Frog Facts Everyone Should Know

There is one fact that must be featured first:

One third of all amphibians are threatened with extinction.

(It is because of this fact that we will continue to reach people through education and engagement every day. Be kind and share with others.)


(Rheobatrachus silus). Photo by: unknown author. Wikipedia.

Southern Gastric-brooding Frog (Rheobatrachus silus). Photo by: unknown author. Wikipedia.

Frogs have been on the Earth for over 200 million years, at least as long as the dinosaurs.

Toads are frogs, but frogs are not toads. Frogs live near ponds, swamps and marshes. Frogs can live on the ground or in trees, but toads live only on the ground. Some frogs live in deserts and only come to the surface during the rainy season and breed in shallow vernal pools and puddles that dry quickly.

Frogs usually have webbed hind feet, and some have webbed front feet. Some frogs, such as tree frogs, have pads on their toes that help frogs climb trees, or even stick to a glass window.

The largest frog is the African Goliath Frog. One of the smallest is smaller than a dime, the Paedophryne amauensis, which was recently discovered on the island of Papua New Guinea.

There are over 6,000 species of frogs worldwide. They exist on all continents except Antarctica.

Some frogs are poisonous and one drop from this type (such as a Dart frog) could kill a human. You’ll notice these frogs by their bright colors.

Frogs have big, bulging eyes, excellent night vision and can see almost 360 degrees around. They do not have the ability to turn their heads. They also use their eyes to help them swallow food by pushing their eyes down.

Frogs are cold-blooded, meaning their body temperatures change with the temperature of their surroundings. When it gets cold, some frogs dig burrows underground or in the mud at the bottom of ponds and hibernate until spring. Hibernation has a summer equivalent called “aestivation.”

Many frogs have incredible camouflage techniques: muddy brown in color or spotty bumpy skin to make them look like moss, leaves, and even trees.

Male frogs call to attract the females. Some frogs have vocal sacs, some do not—pouches of skin that fill with air like balloons. The balloon acts as an amplifier and some frog sounds can be heard from a mile away.

During mating season, the male frogs in a group will croak quite loudly to attract females. When a female finds a male croak she likes, the male will grab her and she will release eggs for him to fertilize.

Frogs will eat any living thing that will fit in its mouth. This includes bugs, spiders, worms, slugs, larvae and even small fish.

To catch prey, the frog’s sticky tongue darts out and pulls the prey into its mouth. A frog’s tongue can snap back into its mouth within 15/100ths of a second.

Some species of tadpoles will swim together in schools like fish for protection from predators and for heat regulation during cold late winter and spring weather.

Frogs can hear both in the air and below water. Instead of the external ear like we have, their external ear is called the “tympanum.” The eardrums are covered by a layer of skin and are the circular area just behind the eyes.

The bromeliad tree frog (Bromeliohyla bromeliacia) is found in Belize, Guatemala, Honduras and southern Mexico. These frogs lay their eggs inside bromeliads or other water-filled spaces in the canopy of trees so the tadpoles can develop. They live their lives in the canopy.

There are approximately 300 species of frogs in Madagascar. There are no toads, salamanders or newts.

The flying frog has brilliant colors, long limbs and its fingers and toes are webbed, giving it the ability to glide or parachute to the forest floor from high in the trees (like flying!)

Frogs have eyes with an upper and lower lid and a membrane which provides extra protection while swimming. Depending on the frog, their irises can range in color and the pupils from horizontal or vertical to triangular and circular.

Some frogs that live in colder regions can survive being frozen. Their essential organs are protected by a high concentration of glucose. Once spring arrives and the temperature warms, the frog’s heart starts beating, and the frog thaws out and hops off.

Male frogs call for females and there are certain types of female frogs that reply. Each frog species has a different sound, some high and some low. Frogs also have different calls for an unreceptive female, an approaching rain storm, or in the case of danger.

One third to possibly one half of all amphibians are threatened with extinction. In response, the global conservation community has formulated the “Amphibian Conservation Action Plan.” Select species that would otherwise go extinct will be maintained in captivity until such time as they can be released back in the wild.

Frogs have weak teeth so they do not chew their food. Instead they are used to hold the food before it is swallowed. They catch flies or other moving prey by extending their coiled tongue. Some frogs do not have a tongue, and just stuff food in their mouths with their hands.

