37 Toadally Cool Facts About Frogs

Frogs are among the most interesting animals in the world! And, unless you’ve spent a fair amount of time studying them, there are plenty of frog facts you might not know!

We all know the basics. They’re generally small and jump away as you approach them, and they usually look wet or slimy. But there is more to frogs than that.

Frogs and toads can be found almost everywhere, and the difference from one species to the next can be astounding. From small, fully-aquatic frogs to brightly colored, gliding arboreal frogs, the diversity is extraordinary!

For this reason, I’ve compiled a list of my favorite frog facts! Let’s begin…

Frog Facts Infographic

1. Frogs swallow with their eyes.

Frogs use their eyes to help them swallow food[1]. The muscles around the eyes retract the eyes into the mouth, pushing food farther into the esophagus.

2. Toads are a type of frog.

From a taxonomic standpoint, there is little difference between a frog and a toad. “Frog” is a common name used to describe the order of Anura, which contains all species of frogs and toads. “Toad” is a common name typically used to describe a warty amphibian, similar to a frog, that can survive a bit longer without water.

Meanwhile, there is the family Bufonidae which contains all “true toads.” The family of Bufonidae is within the order of Anura. So, simply put, toads are a type of frog.

3. They absorb oxygen through their skin.

Frogs have permeable skin. This means their skin allows things to pass through – including oxygen. This means a frog’s skin is a respiratory surface. The skin may account for 1 to 10 percent of respiration[2].

4. Frogs live on every continent except Antarctica.

Nowadays, there are no amphibians living in Antarctica. However, a recent discovery suggests there may have been frogs on the Antarctic Peninsula a long, long time ago.

5. A group of frogs is called an army.

Army of Frogs
An army of frogs. Photo by okonato / Adobe Stock

Groups of animals have special names. For example, a group of wolves is called a “pack.” In the same way, a group of frogs is called an army.

6. The largest frog is the Goliath Frog.

The Goliath frog, also known as the “Giant Slippery Frog,” is the largest frog on planet earth. They can grow up to 12.5-inches in length (vent to snout) or 30-inches (with legs extended), and weigh over 7 lbs.

As of November 26th, 2018, the Goliath Frog is an endangered species with populations decreasing due to human consumption[3].

7. The smallest frog is about 0.3-inches in length.

A species from Papua New Guinea (Paedophryne amauensis) has won the title of the world’s smallest frog. It has an average body length of about 0.3-inches (7.7mm).

8. Tadpoles primarily eat plant matter.

Before tadpoles undergo metamorphosis, they mostly feed on plant matter. One study examined the gut material of Green Frogs (Rana clamitans) before and after metamorphosis [4]. They found that 93.5% of their diet consisted of algae.

While it’s not uncommon for tadpoles to eat larvae or carrion (decaying flesh), they mostly stick to plant matter.

9. Frogs are carnivores.

After metamorphosis, frogs are mostly carnivores. They eat things like butterflies, moths, beetles, wasps, bees, worms, spiders, ants, etc. It’s rare for them to eat plant matter.

One study looked at the gut content of 83 Asian horned frogs (megophyridae) and found that most of their diet consisted of termites, wasps, bees, and ants. The rest of the content was moths, beetles, grasshoppers, and butterflies[5].

10. Frogs are poisonous.

Poison Dart Frog on a Leaf
Poison Dart Frog on a Leaf. Photo by: Dirk Ercken / Shutterstock

Poison is a harmful toxin that is absorbed or swallowed. For example, you get food poisoning by eating something harmful.

In the same way, frogs are poisonous because they have toxins on their skin, and those toxins can be harmful. But don’t worry, most frogs are basically harmless to humans. However, certain frogs can be poisonous to dogs and other small animals.

11. There are venomous frogs.

Venom is a harmful toxin that is injected via fangs or a singer. For example, snakes are venomous because they inject toxins via fangs. With that in mind, there are venomous frogs. They don’t have fangs or singers, however.

