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
