vancouver, B.C.: Lone Pine Publishing. 176 p.
- Corn, J. and P. Hendricks. 1998. Lee Metcalf National Wildlife Refuge bullfrog and painted turtle investigations: 1997. Montana Natural Heritage Program. Helena, MT. 20 pp.
- Corn, P.S. 1994. What we know and don't know about amphibian declines in the west. p. 59-67. In W. Covington and L. DeBano (tech. coords.), Sustainable ecological systems: implementing an ecological approach to land management. USDA Forest Service, Rocky Mountain Forest and Range Experimental Station, Ft. Collins, Colorado. General Technical Report RM-247.
- Crayon, J.J. 1998. Rana catesbeiana (bullfrog) diet. Herpetological Review 29(4): 232.
- Currie, W. and E.D. Bellis. 1969. Home range and movements of the bullfrog, Rana catesbeiana Shaw, in an Ontario pond. Copeia 1969(4): 688-692.
- Dumas, P.C. 1966. Studies of the Rana species complex in the Pacific Northwest. Copeia 1966(1): 60-74.
- Durham, L., and G.W. Bennett. 1963. Age, growth and homing in the bullfrog. Journal of Wildlife Management 27(1): 107-123.
- Ehrlich, D. 1979. Predation by bullfrog tadpoles (Rana catesbeiana) on eggs and newly hatched larvae of the plains leopard frog (Rana blairi). Bulletin of the Maryland Herpetological Society 15: 25-26.
- Flores Nava, A. 2018. Cultured Aquatic Species Information Programme. Rana catesbeiana (Shaw, 1862). Cultured Aquatic Species Information Programme. In: Food and Agriculture Organization of the United Nations Fisheries and Aquaculture Department [online]. Rome. Updated 9 February 2005. [Cited 15 August 2018].
- Giermakowski, J.T. 1998. Microhabitat separation between the bullfrog (Rana catesbeiana) and the Columbia spotted frog (Rana luteiventris) in Western Montana. Undergraduate Thesis, Wildlife Biology Program, University of Montana. Missoula, Montana. 2
- Griffiths, R.A., J. Denton, and A.L.C. Wong. 1993. The effect of food level on competition in tadpoles: interference mediated protothecan algae? Journal of Animal Ecology 62: 274-279.
- Hammerson, G.A. 1982. Bullfrog eliminating leopard frogs in Colorado? Herpetological Review 13: 115-116.
- Hammerson, G.A. 1999. Amphibians and reptiles in Colorado. University Press of Colorado & Colorado Division of Wildlife. Denver, CO. 484 p.
- Hayes, M.P. and M.R. Jennings. 1986. Decline of ranid frog species in western North America: are bullforgs (Rana catesbeiana) responsible? Journal of Herpetology 20: 490-509.
- Hayes, M.P. and M.R. Jennings. 1988. Habitat correlates of distribution of the California red-legged frog (Rana aurora draytonii) and the foothill yellow-legged frog (Rana boylii): implications for management. pp. 144-158. In: R.C. Szaro, K.E. Severson, and D.R. Patton, technical coordinators. Management of amphibians, reptiles, and small mammals in North America. General Technical Report RM-166. U.S. Forest Service, Rocky Mountain Forest and Range Experiment Station, Fort Collins, Colorado.
- 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.
- Howard, R.D. 1983. Sexual selection and variation in reproductive success in a long-lived organism. American Naturalist 122: 301-325.
- Ingram, W.M. and E.C. Raney. 1943. Additional studies on the movement of tagged bullfrogs, Rana catesbeiana Shaw. American Midland Naturalist 29: 239-241.
- Jennings, M.R. and M.P. Hayes. 1985. Pre-1900 overharvest of California red-legged frogs (Rana aurora draytonii): the inducement for bullfrog (Rana catesbeiana) introduction. Herpetologica 41(1): 94-103.
- Kats, L.B., J.W. Petranka and A. Smith. 1988. Antipredator defenses and the persistence of amphibian larvae with fishes. Ecology 69(6): 1865-1870.
- Kiesecker, J.M. 1997. The effects of pathogens, UV-B radiation, and introduced species on amphibians in the Pacific Northwest. Ph.D. Thesis, Oregon State University. 194pp.
- Kiesecker, J.M. and A.R. Blaustein. 1997b. Population differences in responses of red-legged frogs (Rana aurora) to introduced bullfrogs. Ecology 78(6): 1752-1760.
- Kiesecker, J.M. and A.R. Blaustein. 1998. Effects of introduced bullfrogs and smallmouth bass on microhabitat use, growth, and survival of native red-legged frogs (Rana aurora). Conservation Biology 12: 776-787.
- Kirk, W.L. 1964. The nutritional value of bullfrog tadpoles (Rana catesbeiana) as forage for the largemouth bass (Micropterus salmoides). M.S. Thesis, Southern Illinois University. 29p.
- Korschgen, L.J. and D.L. Moyle. 1955. Food habits of the bullfrog in central Missouri farm ponds. American Midland Naturalist 54: 332-341.
- Korschgen, L.J. and T.S. Baskett. 1963. Foods of impoundment and stream dwelling bullfrogs in Missouri. Herpetologica 19(2): 89-99.
- Kruse, K.C. and M.G. Francis. 1977. A predation deterrent in larvae of the bullfrog (Rana catesbeiana). Transactions of the American Fisheries Society 106(3): 248-252.
- Kupferberg, S.J. 1994. Exotic larval bullfrogs (Rana catesbeiana) as prey for native garter snakes: functional and conservation implications. Herpetological Review 25(3): 95-97.
- Kupferberg, S.J. 1997a. Bullfrog (Rana catesbeiana) invasion of a California river: the role of larval competition. Ecology 78(6): 1736-1751.
- Lannoo, M. J., K. Lang, T. Waltz, and G.S. Phillips. 1994. An altered amphibian assemblage: Dickinson County, Iowa, 70 years are Frank Blanchard's Survey. American Midland Naturalist 131:311-319.
- Lawler, S.P., D. Dritz, T. Strange and M. Holyoak. 1999. Effects of introduced mosquitofish and bullfrogs on the threatened California red-legged frog. Conservation Biology 13(3): 613-622.
- Levell, J. 1995. A field guide to reptiles and the law. Serpent's Tale Natural History Book Distribution, Excelsior, MN. 240pp.
- Lewis, W.M. 1962. Stomach contents of bullfrogs (Rana catesbeiana) taken from a minnow hatchery. Transactions of the Illinois State Academy of Science 55: 80-83.
