The bullfrog has an external eardrum behind its head.
The Sea World website describes the North American bullfrog’s appetite as "voracious," noting the amphibian will consume just about any creature it manages to catch and swallow. The bullfrog gets its name from its call, which sounds like the mooing of a cow. This frog has a wide distribution across the continent, living from southeastern Canada to Florida and as far west as the Rockies. Bullfrog populations also exist in some western states as a result of the introduction of this species.
Size and Habitat
The bullfrog can grow to lengths of around eight inches, with the length of its legs adding as much as 10 more inches when the frog stretches out completely. The bullfrog has the ability to reach weights of as much as 1.5 pounds in the largest specimens. The typical bullfrog is smaller, but still the biggest frog in any ecosystem in which it lives. Bullfrogs inhabit lakes, ponds, swamps, marshes and the edges of sluggish streams and rivers, looking for places along the shore where vegetation is dense enough to provide sufficient cover from danger.
Identification
A bullfrog has green to greenish-yellow colors above, with a grayish mottling mixed in. The belly is cream colored or whitish, with flecks of gray. The bullfrog has an obvious eardrum, called a tympanum, which is external. This rounded area behind the head is larger in the males of the species. The bullfrog has webbed hind feet, with the exception of the last joint on the frog’s longest toe. The frog’s teeth are on the roof of its mouth; its long tongue is strong enough to secure prey and bring it into the frog’s mouth.
Diet
The diet of the bullfrog includes smaller fellow bullfrogs as well as other types of frogs. The bullfrog captures its food by ambushing it, sitting still until something edible passes by. The frog leaps out with mouth open, gobbling up its unfortunate victim. Bullfrogs prey upon small fish such as minnows, as well as crayfish, insects, small snakes, small mammals and birds.
Transformation
The female bullfrog will attach her eggs to submerged vegetation in her aquatic environment, with the jelly-like mass containing as many as 20,000 to 25,000 eggs. Once the eggs hatch, the bullfrog is in the tadpole stage, with some reaching lengths of just under seven inches. The bullfrog tadpole remains in this stage of development for up to two years before making the final transformation into an adult bullfrog. The larger tadpoles have the best chance to reach maturity.
Territorial
The male bullfrog is a territorial creature and will vigorously defend whatever ground it stakes out for itself against other males. The bullfrogs will wrestle, attack each other with jumping movements, call out and chase other frogs from their piece of a shoreline. The female frogs, which are slightly bigger in size than the males, base their preference for a male upon the type of territory it possesses, with the availability of food a large part of the equation. In June of 1754, a nocturnal fight among bullfrogs over a drought-stricken pond so frightened the settlers in Windham, Connecticut, that they thought a massacre of some sort had occurred.
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