50 Fun Facts About Amphibians

From the 1930s, doctors injected African clawed frogs with a woman's urine to test for what?

Pregnancy hormones in the urine made the frog produce eggs within 8 to 12 hours. Worked out in Cape Town, the test stayed in use around the world into the 1960s.

Which body parts does a frog retract into its skull to help push food down its throat?

A frog's eyeballs drop through holes in the skull and press down on the food. Frogs swallow prey whole, so the extra push from above helps.

Which puppeteer made the first Kermit puppet from a discarded coat and two halves of a ping-pong ball?

Jim Henson cut the 1955 prototype from a turquoise spring coat that had belonged to his mother. That first Kermit was a vague lizard-like creature and only later became a frog.

Which salamander from the Valley of Mexico keeps its external gills for life and can regrow lost limbs?

The axolotl never grows out of its larval form, a trait called neoteny. It can rebuild limbs, gills and even parts of its brain without leaving a scar.

A frog sheds its outer skin every few weeks; what does it usually do with the old skin?

The frog eats it. The loose skin is worked forwards towards the head and quickly swallowed, and other amphibians often do the same.

Which amphibian, released in Queensland in 1935 to eat crop-destroying beetles, became a notorious Australian pest?

The cane toad failed at the job because the beetles live high on the stalks, out of reach of a poor climber. It spread across northern Australia instead.

South American horned frogs, round hunters with huge mouths, are nicknamed after which video game character?

Pac-Man lent his name to these frogs because of their round shape and enormous mouths. A Pacman frog will swallow mice, fish and even other frogs.

Ancient writers such as Aristotle and Pliny passed on the belief that a salamander could walk unharmed through what?

Fire was said to be the salamander's own element, and Aristotle reported the story that the animal could even put out flames. Linnaeus still noted the legend when he described salamanders in 1758.

Which skin growths, really caused by a human virus, does old folk belief blame on handling a toad?

Warts come from the human papillomavirus, which toads do not carry. The bumps on a toad are glands, and German folklore held that touching one under a full moon was a cure.

Frogs range from the tropics to subarctic regions, yet which continent has no frogs at all?

Antarctica is the only continent without frogs. Everywhere else they are missing mainly from remote islands far from any mainland.

What name is given to the body-wide change that turns a swimming tadpole into a four-legged frog?

Metamorphosis is a sudden switch to the adult form at the end of the tadpole stage. Some species get through it inside the egg and hatch as tiny frogs.

Amphibians share which trait with reptiles and fish, leaving them reliant on their surroundings for body heat?

Being cold-blooded, or ectothermic, means an amphibian cannot warm itself from within. The upside is a low metabolic rate, so it needs very little food and energy.

The word amphibian comes from an Ancient Greek term with what literal meaning?

Both kinds of life is the literal sense of the Greek amphibios. The word was first used for any animal at home on land and in water, seals and otters included.

Which amphibian, found near waterfalls in Cameroon and weighing several kilograms, is the largest of all living frogs?

The goliath frog builds its own nursery pools beside rivers, sometimes shifting large stones to do it. Biologists think that heavy lifting may help explain its size.

The largest living amphibians, giant salamanders that can reach 1.8 metres, live in the rivers of which country?

China is home to the record-holders, which can weigh 50 kg. Prized as a delicacy and farmed in very large numbers, they are critically endangered in the wild.

The golden poison frog, often called the most poisonous animal alive, lives wild only in which country?

Colombia's coastal rainforest is its only home. One wild frog is estimated to carry about a milligram of toxin, enough to kill between 10 and 20 people.

Poison dart frogs bred in captivity are harmless because wild ones get their toxins from what?

Their diet supplies the poison: wild frogs store alkaloids from the ants, mites and centipedes they hunt. Given the right food again, a captive-bred frog can turn toxic.

Which 1908 children's novel features the reckless, motorcar-mad Mr. Toad of Toad Hall?

The Wind in the Willows grew out of bedtime stories Kenneth Grahame told his son. Toad's motoring craze lands him in prison, and he escapes disguised as a washerwoman.

Which American author first found fame with a short story about a champion jumping frog from Calaveras County?

Mark Twain said he heard the tale at a hotel in Angels Camp, California, in 1865. The town now holds a Jumping Frog Jubilee every May and is nicknamed Frogtown.

Frog eggs have no shell; each egg in a clump of frogspawn is instead wrapped in what?

Jelly surrounds each egg as the female releases her spawn. With no shell to stop them drying out, amphibian eggs have to be laid in water or somewhere damp.

Which Central and South American amphibians have belly skin so clear that the beating heart shows through?

Glass frogs take the trick further when they sleep: most of their blood is tucked away in the liver, which makes a resting frog much harder to spot on a leaf.

Chytridiomycosis, a skin disease behind amphibian declines on several continents, is caused by what kind of organism?

A fungus known as a chytrid causes the disease, and in some populations it kills every animal it infects. Its worldwide spread has been put down to international trade.

Which organs are entirely missing in plethodontids, the largest salamander family with over 500 species?

Lungs are absent, so these salamanders take in oxygen through their moist skin and the lining of the mouth. Skin alone handles well over four fifths of the job.

Which limbless, burrowing amphibians, named from the Latin for blind, are often mistaken for worms or snakes?

Caecilians live mostly hidden in tropical soil, so few people ever see one. In some species the mother grows a fatty outer layer of skin that her young peel off and feed on.

Which branch of zoology, named from the Greek for creeping animal, covers both amphibians and reptiles?

Herpetology treats the two groups together because Linnaeus once placed them in a single class. The study of amphibians alone has its own name, batrachology.

The classic ribbit croak so often heard in films is really the call of which North American amphibian?