- Lewis, W.M., G.E. Gunning, E. Lyles, and W.L. Bridges. 1961. Food choice of largemouth bass as a function of availability and vulnerability of food items. Transactions of the American Fisheries Society 90(3): 277-280.
- Livezey, R.L. and A.H. Wright. 1947. A synoptic key to salientian eggs of the United States. American Midland Naturalist 37: 179-222.
- Lutterschmidt, W.I., G.A. Marvin, and V.H. Hutchison. 1996. Rana catesbeiana (bullfrog). Record size. Herpetological Review 27(2): 74-75.
- 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.
- McAtee, W.L. 1921. Homing and other habits of the bullfrog. Copeia 1921: 39-40.
- McAuliffe, J.R. 1978. Biological survey and management of sport-hunted bullfrog populations in Nebraska. Nebraska Game and Parks Commission, Lincoln, Nebraska. 78 pp.
- Moyle, P.B. 1973. Effects of introduced bullfrogs, Rana catesbeiana on the native frogs of the San Joaquin Valley, California. Copeia 1973(1): 18-22.
- National Research Council. 1974. Amphibians. Guidelines for the breeding, care and management of laboratory animals. National Academy of Sciences, Washington, D.C.162pp.
- Nussbaum, R.A., E.D. Brodie, Jr. and R.M. Storm. 1983. Amphibians and reptiles of the Pacific Northwest. University of Idaho Press. Moscow, ID. 332 pp.
- Petranka, J.W. 1989a. Chemical interference competition in tadpoles: does it occur outside laboratory Aquaria? Copeia 1989(4): 921-930.
- Raney, E.C. 1940. Summer movements of the bullfrog, Rana catesbeiana Shaw, as determined by the jaw-tag method. American Midland Naturalist 23(3): 733-745.
- 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.
- Resetarits, W.J., Jr. and H.M. Wilbur. 1989. Choice of oviposition site by Hyla chrysoscelis: role of predators and competitors. Ecology 70: 220-228.
- Rosen, P.C., C.R. Schwalbe, D.A. Parizek Jr., P.A. Holm, and C.H. Lowe. 1995. Introduced Aquatic Vertebrates in the Chiricahua region: effects on declining native ranid frogs. U.S.F.S. Southwestern Region General Technician Report RM 264: 251-261.
- Schwalbe, C.R., Rosen, P.C. 1988. Preliminary report on effect of bullfrogs on wetland herpetofaunas in southeastern Arizona. Pages 166-173 in R.C. Szaro, K.E. Severson, and D.R. Patton, technical coordinators. Management of amphibians, reptiles, and small mammals in North America. General Technical Report RM-166. U.S. Forest Service, Rocky Mountain Forest and Range Experiment Station, Fort Collins, Colorado.
- Sepulveda, A. J., M. Layhee, D. Stagliano, J. Chaffin, A. Begley, and B. Maxell. 2015. Invasion of American bullfrogs along the Yellowstone River. Aquatic Invasions. Volume 10, Issue 1: 69–77
- Stebbins, R.C. and N.W. Cohen. 1995. A natural history of amphibians. Princeton University Press. Princeton, NJ. 316 pp.
- Steinwascher, K. 1978b. The effect of coprophagy on the growth of Rana catesbeiana tadpoles. Copeia 1978(1): 130-134.
- Stinner, J., N. Zarlinga, and S. Orcutt. 1994. Overwintering behavior of adult bullfrogs, Rana catesbeiana, in northeastern Ohio. Ohio Journal of Science 94(1): 8-13.
- Stuart, J.N. 1995. Anura: Rana catesbeiana (Bullfrog). Diet. Herpetological Review 26(1): 33.
- Thomas, L.A., and G.O.U. Wogan. 1999. Rana catesbiana (bullfrog) record size. Herpetological Review 30(4): 223.
- Tyler, J.D. and R.D. Hoestenbach, Jr. 1979. Differences in food of bullfrogs (Rana catesbeiana) from pond and stream habitats in southwestern Oklahoma. Southwestern Naturalist 24: 33-38.
- Werner, E.E., G.A. Wellborn, and M.A. McPeek. 1995. Diet composition in postmetamorphic bullfrogs and green frogs: implications for interspecific predation and competition. Journal of Herpetology 29: 600-607.
- Werner, J.K. and J.D. Reichel. 1994. Amphibian and reptile survey of the Kootenai National Forest: 1994. Montana Natural Heritage Program. Helena, MT. 104 p.
- Werner, J.K. and J.D. Reichel. 1996. Amphibian and reptile monitoring/survey of the Kootenai National Forest: 1995. Montana Natural Heritage Program. Helena, MT. 115 pp.
- Werner, J.K. and T. Plummer. 1995b. Amphibian monitoring program on the Flathead Indian Reservation 1995. Salish Kootenai College, Pablo, MT. 46 p.
- 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.
- Werner, J.K., T. Plummer, and J. Weaslehead. 1998a. Amphibians and reptiles of the Flathead Indian Reservation. Intermountain Journal of Sciences 4(1-2): 33-49.
- Wiese, R.J. 1990. Genetic structure of native and introduced populations of the bullfrog, a successful colonist. Ph.D. Dissertation, Colorado State University. Fort Collins, Colorado. 113 pp.
- Willis, Y.L., D.L. Moyle, and T.S. Baskett. 1956. Emergence, breeding, hibernation, movements and transformation of the bullfrog, Rana catesbeiana in Missouri. Copeia 1956(1): 30-41.
- Wright, A.H. and A.A. Wright. 1949. Handbook of frogs and toads of the United States and Canada. 3rd ed. Comstock Publishing Company Inc. Ithaca, NY. 640 p.
- Additional ReferencesLegend: View Online Publication
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- [WWPC] Washington Water Power Company. 1995. 1994 wildlife report Noxon Rapids and Cabinet Gorge Reservoirs. Washington Water Power Company. Spokane, WA.
- Adams, M.J. 1997. Experimental analysis of tadpole mortality factors: effects of bullfrogs and exotic fish in the puget lowlands, Washington. Ph. D. dissertation, University of Washington. 137pp.
- Adams, M.J. 2000. Pond permanence and the effects of exotic vertebrates on anurans. Ecological Applications 10(2): 559.
- Albertini, G. and B. Lanza. 1987. Rana castesbeiana Shaw, 1892 in Italy. Alytes 6(3-4): 117-129.