Bruno’s casque-headed frog and Greening’s frog have tiny spines on their skulls. The spines can inject a toxin, which is present on their skin. As the spines puncture through their skin, the toxins are injected into their target.

Bruno’s casque-headed frog has a toxin more powerful than a Brazilian pit viper (Bothrops) [6].

12. Some frogs dig burrows.

Terrestrial frogs and toads are known to burrow for multiple reasons. Most of the time they burrow up to their eyes in order to hide, so they can ambush prey as it walks by.

13. Frogs have teeth.

A slight majority of frogs have teeth. There are maxillary teeth, vomerine teeth, and dentary teeth. Most frogs with teeth have maxillary and/or vomerine teeth[7]. They are incredibly small and nearly impossible to see.

14. Only one frog has teeth on its lower jaw.

Guenther’s marsupial frog is the only known frog species with dentary teeth. Dentary teeth are located on the bottom jaw. All other frogs that have teeth have maxillary or vomerine teeth, which are located on or near the upper jaw.

15. Some frogs have fangs.

Limnonectes ingeri
Limnonectes ingeri. Photo by: Jegelewicz / Wikipedia (CC BY-SA 3.0)

The Genus Limnonectes contains around 77 species, many of which have odontoids [8]. Odontoids are fang-like structures, but they’re technically not true teeth.

16. More than 7,000 species of frogs.

At the time of writing this, there are 7,489 species of frogs and toads recorded on AmphibiaWeb, an online database containing detailed information about amphibian species.

Slowly but surely, new species are discovered. Some species go extinct. Other species are reclassified. The number of species is constantly changing.

17. One frog shows its belly to deter predators.

Red-bellied toads have developed a clever method to avoid being eaten. It’s called “unken reflex” and it involves the frog assuming a strange position in order to display its brightly-colored stomach.

The pose works by revealing the frog’s aposematic coloration, which warns predators of its toxicity.

One study aimed to determine if the unken reflex is efficient against birds[9]. Researchers placed clay models in a forest to observe whether or not the reflex was effective at keeping birds away. Roughly 10% were attacked by birds. The results showed varying differences between the normal, red, and green models.

18. Some frogs hear with their lungs.

Some frogs can essentially hear with their lungs. Vibrations cause their lungs to work like an eardrum[10]. Also, their lungs are capable of picking up a lower frequency of sounds than their tympanic membrane.

19. Wood frogs freeze to survive the winter.

Wood frogs have blood that keeps ice crystals from forming in their body. With this, up to 70% of their body can be frozen during the winter.

Their heart stops beating and their lungs stop breathing. Still, when springtime arrives and temperatures increase, wood frogs come back to life.

20. Frogs lay eggs.

Frog guarding clump of eggs
Photo by: G.J. Verspui

This may come as no surprise to you, but not everyone knows this fact. Frogs lay eggs. It’s the first part of the life cycle of a frog. Some species lay up to 20,000 eggs.

21. Male frogs fertilize the eggs outside of the body.

Most Anurans (frogs and toads) fertilize the eggs outside of the body. Male frogs assume a position called amplexus, where he grasps the female around the waist. From there, the female deposits eggs while the male fertilizes them outside of the body.

22. Darwin’s frogs carry their young in their mouth.

Darwin’s frogs are neat because of the way they care for their offspring. After a female lays the eggs, the male stays with them until they begin moving. That this point, he swallows the eggs and holds them in his vocal sac. The eggs eventually hatch and they remain in their father’s vocal sac until they’re big enough to hop out.

23. Marsupial frogs carry their young on their back.

A small skin pouch is used to carry eggs on their back. The tadpoles remain there until they’re froglets, at which point they hope and continue growing into adults.

24. One frog secretes a sunscreen-like wax.

The Giant Waxy Monkey Frog produces a wax-like substance that functions like sunscreen. They apply the wax to their entire body, which protects them from getting sunburned or drying out, especially during the dry season.

