The Nonindigenous Occurrences section of the NAS species profiles has a new structure. The section is now dynamically updated from the NAS database to ensure that it contains the most current and accurate information. Occurrences are summarized in Table 1, alphabetically by state, with years of earliest and most recent observations, and the tally and names of drainages where the species was observed. The table contains hyperlinks to collections tables of specimens based on the states, years, and drainages selected. References to specimens that were not obtained through sighting reports and personal communications are found through the hyperlink in the Table 1 caption or through the individual specimens linked in the collections tables.

Lithobates catesbeianus
Lithobates catesbeianus
(American Bullfrog)
Native Transplant

Copyright Info
Lithobates catesbeianus (Shaw, 1802)

Common name: American Bullfrog

Synonyms and Other Names: Rana catesbeiana, Rana mugiens, Rana scapularis

Taxonomy: available through www.itis.govITIS logo

Identification: Lithobates catesbeianus is the largest true frog native to Eastern North America (Dorcas and Gibbons 2008). Adults range in size between 9 and 15.2 cm (snout vent length) (Powell et al. 2016). Lithobates catesbeianus can be identified by their green or olive smooth skin, often with dark mottling on their backs, while their stomachs are white to cream mottled with dark pigment (Dorcas and Gibbons 2008).  The back of the thighs are flecked with small light spots (Johnson 2007). The hind feet are webbed with the longest toe extending past the webbing (Johnson 2007; Powell et al. 2016). The dorsolateral ridge (ridge around eardrum) that can be found behind the tympanum (eardum) is absent in L. catesbeianus (Dorcas and Gibbons 2008; Powell et al. 2016). Female L. catesbeianus have tympanum approximately the same size as their eye, while males have tympanum twice as large (Dorcas and Gibbons 2008). This is the only species in the southeast U.S. with males larger than females (Dorcas and Gibbon 2008). Tadpoles can be differentiated from other frog species by their large size (approximately 15 cm), olive green color, scattered black dots, and lack of visible intestinal coil (Dorcas and Gibbons 2008). The call of L. catesbeianus is described as a series of deep bass notes (Powell et al. 2016) Lithobates catesbeianus may be confused with other native species, such as the River frog, Lithobates heckscheri, which is darker brown with white spots on the lower lip and dark spots on the upper lip (Dorcas and Gibbons 2008). Pig frogs, Lithobates grylio, are commonly confused with L. catesbeianus, however pig frogs have a more pointed snout and the webbing on their hind feet extends the whole length of the longest toe (Dorcas and Gibbons 2008). Juvenile bullfrogs may be confused with green frogs, Hyla cinerea; however, green frogs have a dorsolateral (on back and sides) ridge extending at least partially down its body (Dorcas and Gibbons 2008).

Size: 9 - 15.2 cm

Native Range: : Native to the eastern United States, but historically absent from the Cape Cod archipelago and associated islands. Not historically present in the southern portion of Florida or the Okefenokee Swamp (Dorcas and Gibbons 2008).

Hydrologic Unit Codes (HUCs) Explained
Interactive maps: Point Distribution Maps

Nonindigenous Occurrences:

Table 1. States with nonindigenous occurrences, the earliest and latest observations in each state, and the tally and names of HUCs with observations†. Names and dates are hyperlinked to their relevant specimen records. The list of references for all nonindigenous occurrences of Lithobates catesbeianus are found here.

