Species: Lithobates catesbeianus

American Bullfrog
Species
Amphibians
Show on Lists
Amphibians of Puget Sound prairie
Terrestrial vertebrates: amphibians
Invasive species: amphibians

Bullfrogs are green or brown, usually with dark spots or mottling (but not large rounded spots). The eardrums are large, with a fold of skin curving around the top and rear edges. The hind toes are more or less fully webbed but the 4th toe extends beyond the webbing. There are no ridges along each side of the back. Maximum snout-vent length is about 8 inches (20 cm). In mature males, the eardrum usually is distinctly larger than the eye (same diameter in female and young), the throat is yellow during the breeding season, and the base of the thumb is swollen. Expansion of the internal vocal sac in adult males causes a bulging of the throat. The breeding call is a deep bellowing um-rum or um-er-rum or something similar. Juveniles are green with many scattered small black dots on the back. In large larvae, the upper surface is green with small black sharp-edged dots (and on tail fin), whereas the upper side is black with gold crossbands in individuals less than one inch (2.5 cm) long. Maximum length of larvae is about 7 inches (18 cm); commonly they are 4 inches long or longer (10+ cm). Eggs are black above, whitish below, deposited in flat jelly masses up to more than 1 meter in diameter and containing thousands of eggs (mass initially floats at surface of water but soon sinks). Source: Hammerson (1999).

Kingdom
Animalia
Phylum
Craniata
Class

Amphibia

Order

Anura

Family

Ranidae

Genus

Lithobates

Natureserve Explorer
Source:
ELEMENT_GLOBAL.2.105926
Classification
Other Global Common Names
Bullfrog - Rana Toro - ouaouaron
Informal Taxonomy
Animals, Vertebrates - Amphibians - Frogs and Toads
Formal Taxonomy
Animalia - Craniata - Amphibia - Anura - Ranidae - Lithobates

Bullfrogs are green or brown, usually with dark spots or mottling (but not large rounded spots). The eardrums are large, with a fold of skin curving around the top and rear edges. The hind toes are more or less fully webbed but the 4th toe extends beyond the webbing. There are no ridges along each side of the back. Maximum snout-vent length is about 8 inches (20 cm). In mature males, the eardrum usually is distinctly larger than the eye (same diameter in female and young), the throat is yellow during the breeding season, and the base of the thumb is swollen. Expansion of the internal vocal sac in adult males causes a bulging of the throat. The breeding call is a deep bellowing um-rum or um-er-rum or something similar. Juveniles are green with many scattered small black dots on the back. In large larvae, the upper surface is green with small black sharp-edged dots (and on tail fin), whereas the upper side is black with gold crossbands in individuals less than one inch (2.5 cm) long. Maximum length of larvae is about 7 inches (18 cm); commonly they are 4 inches long or longer (10+ cm). Eggs are black above, whitish below, deposited in flat jelly masses up to more than 1 meter in diameter and containing thousands of eggs (mass initially floats at surface of water but soon sinks). Source: Hammerson (1999).

Migration
true - true - false - May make seasonal migrations to and from ephemeral bodies of water, or between adjacent permanent aquatic habitats. Usually remains in one pond or in a cluster of adjacent ponds throughout season but may move up to a mile or more from one year to the next. In Missouri, Willis et al. (1956) found that R. catesbeiana made interpond movements of 0.16-2.8 km.
Non-migrant
true
Locally Migrant
true
Food Comments
Metamorphosed frogs eat any animal that can be captured and swallowed, including all kinds of vertebrates and invertebrates. Larvae eat suspended matter, organic debris, algae, plant tissue, and small aquatic invertebrates.
Reproduction Comments
Breeding occurs when water temperatures are relatively warm, mainly in May-July in the northern part of the range, primarily late spring to late summer in Georgia, and mainly March through summer in Louisiana. Individual females produce 1-2 clutches/year. Larvae hatch in 4-20 days. In most areas, larvae overwinter at least once before metamorphosing, but larvae metamorphose in less than a year in warm climates (e.g., 5-6 months in Louisiana; less than 6 months in Hawaii, Tinker 1941). Individuals become sexually mature an average of 1-5 years after metamorphosis, with the oldest ages of maturity occurring in environments with the shortest growing seasons (e.g., average of 5 years after metamorphosis in central Ontario females); in a particular location, males tend to mature a year or so earlier than do females (Shirose et al. 1993).
Ecology Comments
Introduced bullfrogs apparently have detrimental effects on populations of native ranid frogs. <br><br>Bullfrog larvae generally are not palatable to fish predators but are sensitive to invertebrate predators (e.g., see Smith et al. 1999).<br><br>Bullfrogs in hand may go limp, then suddenly "revive" and leap away. Sometimes they produce a loud open-mouthed call lasting up to several seconds.
Length
20
NatureServe Global Status Rank
G5
Global Status Last Reviewed
2009-10-30
Global Status Last Changed
2001-11-15
Other Status

LC - Least concern - Listed as Least Concern in view of its wide distribution, tolerance of a broad range of habitats, presumed large population, and because it is unlikely to be declining fast enough to qualify for listing in a more threatened category. - ñigo Martínez-Solano, Alfredo Salvador, Mario García-París, Ernesto Recuero Gil, Enrique La Marca, Juan Elías García-Pérez

Conservation Status Map
<img src="http://www.natureserve.org/explorer/servlet/GetMapGif?CA.BC=SE&CA.NB=S5&CA.NS=S5&CA.ON=S4&CA.QC=S5&US.AL=S5&US.AZ=SE&US.AR=S5&US.CA=SE&US.CO=SE&US.CT=S5&US.DE=S5&US.DC=S4&US.FL=SNR&US.GA=S5&US.HI=SE&US.ID=SE&US.IL=S5&US.IN=S4&US.IA=S5&US.KS=S5&US.KY=S5&US.LA=S5&US.ME=S5&US.MD=S5&US.MA=S5&US.MI=S4&US.MN=S4&US.MS=S5&US.MO=S5&US.MT=SE&US.NN=SE&US.NE=S5&US.NV=SE&US.NH=S5&US.NJ=S5&US.NM=SE&US.NY=S5&US.NC=S5&US.OH=S5&US.OK=S5&US.OR=SE&US.PA=S5&US.RI=S5&US.SC=SNR&US.SD=S5&US.TN=S5&US.TX=S5&US.UT=SE&US.VT=S5&US.VA=S5&US.WA=SE&US.WV=S5&US.WI=S3&US.WY=S5" alt="Conservation Status Map" style="width: 475px; height: auto;" />
Global Range
H - >2,500,000 square km (greater than 1,000,000 square miles) - H - The native range extends from Nova Scotia, New Brunswick, and southern Quebec, Canada, west to the Great Lakes region, and south through most of the central and eastern United States and south into northeastern Mexico. The western limits of the native range are ambiguous due to widespread introductions in western North America. The species also has been introduced and is established in the Greater Antilles, Hawaii, and many other locations worldwide.
Global Range Code
H
Global Range Description
>2,500,000 square km (greater than 1,000,000 square miles)
ELEMENT_GLOBAL.2.105926