Most frogs start out as eggs and soon emerge as tadpoles. At the end of the tadpole stage, the frog undergoes an amazing metamorphosis. The frog develops lungs and their gills disappear. Their legs begin to grow as the tail recedes. The nervous system adapts for hearing and stereoscopic vision. It’s during this transformation that frogs are most vulnerable because of their lack of motion. ** However, some frogs skip the tadpole stage! Eleutherodactylis planistris, the greenhouse frog, for example, lay their eggs on land, the eggs then hatch out fully developed young frogs.

The gastric-brooding frogs, or platypus frogs (now extinct in the wild), were native to Queensland in eastern Australia. These frogs were unique because they were one of two known species that incubated the prejuvenile stages of their offspring in the stomach of the mother.

Animals that eat frogs include snakes, lizards, birds, shrews, raccoons, foxes, otters, weasels and larger frogs. Underwater frogs must watch out for fish, turtles and water birds. In addition, in many places around the world, there are humans who eat frogs.

Some species of frogs are capable of changing their skin color as their environment changes. Frogs have a huge range of skin colors and patterns, which indeed help protect them from their natural predators. Colors can also aid as a warning to predators that the frog may be toxic.

The glass frog’s general background coloration is primarily lime green but the abdominal skin of some is translucent so we can see the heart, liver and gastrointestinal tract through the skin.

Some tadpoles are herbivorous, feeding on algae and plants, some are omnivorous and some are even cannibals. Adult frogs eat their fair share of mosquitos, which keeps them away from us and our overall environment healthier.

Frogs have graced the pages of literature in such works as, Frog and Toad by Arnold Lobel and as “Mr. Toad” in The Wind in the Willows by Kenneth Graham. There’s also the most famous frog from TV, Kermit the Frog from Sesame Street and The Muppet Show.



Herps Alive! A Reptile Rescue Herpetologist Writes About Frogs

Guest Post by Keith Gisser

I know what you are thinking.

Why is a reptile rescue guy writing about frogs? They aren’t reptiles. And captive frogs don’t need to be rescued. Gators, boas, pythons, maybe even big monitor lizards and iguanas, sure. But frogs?

Herps Alive! The Interactive Reptile and Amphibian Experience, is a traveling educational herpetology program and display. We have presented in 36 states (primarily at college campuses, but also at libraries, festivals elementary and high schools). Now in my fifties, I did my first paid program at age 17,  and now my daughter a degreed Interpretative Naturalist, and my son, a marketing whiz, often travel and help me. We offer display programs and interactive lectures as well as classroom sessions, and have presented an estimated 3,000 programs since we started (we have worked some “real” jobs here and there).

As your reputation builds, you start getting calls to adopt animals. Usually they are pets that people can’t keep. Sometimes they are police seizures or animals from other unfortunate situations.  We have always accepted these animals in an effort to keep a good relationship with the museums, nature centers and law enforcement officials who contact us.

But in the last year or so, the rescue mission has taken on a life of its own.  We have been asked to take in dozens of animals. And for the first time, we began rehoming a few. As a result we are spinning off our rescue mission and working on moving it to a separate location, as we turn it into a charitable foundation.

But what about the frogs?

I have been fascinated with frogs my entire life. My career as a herpetologist probably began at age nine when I caught a toad. I brought him home in a rinsed out pickle jar. (That was 45 years ago when such behavior was acceptable. At the time they were also in the genus Bufo, not Anaxyrus) I have bred several species of frog in captivity and always include a discussion of metamorphosis in my educational programs.

Southern Toad

Right now we have three frogs among our 150 animals.  Our Southern Toad (Anaxyrusterrestris) was living in a Carolina classroom after a student had brought him. He had been in captivity for too long to be released, so when we came in to do a program, the teacher asked if we could take him. Known just as The Toad, he eats crickets and small worms, as well as waxworms.

