Anuran impact and trivia:

"Things" answered (and bookmarked) on this page: 

Random facts. 

Frogs in history and myth. 

Anuran contribution to human life.

Random facts:

-Herpetology is the study of reptiles and amphibians.  In reality, there is little evolutionary relationship between reptiles and amphibians.  Reptiles have amniotic eggs, and amphibians do not have amniotic eggs.  This is a big difference.Amphibians really matter to the health of this planet.  Image from Microsoft clipart.

- Amphibians are often represent the highest percentage of vertebrate biomass in an ecosystem.

-All toads are technically frogs.  However, “toad” usually implies more saggy skin, eggs laid in strings, fast developing tadpoles, and adults having only 4 toes.

-Frogs are concentrated in Central and South America, and relatively few exist in Europe.

-Bullfrogs were sent into space in the 1970s.


Baffoon isn't such an affectionate term.  Again, toads are dissed.  Image by Microsoft clipart.-Humans use the cane toad genus in causal language.  Ever heard the term “buffoon”?

-In 19th century Germany, violinists would rub their hands on toads before a performance; toad toxins stop sweat production.

-There aren’t many amphibian fossils because amphibians have light weight bones and live in flowing waters; neither condition is conducive to fossilization.


Amphibians are an unusual bunch!  Image from Microsoft clipart.-90% of known amphibians are frogs and toads.

 -Anurans breathe through gills, lungs, skin, and through mouth surfaces.

-Unlike other orders of amphibians (Urodela/Caudata and Gynophiona/Apoda), in anurans external fertilization of eggs is the norm.  10% of anurans care for their young.  Amphibians are the only vertebrates whose larvae do not depend on adult care.

-Males and females are often visually distinguishable, at least during breeding season.  Males often have dark-colored throats, as displayed by this gray treefrog (Hyla versicolor).

-Sometimes frogs drink orally; they will open their mouths towards water streams and "eat" such water as if it were prey.

-Through their skin, frogs can change pigmentation to reflect more or less sunlight (and thus passively control their body temperatures) and regulate water release to prevent overheating (essentially choosing to sweat by altering skin permeability).

-Frogs control their body temperatures by altering their level of physical activity, altering the pigmentation of their skin, choosing to release water through the skin, basking or seeking shelter, and metabolically by burning fat.  When infected, frogs elevate their body temperatures.

-During mating, the female signals to the male that she is releasing eggs (and hence he should release sperm) by the arch of her back and the position of her cloaca.  In response, he moves his cloaca closer to hers, and males of some species will use their hindlegs to gather the eggs. 

-In most species, both male and female frogs are capable of giving a “release call” – asking to be released from amplexus.  They also use body vibrations to warn off or get rid of unwanted mates.  However, only some female anurans make use of release signals.  The reason for this difference between species remains unclear.  Few males listen anyway, so why has the release signal evolved? 


-Anurans' gelatinous eggs protect against dessication, minimize predation and    pathogenic infection, ultraviolet radiation, and chemical agent damage.  Egg diameter is dependent upon the size of the female and her nutrition.                These factors can influence the timeing of tadpole development                           and survival.  Pigment in the eggs protects moderates                             temperature and UV exposure.

-Tadpoles may live in a dense group. This raise                                                            temperature and the rate of maturation, provides                                                      a joint chemical defense against predation, and hinders
predation by confusing a predator who tries to                                                       single out a victim.


-Endocrine hormones regulate                                                                                 metamorphosis.    


                         -Frogs breed only after metamorphosis-- not true of salamanders.

-Unlike the human tongue, the frog tongue attaches in the front of the mouth.  One Anuran lacks a tongue completely!


-The largest frog is the Goliath frog (Conraua goliath) in Africa, at 8 pounds (3.6 kg); the cane toad (up to 2.8 kg) is the largest and also the most prolific toad.

-In 2001, the cane toad was one of only 3 amphibians to make it onto the “top 100” list of worst invasive species, a list generated by the conservation group IUNC.

-With regards to exotic species (not specific to anurans), there is a “tens rule”: 15% of exotic species will become established, and 10% of those will become pests.Another picture of some Wyoming toads.  C2001 Suzanne. L. Collins, image from

-In 2004, artificial fertilization was used by the Memphis zoo to save the Wyoming toad species (Bufo baxteri= Anaxyrus baxteri).

Humans helped the Wyoming toad have sex more effectively--without each other.  Image from

-Because frogs do not have closed ribs, they have to suck air into their mouths by lowering the floor of their mouth, then close their nostrils and raise their mouth floor to force air into their lungs.

-When injured, Bufo tadpoles release an odor that causes other Bufo tadpoles to retreat.Oreophrynella, copywrite Valerie C. Clark, image from


-The smallest true toad (Oreophrynella) is all of 0.75 inches, or 2 cm.  The honor of largest true toad depends upon the source, but is either the cane toad (Bufo marinus) or Bufo blombgergi, which can be 9.8 inches (25 cm). 

 Copyright Valerie C. Clark


Frogs in history and myth:

Do toads sing to the rain gods?  Image from Microsoft clipart.-The Mayans thought that toads here on earth sing to toads in heaven, and that the toads in heaven then send rain.