StateFirst ObservedLast ObservedTotal HUCs with observations†HUCs with observations†
AZ1935201533Agua Fria; Bill Williams; Bouse Wash; Brawley Wash; Canyon Diablo; Carrizo; Grand Wash; Havasu-Mohave Lakes; Imperial Reservoir; Lake Mead; Lower Colorado; Lower Gila; Lower Salt; Lower San Pedro; Lower Santa Cruz; Lower Verde; Middle Gila; Middle Little Colorado; Rillito; Rio De La Concepcion; San Bernardino Valley; San Simon; Santa Cruz; Silver; Tyson Wash; Upper Gila-San Carlos Reservoir; Upper Salt; Upper San Pedro; Upper Santa Cruz; Upper Verde; Whitewater Draw; Willcox Playa; Yuma Desert
CA1896201993Aliso-San Onofre; Battle Creek; Big Chico Creek-Sacramento River; Big-Navarro-Garcia; Butte; Butte Creek; California; California Region; Central California Coastal; Central Coastal; Clear Creek-Sacramento River; Cottonwood Creek; Cow Creek; Coyote; Crowley Lake; East Branch North Fork Feather; Fresno River; Goose Lake; Gualala-Salmon; Havasu-Mohave Lakes; Imperial Reservoir; Indian Wells-Searles Valleys; Lake Tahoe; Los Angeles; Lost; Lower American; Lower Klamath; Lower Pit; Lower Sacramento; Lower Sacramento; Lower San Joaquin River; Mad-Redwood; Mattole; McCloud; Middle Fork Eel; Middle Fork Feather; Middle Kern-Upper Tehachapi-Grapevine; Middle San Joaquin-Lower Chowchilla; Mojave; Monterey Bay; Newport Bay; North Fork Feather; Northern Mojave; Owens Lake; Pajaro; Paynes Creek-Sacramento River; Rock Creek-French Camp Slough; Russian; Sacramento-Stone Corral; Salinas; San Diego; San Felipe Creek; San Francisco Bay; San Francisco Bay; San Francisco Coastal South; San Joaquin; San Joaquin Delta; San Luis Rey-Escondido; San Pablo Bay; Santa Ana; Santa Ana; Santa Margarita; Santa Monica Bay; South Fork American; South Fork Eel; South Fork Kern; Suisun Bay; Thomes Creek-Sacramento River; Tomales-Drake Bays; Trinity; Tulare Lake Bed; Upper Amargosa; Upper Bear; Upper Cache; Upper Calaveras California; Upper Coon-Upper Auburn; Upper Cosumnes; Upper Deer-Upper White; Upper Dry; Upper Kaweah; Upper Kern; Upper King; Upper Merced; Upper Mokelumne; Upper Pit; Upper Poso; Upper Putah; Upper San Joaquin; Upper Stanislaus; Upper Stony; Upper Tule; Upper Tuolumne; Upper Yuba
CO1966201813Alamosa-Trinchera; Cache La Poudre; Clear; Colorado Headwaters-Plateau; Frenchman; Middle South Platte-Cherry Creek; Middle South Platte-Sterling; Pawnee; San Luis; St. Vrain; Tomichi; Upper Arkansas; Upper South Platte
FL195920163Florida Southeast Coast; Northern Gulf of Mexico; Western Okeechobee Inflow
HI189720196Hawaii; Kauai; Lanai; Maui; Molokai; Oahu
ID189720166Coeur d'Alene Lake; Lower Boise; Middle Snake-Payette; Middle Snake-Succor; Priest; Upper Snake-Rock
IA193020196Big Papillion-Mosquito; Blackbird-Soldier; Floyd; Little Sioux; Lower Big Sioux; Monona-Harrison Ditch
KS199619963Lower Walnut Creek; North Fork Cimarron; Upper Cimarron
ME193120222Upper Androscoggin River; West Branch Penobscot River
MA188220052Cape Cod; Concord River
MI189419132Black-Presque Isle; Lake Huron
