15 Fascinating Frog Species

There are a lot of frogs on this planet—over 5,000 species with more still being discovered by scientists on a yearly basis. With all those species comes a lot of diversity and variation; these amphibious creatures have evolved to specialize in their environments in ways even the most creative fiction writers couldn't envision.

Species range from the size of a fingernail to over a foot in length, and others have far-fetched adaptations like poisonous skin, the gift of flight, and surviving the cold by simply freezing (and thawing back out when it warms up again). Unfortunately, these specializations can also make frogs sensitive to habitat loss, and they are becoming endangered and facing extinction at a rapid pace.

Here are 15 incredible species that showcase the diversity these amphibians possess and the challenges they face.

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Diane's Bare-Hearted Glass Frog

A glass frog peers over the edge of a leaf — mlorenzphotography / Getty Images

Discovered in 2015, the Diane's bare-hearted glass frog (Hyalinobatrachium dianae) is long in name but small in stature. This inch-long species is one of more than 100 species of glass frogs, unique for their translucent skin, which leaves the internal organs visible. A nocturnal creature, it is native to the rainy foothills of Costa Rica, where it feeds on small insects. Frogs are often seen as indicator species, and this species' discovery is considered a promising sign of forest health in Costa Rica, despite the threat of deforestation worldwide.

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Paedophryne amauensis

Glass frogs may be small, but they have nothing on the Paedophryne amauensis, which at only 0.3 inches in length isn't just the smallest frog, but the world's smallest vertebrate. It's the size of a housefly and has likely evolved to eat tiny invertebrates, such as mites, that larger predators overlook.

This native of Papua New Guinea was discovered in 2009, by researchers who heard its high-pitched call, then scooped leaf litter into a plastic bag to figure out what was making the noise. In addition to its diminutive size, it is unique in that it has no tadpole stage, hatching instead as a miniature of the adult.

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Desert Rain Frog

A rain frog sits on the sandy ground — Ryanvanhuyssteen / Wikimedia Commons / CC BY-SA 4.0

The Desert Rain Frog (Breviceps macrops) is a rare species found only along a 6.2-mile wide strip of coastline in Namibia and South Africa. It's also one of the rare frogs to go viral, thanks to its squeaky voice.

It is nocturnal and buries itself beneath the sand during the day, where it can stay cool and moist, then comes out at night to feed on insects and larvae. As reported on Treehugger, "The small strip of the world that they inhabit is prone to sea fog, which keeps the sand moist in an otherwise arid region. They have a patch on their bellies that is not only transparent, but has numerous blood vessels and capillaries through which they can absorb water from the sand."

The frog's specialized habit of burying itself is threatened by human settlement and open-cast diamond mining, and scientists are concerned that the frog's population is declining. It's listed as "near threatened" on the IUCN's Red List.

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Ornate Horned Frog

The Ornate Horned Frog (Ceratophrys ornata) is also known as the Pacman frog, and for good reason. It has an insatiable appetite packaged in a six-inch body that is half mouth—literally. These frogs are known for their fearless behavior and will prey on anything from to lizards to rodents to other frogs. They have even been found to suffocate on large prey that they chose to consume despite the risk—a real-life case of "biting off more than one can chew," as the old saying goes. The species is endemic to Argentina, where its splotchy red and green coloration helps conceal it on the forest floor.

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Hairy Frog

The hairy frog (trichobatrachus robustus) is another species with a well-earned nickname. Also known as the horror frog or wolverine frog, it will intentionally break its toe bones when threatened, which then poke through the skin to act like claws. These bones later retract and the damaged tissue heals. It's the only animal researchers know of with such a defense mechanism. "Some other frogs have bony spines that project from their wrist, but in those species it appears that the bones grow through the skin rather than pierce it when needed for defence," said one scientist.

The name horror frog is also fitting due to the hairlike growths on the sides of the males called dermal papillae. This growth is thought to help breeding males consume more oxygen, which comes in handy during long periods spent underwater, guarding eggs laid by females. They mostly live in Cameroon, in west-central Africa.

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Vietnamese Mossy Frog

A mossy frog covered in bumps hides in a bed of moss — davemhuntphotography / Shutterstock

The Vietnamese mossy frog (Theloderma corticale) lives in the forests of northern Vietnam, where it spends its days pretending to be a moss-covered rock. With its green and black coloration and bumpy skin covered with spines, it is well suited to the task at hand. It prefers a semiaquatic environment, hunting cockroaches and crickets in caves and stream beds. To ward off predators, which include snakes and tree-dwelling mammals, it can take its disguise one step further by rolling into a ball and playing dead.

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Golden Poison Dart Frog

A golden poison frog (Phyllobates terribilis) sits on a green leaf — The golden poison frog (Phyllobates terribilis) is the most poisonous poison dart frog.
Paul Starosta / Getty Images

The golden poison dart frog (Phyllobates terribilis) might be small, but it packs a mean punch. Each two-inch frog has enough toxin to kill two bull elephants or ten grown men. How the tiny frogs manage to be so toxic is still a mystery to researchers, but one hypothesis is that it can be traced to poisonous plants eaten by their own insect prey. Frogs raised in captivity never become toxic; only the wild frogs are lethal. Historically, the indigenous Emberá people would use the venom on the tips of their blowdarts for more effective hunting.