- Amborski, R.L., T.G. Snider III, R.L. Thune and D.D. Culley, Jr. 1983. A non-hemolytic, group B Streptococcus infection of cultured bullfrogs, (Rana catesbeiana), in Brazil. Journal of Wildlife Diseases 19(3): 180-184.
- Anonymous. 1993. The bullfrog. Ohio Department of Agriculture Division of Conservation Bureau of Science Research Bulletin 32 and 32A. 3pp.
- Aronson, L.R. 1943. Oviposition in the green frog (Rana clamitans) and the bullfrog (Rana catesbeiana). American Museum Nov. 1224:1-6.
- Ashley, H., P. Katti, and E. Frieden. 1968. Urea excretion in the bullfrog tadpole. Effect of temperature, metamorphosis and thyroid hormones. Developmental Biology 17: 293-307.
- Auburn, J.S. and D.H. Taylor. 1979. Polarized light perception and orientation in larval bullfrogs Rana catesbeiana. Animal Behaviour 27: 658-668.
- Austin, J.D., J.A. Dávila, S.C. Lougheed, and P.T. Boag. 2003. Genetic evidence for female-biased dispersal in the bullfrog, Rana catesbeiana (Ranidae). Molecular Ecology 12:3165-3172.
- Austin, J.D., S.C. Lougheed, and P.T. Boag. 2004. Controlling for the effects of history and nonequilibrium conditions in gene flow estimates in northern bullfrog (Rana catesbeiana) populations. Genetics 168(3):1491-1506.
- Bagnara, J.T. and J.J. Kollross. 1956. Abbreviated larval period of Rana catesbeiana in Iowa. Proceedings of the Iowa Academy of Science 63: 729-731.
- Baker, R.H. 1972. The bullfrog. A Texas wildlife resource. Texas Game Fish Oyster Community Bulletin 23. 7pp.
- Baker, R.H. 1972. The bullfrog. A Texas wildlife resource. Texas Game Fish Oyster Community Bulletin 23. 7pp.
- Bee, M.A. 2004. Within-individual variation in bullfrog vocalizations: implications for a vocally mediated social recognition system. Journal of the Acoustical Society of America 116(6):3770-3781.
- Bee, M.A. and A.C. Bowling. 2002. Socially mediated pitch alteration by territorial male bullfrogs, Rana catesbeiana. Journal of Herpetology 36(1):140-143.
- Beringer, J., and T.R. Johnson. 1995. Rana catesbeiana (Bullfrog): Diet. Herpetological Review 26:98.
- Berrill, M., S. Bertram, L. McGillivray, M. Kolohon, and B. Pauli. 1994. Effects of low concentrations of forest-use pesticides on frog embyos and tadpoles. Environmental Toxicology and Chemistry 13(4): 657-664.
- Berrill, M., S. Bertram, P. Toswill, and V. Campbell. 192. Is there a bullfrog decline in Ontario? P. 32-36, In: C.A. Bishop and K.E. Pettit (eds.). Declines in Canadian amphibian populations: designing a natural strategy. Occasional Papers No 76. Cana
- Bingham, D.M., A.J. Sepulveda, and S. Painter. 2021. A small proportion of breeders drive American Bullfrog invasion of the Yellowstone River floodplain, Montana. Northwest Science. 94(3-4):231-242
- Birdsall, C.W., C.E. Grye, and A. Anderson. 1986. Lead concentrations in bullfrog Rana catesbeiana and green frog R. clamitans tadpoles inhabiting highway drainages. Environmental Pollution A 40: 233-247.
- Black, J.H. 1974a. Bullfrog eating a bird. Herpetological Review 5: 104.
- Black, J.H., and A.N. Bragg. 1968. New additions to the herpetofauna of Montana. Herpetologica 24: 247.
- Blair, A.P. 1963b. Notes on anuran behavior, especially Rana catesbeiana. Herpetologica 19: 151.
- Bohnsack, K. 1952. Terrestrial hibernation of the bullforg (Rana catesbeiana Shaw). Copeia 1952: 114.
- Boily, M.H., V.E. Berube, P.A. Spear, C. BeBlois, and N. Dassylva. 2005. Hepatic retinoids of bullfrogs in relation to agricultural pesticides. Environmental Toxicology and Chemistry 24(5):1099-1106.
- Bolek, M.G. and J. Janovy, Jr. 2004. Rana catesbeiana (Bullfrog). Gigantic tadpole. Herpetological Review 35(4):376-377.
- Bolek, M.G. and J. Janovy, Jr. 2004. Rana catesbeiana (Bullfrog). Gigantic Tadpole. Herpetological Review 35(4):376-377.
- Boone, M.D. and R.D. Semlitsch. 2003. Interactions of bullfrog tadpole predators and an insecticide: predation release and facilitation. Oecologia 137(4): 610-616.
- Boone, M.D., E.E. Little, and R.D. Semlitsch. 2004. Overwintered bullfrog tadpoles negatively affect salamanders and anurans in native amphibian communities. Copeia 3:683-690.
- Boundy, J. 2001. Herpetofaunal surveys in the Clark Fork Valley region, Montana. Herpetological Natural History 8: 15-26.
- Boutilier, R.G., M.L. Glass, and N. Heisler. 1986. The relative distribution of pulmocutaneous blood flow in Rana catesbeiana: effects of pulmonary or cutaneous hypoxia. Journal of Experimental Biology 126: 33-39.
- Bowerman, J. 2003. Bullfrogs and spotted frogs in central Oregon: Differences in tolerance to hypoxia may restrict bullfrog invasion of spotted frog habitat. Abstract. Northwestern Naturalist 84:95.
- Boyd, S.H. 1971. The reproductive inhibition of Poecilia reticulata in the presence of water conditioned by Rana catesbeiana tadpoles. M.S. thesis. Southeastern Massachusetts University. 46pp.
- Brodie, E.D. 1968. A case of interbreeding between Bufo boreas and Rana cascadae. Herpetologica 24: 86.
- Brooks, G.R., Jr. 1964. An analysis of the food habits of the bullfrog (Rana catesbeiana) by body size, sex, mouth, and habitat. Virginia Journal of Science 15: 173-186.
- Brown, L.E. 1974. Behavioral reactions of bullfrogs while attempting to eat toads. Southwestern Naturalist 19: 335-336.
- Brown, R.E. 1972. Size variation and food habits of larval bullfrogs, Rana catesbeiana Shaw, in western Oregon. Dissertation. Oregon State University, Corvallis, Oregon, USA.