MN2006202315Cannon; Clearwater-Elk; Des Moines Headwaters; Le Sueur; Leech Lake; Long Prairie; Lower St. Croix; Middle Minnesota; Minnesota; Platte-Spunk; St. Louis; Twin Cities; Upper Cedar; Upper Mississippi-Black-Root; Upper Mississippi-Crow-Rum
MT200420138Bitterroot; Flathead Lake; Lower Flathead; Lower Yellowstone-Sunday; Middle Clark Fork; Stillwater; Upper Yellowstone-Lake Basin; Upper Yellowstone-Pompeys Pillar
NE194220214Big Papillion-Mosquito; Lower South Platte; Middle Niobrara; Snake
NV1933200514Havasu-Mohave Lakes; Ivanpah-Pahrump Valleys; Lake Tahoe; Las Vegas Wash; Lower Virgin; Meadow Valley Wash; Middle Carson; Middle Humboldt; Muddy; Northern Mojave; Surprise Valley; Upper Amargosa; Upper Carson; White
NH192119211Upper Androscoggin River
NJ199620052Cohansey-Maurice; Mullica-Toms
NM1905201933Animas Valley; Caballo; Canadian Headwaters; Carrizo; Cimarron; Conchas; El Paso-Las Cruces; Elephant Butte Reservoir; Jemez; Lost Draw; Middle San Juan; Mimbres; Mora; Pecos Headwaters; Pintada Arroyo; Plains of San Agustin; Playas Lake; Rio Chama; Rio Grande-Albuquerque; Rio Grande-Santa Fe; Rio Penasco; San Francisco; San Simon; Upper Canadian; Upper Canadian-Ute Reservoir; Upper Gila; Upper Gila-Mangas; Upper Pecos-Black; Upper Pecos-Long Arroyo; Upper Rio Grande; Upper San Juan; Ute; Western Estancia
OH189418941Lake Erie
OK194219421Lower Beaver
OR1900201852Alsea; Applegate; Chetco; Clackamas; Coast Fork Willamette; Coos; Crooked-Rattlesnake; Goose Lake; Harney-Malheur Lakes; Illinois; John Day; Little Deschutes; Lost; Lower Columbia; Lower Columbia-Clatskanie; Lower Columbia-Sandy; Lower Crooked; Lower John Day; Lower Owyhee; Lower Rogue; Lower Snake; Lower Willamette; Mckenzie; Middle Columbia-Lake Wallula; Middle Fork Willamette; Middle Rogue; Middle Snake-Boise; Middle Willamette; Molalla-Pudding; Nehalem; North Santiam; North Umpqua; Pacific Northwest Region; Siletz-Yaquina; Silver; Silvies; Siuslaw; Sixes; South Santiam; South Umpqua; Sprague; Tualatin; Umatilla; Umpqua; Upper Crooked; Upper Deschutes; Upper Grande Ronde; Upper Klamath Lake; Upper Rogue; Upper Willamette; Warner Lakes; Williamson
PR196720235Cibuco-Guajataca; Culebrinas-Guanajibo; Eastern Puerto Rico; Puerto Rico; Southern Puerto Rico
SD200020205Lac Qui Parle; Lower Big Sioux; Middle Cheyenne-Spring; Middle White; Missouri Region
TX1890202111Big Bend; Coyanosa-Hackberry Draws; El Paso-Las Cruces; Lower Prairie Dog Town Fork Red; Lower Wolf; North Corpus Christi Bay; Rio Grande-Fort Quitman; San Ambrosia-Santa Isabel; South Concho; Turkey; Upper San Antonio
UT196620155Great Salt Lake; Lower San Juan; Lower Virgin; Southern Great Salt Lake Desert; Upper Colorado-Kane Springs
WA1931202221Klickitat; Lake Washington; Lower Chehalis; Lower Columbia; Lower Columbia-Clatskanie; Lower Columbia-Sandy; Lower Cowlitz; Lower Crab; Lower Snake-Tucannon; Lower Yakima; Middle Columbia-Hood; Middle Columbia-Lake Wallula; Nisqually; Nooksack; Pacific Northwest Region; Puget Sound; Puyallup; San Juan Islands; Snoqualmie; Strait of Georgia; Upper Columbia-Priest Rapids
WY196620052Horse; Snake Headwaters