25. Glass frogs have translucent skin.

Stomach of a Glass Tree Frog - Transparent Skin
The stomach of a Glass Tree Frog with translucent skin. Photo by: Dirk Ercken / Shutterstock

Some members of the family Centrolenidae have translucent skin, hence the common name “Glass Frog.” The see-through portion is located on their belly.

26. Frogs have three means of respiration.

Another amazing fact about frogs is that they have three ways of breathing. Their lungs aren’t developed as well as other animals, but most frogs have them regardless. They can also exchange gas on the lining of their mouth. A frog’s skin is capable of dissolving oxygen from air and water, too.

27. One frog is lungless.

At the time of writing this, there is one type of frog without lungs. The Bornean flat-headed frog is an endangered species and it does not have lungs.

28. Wolverine frogs appear to have hair.

Male wolverine frogs, also known as “Harry frogs,” have hair-like strands on their hind legs. Despite the appearance, it’s not actually hair. It’s called dermal papillae, which is an outgrowth of skin.

Scientists believe it serves a purpose, too. The outgrowths increase the surface area of the skin, which may allow this frog to be more efficient at dissolving oxygen from the water[11].

29. Some frogs can glide.

Wallace’s flying frog has unusual webbing between its toes and fingers. The increased surface area allows this “flying frog” to glide from one location to the next, sometimes up to 50 feet in length.

30. Frogs have amazing camouflage.

Vietnamese Mossy Frog
Vietnamese Mossy Frog (Theloderma Corticale). Photo by davemhuntphoto / Adobe Stock

Most frogs are perfectly suited to the environment they live in. Their colors and patterns help them to hide from predators. One of the best examples of this is the Vietnamese Mossy Frog. The color, pattern, and shape of their skin looks almost identical to moss.

31. One frog mimics a deadly viper.

The Congolese Giant Toad looks almost identical to the head of a Gaboon Viper [12]. This phenomenon is called Batesian mimicry, and its purpose is to appear to be something dangerous, in order to scare away potential predators.

32. A frog’s bright coloration is a warning.

Aposematic coloration is a warning of danger to other animals. When an animal is brightly colored, it means “hey, back off, I’m dangerous.”

This can be seen in poison-dart frogs, which are some of the most brightly colored animals in the world. They carry potent toxins on their skin.

33. One frog has spikes around its mouth.

The Emai Mustache Toad, found in parts of China, grows a spiky mustache during the mating season. They use their spikes while fighting for territory.

34. Frogs may have devolved teeth up to 20 times.

Toothlessness is usually associated with a specialized diet. For example, a large toad eating small ants. The toad swallows the ants whole and doesn’t really need teeth. Due to this, some frogs might have devolved teeth. The teeth simply went away. That’s one theory, at least.

A group of researchers studied the dental history of several families of frogs. They found that frogs may have devolved teeth up to 20 times[13].

35. Frogs sleep with their eyes open.

Sleeping Frog Posture (Labeled Diagram)

We still have a lot to learn about the sleeping behavior of frogs. What we believe so far is that frogs enter into a sleep-like state of rest[14]. It’s different from how mammals sleep.

During one stage of rest, most frogs sleep with their eyes open. Some of them, including Red-Eyed Tree Frogs, have a “nictitating membrane,” which is similar to an eyelid, that covers their eyes.

36. Tree frogs use geometry to stick to surfaces.

The toe pads of some tree frogs are coated in a thin layer of mucus. The mucus is used to adhere to surfaces, in a process known as wet adhesion. One study found hexagonal microstructures on the pads of White’s Tree Frogs, too[15]. It could be that tree frogs are using angles and geometry to create friction in order to stick to a surface.

37. Tree Frogs are known as Leaf Frogs

While the name “tree frog” is common for arboreal species of frogs, some people choose to call them “leaf frogs” instead.


