The Characteristics of a Bullfrog

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A male bullfrog waiting for an unsuspecting insect.

In the world of amphibians, not all frogs were created equal. In fact, not all frogs are frogs. Frogs are moist-skinned, live in or near the water and have webbed feet. True frogs' preferred method of travel is hopping or swimming. They should not be mistaken for toads that have drier, warty skin and walk and live on land. The Rana catesbeiana, or North American bullfrog, takes the prize as being the largest of the "true frogs."


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Bullfrog Physical Facts

Bullfrogs are the largest frog found in North America, weighing in at around 1 lbs. and reaching up to 8 inches in length. Bullfrogs range in color and can be found in shade variations of green or brown, usually with spots of darker color along their backs. Bullfrogs have webbed hind feet to help propel them in the water. On land, they are able to hop between 3 and 6 feet per leap. Telling the sex of a bullfrog is a little different than in mammals. Determining bullfrog sex is done by judging the size of the external ear or tympanum relative to the bullfrog's eye. The bullfrog tympanum is the circle on the side of a bullfrog's head, close to his eye. If the bullfrog is male, the circle is much larger than the eye. In females, the circle is the same size or smaller than the eye. In addition, during the bullfrog mating season the male's throat is yellow, and the female's is white. Bullfrogs have either brown or gold eyes, and broad, flat heads and bodies.


Bullfrog Behavior

Bullfrogs are warm weather creatures, preferring a moist, temperate climate. In winter months, a bullfrog will construct himself a mud cave and hibernate, waiting out the cold days in relative comfort. Males are territorial and will fight for supremacy with other males for the area they have claimed. Bullfrog conflict is usually done with loud calls, displays of aggression, chasing and jump attacks, and if none of this works to scare off the intruder, the bullfrog is not to proud to engage in some wrestling.


The Bullfrog Diet

The bullfrog is an ambush predator with patience, lying in wait for exceptionally long periods of time for a hapless insect to cross his path. With a lightening fast flick of the tongue, the bullfrog snatches the insect right out of they air and eats it. Luckily for the insect, it never knew what hit it. Bullfrogs have voracious appetites, eating anything it is able swallow. Bullfrogs are not beyond or incapable of eating mice, small birds, lizards, small fish, and if necessary, other frogs.


Bullfrog Reproduction

Male bullfrogs "sing" at ponds where breeding females congregate. Singing is how the male attracts the female. Females make calls responding to the singing male that offers the best amenities. Females are attracted to the males with the best and largest territories providing the most food. Frogs breed once per year: May through July in the northern U.S. and February through October in the southern U.S.. Female bullfrogs reach sexual maturity around the age of 3 and are capable of laying up to 20,000 eggs at one time.


Telling a Bullfrog From a Toad

Frogs and toads are similar in size and appearance to the casual observer, but there are distinct differences if someone knows what to look for. Frogs are smooth and moist, while toads are dry and warty. Frogs live in water, whereas toads only use water to lay eggs. Frogs have long, strong, web-footed legs, ideal for swimming or hopping. Toads have short, stubby legs made for walking. Frogs lay eggs in clusters,and toads lay them in a strand that attaches to a plant in the water. Toads also have a gland that secretes a poison to ward off predators. Frogs prefer a warm, moist climate, and toads are more fond of dry heat.