Table last updated 7/18/2024

† Populations may not be currently present.

Ecology: Lithobates catesbeianus are habitat generalists and can be found in permanent aquatic habitats such as, ponds, lakes, reservoirs, backwater rivers, ditches, swamps, marsh, bogs, cattle tanks, irrigation canals, and occasionally temporary water bodies (Dorcas and Gibbons 2008; Powell et al. 2016). Juveniles can disperse large distances overland (Dorcas and Gibbons 2008). Adult home ranges have been estimated to be approximately 1.6 km (Cooper 2017).
This species hibernates buried in the mud underwater, while some individuals may overwinter in burrows on land and emerge later in the spring than most true frogs (Powell et al. 2016). The persistence of water bodies is essential for tadpoles to mature and overwinter (Dorcas and Gibbons 2008).
Lithobates catesbeianus are nocturnal generalist predators and have been shown to consume various prey including insects, leeches, centipedes, scorpions, fishes, other frogs, small alligators, turtles, snakes, rodents, bats, birds, and juvenile mink (Kats and Ferrer 2003; Dorcas and Gibbons 2008; Flynn et al. 2017). Bullfrogs have also been known to cannibalize in dense populations (Dorcas and Gibbons 2008; Flynn et al. 2017). Bullfrog tadpoles’ chemical cues affect behavior of native larvae (Kiesecker and Blaustein 1997; Anderson and Lawler 2016). This species also serves as a host to the glochidia of native unionid mussel Utterbackis imbecilis, the paper pondshell (Watters and O’Dee 1998).
Female L. catesbeianus can lay 6,000-20,000 eggs at a time (Urbina et al. 2020). Eggs hatch in 2-5 days and can take four months up to two years to metamorphosize (Urbina et al. 2020). In the bullfrog’s native southern U.S. range, breeding occurs from February – October (Urbina et al. 2020.) However, breeding is limited to the warm summer months in introduced populations in the Pacific northwest (Urbina et al. 2020).

Means of Introduction: Lithobates catesbeianus was introduced to the West Coast of the U.S. as a food source in the 1850s (Jennings and Hayes 1985). It is also thought that accidental introduction through fish stocking may have also contributed to the spread in the western U.S. Lithobates catesbeianus was introduced globally as a food source and through aquaculture escape (Ottens 2016). 

Status: In the U.S. Lithobates catesbeianus is established in coastal regions along the west coast in Washington, Oregon, and California. There have also been populations found in Arizona, New Mexico, Colorado, Nebraska and Montana. In the eastern U.S., the species has been introduced to Maine, Rhode Island, Iowa, Minnesota, and Southern Florida. Lithobates catesbeianus has spread globally to Europe, Asia, and South America and has been ranked among the top 100 of the world’s worst invasive species (Lowe et al. 2000; Giovanelli et al. 2008).

Impact of Introduction:
Summary of species impacts derived from literature review. Click on an icon to find out more...


Lithobates catesbeianus prey on native frog species in their introduced range and jeopardize endemic pupfish through predation and competition (Jameson 1956; U.S. Department of Interior Desert Pupfish Task Force 1971; Dumas 1996). Presence of this species can lead to decreased breeding in populations of the native northern leopard frog,  Lithobates pipiens. (Johnson et al. 2011). Larval bullfrogs may also affect nutrient cycling by altering levels of phosphorus and nitrogen in the water column (Guariento et al. 2018).  Lithobates catesbeianus is known to spread fatal Chytrid fungus; Batrachochytrium dendrobatidis, and cotton moulds, Saprolegnia ferax (Yap et al. 2018). In its native range L. catesbeianus is also a host to Lernaea cyprinacea (European copepod parasite) (Matson 2019). This parasite may pass to other species of frogs and fishes and cause death (Khalifa and Post 1976; Matson 2019). Lithobates catesbeianus are farmed commercially for harvest and hunted in their nonnative range (Jennings and Hayes 1994; Treanor and Nicola 1972). Individuals have been hired to eradicate L. catesbeianus in East Kootney, Canada (Anonymous 2023).

Remarks: The genus Rana was revised, and North, Central, and South American “true frogs” were placed into the genus Lithobates (Frost et al. 2006). In 2005 the National Park Service in Yosemite Valley, Yosemite National Park started using eDNA paired with audio recording devices to detect bullfrogs and subsequently remove them. This long-term eradication and monitoring effort is the first successful bullfrog removal at the landscape level and allowed for the reintroduction of the federally endangered Rana draytonii (California red-legged frog) to Yosemite Valley in 2016 (Kamoroff et al. 2020). Another control method for this species that is being investigated is the sterile male release technique, sterile males are released into the population to reduce breeding (Descamps and De Vocht 2022).

References: (click for full references)

Anderson, R.B. and S.P. Lawler. 2016. Behavioral changes in tadpoles after multigenerational exposure to an invasive intraguild predator. Behavioral Ecology 27(6):1790-1796. https://doi.org/10.1093/beheco/arw112.

