Reticulated Glass Frog
A small frog the length of a quarter leaps from one plant leaf to another, flaunting its little belly as it soars. The skin on the frog’s underside is see-through. So as the amphibian jumps you can view some of its internal organs, including its beating heart. This is a reticulated glass frog, a creature that has a lot of supercool secrets to reveal.
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Reticulated glass frogs can be found in the rain forests of Costa Rica , Panama , Colombia , and Ecuador . These animals, which are active at night, inhabit vegetation along streams. Males can get pretty territorial, making squeaking noises to warn trespassing frogs to stay away from their leafy hangout spots. If an intruder doesn’t leave, the frog will wrestle it to show who’s boss.
Males are also very protective of their mates’ eggs. Females lay a mass of eggs (called a clutch) on the underside of leaves, sticking them in place with a jelly-like substance. Afterward, the females leave and the males go on guard duty. They watch the eggs 24/7 until they hatch, protecting them from enemies such as wasps. The frog has even been known to kick away wasps that get too close to the egg cluster!
Scientists still aren’t sure why these frogs have see-through skin on their undersides. But they think the spotted pattern on the backs of the amphibians is meant to resemble a mass of eggs. This camouflage pattern helps the males protect their offspring by confusing predators trying to get at the clutch. Sounds like these eggs are in good webbed hands!
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Ghost Glass Frog
The ghost glass frog belongs to the ‘glass frog’ family that is primarily found in parts of South America. These frogs are named so for their protruding eyes with black marks, giving them a bizarre look.
Scientific Name – Sachatamia ilex
Classification – Sachatamia
Gender Names – Male – male; Female – female; Baby – tadpole
Collective Noun – Knot
Length/Size – Up to 37 mm
Life Expectancy – 10 and 14 years in the wild
Mating Season – Rainy season
Special Features – The eyes are silvery white having black reticulations
Geographical Distribution – In the wet forests of Panama, Costa Rica, Colombia, Nicaragua, and Ecuador
Natural Habitat – Prefers living in the spray zone of waterfalls or streams, and on large low-lying leaves
Diet – Insects, worms, larvae
Predators – Different snakes, mammals and birds
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Facts About Animals
Glass Frog Facts
Glass frog profile.
Glass frogs , or to use their scientific name – centrolenidae, are tiny and quite magical little creatures that inhabit warm and humid montane forests in Central and South America.
The nickname ‘glass frog’ is born from these amphibians’ translucent appearance, which aids them hiding from predators when asleep in trees.
Glass Frog Facts Overview
There are around 160 species of glass frog in 12 genera. These tiny and elusive creatures range from 20-30mm in length, although a few species can reach lengths of up to 80mm.
Glass frogs are nocturnal, riparian (living along streams) and arboreal , meaning that they sleep during the day, hiding in the leaves high up in the trees lining streams and waterways.
To protect themselves from predators during this vulnerable time, glass frogs have translucent undersides which blur the edges of their bodies when they sleep clinging to the undersides of leaves.
This remarkable feature means that from above, the frog has a very indistinct silhouette and all that can be clearly seen are the small blobs of the creature’s heart and intestinal organs, which are not immediately eye-catching to potential predators . Through the abdomen of a glass frog, therefore, one can clearly see its internal organs, and its tiny heart beating. It is also possible to see all of a female’s eggs before she lays them.
Glass frogs are a pale green color elsewhere on their bodies and on their backs, often speckled with pale white or yellow spots which also acts as a form of camouflage. They generally have short snouts, golden irises and yellow suction pads on their fingers and toes.
Living on a diet of small invertebrates, flies and spiders, glass frogs use their long digits for climbing high into the trees during dry season, to escape predators on the forest floor such as lizards, snakes and small mammals. During the wet season the males move close to streams of rivers for mating.
Glass frogs have the ability to jump forward and laterally from a sprawled position using their powerful lateral bender legs. Rather than a croak, male glass frogs emit a high-pitched whistling call which can increase in volume with age or maturity.
Interesting Glass Frog Facts
1. glass frogs have the ability to make themselves 60 percent more transparent while they sleep.
In a fascinating study, scientists watched with awe as glass frogs were observed to drain almost all their red blood cells into sacs within their liver when they slumber.
These sacs are coated with light-reflecting crystals, which can enable the frog to be almost completely invisible. As red blood cells absorb a lot of light and are so brightly coloured, the incredible ability of glass frogs to hide them within their own liver has been a source of amazement for scientists.