References

  1. Levine, Robert P., et al. “Contribution of Eye Retraction to Swallowing Performance in the Northern Leopard Frog, Rana Pipiens.” Journal of Experimental Biology, vol. 207, no. 8, 2004, pp. 1361–68. Crossrefdoi.org/10.1242/jeb.00885.[]
  2. Hofrichter, Robert. “The Encyclopedia of Amphibians.” The Encyclopedia of Amphibians, Gardners Books, 2000, p. 78.[]
  3. IUCN SSC Amphibian Specialist Group (IUCN SSC). “Giant Slippery Frog (Conraua Goliath).” IUCN Red List of Threatened Species, 26 Nov. 2018, www.iucnredlist.org/species/5263/96062132#threats.[]
  4. Jenssen, Thomas A. “Food Habits of the Green Frog, Rana Clamitans, before and during Metamorphosis.” Copeia, vol. 1967, no. 1, 1967, p. 214. Crossrefdoi:10.2307/1442196.[]
  5. University Malaysia Sarawak. “Diet Habits of Frogs (Family: Megophryidae) in Kubah National Park.” Research Gate, 2018. ResearchGatedx.doi.org/10.13140/RG.2.2.28317.61927.[]
  6. Jared, Carlos, et al. “Venomous Frogs Use Heads as Weapons.” Current Biology, vol. 25, no. 16, 2015, pp. 2166–70. Crossrefhttps://doi.org/10.1016/j.cub.2015.06.061[]
  7. Paluh, Daniel J, et al. “Rampant Tooth Loss across 200 Million Years of Frog Evolution.” eLife, vol. 10, 2021. Crossrefhttps://doi.org/10.7554/elife.66926.[]
  8. STUART, BRYAN L., et al. “A New Fanged Frog in the Limnonectes Kuhlii Complex (Anura: Dicroglossidae) from Northeastern Cambodia.” Zootaxa, vol. 4894, no. 3, 2020, pp. 451–73. Crossrefhttps://doi.org/10.11646/zootaxa.4894.3.11.[]
  9. Bordignon, Debora Wolff, et al. “Are the Unken Reflex and the Aposematic Colouration of Red-Bellied Toads Efficient against Bird Predation?” PLOS ONE, edited by Daniel Osorio, vol. 13, no. 3, 2018, p. e0193551. Crossref, https://doi.org/10.1371/journal.pone.0193551.[]
  10. Ehret, G., et al. “Hearing through the Lungs: Lung-Eardrum Transmission of Sound in the frogEleutherodactylus Coqui.” Naturwissenschaften, vol. 77, no. 4, 1990, pp. 192–94. Crossref, https://doi.org/10.1007/bf01131168.[]
  11. Hofrichter, Robert. The Encyclopedia of Amphibians. Gardners Books, 2000., p. 83[]
  12. Vaughan, Eugene R., et al. “A Remarkable Example of Suspected Batesian Mimicry of Gaboon Vipers (Reptilia: Viperidae:Bitis Gabonica) by Congolese Giant Toads (Amphibia: Bufonidae:Sclerophrys Channingi).” Journal of Natural History, vol. 53, no. 29–30, 2019, pp. 1853–71. Crossref, https://doi.org/10.1080/00222933.2019.1669730.[]
  13. Paluh, Daniel J., Edward L. Stanley, et al. “Evolution of Hyperossification Expands Skull Diversity in Frogs.” Proceedings of the National Academy of Sciences, vol. 117, no. 15, 2020, pp. 8554–62. Crossrefhttps://doi.org/10.1073/pnas.2000872117.[]
  14. Libourel, P. A., & Herrel, A. (2015). Sleep in amphibians and reptiles: a review and a preliminary analysis of evolutionary patterns. Biological Reviews91(3), 833–866. https://doi.org/10.1111/brv.12197[]
  15. Barnes, W. Jon. P., et al. “Comparative Cryo-SEM and AFM Studies of Hylid and Rhacophorid Tree Frog Toe Pads.” Journal of Morphology, vol. 274, no. 12, 2013, pp. 1384–96. Crossrefhttps://doi.org/10.1002/jmor.20186[]