- Bruggers, R.L. 1974. Food habits of bullfrogs in northwest Ohio. Ohio Journal of Science 73: 185-188.
- Bruggers, R.L. and W.B. Jackson. 1974. Eye-lens weight of the bullforg (Rana catesbeiana) related to larval development, transformation, and age of adults. Ohio Journal of Science 74: 282-286.
- Burggren, W.W. and N.H. West. 1982. Changing respiratory importance of gills, lungs, and skin during metamorphosis in the bullfrog Rana catesbeiana. Respiratory Physiology 47: 151-164.
- Burggren, W.W., M.E. Feder, and A.W. Pinder. 1983. Temperature and the balance between aerial and aquatic respiration in larvae of Rana berlandeiri and Rana catesbeiana. Physiological Zoology 56: 263-273.
- Capranica, R.R. 1968. The vocal repertoire of the bullfrog (Rana catesbeiana). Behaviour 31: 302-325.
- Carlander, K.D. and R.B. Moorman. 1950. The bullfrog and his next of kin. Iowa Conservationist 9: 33-38.
- 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.
- Carr, A.H., R.L. Amborski, D.D. Culley, Jr. and G.F. Amborski. 1976. Aerobic bacteria in the intestinal tracts of bullfrogs (Rana catesbeiana) maintained at low temperatures. Herpetologica 32: 239-244.
- Cauble, K. and R.S. Wagner. 2004. Herbicide effects on metamorphosis of amphibian larvae. Abstract. Northwestern Naturalist 85:70.
- Cecil, S.G. and J.J. Just. 1979. Survival rate, population density and development of a naturally occurring anuran larvae (Rana catesbeiana). Copeia 1979: 447-453.
- Cohen, N.W., and W.E. Howard. 1958. Bullfrog food and growth at the San Joaquin Experimental Range, California. Copeia 1958(3): 223-225.
- Collins, J.P. 1975. A comparative study of the life history strategies in a community of frogs. Dissertation. University of Michigan, Ann Arbor, Michigan, USA.
- Collins, J.P. 1979. Intrapopulation variation in the body size at metamorphosis and timing of metamorphosis in the bullfrog, Rana catesbeiana. Ecology 60: 738-749.
- Combs, A., G. Hess, C. Chapman, A. Stovall, Z. Burns, S. Matthews, and J.D. Goins. 2005. Rana catesbeiana (American Bullfrog). Diet. Herpetological Review 36(4):439.
- Cook, D. and M. Jennings. 2001. Rana aurora draytonii (California red-legged frog) predation. Herpetological Review 32(3): 182-183.
- Corkran, C.C., and C. Thoms. 1996. Amphibians of Oregon, Washington, and British Columbia. Lone Pine Publishing, Edmonton, Alberta. 175 pp.
- Corse, W.A. and D.E. Metter. 1980. Economics, adult feeding and larval growth of Rana catesbeiana in a fish hatchery. Journal of Herpetology 14: 231-238.
- Crawshaw, L.I., R.N. Rausch, P. Wollmuth, and E.J. Bauer. 1992. Seasonal rhythms of development and temperature selection in larval bullforgs (Rana catesbeiana Shaw). Physiological Zoology 65: 346-359.
- Cross, C.L. and S.L. Gerstenberger. 2002. Rana catesbeiana. Diet. Herpetological Review 33(2):129-130.
- 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.
- Crowder, W.C., M. Nie, and G.R. Ultsch. 1998. Oxygen uptake in bullfrog tadpoles (Rana catesbeiana). Journal of Experimental Zoology 280: 121-134.
- Culley, D.D., Jr. 1973. Use of bullfrogs in biological research. American Zoologist 13: 85-90.
- Culley, D.D., Jr. 1981. Have we turned the corner on bullfrog culture? Aquaculture Magazine 7: 20-24.
- Culley, D.D., Jr., N.D. Horseman, R.L. Amborski, and S.P. Meyers. 1978. Current status of amphibain culture with emphasis on nutrition , diseases and reproduction of the bullfrog (Rana catesbeiana). Proceedings of the World Mariculture Society 9: 653-66
- DeGrauw, E. 2002. Lymphatic and plasma volume determinations in Rana catesbeiana and Bufo marinus. Northwestern Naturalist 83(2):68.
- Dietrich, S.E. 1960. Field observations of a bullfrog attack on a bluebird. Bulletin of the Philadelphia Herpetological Society 8(1): 16.
- Dowe, B.J. 1979. The effect of time of oviposition and microenvironment on growth of larval bullfrogs (Rana catesbeiana) in Arizona. M.S. Thesis, Arizona State University, Tempe. 55 pp.
- Eklov, P. 2000. Chemical cues from multiple predator-prey interactions induce changes in behavior and growth of anuran larvae. Oecologia 123: 192-199.
- Elinson, R.P. 1981. Have you seen a bullfrog-green frog hybrid? Herpetological Review 12:104.
- Emlen, S.T. 1968. Territoriality in the bullfrog Rana catesbeiana. Copeia 1968: 240-243.
- Emlen, S.T. 1976. Lek organization and mating strategies in the bullfrog. Behavioral Ecology and Sociobiology 1: 283-313.
- Emlen, S.T. 1977. "Double clutching" and its possible significance in the bullfrog. Copeia 1977(4): 749-751.
- Evenson, E.J. 1978. The dietary effects of Rana catesbeiana on Micropterus salmoides. M.S. Thesis. University of Nebraska at Lincoln. 24 pp.
- Fellers, G.M., D.E. Green, and J.E. Longcore. 2001. Oral chytridiomycosis in mountain yellow-legged frogs (Rana muscosa). Copeia 2001(4): 945-953.
- Fenton, M.H. 1928. Scientific method of bullfrog culture in connection with muskrat farming. Pickerel, Ontario. 53pp. [publisher unknown].
- Fenton, M.H. 1932. Scientific method of raising jumbo bullfrogs. Chariton Fur Corp., Chicago, Illinois. 80pp.
- Ferguson, D.E., J.P. McKeown, O.S. Bosarge, and H.F. Landreth. 1968. Sun-compass orientation of bullfrogs. Copeia 1968: 230-235.
- Forbes, M.R., D.L. McRuer, and P.L. Rutherford. 2004. Prevalence of Aeromonas hydrophilia in relation to timing and duration of breeding in three species of ranid frogs. Ecoscience 11(3):282-285.