To accommodate this increase in blood, the liver can enlarge by up to 40 percent. When the frog awakes, the blood is redispersed and the liver decreases in size.
It is very rare to see translucent creatures on land, although it is slightly more common in sea creatures, such as krill. Vertebrates’ skeletons and organs are full of opaque substances that light can’t penetrate, and much of this is vital for life.
The glass frog’s ability to become so translucent is therefore quite amazing, and helps these tiny creatures to avoid predation during their vulnerable periods of daytime slumber. 1 2
2. Glass frogs mate on leaves, not in the water
When a male glass frog is ready to mate, he will find a suitable large leaf overhanging a stream, river or lake edge. From there, he will begin his mating calls until a female joins him on his leaf. They mate on the leaf, with the male resting on the female’s back and wrapping his arms around her waist.
The female will deposit a clutch of 18-20 eggs onto the underside of the leaf, securing them with a sticky jelly-like substance.
Once the eggs hatch into tadpoles, they fall from the leaf into the water below and remain to feed and grow amongst the leafy detritus at the water’s edge until they metamorphose into froglets. In optimal conditions, glass frogs can live for more than 10 years, even up to 14. 3
3. The male glass frog takes on the role of protector for their spawn
Once the eggs have been laid by the female after mating, the female frog will depart, leaving the male frog to act as protector for their clutch of eggs. The male will remain on the leaf watching over the eggs until they hatch into tadpoles and fall into the water below.
Sometimes the male will copulate with several different females and keep watch over several clutches of eggs in different stages of development.
The frogs are fierce protectors and will keep a constant watch over their eggs until they hatch. Males have been known to kick out at potential predators, such as wasps in order to keep them away from their precious eggs.
4. Male glass frogs can get territorial over their leafy hangouts
Mostly inhabiting leafy vegetation along streams, the male glass frogs can create loud squeaking sounds in order to warn other male frogs to keep away from their chosen spot.
If necessary, the frog may resort to a wrestling match to remove unwanted intruders from his leaf.
5. The spotted patterns on the frogs’ backs can resemble a clutch of eggs
This helps the male frog to protect his spawn by confusing potential predators.
6. ‘Frog flies’ are a major threat to unhatched spawn
Frog flies will lay their eggs on the top of the glass frog eggs. The fly eggs hatch very quickly into maggots, which then feed on the vulnerable frog embryos.
7. Glass frogs have extended digit tips
Their long digits help them to be efficient climbers, and enable them to be tree-dwelling.
8. They can travel 10 feet in a single jump
Glass frogs move by bipedal jumping, also known as saltation, to escape predators.
They have been known to travel distances of more than 3 metres (10 feet) in one jump if necessary. 4
9. Glass frogs can reflect infrared light
This can aid them in evading predators such as the eyelash viper, which use infrared light to seek their prey.
The glass frogs’ ability to reflect this infrared light offers them excellent protection from detection.
10. Glass frogs have forward-facing eyes
This is quite a unique feature as, generally speaking, prey will have side-facing eyes, while predator’s eyes are forward facing.
11. They have short tongues
In contrast to many other amphibians, glass frogs have relatively short tongues, which means the catching of their prey requires more care and patience then for some.
They wait patiently until their prey comes close enough before pouncing on it with an open mouth to snatch it up.
12. They could assist with major advances in medicine
For decades, scientists and medical researchers in hematology have been searching for a biological mechanism to control excessive bleeding while still preventing excessive clotting, and the glass frog’s fantastic ability to control their red blood cells could offer what has been called the ‘Holy Grail of hematology’.
The fact that glass frogs seem to be able to cram their red blood cells together in a small space with no ill-effects could help scientists to gain a deeper understanding of the way these blood cells work and possibly help to prevent dangerous blood clots in other animals and even humans. 5 6
Glass Frog Fact-File Summary
Scientific classification, fact sources & references.
- Corryn Wetzel (2022), “ Glass frogs turn translucent by ‘hiding’ blood in their liver “, New Scientist.
- Katherine J. Wu (2022), “ How Glass Frogs Weave the World’s Best Invisibility Cloak “, The Atlantic.
- “ Northern Glass Frog “, Rainforest Alliance.
- Andrea Murphy (2022), “ Glass Frog Facts & Habitat | Where Do Glass Frogs Live? “, Study.com.
- Veronique Greenwood (2022), “ How See-Through Glass Frogs Hide Their Red Blood From Predators “, The New York Times.
- Jason Bittel (2022), “ What makes glass frogs transparent? The secret is in their blood “, National Geographic.
