Thursday, May 25, 2023

Episode 657 (6-12-23): American Bullfrog

CLICK HERE to listen to episode audio (4:05).

Sections below are the following:
Transcript of Audio
Audio Notes and Acknowledgments
Extra Information

Related Water Radio Episodes
For Virginia Teachers (Relevant SOLs, etc.).

Unless otherwise noted, all Web addresses mentioned were functional as of 5-24-23.


From the Cumberland Gap to the Atlantic Ocean, this is Virginia Water Radio for the weeks of June 12 and June 19, 2023.  This is a revised version of an episode from August 2011.

MUSIC – ~12 sec – instrumental.

That’s part of “Frog Legs Rag,” composed in 1906 by James Scott of Missouri.  It opens an episode on a frog known for its large size, deep voice, and big appetite.  Have a listen for about 15 seconds to the following mystery sounds, and see if you know what’s making the croaks.  And here’s a hint: what would you get if you combined a male hoofed mammal with a jumping amphibian?

SOUNDS - ~16 sec

If you guessed a bullfrog, you’re right!  You heard calls of the American Bullfrog, the largest native frog in North America, with a length typically of 4 to 6 inches and sometimes as much as 8 inches.  This large size helps account for the males’ deep mating call, often described as “jug-o-rum” and audible over considerable distances. 

Bullfrogs are found all over Virginia in ponds, lakes, and still-water sections of streams.  These kinds of permanent water bodies with shallow water and vegetation are needed for mating, for the laying of thousands of eggs in sheets on the water surface, and for the tadpoles’ development period of one to two years.  Bullfrog tadpoles feed mostly on algae, aquatic plants, and insects or other invertebrates, while adults feed on insects, crayfish, other frogs, snakes, small mammals, and—according to one source—“anything that is moving and that they can at least partially swallow”.  In turn, bullfrogs are prey for various wildlife species and in some states are a game species for humans.  The American Bullfrog’s native range is from the East Coast to the Great Plains.  Some of these native populations have declined due to habitat loss, water pollution, and pesticides, while the species’ range has expanded through introductions into several western states.

Thanks to the U.S. Geological Survey for providing the American Bullfrog recording.  Thanks also to Free Music Archive for providing access to a public domain version of “Frog Legs Rag,” and we close with another 20 seconds of that music.

MUSIC – ~22 sec – instrumental.


Virginia Water Radio is produced by the Virginia Water Resources Research Center, part of Virginia Tech’s College of Natural Resources and Environment.  For more Virginia water sounds, music, or information, visit us online at, or call the Water Center at (540) 231-5624.  Thanks to Ben Cosgrove for his version of “Shenandoah” to open and close this episode.  In Blacksburg, I’m Alan Raflo, thanking you for listening, and wishing you health, wisdom, and good water.


This Virginia Water Radio episode revises and replaces Episode 74, 8-8-11.

The sounds of the American Bullfrog heard in this episode were from the U.S. Geological Survey Upper Midwest Environmental Sciences Center, online at

“Frog Legs Rag” was composed by James Scott (1885-1938) in 1906.  The version heard in this episode was from 1906 piano roll, accessed from Free Music Archive, online at  The version was published as part of the 2010 album “Frog Legs: Ragtime Era Favorites,” online at  The site indicates that the “Frog Legs Rag” piano roll version is provided for use under Creative Commons Public Domain Mark 1.0.  More information about “Frog Legs Rag” and about James Scott is available from Gonzaga University, online at, and from the Library of Congress online at

Click here if you’d like to hear the full version (2 min./22 sec.) of the “Shenandoah” arrangement/performance by Ben Cosgrove that opens and closes this episode.  More information about Mr. Cosgrove is available online at


American Bullfrog photographed in Alexandria, Va., May 21, 2023.  Photo by Caroline Quinn, made available on iNaturalist at (as of 5-25-23) for use under Creative Commons license “Attribution—Non-commercial 4.0 International (CC BY-NC 4.0).”  Information about this Creative Commons license is available online at
American Bullfrog at Gavins Point National Fish Hatchery at Yukton, South Dakota, July 31, 2018.  Photo by Sam Stukel, made available for public use by the U.S. Fish and Wildlife Service’s National Digital Library, online at; specific URL for the photo was, as of 5-25-23.