- Fordham, C.L., J.D. Tessari, H.S. Ramsdell, and T.J.Keefe. 2001. Effects of malathion on survival, growth development, and equilibrium posture of bullfrog tadpoles (Rana catesbeiana). Environmental Toxicology and Chemistry 20(1): 179-184.
- Friet, S.C. 1993. Aquatic overwintering of the bullfrog (Rana catesbeiana) during natural hypoxia in an ice-covered pond. M.S. Thesis, Dalhousie University.
- Frost, S.W. 1935. The food of Rana catesbeiana Shaw. Copeia 1935: 15-18.
- Fulk, F.D. and J.O. Whitaker, Jr. 1969. The food of Rana catesbeiana in three habitats in Owen County, Indiana. Proceedings of the Indiana Academy of Science 78: 491-496.
- Funkhouser, A. 1976. Observations on pancreas: body weight ratio change during development of the bullforg (Rana catesbeiana). Herpetologica 32: 370-371.
- George, I.D. 1938. Late external sex distinction of the bullfrog (Rana catesbeiana) based on tympanum measurements. Proceedings of the Louisiana Academy of Science 4: 255-259.
- George, I.D. 1940b. A study of the life history of the bullfrog (Rana catesbeina Shaw) at Baton Rouge, Louisiana. Dissertation. University of Michigan, Ann Arbor, Michigan, USA.
- Gerstenberger, S. and R. Pearson. 2002. Mercury concentrations in bullfrogs (Rana catesbeiana) collected from a southern Nevada, USA, wetland. Bulletin of Environmental Contamination and Toxicology 69(2): 210-218.
- Glorioso, J.C., G.F. Amborski, and D.D. Culley. 1973. Microbiological studies on septicemic bullfrogs (Rana catesbeiana). American Journal of Veterinary Research 335: 1241-1245.
- Goodyear, C.P. and R. Altig. 1971. Orientation of bullfrogs (Rana catesbeiana) during metamorphosis. Copeia 1971: 362-364.
- Gradwell, N. 1970. The function of the ventral velum during gill irrigation I Rana catesebeiana. Canadian Journal of Zoology 50: 481-499.
- Gradwell, N. 1972a. Gill irrigation in Rana catesbeiana. I. On the anatomical basis. Canadian Journal of Zoology 50: 481-499.
- Gradwell, N. 1972b. Gill irrigation in Rana catesbeiana. II. On the musculoskeletal mechanism. Canadian Journal of Zoology 50: 501-521.
- Gradwell, N. and B. Walcott. 1971. Dual functional and structural properties of the interhyoideus muscle of the bullfrog tadpole (Rana catesbeiana). Journal of Experimental Zoology 176: 193-218.
- Green, D.M. 1978. Northern leopard frogs and bullfrogs on Vancouver Island. Canadian Field Naturalist 92: 78-79.
- 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.
- Haskell, W.L. 1956. Bullfrog study-lower Colorado River. Arizona Game and Fish Report 3839.
- Hayes, M.P. and J. Warner. 1985. Rana catesbeiana (bullfrog). Food. Herpetological Review 16: 109.
- Hecnar, S.J. and R.T. M'closkey. 1997. Changes in the composition of a ranid frog community folllowing bullfrog extinction. American Midland Naturalist 137(1): 145-150.
- Hedeen, S.E. 1949. Premetamorphic growth of Rana catesbeiana in southwestern Ohio. Ohio Journal of Science 75: 182-183.
- Heller, J.A. 1927. Brewer's mole as food of the bullfrog. Copeia 4: 116.
- Hendricks, P. 1997. Lee Metcalf National Wildlife Refuge preliminary amphibian and reptile investigations: 1996. Montana Natural Heritage Program, Helena, MT. 21 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.
- Hendricks, P. and J.D. Reichel. 1996a. Amphibian and reptile survey of the Bitterroot National Forest: 1995. Montana Natural Heritage Program. Helena, MT. 95 p.
- Hewitt, O.H. 1950. The bullfrog as a predator on ducklings. Journal of Wildlife Management 14: 244.
- Höbel, G. 2005. Rana clamitans (Green Frog) and Rana catesbeiana (American Bullfrog). Reproduction. Herpetological Review 36(4):439-440.
- Hoff, J.G. and S.A. Moss. 1974. A distress call in the bullfrog (Rana catesbeiana). Copeia 1974: 533-534.
- Holman, J.A. 1957. Bullfrog predation on the eastern spadefoot (Scaphiopus holbrooki). Copeia 1957: 229.
- Hopkins, W.A., J. Congdon and J.K. Ray. 2000. Incidence and impact of axial malformations in larval bullfrogs (Rana catesbeiana) developing in sites polluted by a coal-burning power plant. Environmental Toxicology and Chemistry 19(4): 862-868.
- Horseman, N.D., A.H. Meier and D.D. Culley, Jr.. 1976. Daily variations in the effects of disturbance on growth, fattening, and metamorphosis in the bullfrog (Rana catesbeiana) tadpole. Journal of Experimental Zoology 198(3): 353-358.
- Hovey, T.E. and D.R. Bergen. 2003. Rana catesbeiana (Bullfrog). Herpetological Review 24(4):360-361.
- Howard, R.D. 1978a. The evolution of mating strategies in bullfrogs (Rana catesbeiana). Evolution 32: 850-871.
- Howard, R.D. 1978b. The influence of male-defended oviposition sites on early embryo mortality in bullfrogs. Ecology 59(4): 789-798.
- Howard, R.D. 1979. Estimating reproductive success in natural populations. American Naturalist 114(2): 221-231.
- Howard, R.D. 1980. Male age-size distribution and mating success in bullfrogs. In R.D. Alexander and D.W. Tinkle, editors. Natural selection and social behavior: recent research and new theory. Chiron Press, Newton, Massachusetts, USA.
- Howard, R.D. 1981. Sexual dimorphism in bullfrogs. Ecology 62: 303-310.
- Howard, W.E. 1950. Birds as bullfrog food. Copeia 1950: 152.
- Hutchinson, V.H. and I.G. Hill. 1978. Thermal selection of bullfrogs tadpoles (Rana catesbeiana) at different stages of development and acclimation temperatures. Journal of Thermal Biology 3: 57-60.
- Jennings, M.R., J.J. Crayon, and R.L. Hothem. 2005. Bufo boreas halophilus (California Toad) and Rana catesbeiana (American Bullfrog). Amplexus. Herpetological Review 36(1):53.
