bull frog
In the summer, just after dark, a choir of frogs begins to call at Webster Lake. In our cove, a deep bass voice, much like the roar of a bull, sounds after the others are in full voice. This singer is the American bullfrog or simply bullfrog as most of us call it. A familiar amphibian frog found in the United States and Canada is a member of the family Ranidae, or “true frogs.” Native to eastern North America, its natural range extends from the Atlantic coast to western Oklahoma and Kansas. Recently introduced to Nantucket Island, Arizona, Utah, Colorado, Nebraska, Nevada, California, Washington, and Hawaii. It is considered an invasive species in these states, as it can outcompete native amphibian species, upsetting the local ecological balance. In some foreign countries such as Mexico, China, South Korea, and Argentina, the bullfrog was intentionally released, either as a food source or as a kind of biological control agent.
So how do you spot a bullfrog? Look for a colorful frog with an olive green back and sides and brown markings. On the belly of the bullfrog, it will be white with gray or yellow spots. Specifically, the upper lip is often bright green, and the lower lip is much paler. It should be noted that the male’s throat is yellow and it is smaller than the female in general. Inside the frog’s mouth are tiny teeth that are used to grasp small objects. The bullfrog’s brown eyes bulge out and have almond-shaped irises. You will find the eardrums (eardrums) just behind the eyes and the dorsolateral skinfolds end near them. A male’s eardrums are larger than his eyes, while a female’s are smaller than her eyes. The limbs of the bullfrog are spotted or have gray bands. The forelegs are stocky and short, with the hind legs long and slender, capable of leaping distances 10 times the length of its body. Only the hind toes are webbed, except for the fourth toe. Most bullfrogs are about 3.6 to 6 inches from end to end. Growth is rapid for the first eight months of life, and weight increases from 0.18 ounces to 6.17 ounces. A larger, more mature bullfrog can weigh anywhere from 1.5 pounds to as long as 8 inches.
Found in large permanent bodies of water such as ponds, swamps, lakes, and streams, a male bullfrog will defend his territory during the two to three month breeding season. This season is from late May to July. Males will claim sites that are generally 9.8 to 10.7 feet apart. They call loudly using at least three different territorial calls that serve not only as threats to other males, but also to attract females and find calls that precede combat.
Male bullfrogs form groups called choirs. These choirs are dynamic, they form and stay together for a few days. After the short period, they go on to form new choirs with different males. To establish dominance within a chorus, the male demonstrates a variety of aggressive behaviors, especially visually. Territorial males have inflated postures to show off their yellow throats, while non-territorial males remain in the water with only their heads showing. When two dominant males come into contact, they fight! After all the male jousting, a female will finally select a mate. When she is done, she lays about 20,000 eggs on her territory in shallow water.
As a kid growing up on Table Rock Lake in Missouri, I remember many nights when my dad, two brothers, and I would go “frog making.” American bullfrogs are often found at the dinner table, especially in the midwestern and southern United States. When the deep call is heard, a light shines on the frog, temporarily blinding it. Then, when approached slowly, carefully, and quietly, the bullfrog is struck with a multi-pronged spear (if legal), seized, or captured by hand. The hind legs are usually eaten as small thighs and cooked in the same way. A little trivia: the American bullfrog is the state amphibian of Missouri, Ohio, and Oklahoma.
Most of us who grew up in the United States share another memory of the American bullfrog: dissection in biology class. I would not like to repeat, thank you!
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