-Indigenous people in Indonesia belief frogs are in charge of rain cycles.

-In India, frogs are sometimes taken to a wedding and then released in hopes of rain.

-There is an Indonesian legend of a frog who thought so much that he could fly that he finally did; this sounds similar to the American little train story for kids (“I think I can, I think I can”), but may be based on the Indonesian gliding tree frogs.

-The Aztecs thought that a toad symbolized a ceaseless death.Toads and witches are best friends, right?  Image from Microsoft clipart.

-During the middle ages, Europeans thought that toads and anything they touched were contaminated with poisons, and that toads were friends of witches.

-Gypsies believed that toads could protect them from plagues, brought good fortune or marriage, brought on the rains, and were the spirits of the unborn and prematurely dead.  Hence, toads were somewhat of a resurrection symbol.


The wood frog can freeze solid without a problem.  Image from northern most frog, Rana temporaria, occurs at 71 N longitude.  In North America, the wood frog (Rana sylvatica) can live in the arctic circle.  It freezes solid with high concentrations of glycogen, which act as an antifreeze to keep cells from rupturing (due to water crystallization).  Fertilized eggs freeze and then thaw without a problem. 

-The Chinese made a topical ointment from dried toad skins, but in the 1990s people ate it and died.  This is a problem to similar to that in Australia, where teens have tried licking toads for hallucinogenic effect but have experienced a lethal effect!

Toads as symbols of pregnancy!  Image from Microsoft clipart.

-Sumerians used 9 frogs to symbolize the 9 months of pregnancy.

-Ancient Egyptians placed frogs on the bellies of pregnant women – for fetal safety.

-The fable of “kiss a toad and turn him into a prince”—'nough said.


-In Homer’s “The battle of frogs and mice”, frog sounds keep a traveling goddess awake.  In her rage, she turns against frogs.

-In Egypt, Rome, and Greece, oil lamps decorated with frogs have been discovered; sayings on these lamps translate to “I am the resurrection”.

-In the Bible, both the frog plague with Moses or Revelations 16:13: “And I saw there unclean spirits like toads…”

-The word “tadpole” comes from the medieval English for “toad head”.


How anurans have contributed to life as humans know it.

-Frogs have been used to time geological and climatic changes.

Electrical impulses in nerves, and much of the workings of the heart, is known from research on frogs.  Their hearts have 3 chambers, rather than 4 like the human heart.  Image from Microsoft clipart.-Much scientific research has depended upon frogs.  In 1487, Leonardo daVinci discovered that frog brains controlled frog organs.  Anton van Leeuwenhoek discovered that blood flows through capillaries, thanks to his frog models.  Luigi Galvani later discovered that frog nerves use electrical impulses in order to transmit information.  Studies of vertebrate embryology and developmental processes are based on amphibians, as is much research on vocalization and acoustic communication.  Clawed frogs are the most common vertebrate model in labs.  Knowledge on skin transplants has its roots in frog research.

-Frogs live over a wide range of temperatures, and as such their skin is viable over a wide range of temperatures.  Scientists use frogs for tissue preps in laboratory experiments because preparations from frogs can have longer prep lives.  This simplifies research and its costs. 

-Frogs (including cane toads) were among the first pregnancy tests: urine was injected into the frog.  If the urine was from a pregnant woman, the hormones in the urine would induce a frog to lay eggs.

-Frogs are used to teach anatomy and dissection in many schools and colleges. 

-Stem cell research in frogs carries no ethical issues. 

-Frogs were the first animal to be cloned.

-Frogs are carriers for tuberculosis but do not get sick with TB; as such, they are being studied on TB resistance. 


Message in a bottle...frogstyle weather prediction!  Image from Microsoft clipart.-In Germany people used to keep treefrogs in bottles as living barometers; they would climb up or down in the bottle depending upon weather changes.

-In Japan, cane toad toxin is used medicinally to slow the heart for surgery.

-Tadpoles help to keep aquatic life in check, thus preventing overgrowth and crash cycles.

Luckily frogs help us with pest control!  More frogs means less buy spray is needed.  Image from Microsoft clipart.

Flies bring disease...toads eat flies.  Image from Microsoft clipart.-Frogs eat insects and thus decrease pests, disease, and human expense both on pesticides and medical costs related to insect-borne diseases. For example, they eat mosquitoes, which can carrier the causative agent of malaria.

-Frog skin is moist and sometimes mucus-coated.  This is a perfect environment for bacteria, but frog skin contains a peptide called magainin, which is anti-bacterial for both gram positive and negative bacteria.  Frog skin and its components are being studied as a potential source for antibiotics.

-Frogs (but not cane toads) are a major food source for humans in many parts of he world.  Amphibians are sensitive to changing conditions and thus are bioindicators.  Image from Microsoft clipart.

-Frogs are bioindicators of environmental health (for an explanation, see section on why amphibians are declining).


-There is discussion as to whether vehicles in Australia have hit cane toad carcuses and lost control of their vehicles, resulting in accidents.  Look up “Cane Toad Blues” on for some amusement: “Cane toads are coming, cane toads are coming, Main roads are humming with the cane toad blues.”


Next, let's learn about cane toad (and other Anuran) populations.