40 Fun Facts About Glass Frog

Which part of a glass frog's body has see-through skin, giving the whole family its common name?

Belly skin so clear that the gut and other organs show through is what earned these small tree-dwellers their name. From above, most look like ordinary lime-coloured frogs.

Which organ can be seen completely exposed inside Ecuador's glass frog Hyalinobatrachium yaku?

Heart muscle can be watched at work in this species because the usual covering tissues are clear too. In some relatives a layer of pale tissue hides the organ from view.

Where do sleeping glass frogs hide most of their red blood cells to make themselves harder to see?

Liver tissue takes in most of the red cells at rest, which is why a dozing glass frog turns far more see-through. Once the animal is awake and active, the cells circulate again.

The glass frog nicknamed the Kermit frog was discovered in the Talamanca Mountains of which country?

Costa Rica had hidden the species from earlier surveys, probably because its whistling call sounds more like an insect than a frog. Its bulging, puppet-like eyes then made it an internet star.

Which body parts of the emerald glass frog are coloured green by a pigment called biliverdin?

Bones tinted green can be seen through the thin skin of the living animal. Biliverdin is the same pigment that turns a healing bruise greenish.

How does a father Fleischmann's glass frog stop his eggs from drying out while he stands guard?

He urinates on them, keeping the jelly-coated clutch moist on its leaf above the water. The guarding father also stays to protect the clutch from predators until the tadpoles hatch.

The Rio Azuela glass frog of Ecuador and Peru is described as about the size of what?

A fingernail is about right, since adults measure only around two centimetres from snout to rump. The species name, pellucidum, is Latin for transparent.

Which company released a playful interview with Kermit after a look-alike glass frog species went viral?

Disney, owner of the Muppets, had Kermit welcome his newly found look-alike in an official interview. The scientist who found the species said he had not noticed the resemblance himself.

Glass frogs differ from look-alike tree frogs because their eyes face in which direction?

Forward is the telltale difference, because the similar tree frogs of the family Hylidae have eyes that point out to the sides of the head.

Glass frog tadpoles often hatch and drop off their leaf during which kind of weather?

Heavy rain helps wash the wriggling hatchlings off the leaf and into the stream below. The eggs need roughly ten to twenty days on the leaf to reach that point.

Scientist Brian Kubicki named the Kermit-like glass frog species dianae in honor of which relative?

His mother, Janet Diane Kubicki, supplied the name dianae. It took DNA testing to confirm that the little whistler was a species new to science.

Glass frogs live wild beside forest streams in which part of the world?

Central and South America are the family's home, and DNA studies suggest glass frogs first arose on the southern continent before spreading north several times.

The bare-hearted glass frog has another common name taken from which insect that the male's call resembles?

Cricket glass frog is its other name, because calling males sound so much like the insect. Rivals wrestle over the best calling leaf until one pins the other down.

The world's richest mix of glass frog species lives in which mountain range?

The Andes hold the richest mix of species. Before a big 1970s study of Ecuador's frogs showed that, most known glass frogs had come from farther north, around Panama.

The powdered glass frog gets its name from a scattering of what across its back?

Small white spots speckle its back like a sprinkle of flour, and its scientific name, pulverata, means the powdered one.

What colour are the eyes of both Fleischmann's glass frog and the bare-hearted glass frog?

Golden eyes and raised nostrils mark out the bare-hearted species, whose underside is among the clearest of any glass frog.

Glass frogs reach their greatest variety in which type of damp, tree-covered tropical habitat?

Cloud forest stays wrapped in mist for much of the time, and that constant damp suits small frogs that dry out easily. Some species also live in lowland jungle.

Glass frogs such as the red-spotted species grip wet leaves using what on the tips of their fingers?

Adhesive discs widen each fingertip into a sticky pad, letting the frog walk across wet leaves high above a stream. The widened tips are a family trademark.

Which part of a resting glass frog is the most see-through and so blurs its outline on a leaf?

Legs tucked against the sides let leaf colour fade gradually into frog colour, leaving no crisp outline for a predator to spot. The body itself changes brightness far less.

Which insects steal bare-hearted glass frog eggs one at a time while the father is away by day?

Wasps can carry off a whole clutch egg by egg, because the night-active father is not on guard in daylight. After dark he returns to protect and moisten what is left.