- Jones, Lawrence L. C., W. P. Leonard and D. H. Olson, eds. 2005. Amphibians of the Pacific Northwest. Seattle Audubon Society: Seattle, WA, 227 pp.
- Joslin, Gayle, and Heidi B. Youmans. 1999. Effects of recreation on Rocky Mountain wildlife: a review for Montana. [Montana]: Montana Chapter of the Wildlife Society.
- Justis, C.S. and D.H. Taylor. 1976. Extraocular photoreception and compass orientation in larval bullfrogs (Rana catesbeiana). Copeia 1976: 98-105.
- Kiesecker, J.M., C.L. Miller, and A.R. Blaustein. 2001. Potential mechanisms underlying the displacement of native red-legged frogs by introduced bullfrogs. Ecology 82(7): 1964-1970.
- Kirkpatrick, R.D. 1982. Rana catesbeiana (bullfrog). Food. Herpetological Review 13: 17.
- Klimstra, W.D. 1949. Early bullfrog transformation. Copeia 1949(3): 231.
- Kmieciak, R. 2004. Red-winged blackbird and bullfrog. Colorado Birds 38(2):91.
- Krupa, J.J. 2002. Temporal shift in diet in a population of American Bullfrog (Rana catesbeiana) in Carlsbad Caverns National Park. Southwestern Naturalist 47(3): 461-467.
- Kupferberg, S.J. 1993. Bullfrogs (Rana catesbeiana) invade a northern California river: a plague or species coexistence? Bulletin of the Ecological Society of America 74: 319-320.
- Kupferberg, S.J. 1996. The ecology of native tadpoles (Rana boylii and Hyla regilla) and the impact of invading bullfrogs (Rana catesbeiana) in a northern California river. Ph.D. dissertation, University of California at Berkeley. Berkeley, CA. 289 p.
- Lardie, R.L. 1963. A brief review of the bullfrog as a conservation problem with particular reference to its occurrence in Washington State. TriCor (Western Herpetological Society) 3: 7-9.
- Larson, P.M. and S.M. Reilly. 2002. Functional morphology of feeding and gill irrigation in the Anuran Tadpole: electromyography and muscle function in larval Rana catesbeiana. Journal of Morphology 255: 202-214.
- Lee, D.S. 1969. Notes on the feeding behavior behavior of cave-dwelling bullfrogs. Herpetologica 25: 211-212.
- Lefcort, H., and S.M. Eiger. 1993. Antipredatory behaviour of feverish tadpoles: implications for pathogen transmission. Behaviour 126: 13-27.
- Licht, L.E. 1969b. Palatability of Rana and Hyla eggs. American Midland Naturalist 82: 296-298.
- Lillywhite, H.B. 1970. Behavioral temperature regulation in the Bullfrog (Rana catesbeiana). Copeia 1970: 158-168.
- Lillywhite, H.B. 1971. Temperature selection by the bullfrog, Rana catesbeiana. Comparative Biochemistry and Physiology A 40: 213-227.
- Lombardi, J.V., T.R. Perpetuo, C.M. Ferreira, J.G. Machado-Neto, and H.L.A. Marques. 2002. Acute toxicity of the fungicide copper oxychloride to tadpoles of the bullfrog Rana catesbeiana. Bulletin of Environmental Contamination and Toxicology 69(3): 415-420.
- Lopez, T.J., and L.R. Maxson. 1990. Life history notes: Rana catesbeiana. Herpetological Review 21: 90.
- Lotshaw, D.P. 1977. Temperature adaptation and effects of thermal acclimation in Rana sylvatica and Rana catesbeiana. Comparative Biochemistry and Physiology A 56: 287-294.
- Mahon, R. and K. Aiken. 1977. The establishment of the North American bullfrog (Rana catesbeiana) (Amphibia, Anura, Ranidae) in Jamaica. Journal of Herpetology 11: 197-199.
- 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.
- McCoy, C.J. 1967. Diet of bullfrogs (Rana catesbeiana) in central Oklahoma farm ponds. Proceedings of the Oklahoma Academy of Science 48:44-45.
- McGrath, E.A. and M.M. Alexander. 1979. Observations on the exposure of larval bullfrogs to fuel oil. Proceedings of the Northeast Fish and Wildlife Conference 80: 45-51.
- McIntyre, P.B. and S.A. McCollum. 2000. Responses of bullfrog tadpoles to hypoxia and predators. Oecologia 125: 301-308.
- McKamie, J.A. and G. Heidt. 1974. A comparison of spring food habits of the bullfrog (Rana catesbeiana) in three habitats of central Arkansas. Southwestern Naturalist 19: 107-111.
- Minton, J.E. 1949. Coral snake preyed upon by the bullfrog. Copeia 1949: 288.
- Mitchell, J.C. and L. McGranaghan. 2005. Albinism in American bullfrog (Rana catesbeiana) tadpoles from Virginia. Banisteria 25:51.
- Moore, J.A. 1942a. Embryonic temperature tolerance and rate of development in Rana catesbeiana. Biology Bulletin, 83: 375-388.
- Moosman, D.L. 2005. Rana catesbeiana (Bullfrog). Microhabitat. Herpetological Review 36:298.
- Mulla, M.S. 1963. Toxicity of organochlorine insecticides to the mosquito fish Gambusia affinis and the bullfrog Rana catesbeiana. Mosquito News 23(4): 299-303.
- Mullen, D.A. 1976. Geographic distribution: Rana catesbeiana. Herpetological Review 7: 122.
- Neck, R.W. 1981. Probable native population of bullfrog (Rana catesbeiana) in south Texas. Herpetological Review 12: 68.
- Needham, J.G. 1905. The summer food of the bullfrog (Rana catesbeian Shaw) at Saranac Inn. New York State Museum Bulletin 86:9-15.
- Nie, M., J.D. Crim and G.R. Ultsch. 1999. Dissolved oxygen, temperature, and habitat selection by bullfrog (Rana catesbeiana) tadpoles. Copeia 1999(1): 153-162.
- Northrop, Devine and Tarbell, Inc. 1995. Cabinet Gorge and Noxon Rapids Hydroelectric Developments, 1994 Wetland Mapping and Assessment Study, Volume I of II. 27 pp. plus appendices.
- Olson, D.H. 1991. Ecological susceptibility of amphibians to population declines. Proceedings of the Symposium on Biodiversity of Northwestern California, October 28-30: 55-62.
