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Wildlife Guide · North America

American Bullfrog

Lithobates catesbeianus

North America's largest and loudest frog

IUCN: Least Concern
Large green American bullfrog sitting at the edge of a pond among reeds

Image: Photo: Carl D. Howe / Wikimedia Commons (CC BY-SA 2.5)

In brief

The American bullfrog (Lithobates catesbeianus) is North America's largest frog, reaching 9 to 20 cm in body length and weighing up to about 0.5 kg. It lives in and around ponds, lakes, marshes and slow streams, where the male's deep, resonant call carries far across the water.

By the WARN Research & Conservation TeamChecked against IUCN Red List & CITES sourcesLast updated

The American bullfrog (Lithobates catesbeianus) is North America's largest frog, reaching 9 to 20 cm in body length and weighing up to about 0.5 kg. It lives in and around ponds, lakes, marshes and slow streams, where the male's deep, resonant call carries far across the water. A voracious carnivore, it will eat almost anything it can swallow, from insects to fish and small vertebrates. In the wild bullfrogs live around seven to nine years.

0.2 m

Typical length

500 g

Typical weight

16 km/h

Top speed

8 yrs

Lifespan

Figures sourced from Wikidata — American Bullfrog .

American Bullfrog: Quick Facts

Vital statistics and key facts about the American Bullfrog
Scientific name Lithobates catesbeianus
Diet Carnivore (insects, fish, small vertebrates)
Habitat Ponds, lakes, marshes, slow streams
Lifespan 7–9 years in the wild
Weight Up to 0.5 kg (1.1 lb)
Size 9–20 cm (3.5–8 in) body length
Conservation status Least Concern (IUCN)

Scientific Classification

Scientific classification of the American Bullfrog
Kingdom Animalia
Phylum Chordata
Class Amphibia
Order Anura
Family Ranidae
Genus Lithobates

Conservation Status

IUCN Status
Least Concern (IUCN Red List category)
Population
Global population not compiled for this guide
Trend
See the IUCN Red List assessment
Assessed
See the IUCN Red List assessment
CITES
See CITES appendices

Conservation figures are drawn from the IUCN Red List and CITES; this guide links to the authoritative sources rather than restating population counts.

Key Facts: American Bullfrog

  • The American bullfrog is a heavyweight among frogs, with a body 9 to 20 cm (3.5 to 8 inches) long and a weight of up to about 0.5 kg (1.1 lb).
  • Bullfrogs are ambush carnivores with an enormous appetite and famously indiscriminate tastes.
  • On land the bullfrog travels in long, powerful hops, launching itself with muscular hind legs that let it clear several times its own body length in a single leap.

Size and appearance

The American bullfrog is a heavyweight among frogs, with a body 9 to 20 cm (3.5 to 8 inches) long and a weight of up to about 0.5 kg (1.1 lb). Its skin is olive-green to brownish, often mottled, with a pale, sometimes yellow throat in breeding males. A prominent fold of skin curves around each large, exposed eardrum, or tympanum, which in males is noticeably bigger than the eye. Powerful, fully webbed hind feet make it a strong swimmer and an impressive jumper.


Diet and feeding

Bullfrogs are ambush carnivores with an enormous appetite and famously indiscriminate tastes. They eat insects, fish and small vertebrates, and larger individuals will take anything they can cram into their mouths, including other frogs, small snakes, mice, and even ducklings. The frog sits motionless until prey comes within range, then lunges forward and engulfs it, using its bulging eyes to help push the meal down its throat. This willingness to eat almost anything has helped it thrive across a wide range of wetlands.


Movement on land and water

On land the bullfrog travels in long, powerful hops, launching itself with muscular hind legs that let it clear several times its own body length in a single leap. In the water it is an accomplished swimmer, its webbed feet driving it forward with strong kicks and its top speed reaching around 16 km/h (10 mph). When startled at the water's edge it will make a rapid dive, kicking down into mud or vegetation to hide. This ability to both hop and swim lets it move easily between land and water to hunt and escape danger.


The bullfrog's call

The bullfrog takes its name from the male's deep, booming call, often written as a resonant jug-o-rum that carries far across a pond on warm nights. He produces the sound by pumping air back and forth over his vocal cords while inflating a large throat sac, and the low pitch travels much further than the calls of smaller frogs. Males call to defend territory and to attract females during the breeding season, and a chorus of many bullfrogs can be heard from a considerable distance. Each male's call also signals his size, since bigger frogs produce deeper notes.


Life cycle and tadpoles

Bullfrogs breed in late spring and summer, and a single female can lay a film of up to twenty thousand eggs across the water's surface. The tadpoles are exceptionally large and can take one to three years to complete their transformation into froglets, depending on climate. During this long larval stage they graze on algae and plant matter before switching to a carnivorous adult diet. Adult bullfrogs typically live around seven to nine years in the wild.

What WARN Does

WARN does not run a dedicated american bullfrog programme — this guide is part of the World Animal Rescue Network's free educational library. The american bullfrog is currently widespread and not globally threatened, and this guide helps readers understand the pressures that can change that. Building public understanding of species like the american bullfrog supports the broader conservation awareness that underpins WARN's partner-led rescue work across its network.

If clear, science-based wildlife guides like this help you understand and value animals, please consider supporting the World Animal Rescue Network's educational and rescue work so we can keep producing them.

American Bullfrog: Frequently Asked Questions

How big do American bullfrogs get?

They are North America's largest frog, with a body 9 to 20 cm (3.5 to 8 inches) long and a weight of up to about 0.5 kg (1.1 lb). Females tend to be slightly larger than males.

What do bullfrogs eat?

Bullfrogs are carnivores with a huge appetite, eating insects, fish and small vertebrates. Large individuals will swallow almost anything that fits in their mouths, including other frogs, small snakes, mice and even ducklings.

Why are bullfrogs so loud?

Male bullfrogs make a deep, resonant call by pumping air over their vocal cords and inflating a large throat sac. The low pitch carries far across water, helping them defend territory and attract females.

How long do bullfrogs live?

In the wild American bullfrogs live around seven to nine years. Their tadpoles alone can take one to three years to transform into froglets before adulthood.

Can bullfrogs jump far?

Yes. Their powerful hind legs let them leap several times their own body length in a single hop. In water they are also strong swimmers, reaching speeds of around 16 km/h (10 mph).

Are bullfrogs invasive?

Outside their native eastern North America they can be highly invasive. Their enormous appetite and rapid breeding let them outcompete and eat native amphibians where they have been introduced, making them a problem in parts of the western United States and beyond.

Where do bullfrogs live?

American bullfrogs inhabit ponds, lakes, marshes and slow streams across eastern North America, where males call from the water's edge. They are strong swimmers and ambush predators that sit motionless until prey comes within lunging range.

Are bullfrogs dangerous?

Bullfrogs are not dangerous to people, but their voracious appetite makes them ecologically damaging where introduced. Large individuals will swallow almost anything that fits in their mouths, including other frogs, small snakes and ducklings, outcompeting native amphibians.

Sources & References

Population figures, conservation status and biological facts on this page are drawn from authoritative scientific and intergovernmental sources.

Terms used on this page

Plain-English definitions, from our wildlife and conservation glossary.

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