Tall tails: Seven tadpole species you won’t believe

What are tadpoles? 

It’s typically taught that frogs begin as eggs or frogsprawn, before entering the larval stage, when they are known as tadpoles. Unlike the frogs they will become, they are not amphibious. They have gills, a mouth, and a long tail needed for swimming while waterbound. Step by step, their bodies change: legs grow, tails shrink away, skin grows over gills, and lungs and eardrums develop.

But in reality, it’s more complicated than that.  

Across the globe, tadpoles have evolved to survive in a huge range of environments – and there is so much diversity to show for it. Here’s the amazing adaptations of seven species. 

Ghost frog tadpoles – Table Mountain, South Africa  

The young of this species have adapted to a very specific habitat: living in headwater mountain streams, they must survive in fast-flowing waters. Their adaptations include a large oral disc – an organ around the mouth – to suck onto rocks and prevent getting washed to lower elevations, a streamlined body, and a long tail.  

Ghost frog tadpoles are also unique in that they have lost functional lungs, making them reliant on cold, fast-flowing, and highly oxygenated streams. (During periods of strong flow, it’s unlikely they’d be able to swim to the surface, so it wouldn’t be particularly useful to have lungs processing air-derived oxygen.)  

Amazingly, ghost frog tadpoles can use their large oral disc to suck themselves out of the water and move between isolated pools!  

Dancing frog tadpoles – Western Ghats, India

Indian dancing frogs achieved their name for their well-known mating displays – waving their legs atop stream boulders. Despite this, their young had never been discovered. In fact, their secret lives as tadpoles remained a mystery for 125 years until 2016, when they were unearthed from the streambeds of the Western Ghats in India. But why?

Unlike most tadpoles, this species has a rare fossorial nature. Adults lay their eggs in a small depression made in the sandy stream bed. Then, when hatched, the young immediately burrow down and live underground live hidden underground in dark, deep recesses until metamorphosis. This helps explain their elusiveness (and means they are extremely challenging to find or photograph!).

Unusually, they have ribs – which is totally unique among tadpoles. Their muscular, eel-like bodies and skin-covered eyes allow them to move through gravel beds, where they eat sand and decaying matter.

Eiffinger’s tree frog – Ishigaki and Iriomote, Japan   

Eiffinger’s tadpoles spawn in tiny bodies of water like tree hollows and bamboo stumps. This can make waste management difficult.   

Other species can harmlessly excrete faeces and toxic ammonia which dilutes into larger areas of water, but the confined spaces where Eiffinger’s tree frogs rear their young would quickly become contaminated, threatening their survival.  

The need to keep their water clean has led to a unique adaptation: as well as excreting much less ammonia than other species, its tadpoles do not defecate externally, but store it in their intestines.  

Flying vampire frog – Lang Bian Plateau, Vietnam  

Discovered in the cloud-forests of Vietnam in 2008, this arboreal species has no need to descend to the ground: instead, adult frogs keep their offspring safe by depositing eggs in the water pools of tree trunks.  

While the ‘flying’ element of this frog’s name comes from its ability to glide between trees using webbed toes, the ‘vampire’ part is thanks to their truly unique tadpoles, which are endowed with ‘fangs’.  

In place of typically beak-like mouthparts, they have a pair of curved black hooks. With scarce food, this adaptation likely allows the tree-hole-dwelling young to devour the unfertilised eggs their mothers deliver.   

Paradoxical frog – Northern South America and Trinidad

Next, we have the curious case of the paradoxical frog – otherwise known as shrinking frogs. As the name suggests, this species gets smaller as it ages, and tadpoles can be three to four times as big as the adults. For scale, while adults are three inches long, tadpoles can measure up to nine inches – the world’s longest! 

Their impressive size is partly thanks to the fact that they keep growing for longer than other species: by the time they undergo metamorphosis, their body length is about the same as a mature adult. The later loss of their very long tails is what causes them to ‘shrink’.

Darwin’s frogs tadpoles – Chile and Argentina 

Darwin’s frogs have a distinctive reproductive cycle: after fertilising the females’ eggs on the forest floor, males return to two to three weeks later to collect them in their mouths. The developing tadpoles are then transferred to a specialised vocal sac, where they undergo metamorphosis, before emerging as fully formed froglets. 

False Malabar gliding frog – India  

There are lots of interesting tree frog tadpoles – for example, the tree frog tadpoles of the genus Leptopelis in sub-Saharan Africa hatch in muddy nests and then wriggle their way to open water.

But the false Malabar gliding frog, a tree frog species in the Anaimalai Hills of India, has a slightly easier start to life.

These tadpoles hatch from foam nests, created by their parents mixing excretions with their hind legs. Mothers generally build these above streams so tadpoles can hatch straight into the water. 

This Critically Endangered species is threatened by illegal collection for the pet trade and habitat loss, so when our partner Wildlife Trust of India found one of their foam nests laid in a dangerous spot on a recent survey, they decided to take it into captivity as it would be unlikely to hatch in the wild. Their babies have now been released.   

Research as a lifeline  

Without research, we would not know about these fascinating species – but there is still so much we do not know. Some species may be lost before they are even discovered. Synchronicity Earth prioritises improving this knowledge base to guide amphibian conservation and ensure species have a better chance of survival.   

Thank you to our Amphibian Programme partners, and tadpole specialist Jack Phillips, for their suggestions and contributions. With years of experience researching and conserving Africa’s amphibians, Joshua Weeber from Endangered Wildlife Trust and Jeanne Tarrant of Anura Africa shared their knowledge of the remarkably resilient ghost frog tadpole. Harikrishnan Surendran from Wildlife Trust of India suggested the Indian dancing frogs and the team shared the story of their nest relocation.  

Amphibians face an extinction crisis.

Our Amphibian Programme works to reverse this by protecting species, advancing knowledge, and building the capacity of amphibian organisations.