Anonymous. 2023. Experts leap into action to protect endangered leopard frogs. East Kootenay News Online Weekly. https://www.e-know.ca/regions/ktunaxa-nation/experts-leap-into-action-to-protect-endangered-leopard-frogs/. Created on 04/08/2023. Accessed on 04/26/2023.

Cooper, M. 2017. Movement, habitat, and home range of introduced bullfrogs (Lithobates catesbeianus) on Mad River gravel ponds (Humboldt Co., Ca, USA), with implications for hydro-modification as a method of management. Unpublished M.S. thesis. Humboldt State University, Humboldt, CA.

Descamps, S., and A. De Vocht. 2022. Bisazir as a chemosterilant to control invasive vertebrates: ecotoxicity and efficacy to induce male sterility in Lithobates catesbeianus. Management of Biological Invasions 13(4):769-780. https://doi.org/10.3391/mbi.2022.13.4.12.

Dorcas, M., and W. Gibbons. 2008. Frogs and toads of the southeast. The University of Georgia Press 238 pp.

Dumas, P.C. 1966. Studies of the Rana species complex in the Pacific northwest. Copeia 1966(1):60-74. https://www.jstor.org/stable/1440762.

Flynn, L.M., T.M. Kreofsky, and A.J. Sepulveda. 2017. Introduced American Bullfrog distribution and diets in Grand Teton National Park. Northwest Science 91(3):244-256. https://doi.org/10.3955/046.091.0305.

Frost, D., T. Grant, J. Faivovich, R. Bain, A. Haas, C. Haddad, R. De Sá, A. Channing, M. Wilkinson, S. Donnellan, C. Raxworthy, J. Campbell, B. Blotto, P. Moler, R.C. Drewes, R. Nussbaum, J. Lynch, D. Green & W. Wheeler. 2006. The amphibian tree of life. Bulletin of the American Museum of Natural History 297:1-370. http://www.cnah.org/pdf_files/491.pdf.

Giovanelli, J.G.R., C.F.B. Haddad, and J. Alexandrino. 2008. Predicting the potential distribution of the alien invasive American bullfrog (Lithobates catesbeianus) in Brazil. Biological Invasions 10:585-590

Guariento, R.D., L.S. Carneiro, J.S. Jorge and A. Caliman. 2018. Assessing the risk effects of native predators on the exotic American bullfrog (Lithobates catesbeianus) and their indirect consequences to ecosystem function. Acta Oecologica 91:50-56. https://doi.org/10.1016/j.actao.2018.06.004.

Jameson, D.L. 1956. Growth, dispersal and survival of the Pacific tree frog. Copeia 1:25-29. https://www.jstor.org/stable/1439240.

Jennings, M.R, and Hayes, M.P. 1994. Amphibian and reptile species of special concern in California. California Department of Fish and Game, Inland Fisheries Division, Rancho Cordova, CA.

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.

Johnson, S.A. 2007. "True" frogs (family Ranidae). https://ufwildlife.ifas.ufl.edu/frogs/americanbullfrog.shtml. Created on 01/13/2020. Accessed on 01/11/2024.

Johnson, P.T.J., V.J. McKenzie, A.C. Peterson, J.L. Kerby, J. Brown, A.R. Blaustein, and T. Jackson. 2011. Regional decline of an iconic amphibian associated with elevation, land-use change, and invasive species. Conservation Biology 25(3):556-566. http://onlinelibrary.wiley.com/doi/10.1111/j.1523-1739.2010.01645.x/pdf.

Kamoroff, C., N. Daniele, R.L. Grasso, R. Rising, T. Espinoza, and C.S. Goldberg. 2020. Effective removal of the American bullfrog (Lithobates catesbeianus) on a landscape level: long term monitoring and removal efforts in Yosemite Valley, Yosemite National Park. Biological Invasions 22:617-626. https://doi.org/10.1007/s10530-019-02116-4.

Kats, L.B., and R.P. Ferrer. 2003. Alien predators and amphibian declines: review of two decades of science and the transition to conservation. Diversity and Distributions 9(2):165-163. https://doi.org/10.1046/j.1472-4642.2003.00013.