- Patla, D.A. and C.R. Peterson. 2001. Status and trends of amphibian populations in the Greater Yellowstone Ecosystem, progress report, February 2001. Greater Yellowstone Ecosystem Amphibian Survey and Monitoring Program, Herpetology Laboratory, Department of Biological Sciences, Idaho State University, Pocatello, ID. 8 p.
- Pearl, C.A. and D.E. Green. 2005. Rana catesbeiana (American Bullfrog). Chytridiomycosis. Herpetological Review 36:305-306.
- Pearl, C.A., M.J. Adams, R.B. Bury, and B. McCreary. 2004. Asymmetrical effects of introduced bullfrogs (Rana catesbeiana) on native ranid frogs in Oregon, USA. Copeia 11-20.
- Pearl, C.A., M.P. Hayes, R. Haycock, J.D. Engler, and J. Bowerman. 2005. Observations of interspecific amplexus between western North American ranid frogs and the introduced American bullfrog (Rana catesbeiana) and an hypothesis concerning breeding interference. American Midland Naturalist 154(1):126-134.
- Perez, M.E. 1951. The food of Rana catesbeiana in Puerto Rico. Herpetologica 7: 102-104.
- Pinder, A.W. 1987. Cutaneous diffusing capacity increases during hypoxia in cold submerged bullfrogs (Rana catesbeiana). Respiration Physiology 70: 85-95.
- Pine, R.H. 1975. Star-nosed mole eaten by bull frog. Mammalia 39: 713-714.
- Pryor, G.S. 2003. Growth rates and digestive abilities of Bullfrog tadpoles (Rana catesbeiana) fed algal diets. Journal of Herpetology 37(3):560-566.
- Pryor, G.S. and K.A. Bjorndal. 2005. Effects of the nematode Gyrinicola batrachiensis on development, gut morphology, and fermentation in bullfrog tadpoles (Rana catesbeiana): a novel mutalism. Journal of Experimental Zoology Part A Comparative Experimental Biology 303A(8):704-712.
- Raimondo, S.M., C.L. Rowe and J.D. Congdon. 1998. Exposure to coal ash impacts swimming performance and predator avoidance in larval bullfrogs (Rana catesbeiana). Journal of Herpetology 32(2): 289-292.
- Raney, E.C. and W.M. Ingram. 1940. Growth of tagged frogs in nature. Bulletin of the Ecological Society of America 21(4):30.
- Raney, E.C. and W.M. Ingram. 1941. Growth of tagged frogs (Rana catesbeiana Shaw and Rana clamitans Daudin) under natural conditions. American Midland Naturalist 26: 201-206.
- Reichel, J. and D. Flath. 1995. Identification of Montana's amphibians and reptiles. Montana Outdoors 26(3):15-34.
- Relyea, R.A. 2005b. The lethal impacts of Roundup and predatory stress on six species of North American tadpoles. Archives of Environmental Contamination and Toxicology 48:351-357.
- Relyea, R.A., and E.E. Werner. 1999. Quantifying the relation between predator-induced behavior and growth performance in larval anurans. Ecology 80(6): 2117-2124.
- 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.
- Roedel, M.D. and P. Hendricks. 1998b. Amphibian and reptile inventory on the Headwaters and Dillon Resource Areas in conjunction with Red Rocks Lakes National Wildlife Refuge: 1996-1998. Montana Natural Heritage Program, Helena, MT. 46 p.
- Rogers, C.P. 1996. Rana catesbeiana (bullfrog) predation. Herpetological Review 27(2): 75.
- Rosen, P.C. and C.R. Schwalbe. 1995. Bullfrogs: introduced predators in southwestern wetlands. In: LaRoe ET, G.S. Farris, C.E. Puckett, P.D. Doran, and M.J. Mac (eds.). Our living resources: a report to the nation on the distribution, abundance, and hea
- Rowe, C.L., O.M. Kinney, A.P. Fiori, and J.D. Congdon. 1996. Oral deformities in tadpoles (Rana catesbeiana) associated with coal ash deposition: effects on grazing ability and growth. Freshwater Biology 36: 723-730.
- Rowe, C.L., O.M. Kinney, and J.D. Congdon. 1998. Oral deformities in tadpoles of the bullfrog (Rana catesbeiana) caused by conditions in a polluted habitat. Copeia 1: 244-246.
- Ryan, M.J. 1978. A thermal property of the Rana catesbeiana (Amphiba, Anura, Ranidae) egg mass. Journal of Herpetology 12: 247-248
- Ryan, M.J. 1980. The reproductive behavior of the bullfrog (Rana catesbeiana). Copeia 1980(1): 108-114.
- Schroeder, E.E. 1975. The reproductive cycle in the male bullfrog (Rana catesbeiana) in Missouri. Transactions of the Kansas Academy of Science 77: 31-35.
- Schroeder, E.E. and T.S. Baskett. 1968. Age estimation, growth rates and population structure in Missouri bullfrogs. Copeia 1968(3): 583-592.
- Schwartz, J.J., M.A. Bee, and S.D. Tanner. 2000. A behavioral and neurobiological study of the responses of gray treefrogs, Hyla versicolor, to the calls of a predator, Rana catesbeiana. Herpetologica 56(1): 27-37.
- Seale, D. 1973. Impact of amphibian larval populations on an aquatic community. Dissertation. Washington University, St. Louis, Missouri, USA.
- Shaw. 1802. General Zoology, Vol. 3, Pt. 1, p. 106, pl. 33.
- Shirose, L.J. 1990. Population ecology of the postmetamorphic bullfrog (Rana catesbeiana Shaw) in Algonquin Provincial Park, Ontario. M.S. Thesis, University of Guelph, Guelph, Ontario, Canada.
- Shirose, L.J. and R.J. Brooks. 1995a. Age structure, mortality, and longevity in syntopic populations of three species of ranid frogs in central Ontario. Canadian Journal of Zoology 73: 1878-1886.
- Shirose, L.J., R.J. Brooks, J.R. Barta, and S.S. Desser. 1993. Intersexual differences in growth, mortality, and size at maturity in bullfrogs in central Ontario. Canadian Journal of Zoology 71: 2363-2369.
- Skelly, D.K. 1992. Field evidence for a cost of behavioral antipredator response in a larval amphibian. Ecology 73: 704-708.
- Smith, A.K. 1977. Attraction of bullfrogs (Amphibia, Anura, Ranidae) to distress calls of immature frogs. Journal of Herpetology 11: 234-235.
