• Carrie Gardner

Jeremiah Was a Bullfrog

Updated: Jan 22, 2020

I admit that I’m not as familiar with amphibians as I should be. But I love American bullfrogs. Kermit was one until a little bright green one-inch glass frog in Costa Rica is now being called Kermit. Then there was the Budweiser Frogs! And the lizards, ferret, and iguana. That was a classic string of ads. For as long as I remember, I’ve wanted a bullfrog, and I’ve wanted to name him Jeremiah. Thank you Three Dog Night!

Lithobates (or Rana) castesbeianus, otherwise known as the American bullfrog has obscured their range in the United States, actually North America. Originally found in the eastern states from Ontario and southern Quebec to Florida and west to the Mississippi, it is now introduced everywhere. And I mean everywhere. It was introduced in the western states during the Great Depression to start farms for frog legs. When you look at a small frog’s legs, you think how? Or why? Well, it’s because bullfrogs are the largest frog in the United States, and they have some long, meaty, nutritious, low in calories legs. Those meaty legs and the pet trade brought it to Europe, South America, Mexico, Cuba, and Asia. They are considered invasive except in their natural habitats. They may have also been introduced through introductions to trout streams during stocking operations, biological operations (remember science class and frog dissection? Better yet, remember the scene in “E.T. where Elliott let all the frogs go?) Various state fish and wildlife agencies also introduced them for people to hunt.

Eggs. Lots and lots of bullfrog eggs.

How did they become so invasive? We’ll start at the beginning. They’re solitary except for when they come out of hibernation. Females are hopping around, growing eggs and feeding the young their yolk feeding the young their yolks while the men are establishing their 3-25 meter territory and aggressively protect it while giving out a loud mating call that sounds like a bull (hence the name). Desperate females come hopping over ready to spawn. Males move on top of her and grasps her at her sides. They even have special toes called nuptial pads that have a rough pad on each foot so they don’t slip off. At the same exact time that the female releases her eggs, the male releases his sperm. The eggs are in a gigantic egg mass protected by a jelly substance. This egg mass is about the size of a small watermelon - sometimes even 3.3 feet long. I guess that’s what it takes to fit in the few 22,000 eggs the female lays. She then leaves and the eggs are one their own. The mass floats near the surface for three to five days before hatching out into Rambo sized tadpoles. Depending on where they live, the metamorphosis occurs in a few months to a couple of years. The tadpoles are extremely unappetizing and not many like to eat them. They are very prolific breeders and this is one of the reasons for the sheer number of invasive frogs.

Bullfrogs can be over eight inches long and weigh up to 1.5 pounds. The hind legs can then be anywhere from seven to 14 inches! They are powerful swimmers as they move about the lake, river, swamp, bog, stream, or pond and can jump as high as six feet. They are large and green with some black dots. They can also take off for parts unknown by hopping up to a mile a day, staying at the local cheap ponds rather than a five-star lake, until they reach somewhere that feels like home. Males have a yellow chin and belly and a tympanum membrane (eardrum) much bigger than their eyes. They also have teeth in the roof of their mouths. Females have a creamy white throat and a tympanum membrane that is the size of their eyes. Tadpoles are yellow with spots that can be over six inches long. The longer they remain tadpoles, the bigger they will be as frogs.

They prefer warm weather to cold (so do I. That’s why this Chicagoan is living in Florida.) In warm habitats, they can remain active all year. In cold weather, they brumate (reptile and amphibian hibernation) by burying themselves in the mud, making a cave-like structure. Hopping out when it’s warm enough for them to become toasty. They are also active during the day and at night, especially when it’s hot and humid. Having excellent vision and hearing, they can honestly be referred to as ectothermic pigs. They eat basically whatever they can stuff in their mouths, but it wouldn’t be fun if I didn’t give you a list of some animals, it would be boring. Plus, I don’t want to influence anyone to try and get bullfrogs to eat anything. I don’t know if they can take the 11 herbs and spices found in KFC chicken and please NO TACO BELL! So, here we go: they eat snakes, worms, insects, crustaceans, frogs, tadpoles, fish eggs, frog eggs, or insect eggs, their own children, birds, bats, small turtles, rodents, snails, musks, beetles, and so much more. If they can’t get it all the way in their mouths, they use their forelimbs to shove it in. The tadpoles are for the most part grazers, though they are also cannibals. (Did someone say food??)

The Study of Frog Jumping

How do they swallow so many prey that are so big? Never fear! I wouldn’t have thrown out a hypothetical question unless I planned to answer it. First, they see something yummy and hops around so they are facing their dinner. They hop-up to it, if it has to, and all at once they close their eyes, open their mouths and extend their fleshy mucous-covered tongue toward the prey, engulfing it while the jaws continue to move forward until it can bite. As stated, sometimes they require the help of their forelimbs. In studies, they would dive into the water with a mouse so the water’s resistance helps push it into their mouths.

Bullfrog Call

Tired of swimming around, the bullfrog tadpole has funny grown a pair...of legs.

Considering how widespread they've become, are bullfrogs good or bad for the environment? Where they are native, they help control insects and other animals, become food for herons, turtles, water snakes, raccoons, and humans. They are also used for medical research (and dissections in science classes). The bad would be where they’re invasive. They don’t have a lot of natural predators, tadpoles are more successful and they stuff way too much wildlife into their big mouths. Several things have been tried to reduce their populations. Including predatory fish. I would like to tell them that introducing another non-native animal will not help control another non-native’s overpopulation!! These fish are not just going to eat the bullfrogs but will compete with bullfrogs for the native wildlife. An excellent example would be cane toads. Australians and Floridians both brought them up from their native South America because they ate the cane beetle. They found other things to eat. When they are threatened, they spread this slimy stuff all over their bodies. In South America, this would just be distasteful to local animals, who would learn not to eat it. In Florida and Australia, they killed animals with their slime...and they are also prolific breeders. Australian animals have a harder time. One more bad thing is that they are carriers of Batrachochytrium denaturation (also known as Chytrid) - a fungus that has raced through amphibian populations throughout the world, putting many species in danger of extinction. It blocks the animal from exchanging oxygen through the skin. Chytridiomycosis can kill bullfrog tadpoles in high numbers. Scientists are working hard on Chytrid. In the meantime, there are a lot of people who keep frogs and are preventing species from being wiped off the planet. (Photo: Tadpole beginning metamorphosis)

As I close this out, I would like everyone to remember that kissing a bullfrog won’t get you a handsome prince or a beautiful princess, licking will not cause a high. However, if you have the time and you’re in the right place, put on some DEET and go sit outside at night and close your eyes. Listen to the musical extravaganza that nature gives every night. You’ll hear the bullfrog here...helping to make it all a splendid show.

Please see some more pictures below

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