The Canadian Encyclopedia — neutral, cited, updated
July 26, 2026Sources cited
Canadianwire.
Canada’s encyclopedia & explainer
HomeScience & NatureAmphibianBullfrog
Science & Nature • Amphibian

Bullfrog

Bullfrog is a common name for large frogs in the genus Lithobates, especially the American bullfrog, a widespread species native to eastern North America.

By Ethan Anderson| Reviewed by Olivia Bennett, Standards & Fact-Checking Lead| Updated July 26, 2026|2 min read| Fact-checked

Bullfrog is a common name for large frogs in the genus Lithobates, especially the American bullfrog, a widespread species native to eastern North America. It is the largest frog in North America and is known for its deep, resonant call, aquatic habits, and invasive populations outside its native range.

Description

Bullfrogs are large, heavy-bodied frogs with smooth green to brown skin and prominent eardrums. Adults are among the largest frogs in North America and are often identified by their size and deep call.

Distribution and habitat

The American bullfrog is native to eastern North America and occurs naturally in parts of Canada and the United States. It has also been introduced to western North America and many other regions worldwide.

Behaviour and diet

Bullfrogs are mostly aquatic and feed as opportunistic predators. They eat a broad range of prey and may also consume other frogs, making them important predators in wetland ecosystems.

Conservation and ecological impact

The species is listed as least concern and is widely distributed. In areas where it has been introduced, it can be invasive and associated with declines in native amphibians and reptiles.

Key facts

  • Bullfrogs are the largest frogs in North America.
  • The American bullfrog is native to eastern North America and occurs in parts of Canada and the United States.
  • They live in freshwater habitats such as ponds, lakes, marshes, and other permanent water bodies.
  • Bullfrogs are opportunistic predators that eat a wide range of animals, including insects, fish, amphibians, reptiles, and small mammals.
  • Outside their native range, bullfrogs are considered invasive in many places because they can prey on native species.
🍁
Canadian context

Bullfrogs occur in southern parts of Canada, and the American bullfrog is a familiar species in Canadian freshwater habitats. Canadian readers may also encounter conservation concerns where introduced bullfrogs affect native wetland species.

Frequently asked questions

What is a bullfrog?
A bullfrog is a large frog, most commonly referring to the American bullfrog, Lithobates catesbeianus.
Where are bullfrogs native to?
American bullfrogs are native to eastern North America, including parts of Canada and the United States.
How big do bullfrogs get?
They usually grow about 6 to 8 inches long, and some can weigh up to about 2 to 3 pounds.
What do bullfrogs eat?
Bullfrogs eat a wide variety of prey, including insects, fish, amphibians, reptiles, and small mammals.
Are bullfrogs invasive?
In their native range they are not invasive, but introduced populations are considered invasive in many regions because they can harm native species.
What sound do bullfrogs make?
Their call is a deep, resonant sound often described as "jug-o-rum."

References

  1. North Carolina Wildlife Resources Commissionhttps://www.ncwildlife.gov/education/american-bullfrog-species-profile/open
    Supports: Size, native range, and general species profile.
  2. National Geographichttps://www.nationalgeographic.com/animals/amphibians/facts/american-bullfrog
    Supports: Scientific name, range, size, and conservation status.
  3. BioKIDS, University of Michiganhttps://www.biokids.umich.edu/critters/Lithobates_catesbeianus/
    Supports: Identification, range, size, diet, and introduced populations.
  4. University of Georgia SREL Herpetologyhttps://srelherp.uga.edu/frogs-and-toads/bullfrog/
    Supports: Description, habitat, call, breeding, eggs, tadpole development, and invasive status.
  5. U.S. National Park Servicehttps://www.nps.gov/articles/000/american-bullfrogs-fast-facts.htm
    Supports: Species being the largest frog in the U.S. and amphibian life-cycle context.
  6. Encyclopaedia Britannicahttps://www.britannica.com/animal/bullfrog
    Supports: Definition as a semi-aquatic frog, naming, and native/introduced range.