The frog is abundant in its rainforest habitat of coastal Colombia, but the small size of this shrinking forest has put the frog on endangered species lists.

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Indian Bullfrog

A yellow bullfrog with blue vocal sacs sits in the grass — Vivek Parab / Getty Images

Not all yellow frogs will kill you. Some, like the Indian bullfrog (Hoplobatrachus tigerinus), will just entertain you with their singing skills and vivid colors. For most of the year, these frogs are a dull, olive-green color. However, during mating season, the males turn a Day-Glo yellow with indigo vocal sacs on their throats. With a body about six inches long, this is the largest of the Indian frog species.

In the 1990s, people started farming the frogs as a food source (its legs were considered desirable). They have also become an invasive introduced species in the Andaman Islands. They live in freshwater settings, both natural and artificial, particularly rice paddy fields.

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Brazilian Horned Frog

Like the ornate horned frog, the Brazilian horned frog (Ceratophrys aurita) is an aggressive predator. It grows to an even bigger size, up to eight inches long, and is a "sit and wait" predator, burrowing itself in leaf litter with only its eyes visible, and waiting for prey to pass by. It will attack anything nearby, using its abnormally powerful jaws to go after animals of all sizes, including larger animals that it doesn't consider prey. It inhabits tropical and subtropical lowlands, freshwater marshes, and ponds, and is endemic to Brazil.

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Wallace's Flying Frog

The Wallace's flying frog's name gives away its secret. This species found in the jungles of Malaysia and Borneo has the unique ability to fly—or more accurately, deploy a leg-powered parachute. It has long, webbed toes that can flex and spread out to act as tiny wind sails, which it uses when it feels threatened. To escape danger, it will leap from branches, spreading its feet to glide as far as 50 feet to safety.

It spends almost its entire life in trees, venturing to the ground only to mate and lay eggs. The female lays eggs in a nest that's suspended over water. When the embryos have developed into tadpoles within the eggs, the nest breaks open and the tadpoles fall into the water below, where they grow and develop further. If the nest happens to open onto land, the tadpoles will dry up and die.

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Venezuela Pebble Toad

A black pebble toad sits on a sandy surface — Gérard Vigo / Wikimedia Commons / CC BY-SA 3.0

The Venezuela pebble toad (Oreophrynella nigra) is a small frog (toads are types of frogs that prefer drier climates) that lives in the Guiana Highlands of Venezuela. It has evolved a unique defensive technique that only works on the steep slopes of its mountainous habitat. When threatened, it tightens its muscles to become rigid and tumbles down the hill to safety. Because it's so light, bouncing along the cliff face doesn't harm the little toad, and it can land uninjured in puddles (as long as they're not deep) or crevices. The strategy provides a quick escape from predators, like tarantulas or snakes, and makes up for its lack of jumping ability.

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Surinam Toad

The Surinam toad (Pipa pipa) is a Southern American species distinguished by its large size, flat back, and small eyes. It also has no tongue and cannot croak. Instead, it taps two bones in its throat to make a high-pitched, sharp click noise. This toad is an aquatic ambush hunter, camouflaging itself like a leaf against the bottom of rivers and flooded forest areas, and lying in wait until prey comes along. It eats small fish, crustaceans, worms, and other invertebrates.

Its reproductive habits are perhaps its strangest feature. The toads mate underwater, and the female releases batches of three to 10 eggs at a time, which the male ushers onto her back. The eggs sink into the skin, forming pockets that hold the young through the tadpole stage. When her offspring finally emerge, it is as fully developed toads.

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Purple Frog

The purple frog (Nasikabatrachus sahyadrensis) can be found only in the Western Ghats range in India, and is best known for its formless, bloated shape and underground lifestyle. In fact, it only emerges for two weeks during monsoon season to mate, and lives the rest of its life as a burrowing animal. While it's not the only frog that lives below ground, it is the only one that can feed itself without surfacing, relying solely on termites and ants it finds in the soil.

Also known as the pignose frog due to its long snout, this species can thank 120 years of independent evolution for its unique characteristics. It is threatened by the encroachment of human settlements and the loss of up to 90% of its forested habitat.

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Malagasy Rainbow Frog

The impressive Malagasy rainbow frog (Scaphiophryne gottlebei) from Madagascar goes by many unofficial names, including the ornate hopper and the red rain frog. Perhaps this is because just one name can't describe its coloration accurately, which varies from white to red to green, with black stripes in between. It's good at burrowing and rock-climbing; this latter skill is good for escaping flash floods.

The species was listed as critically endangered from 2004 to 2008, until researchers discovered it was more abundant than once thought. It remains an endangered species due to shrinking habitat and high demand in the pet trade, though its export has been illegal since 2014.

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Malayan Horned Frog

The Malayan horned frog or long-nosed horned frog (Megophrys nasuta) is a ground-dwelling frog that lives in the rainforests of Southeast Asia. It has an angular, mottled brown body, complete with a triangular nose and prominent horns over the eyes, that help it hide in the leaf litter where it finds prey. In fact, you're unlikely to see it at all unless it moves to snatch up some prey. This large species can grow to over five inches in length, and is a prodigious croaking talent with a loud "honking" call.