The scientific name of the American Bullfrog is Lithobates catesbianus; formerly, the scientific name was Rana catesbiana.

The following information is quoted from the Virginia Department of Wildlife Resources (formerly Department of Game and Inland Fisheries), “Fish and Wildlife Information Service/American Bullfrog Life History,” online at, and “Food Habits,” online at

Physical Description

This is the largest native North American frog species in Virginia.  Lengths range from 85-200mm (3.5-6 in).  ...Males are generally smaller than females, have a yellowish wash on their throat, and a larger tympanum [eardrum], thumb, and forearm.  The male breeding call is a deep, full series of notes best described as “jug-a-rum.”...


This species breeds from the late spring to early fall.  Males are territorial.  Mating success is influenced by the quality of the territory. ... Females lay one or two clutches per season.  Average clutch size is 12,000 eggs.  Clutches are laid in a film on the water surface.  Eggs hatch in approximately 5 days.  Tadpoles can be very large, 125-150 mm.  Metamorphosis usually takes 1 year [and] larvae will overwinter in ponds.  Larval survivorship is <18%.  This species typically reaches sexual maturity one year after metamorphosis.  In mountain localities, transformation may take 2 years.


This is a wary and solitary species that prefers large ponds, lakes, and still portions of streams.  Males of this species defend territories typically within vegetated areas of ponds.  Defending behaviors include encounter calls, postural displays, chasing the intruder, and combat.  Size and age strongly determine territory success.  This is a voracious predator feeding on insects, crayfish, small mammals, snakes and other frogs.  Experiments have demonstrated that this species has the ability to orient to stellar patterns or the moon.

Limiting Factors and Aquatic/Terrestrial Associations

This species requires medium to large permanent bodies of water to meet their one to two year early developmental period.  This species prefers large ponds, lakes and quiet sections of streams.  It prefers larger bodies of water than most frogs.  It is usually found in aquatic vegetation or snags in which it can hide.  Clutches of eggs are laid in still shallow water.

Food Habits

The adults will eat anything that is moving and they can at least partially swallow.  Food importance varies by season.  Crayfish and amphibians are most important in the spring.  Crayfish and insects are important in the summer with insects and crayfish the most important food items.  Plant food is considered accidental.


Used for Audio

John D. Kleopfer and Chris S. Hobson, A Guide to the Frogs and Toad of Virginia, Special Publication Number 3, Virginia Department of Game and Inland Fisheries (now Department of Wildlife Resources), Richmond, Va., 2011.

Bernard S. Martof, et al., Amphibians and Reptiles of the Carolinas and Virginia, University of North Carolina Press, Chapel Hill, 1980.

National Aquarium, “American Bullfrog,” online at

Oregon State University/Oregon Sea Grant, “Species at a Glance: American Bullfrog,” online (as a PDF) at

University of Michigan Museum of Zoology, “Animal Diversity Web,” online at, “Biokids: American Bullfrog,” online at

Virginia Herpetological Society, “Frogs & Tads of Virginia,” online at  (Herpetology is the study of amphibians and reptiles.)  The American Bullfrog entry is online at

Virginia Department of Wildlife Resources (formerly Department of Game and Inland Fisheries), “Fish and Wildlife Information Service,” online at  This site has detailed information on life history, distribution, habitat, and other aspects of species.  The American Bullfrog entry is online at; this is the source for the quotation in the audio about feeding.

For More Information about Frogs, Toads, and Other Amphibians in Virginia and Elsewhere

J.C. Mitchell and K.K. Reay, Atlas of Amphibians and Reptiles in Virginia, Virginia Department of Game and Inland Fisheries/Richmond (now Department of Wildlife Resources), 1999; available online (as a PDF) at, courtesy of the Virginia Herpetological Society.