- Smith, G.R. 1999. Among family variation in tadpole (Rana catesbeiana) responses to density. Journal of Herpetology 33(1): 167-169.
- Smith, G.R., D.A. Vaala, H.A. Dingfelder, and K.G. Temple. 2004. Effects of nitrite on bullfrog (Rana catesbeiana) tadpoles from central Ohio, USA. Bulletin of Environmental Contamination and Toxicology 72(5):1012-1016.
- Smith, H.M., R. Mixter, and T. Spangler. 1966. The bullfrog and other reptiles and amphibians in western South Dakota. Journal of the Ohio Herpetological Society 5: 106-107.
- Soileau, C. 1977. Froglegs forever (or bye-bye bullfrog)? La Conservation 29:4-7.
- Stebbins, R. C. 2003. A field guide to western reptiles and amphibians. 3rd Edition. Houghton Mifflin Company, Boston and New York. 533 p.
- Stewart, M.M. and P. Sandison. 1972. Comparative food habits of sympatric mink frogs, bullfrogs, and green frogs. Journal of Herpetology 6: 241-244.
- Stewart, R.E., S.A. Reese, and G.R. Ultsch. 2004. The physiology of hibernation in Canadian leopard frog (Rana pipiens) and bullfrogs (Rana catesbeiana). Physiological and Biochemical Zoology 77(1):65-73.
- Storer, T.I. 1922. The eastern bullfrog in California. California Fish and Game 8: 219-224.
- Storm, R.M. 1952. Interspecific mating behavior in Rana aurora and Rana catesbeiana. Herpetologica 8: 108.
- Stoutamire, R. 1932. Bullfrog farming and froging in Florida. State of Florida, Department of Agriculture Bulletin (n.s.) 56: 1-12.
- Stumpel, A.H.P. 1992. Successful reproduction of introduced bullfrogs Rana catesbeiana in northwestern Europe: a potential threat to indigenous amphibians. Biological Conservation 60: 61-62.
- Suggs, D.N. and A.M. Simmons. 2005. Information theory analysis of patterns of modulation in the advertisement call of the male bullfrog, Rana catesbeiana. Journal of the Acoustical Society of America 117(Part1)(4):2330-2337.
- Sype, W.E. 1975. Breeding habits, embryonic thermal requirements and embryonic amd larval development of the Cascade frog, Rana cascadae Slater. Corvallis, OR: Oregon State University. 113pp. PhD Dissertation.
- Taylor, R.J. and E.D. Micheal. 1971. Habitat effects on monthly foods of bullfrogs in eastern Texas. Proceedings of the Conference of the Southeastern Association of Game Fish Commerce 25: 176-186.
- Terres, J.K. 1968. Kingfishers eating bullfrog tadpoles. Auk 85: 140.
- Terres, J.K. 1968. Kingfishers eating bullfrog tadpoles. Auk 85: 140.
- Thrall, J. 1971. Excavation of pits by juvenile Rana catesbeiana. Copeia 1971: 751-752.
- Thrall, J. 1972. Food, feeding, and digestive physiology of the larval bullfrog (Rana catesbeiana Shaw). Dissertation 33B: 1861.
- Treanor, R.R. 1975. Management of the bullfrog resource in California. California-Nevada Wildlife Transactions 1975: 81-92.
- Treanor, R.R. and S.J. Nicola. 1972. A preliminary study of the commercial and sporting utilization of the bullfrog, Rana catesbeiana Shaw, in California. Inland Fisheries Administrative Report No. 72-4, California Department of Fish and Game. Sacram
- Tucker, J.K. and M.E. Sullivan. 1975. Unsuccessful attempts by bullfrogs to eat toads. Transactions of the Illinois State Academy of Science 68: 167.
- Van Kirk, R., L. Benjamin, and D. Patla. 2000. Riparian area assessment and amphibian status in the watersheds of the Greater Yellowstone Ecosystem. Greater Yellowstone Coalition, Bozeman, MT. 102 p.
- Veldhoen, N. and C.C. Helbing. 2001. Detection of environmental endocrine-disruptor effects on gene expression in live Rana catesbeiana tadpoles using a tail fin biopsy technique. Environmental Toxicology and Chemistry 20(12): 2704-2708.
- Viosca, P., Jr. 1931. Principles of bullfrog (Rana catesbeiana) culture. Transactions of the American Fisheries Society 61: 262-269.
- Viosca, P., Jr. 1934. Principles of bullfrog culture. Southern Biological Supply Co., New Orleans, Louisiana. 31pp.
- Viparina, S. and J.J. Just. 1975. The life period, growth and differentiation of Rana catesbeiana larvae occurring in nature. Copeia 1975(1): 103-109.
- 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.
- Wassersug, R.J. 1972. The mechanism of ultraplanktonic entrapment of anuran larvae. Journal of Morphology 137: 279-288.
- Weis, J.S. 1975. The effect of DDT on tail regeneration in Rana pipiens and R. catesbeiana tadpoles. Copeia 1975: 765-767.
- Werner, J.K. and T. Plummer. 1995a. Amphibian and reptile survey of the Flathead Indian Reservation 1993-1994. Salish Kootenai College, Pablo, MT. 55 pp.
- Werner, J.K., T. Plummer, and J. Weaselhead. 1998b. The status of amphibians on the Flathead Reservation, Montana. Intermountain Journal of Sciences 4(3-4): 88.
- Werner, Y.L. 2003. Mechanical leverage in the middle ear of the American bullfrog, Rana catesbeiana. Hearing Research 175:54-65.
- Western EcoTech, Helena, MT., 1999, Wetland delineation report for the Haskins Landing Proposed Wetland Mitigation Area. MWFE? June 2, 1999.
- Wiese, R.J. 1985. Ecological aspects of the bullfrog in northeastern Colorado. M.S. Thesis, Colorado State University, Fort Collins, Colorado.
- Wiewandt, T.A. 1969. Vocalization, aggressive behavior, and territoriality in the bullfrog, Rana catesbeiana. Copeia 1969(2): 276-285.
- Wilcox, J.T. 2005. Rana catesbeiana (American Bullfrog). Diet. Herpetological Review 36:306.
- Willson, J.D. and M.E. Dorcas. 2004. A comparison of aquatic drift fences with traditional funnel trapping as a quatitative method for sampling amphibians. Herpetological Review 35(2):148-150.
- Wollmuth, I.P. and I.I. Crawshaw. 1988. The effect of development and season on temperature selection in bullfrog tadpoles. Physiological Zoology 61: 461-469.
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