Khalifa, K.A. and G. Post. 1976. Histopathological effect of Lernaea cyprinacea (a copepod parasite) on fish. The Progressive Fish-Culturist 38(2):110-113. https://doi.org/10.1577/1548-8659(1976)38[110:HEOLCA]2.0.CO;2.
Kiesecker, J.M., and A.R. Blaustein. 1997. Population differences in responses of red-legged frogs (Rana aurora) to introduced bullfrogs. Ecology 78(6):1752-1760. http://links.jstor.org/sici?sici=0012-9658%28199709%2978%3A6%3C1752%3APDIROR%3E2.0.CO%3B2-B.

Lowe, S., M. Browne, S. Boudjelas, and M. De Poorter. 2000. 100 of the World's Worst Invasive Alien Species: A selection from the global invasive species database. The Invasive Species Specialist Group (ISSG) a specialist group of the Species Survival Commission (SSC) of the World Conservation Union. www.issg.org/booklet.pdf.

Matson, T.O. 2019. Infection of American Bullfrog Tadpoles, Lithobates catesbeianus (Shaw), by Anchor Worm, Lernaea cyprinacea L., in Streams of Northeastern Ohio. Ohio Biological Survey Notes 9:35-40. http://ohiobiologicalsurvey.org/wp-content/themes/ohio/images/Matson_2019_3.pdf.

Ottens, R. 2016. Species at a glance; American bullfrog. https://seagrant.oregonstate.edu/sites/seagrant.oregonstate.edu/files/bf-species-guide.pdf. Accessed on 01/11/2024.

Powell, R., R. Conant, and J.T. Collins. 2016. Peterson field guide to reptiles and amphibians of eastern and central North America. 4th edition. Houghton Mifflin Harcourt Publishing Company, New York, NY.

Treanor, R.R., and S.J. Nicola, S.J. 1972. A Preliminary Study of the Commercial and Sporting Utilization of the Bullfrog, Rana catesbeiana Shaw, in California. California Department of Fish and Game.

Urbina, J., E.M. Bredeweg, C. Cousins, A.R. Blaustein, and T.S. Garcia. 2020. Reproductive characteristics of American bullfrogs (Lithobates catesbeianus) in their invasive range of the Pacific Northwest, USA. Scientific Reports 10:16271. https://doi.org/10.1038/s41598-020-73206-w.

U.S. Department of Interior Desert Pupfish Task Force. 1971. Status of the desert pupfish. U.S. Department of Interior, Washington, D.C. https://ecos.fws.gov/ServCat/DownloadFile/56698.

Watters, T.G., and S.H. O’Dee. 1998. Metamorphosis of freshwater mussel glochidia (Bivalvia: Unionidae) on amphibians and exotic fishes. American Midland Naturalist 139:49-57.

Watters, T.G., and S.H. O'Dee. 1998. Metamorphosis of freshwater mussel glochidia (Bivalvia: Unionidae) on amphibians and exotic fishes. American Midland Naturalist 139:49-57.

Yap, T.A., M.S. Koo, R.F. Ambrose, and V.T. Vredenberg. 2018. Introduced bullfrog facilitates pathogen invasion in the western United States. PLoS ONE 13(4):e0188384. https://doi.org/10.1371/journal.pone.0188384.

Author: Audrey Jordon

Revision Date: 3/21/2024

Peer Review Date: 3/21/2024

Citation Information:
Audrey Jordon, 2024, Lithobates catesbeianus (Shaw, 1802): U.S. Geological Survey, Nonindigenous Aquatic Species Database, Gainesville, FL, https://nas.er.usgs.gov/queries/factsheet.aspx?SpeciesID=71, Revision Date: 3/21/2024, Peer Review Date: 3/21/2024, Access Date: 7/18/2024

This information is preliminary or provisional and is subject to revision. It is being provided to meet the need for timely best science. The information has not received final approval by the U.S. Geological Survey (USGS) and is provided on the condition that neither the USGS nor the U.S. Government shall be held liable for any damages resulting from the authorized or unauthorized use of the information.


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Citation information: U.S. Geological Survey. [2024]. Nonindigenous Aquatic Species Database. Gainesville, Florida. Accessed [7/18/2024].

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