U.S. Geological Survey (USGS), “ARMI (Amphibian Research and Monitoring Initiative),” online at

Virginia Department of Wildlife Resources:
“A Guide to the Salamanders of Virginia,” online at;
“A Guide to Virginia’s Frogs & Toads,” online at;
“List of Native and Naturalized Fauna in Virginia, August 2022,” online (as a PDF) at;
“Virginia is for Frogs,” online at


All Water Radio episodes are listed by category at the Index link above (  See particularly the “Amphibians” subject category.

Following are links to other episodes with some mention of the American Bullfrog.

371, 6-5-17 – on the Virginia Herpetology Society’s “Herp Blitz.”
381, 8-14-17 – on sounds heard beside water at midnight.
408, 2-19-18 – a medley of frog and toad calls.
524, 5-11-20 – a tour of sounds by water-connected creatures.


Following are some Virginia Standards of Learning (SOLs) that may be supported by this episode’s audio/transcript, sources, or other information included in this post.

2020 Music SOLs

SOLs at various grade levels that call for “examining the relationship of music to the other fine arts and other fields of knowledge.”

2018 Science SOLs

Grades K-4: Living Systems and Processes
K.7 – Plants and animals have basic needs and life processes.
1.5 – Animals, including humans, have basic life needs that allow them to survive.
2.4 – Plants and animals undergo a series of orderly changes as they grow and develop, including life cycles.
2.5 – Living things are part of a system.
3.4 – Adaptations allow organisms to satisfy life needs and respond to the environment.
3.5 – Aquatic and terrestrial ecosystems support a diversity of organisms.
4.2 – Plants and animals have structures that distinguish them from one another and play vital roles in their ability to survive.
4.3 – Organisms, including humans, interact with one another and with the nonliving components in the ecosystem.

Grades K-5: Earth and Space Systems
2.7 – Weather patterns and seasonal changes affect plants, animals, and their surroundings.
3.7 – There is a water cycle and water is important to life on Earth.

Grades K-5: Earth Resources
3.8 – Natural events and humans influence ecosystems.
4.8 – Virginia has important natural resources.

Grade 6
6.6 – Water has unique physical properties and has a role in the natural and human-made environment.
6.8 – Land and water have roles in watershed systems.
6.9 – Humans impact the environment and individuals can influence public policy decisions related to energy and the environment.

Life Science
LS.5 – Biotic and abiotic factors affect an ecosystem.
LS.6     – Populations in a biological community interact and are interdependent.
LS.7 – Adaptations support an organism’s survival in an ecosystem.
LS.8 – Change occurs in ecosystems, communities, populations, and organisms over time.
LS.9 – Relationships exist between ecosystem dynamics and human activity.
LS.11 – Populations of organisms can change over time.

BIO.7 – Populations change through time.
BIO.8 – Dynamic equilibria exist within populations, communities, and ecosystems.

Virginia’s SOLs are available from the Virginia Department of Education, online at

Following are links to Water Radio episodes (various topics) designed especially for certain K-12 grade levels.

Episode 250, 1-26-15 – on boiling, for kindergarten through 3rd grade.
Episode 255, 3-2-15 – on density, for 5th and 6th grade.
Episode 282, 9-21-15 – on living vs. non-living, for kindergarten.
Episode 309, 3-28-16 – on temperature regulation in animals, for kindergarten through 12th grade.
Episode 333, 9-12-16 – on dissolved gases, especially dissolved oxygen in aquatic habitats, for 5th grade.
Episode 404, 1-22-18 – on ice on ponds and lakes, for 4th through 8th grade.
Episode 407, 2-12-18 – on snow chemistry and physics, for high school.
Episode 483, 7-29-19 – on buoyancy and drag, for middle school and high school.
Episode 524, 5-11-20 – on sounds by water-related animals, for elementary school through high school.
Episode 531, 6-29-20 – on various ways that animals get water, for 3rd and 4th grade.
Episode 539, 8-24-20 – on basic numbers and facts about Virginia’s water resources, for 4th and 6th grade.
Episode 606, 12-6-21 – on freezing and ice, for kindergarten through 3rd grade.