10 Incredible Glass Frog Facts
These unusual amphibians are full of surprises.
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Olivia Young is a writer, fact checker, and green living expert passionate about tiny living, climate advocacy, and all things nature. She holds a degree in Journalism from Ohio University.
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- Animal Rights
- Endangered Species
Glass frogs are named for their translucent skin, which helps display their internal organs from underneath (you can even watch their hearts beat). Although there are more than 150 different glass frog species worldwide, scientists have only recently come to understand many of their characteristics and quirks. And due to their tiny size and elusive nature, experts assume there are even more species hiding away, waiting to be discovered.
Here are 10 glass frog facts to help you get familiar with one of nature's most unique amphibians.
- Common Name : Glass frog
- Scientific Name : Centrolenidae
- Average Lifetime in the Wild : Up to 14 years
- IUCN Red List Status : Least Concern to Critically Endangered, depending on species.
- Current Population : Unknown
1. Glass Frogs Are Found Only in South and Central America
Glass frog species live only in the humid montane rainforests and tropical lowland to mid-elevation mountain forests of South and Central America, including Mexico, Belize, Costa Rica, Panama, Colombia, Guatemala, and Honduras.
2. They Spend Most of Their Time in Trees
webguzs / Getty Images
Glass frogs are arboreal, meaning they live primarily in trees and only come down to the ground during mating season. They are most often found near streams and rivers.
3. Glass Frogs Can Jump Long Distances
When faced with predators, glass frogs will use their climbing skills to move further into the safety of dense trees to avoid danger. If that doesn't do the trick, glass frogs will jump more than 10 feet in a single bound.
4. Only Their Undersides Are Translucent
Thorsten Spoerlein / Getty Images
Glass frogs are one of the best examples of animal transparency in nature. The skin on their backs is typically a bright lime green, while their bones, intestines, heart, and other organs are visible through their underbelly. In fact, most glass frog species look much like any other type of tree frog when observed from above.
5. They're Nocturnal
Most species of glass frogs are nocturnal, staying hidden or sleeping under tree leaves and branches during the day near streams and becoming more active at night. Once the sun goes down, glass frogs venture out into the forest to mate and hunt for food.
6. Glass Frogs Are Great at Camouflage
Kevin Schafer / Getty Images
The evolution of their namesake glass-like skin wasn't widely studied until 2020. Scientists found evidence that the frogs' translucency helps them blend in with their surroundings and avoid being spotted by predators. They are less likely to be seen (and thus more likely to survive for longer) than opaque frogs.
7. They Lay Their Eggs on the Undersides of Leaves
Rather than laying eggs in the water like most types of frogs, glass frogs lay their eggs on the underside of leaves overhanging a stream. After the eggs hatch, the tadpoles fall from the leaf into the water below, where they develop into frogs.
8. Male Glass Frogs Guard Their Eggs Against Predators
KenCanning / Getty Images
Male glass frogs are very territorial and choose to stand guard over their eggs around the clock until they become tadpoles. They often find themselves fighting predators like carnivorous wasps to ensure their eggs reach the next stage of maturity unharmed.
Parental care is rare in other frogs, as only about 10% to 20% of extant species care for young after they're born.
9. Glass Frogs Are Carnivores
Given their lack of teeth and short tongues, you may be surprised to know that glass frogs are indeed carnivores. Their diet consists mainly of small insects like ants, tiny spiders, flies, and crickets. They will even prey on other smaller frogs when the opportunity arises.
10. They Are Mainly Threatened by Deforestation
Glass frogs have plenty of predators, from giant wasps to snakes, but the most significant risk to their existence is the loss of habitat from deforestation. The Central and South American regions where glass frogs live are continuing to decrease as rainforests are cut down to make room for human and agricultural development. In 2021, for example, Mexico lost 186,000 hectares of natural forest.
Glass frogs are generally very small, weighing anywhere from 0.2 to 0.5 ounces. The Hyalinobatrachium fleischmanni, also known as the Fleischmanni's glass frog or northern glass frog, typically doesn't grow much longer than 25 millimeters.
Some species of glass frog are incredibly rare, such as the endangered Bolivian Cochran frog, which has gone more than a decade without being seen since the year 2000. Because of their small size and arboreal nature, glass frogs are also difficult to spot in the wild.
Glass frogs make a high-pitched whistling or chirping sound to ward off predators and attract mates.