Beatrice is an African Clawed Frog (Xenopuslaevis) who was raised from a small size by my son’s ex-girlfriend. When she moved into a new home, she asked us to take her on. Beatrice was raised in a 10 gallon aquarium. When we tried to move her to a larger one, she went off feed and seemed generally unhappy. So back into the ten she went even though it really is too small for her. She loves her goldfish and nightcrawlers and eats anywhere from 10-30 a week. Unfortunately, her relatives have been taking a bad rap lately as they have been identified as the culprits that carried of the dreaded chytrid fungus.  It’s not really their fault. In everywhere except their African home, they were used as lab animals. They were used as part of a pregnancy test. The problem is not with them carrying the fungus, but rather with the irresponsible people who have released them outside their normal environment.

African Clawed Frog

Finally, there is Poncherello Pegone Pixiefrog, our African Bullfrog (Pyxicephalusadsperus). “Ponch” is named for the  mayor on the cartoon My Gym Partner’s a Monkey., who is also a Pixie, or African Bullfrog. We adopted him from a breeder because he appears to be blind in one eye and the breeder did not want him. Ponch eats thawed mice off tongs, usually one or two a week. He is also a regular in our programs, having traveled to 14 states since we got him two years ago. While our other frogs are kept in our entrance hallway (Our facility is not air conditioned), Ponch loves the heat and his aquarium is kept in our snake and lizard room, where the high ambient temperature helps him with digestion.

We hope to see you some time in the future…

About Keith Gisser:

Keith caught a toad (Anaxyrus ssp) when he was nine and his herpetology career began. He has presented Herps Alive! an award-winning, nationally recognized interactive reptile and amphibian program based in Ohio, at over 170 college campuses and hundreds of other venues in 39 states.

Gisser, who has been a herpetology educator for over thirty years and currently maintains about 140 reptiles, amphibians and crocodilians, nearly all of which are adoptions or rescues, about half of which are used in his programs. The rescue and adoption mission has taken more and more of his time and efforts in recent years and will soon be “spun off” as the Herps Alive! Foundation, which is in the process of seeking non-profit status and accreditation as a rescue.


Spring to Life: From Tadpole to Frog

It’s finally Spring, and in our part of the world, we’re ecstatic. We’ve had a rough winter—we had snow and ice on our city streets every day for about 40 days in a row! The crocuses are blooming in my backyard, and outside the city, frogs are springing to life.

In a way, Spring is a good time to think about our “inner amphibian.” After all, mammals are descended from animals that moved from aquatic environments onto the land over three million years ago. As embryos, our heads in the early stages of development look remarkably similar to shark embryos—with gill arches and all. The metamorphosis of frogs is a process that’s not all that different from what all vertebrates go through, but the difference is that most of the development of birds, reptiles, and mammals—such as the growth of the lungs and limbs—takes place inside an egg or inside the mother instead.*


A female frog first lays eggs underwater, sometimes hundreds of eggs, which form into a jelly-like clump called frogspawn, which floats on the water. Most of these eggs become food for other pond life, but some survive.

Tadpoles developing in eggs. © Dan L. Perlman/EcoLibrary.org

The tiny animal inside the egg grows for about a month, then hatches out of the egg. It looks like a small black fish and breathes underwater with feathery gills on each side of its head.

The tadpole’s tail begins to grow; it wiggles its tail to swim. Tadpoles are also called polliwogs. (The word “polliwog” is from Middle English polwygle. Pol means “head” and wiglen means to “to wiggle”). The tadpole eats algae and other plants that grow underwater.

Tadpole. Photo from Wikipedia.


After several weeks, tadpoles begin their metamorphosis. Two tiny bumps appear near the tadpole’s tail—these will grow into back legs.

Two more bumps appear near the frog’s head—these will grow into front legs. Lungs begin to grow inside the tadpole’s body and the feathery gills disappear so that the tadpole will be able to breathe air.

The tadpole now has legs for hopping and walking, lungs for breathing air, but its long tail is awkward on land. Until the tail shrinks and is absorbed into its body, the froglet stays in or near the water.

Froglet with tail. Photo courtesy of www.scienceprojectlab.com


When the tail is gone, the frog has completed its metamorphosis. The young frog will now feed on small insects, caught with their long, sticky tongues. It will eventually move away from the pond and find a safe place to grow.

This Spring, take some time to visit a nearby pond or swamp and see this process yourself. And check out the poster below that Susan designed for Earth Day, inspired by a photo by FROGS ARE GREEN photographer friend Joe Furman. All proceeds go to help our amphibian friends.

*I found this idea in Thomas Marent’s lovely and informative book, FROG.