The fringe-lipped bat tracks down male Fleischmann's glass frogs to eat by homing in on what?

Their mating calls give them away, so the same peeps that attract a female can also bring a hungry bat. Males fall silent while they are busy guarding eggs.

Unlike leaf-laying relatives, the giant Pacific glass frog sticks its eggs to wet rocks beside what?

Waterfalls keep the eggs soaked in spray on the wet rock, and males call from those same splashed rocks. It is the largest species in the family, about three times the length of a typical glass frog.

In tests of glass frog camouflage, which predators attacked see-through models less often than solid ones?

Birds struck the see-through models far less often, giving the first experimental evidence that a glassy body really does work as camouflage.

Scientists testing glass frog camouflage made their model frogs from which kitchen ingredient?

Gelatine let the team cast both clear and solid-coloured fakes and set them out on leaves to see which were attacked. People were also tested on spotting frogs in computer images.

Emerald glass frog numbers fell sharply at Monteverde from the 1980s, and scientists suspect what kind of germ?

A fungus called chytrid attacks the skin that amphibians partly breathe through. The emerald species came through the outbreak and is still rated as being of least concern.

Sleeping glass frogs pack their red cells tightly together without suffering which dangerous problem?

Blood clots would be the likely result in most animals, humans included, so doctors hope the frogs' trick can teach them how to prevent dangerous clotting.

Fleischmann's glass frog, or northern glass frog, reaches the northern limit of its range in which country?

Mexico is as far north as any glass frog lives, and only in the country's tropical south. The species is named after Carl Fleischmann, who collected animals in the 1890s.

How do rival male emerald glass frogs position themselves when they grapple over a territory?

Hanging by their toes from a leaf, the two males lock together chest to chest. The loser signals defeat by dropping to a lower leaf or flattening himself.

Researchers say glass frogs are not truly transparent but are better described by which word?

Translucent is the better word, since light passes through their bodies but is tinted on the way. True transparency is rare on land and far more common among sea creatures.

What was written to celebrate Sabin's glassfrog of Peru becoming the 7,000th amphibian on AmphibiaWeb?

A song marked the milestone, a rare honour for a frog known from just two streams in Manu National Park. Its name thanks Andrew Sabin, a supporter of reptile and amphibian research.

Bolivia's glass frog Cochranella nola is named in Latin after which object, for the male's high call?

A small bell is what nola means in Latin, a nod to the single sharp ringing note each male gives about every half minute.

The Magdalena giant glass frog, whose females rather than males guard the eggs, lives only in which country?

Colombia's Sierra Nevada de Santa Marta is its only home. When researchers removed the guarding females, far more of the eggs died.

The skin of Fleischmann's glass frog reflects which invisible kind of light, just as living leaves do?

Infrared reflection means the frog matches its leaf even in wavelengths people cannot see. That may help it stay cool, or hide it from predators able to sense such light.

Besides habitat loss and pollution, which illegal business is among the biggest threats to glass frogs?

The pet trade is listed beside deforestation and pollution, and every glass frog species is now covered by the CITES wildlife treaty, so international sales need permits.

The southernmost glass frogs live in southeastern Brazil and the northeast of which neighbouring country?

Argentina's far northeast and southern Brazil share the family's southernmost species, which clings to leaves beside running water in forests below 1,200 metres.

Male red-spotted glass frogs fight rivals with a hooked spur that grows on which part of the body?

Upper arm spurs are used to grapple with rivals over calling perches, and the fighters are sometimes injured. Scientists call the weapon a humeral spine.

What name did scientists give the glass frog camouflage that softens the animal's outline on a leaf?

Edge diffusion was new to science in 2020: rather than vanishing, the frog looks brighter or darker to match whatever leaf it is sitting on.

Glass frogs make up which scientific family, first proposed by the herpetologist Edward H. Taylor?

Centrolenidae was needed because its members had usually been lumped in with the tree frogs, which they closely resemble.

What is the scientific term for the mating embrace in which a male glass frog clasps the female's back?

Amplexus takes place on a leaf above the water, and in the emerald glass frog the pair may stay clasped for almost three hours.

The eastern glass frog lives in the coastal mountains of Venezuela and on which Caribbean island?

Tobago's population is distinct enough to have been described as its own subspecies, sometimes called the Tobago glass frog.