Bullfrog

Rana catesbeiana

Jim Harding

The Bullfrog is the largest frog in North America. The females grow larger than the males, up to eight inches. Bullfrogs vary in color, from dark olive to pale green above, and from white to cream underneath. They often have dark gray mottling (splotches) on their back legs.

Bullfrogs have large eardrums behind the eye, and this is how to tell the male from the females. Males have larger eardrums, which will be bigger than the eye. Females have smaller eardrums, which will be the same size, or smaller, than the eye.

You can tell a Bullfrog from other frogs, like the Green Frog or Pig Frog, by its lack of dorsolateral ridges. These are the two long lines down the back of most frogs.

Photo by Mike Mossman

Bullfrogs are solitary (live alone) animals, and are very territorial. They rarely meet, except to fight over territory or mate. Bullfrogs mate in the Spring.

Bullfrogs lay up to 20,000 eggs in huge sheets, attached to plants under the water. They taste bad to most predators, which gives them some protection.

Eggs hatch into tadpoles, which grow to four to six inches before turning into frogs.

Copyright, William Leonard, California Academy of Sciences

Tadpoles can live up to two years before turning into frogs. The longer they remain a tadpole, the bigger the frog will be.

Tadpoles eat algae, plant tissue (they nibble underwater plants), and aquatic insects. The tadpoles are also protected because they taste bad.

Adult Bullfrogs alway stay near water. They live in ponds, lakes, and streams with slow-moving water. Bullfrogs hang out on banks or at the waters edge. If frightened, they may jump in the water, or hide in plants on the shore. Bullfrogs usually hide among tall plants, such as cattails, or among lilypads. They like to ambush their prey.

Copyright, Mike Mossman

Mark Moran

Bullfrogs are voracious eaters (they eat a lot), and will eat just about any animal they can swallow. These include: insects, crayfish, worms, minnows, other frogs (even Bullfrogs), small turtles, snakes, baby birds, and small mammals.

They are most active at night.

The above picture shows a sheet of Bullfrog eggs. Photo by Charlotte C. Corkran

Bullfrogs are good swimmers, kicking out with their strong hind legs. They are helped by their webbed hind feet.

Bullfrogs hibernate in the winter, usually burying themselves in mud.

Bull frogs have a deep, loud call which can be heard up to a quarter of a mile.

Mark Moran

Bullfrogs have many predators, especially when they are young. Snakes, turtles, fish, and birds will eat both tadpoles and smaller frogs. Even adult Bullfrogs can be taken by larger animals, such as Great Blue Herons and Raccoons.

Mark Moran

Additional Media

Description
Type
Credit
Bullfrog Call
Sound
Unknown
Bullfrog Calling #1
Video
Phil Heine
Bullfrog Calling #2
Video
Phil Heine
Bullfrog Skeleton
Link to Image
John White
Download Quicktime if you are unable to play video.

Relationships in Nature:

PREY
PREDATORS
SHELTER
OTHER

Crayfish

Great Blue Heron

Common Cattail

Freshwater Leech Pa

Northern Ringneck Snake

Largemouth Bass

Common Duckweed

Muskrat SP

Earthworm

Raccoon

Yellow Pond Lily

Beaver SP

Creek Chub

Barred Owl

Pickerelweed

The Big Red Worm Pa

Golden Shiner

Green Darner

Common Reed

Meadow Vole

Channel Catfish

Tussock Sedge

Golden Northern Bumble Bee

Red-tailed Hawk

Green Algae

Spring Peeper

Yellow Perch

Lizard's Tail

Common Snapping Turtle

Eastern Newt

Dodder

Eastern Dobsonfly

Large Diving Beetle

Hydrilla

Wood Frog

Muskrat

Greater Bladderwort

Five-lined Skink

Virginia Opossum

Spotted Jewelweed

Pennsylvania Firefly

Eastern Painted Turtle

Poison Ivy

Green Darner

Common Snapping Turtle

Wild Grape

Water Flea

Black Crappie

Marsh Bulrush

Euglena

Bald Eagle

Buttonbush

Field Cricket

Ring-billed Gull

Arrow Arum

Muskrat

Double-crested Cormorant

Swamp Rose Mallow

Chinese Mantid

Aquatic Worm

Relationship to Humans:

Bullfrogs help humans by eating large amounts of pesky insects, such as mosquitos. Many people eat frog legs, which are almost always from Bullfrogs. Bullfrogs are frequently used for medical research, because their body systems are similar to higher animals. Bullfrogs are currently dissected in many high school biology classes so students can learn animal anatomy.

SCIENTIFIC CLASSIFICATION

KINGDOM
Animal
PHYLUM
Chordate
CLASS
Amphibian
ORDER
Salientia
FAMILY
Ranidae
GENUS
Rana
SPECIES
Rana catesbeiana

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