Barnett, James, et al. " Imperfect transparency and camouflage in glass frogs ." Proceedings of the National Academy of Sciences , vol. 117, 2020, pp. 12885-12890., doi:10.1073/pnas.1919417117
Delia, J., et al. " Patterns of parental care in neotropical glassfrogs ." Journal of Evolutionary Biology , vol. 30, 2017, pp. 898-914., doi:10.1111/jeb.13059
" Mexico Deforestation Rates & Statistics ." Global Forest Watch.
" Fleischmann's Glass Frog ." Encyclopedia of Life .
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General habitat alteration and loss
FAQ about glass frogs
With their bright green bodies and bulging, forward-facing eyes, glass frogs bear a striking resemblance to Kermit the Frog. But being a Muppet lookalike isn’t the most fascinating thing about their appearance. If you look at certain glass frogs from underneath, you can see a skeleton, intestines and beating heart on full display through their semi-transparent belly skin.
These odd-looking amphibians are now targeted for the exotic pet trade and they urgently need our protection. Here’s everything you need to know about glass frogs.
what are glass frogs?
There are 158 known species of glass frogs , but that number fluctuates as people discover, study and formally describe more. Some are so little known that they only have Latin scientific names and no common names. Each of those species belong to the Centrolenidae family.
Glass frogs are hard to study, but from what we can tell, all known species eat insects, mate after it rains and use whistling as a mating call. Their calls, behaviours and looks differ slightly between species, though. Some glass frog species have spots or subtle stripes down their backs, and some species have white, gold or grey eyes.
When the males and females pair up, the female lays eggs, then the male fertilises and protects them until they hatch. Tadpoles fall into the water below the leaves.
Glass frogs are very small, weighing only 5 to 14 grams (0.2 to 0.5 ounces) each, depending on the species. Some could rest on the end of your finger.
where can I find a glass frog?
Glass frogs live exclusively in the humid forests of Central and South America. Sadly, most people will never see a glass frog in the wild. One reason is because they’re so tiny. Also, glass frogs are arboreal, meaning they live in trees, and spend most of their time near water. They hunt at night and hide motionless during the day—another reason why it’s so hard to find them. Because they are semi-transparent, glass frogs are also famously good at camouflage, blending into the undersides of leaves.
are glass frogs endangered?
Currently, approximately 50% of all glass frog species evaluated by the IUCN Red List are threatened with extinction. Within the Centrolenidae family, 10 species are classified as Critically Endangered, 28 are Endangered, and 21 are considered Vulnerable.
glass frogs as pets?
Some people, compelled by the strange beauty of glass frogs, keep these animals as pets. However, they require housing that is similar to their native environment and, like all exotic animals, specialised care. Glass frogs cannot thrive without a warm, wet environment like the one in which they are adapted to living.
Most glass frogs in the pet trade reportedly come from captive breeding programs, but some are taken from the wild. Glass frogs have been found hidden in shipments of animals exported from Central America to Europe. Additionally, United States Fish and Wildlife Service (USFWS) Law Enforcement Management Information System (LEMIS) trade data and an analysis of online advertisements reported that over nine species of glass frogs are currently found in international trade.
In response, IFAW and other NGOs support increased restrictions on trade in glass frogs to minimize the impact of poaching and trafficking on these unique animals.
what other threats do glass frogs face?
In addition to their popularity in the global pet trade, glass frog species face several other threats. The expansion of agriculture, human settlement, logging and mining all lead to the loss and fragmentation of their habitat. Also, climate change is causing the forests where glass frogs live to become hotter and drier, decreasing the moisture that is critical to their survival.
what are people doing to protect glass frogs?
The trade in glass frogs for the pet trade may soon be better regulated thanks to conservation efforts from animal protection organizations.
CITES (the Convention on International Trade in Endangered Species of Wild Fauna and Flora) is the international body that determines protection of more than 38,000 species around the world. Despite previous attempts, the upcoming 19th Conference of the Parties (CoP19) will again petition for increased protections for glass frogs.
Trade in glass frogs must be limited to legal and sustainable levels so as not to compound the other threats these animals already face. A CITES Appendix II listing would allow for an increase in data collection on many glass frog species, providing better insight into the demand and global trade network that exists but remains largely unstudied.
With the support of researchers concerned about how uncontrolled trade can affect wild populations, the governments of Costa Rica, Argentina, Panama, Brazil, Peru, Dominican Republic, Ecuador, El Salvador, United States, Gabon, Guinea, Niger, Togo and Côte d'Ivoire are requesting support to their proposal to include the Centrolenidae family in CITES Appendix II.
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