The Pacific tree frog's males call so loudly that one can sound like several frogs at once. That croak became the stock frog noise of cinema.

Which Italian scientist found in 1780 that a dead frog's legs twitch when touched by an electric spark?

Luigi Galvani's twitching frogs were an early study of bioelectricity. His reports were on Mary Shelley's reading list in the summer that produced Frankenstein.

In whose 1812 telling of The Frog Prince is the frog thrown against a wall rather than kissed?

The Brothers Grimm made it the very first tale in their collection. The spell-breaking kiss came later, apparently appearing first in English translations.

Wood frogs survive being frozen solid in winter by flooding their cells with which sugar as an antifreeze?

Glucose pours out of the liver once ice starts to form, limiting how much of the body freezes. A frozen wood frog has no heartbeat or breathing, yet it revives in spring.

Male Darwin's frogs of Chile and Argentina carry their growing tadpoles inside which part of the body?

The vocal sac becomes a nursery once the father gulps down the eggs just before they hatch. The tadpoles stay there, living on yolk and on secretions from its wall, until they have turned into frogs.

Slovenia's olm, a blind cave salamander washed out by floods, was once taken for the young of which creature?

A dragon was thought to live deep in the caves, and in 1689 a local naturalist recorded the belief that olms were its offspring. An olm can survive up to ten years without food.

The coquí, a tiny frog named for the male's two-note night call, is a beloved symbol of which island?

Puerto Rico treats the coquí as an unofficial emblem. Each half of the call has a job: the first note warns off rival males and the second attracts females.

Wallace's flying frog glides through the rainforest canopy by spreading which oversized parts of its body?

Webbed feet act as four small parachutes, carrying the frog 15 metres or more to another branch. It is named after Alfred Russel Wallace, who collected the first known specimen.

Which island's native amphibians are all frogs, with almost every species found nowhere else on Earth?

Madagascar has hundreds of amphibian species and not one native toad, newt or salamander among them. Its best-known residents include the tomato frog and the golden mantella.

What is the tympanum, the flat round disc visible on each side of a frog's head?

The eardrum of a frog sits on the surface instead of inside the head, yet it works much like a human one. It is a large oval membrane of bare skin that passes vibrations inwards.

In which organ did Australia's extinct platypus frogs, last seen in the 1980s, brood their young?

The stomach became a womb after the mother swallowed her fertilised eggs, and a chemical from the eggs shut down her digestive acid. The young frogs later emerged from her mouth.

Which river-dwelling giant, nicknamed the snot otter, is the heaviest salamander in North America?

The hellbender also answers to lasagna lizard, devil dog and Allegheny alligator. One tale says settlers thought it a creature from hell that was bent on returning there.

Which flat, tongueless amphibian hatches its young from honeycomb-like pockets in the skin of the mother's back?

The Surinam toad's eggs sink into the skin of the mother's back and stay there for months. The young skip a free-swimming tadpole stage and emerge as fully formed froglets.

Because their permeable skin soaks up pollutants, amphibians are often treated by ecologists as what kind of species?

Indicator species reveal the state of their surroundings, and amphibians suit the role because toxic chemicals pass easily through their skin. Frogs and toads are widely used to track pollution.

Which North American reptile has evolved resistance to the deadly tetrodotoxin of the rough-skinned newt?

The garter snake is the only animal known to swallow one of these newts and survive. Some of the snakes can even judge whether a particular newt is too toxic to tackle.

Anura, the scientific name of the order containing every frog and toad, comes from Ancient Greek for what?

Without a tail is the meaning, a fair description of the adults even though every tadpole has one. The order holds about 87% of all amphibian species.

In 1958 John Gurdon used a cell nucleus from an African clawed frog tadpole to pioneer which technique?

Cloning a frog from a tadpole's body cell earned Gurdon a share of the 2012 Nobel Prize in medicine, more than fifty years after the experiment.

Which Central African amphibian apparently breaks its own toe bones to push sharp claws out through its skin?

The hairy frog is named for the hair-like strands of skin that breeding males grow along their flanks and thighs. Its claws are bare bone, with none of the keratin of a true claw.

The golden toad, last seen in 1989 and now extinct, lived only in the Monteverde cloud forest of which country?

Costa Rica's golden toad was discovered only in 1964. Ten or eleven were counted in 1988, a single male in 1989, and none has been seen since.

In which geological period, nicknamed the Age of Fishes, did the first amphibians evolve from lobe-finned fish?

The Devonian closed about 360 million years ago with the land still almost empty of backboned animals. Pioneers such as Ichthyostega may only have hauled themselves out of the water now and then.

What is the term for the dormant state in which some burrowing frogs wait out months of heat and drought?

Aestivation lets Australia's striped burrowing frog go nine or ten months of the year without food or water. Related frogs first seal themselves inside a waterproof cocoon.

Paedophryne amauensis, a frog under eight millimetres long found by scientists in 2009, lives in which country?

Papua New Guinea's forest floor hid it well: researchers traced an insect-like peeping to the leaf litter and found the frog by bagging handfuls of leaves. It has no tadpole stage.

Which swollen glands behind a toad's head ooze milky bufotoxins to deter predators?

Parotoid glands sit on the neck and shoulders of toads and of some salamanders too. They are named for lying roughly where a mammal's parotid salivary glands do.

What Latin-derived term, literally meaning embrace, describes a male frog clasping a female as her eggs are released?

Amplexus varies between groups: depending on the species, the male grips the female by the head, the waist or the armpits. Horseshoe crabs mate in the same way.

Which extinct frog of the Cretaceous period may have preyed on hatchling dinosaurs?

Beelzebufo, a name meaning devil toad, had a mouth wide enough to tackle large prey. Even its biggest known skulls have open sutures, a sign that the animal could have grown bigger still.