KOCHI: Frogs have survived on Earth for nearly 400 million years, outliving dinosaurs and withstanding five major mass extinctions. Their presence is a living link to ancient evolutionary history, their croaks a timeless rhythm in the natural symphony of life. Yet today, these ancient survivors are falling silent at an unprecedented rate.
“Two out of every five amphibians are threatened with extinction. Why are we losing frogs?” asks Prof. S D Biju, aka ‘Frogman of India’, who recently presented an engaging seminar on the subject at an event commemorating the Zoological Society of Kerala’s anniversary.
The croak of frogs has long been a soundtrack to the quiet of the night. For those who listen closely, the absence of this nocturnal refrain is becoming all too apparent.
Speaking to TNIE, Biju, a senior professor at Delhi University, stresses that with each missing croak, we lose a “vital piece of the intricate web that supports our ecosystems”, highlighting the “urgent” need to address the growing threats to amphibian life.
The figures are alarming indeed. According to a study published in Nature, 41 per cent of amphibian species worldwide are now threatened with extinction, making them the most endangered group of land vertebrates.
This comprehensive assessment, coordinated by the Amphibian Red List Authority, evaluated the extinction risk of over 8,000 species.
India is home to 458 amphibian species, with 440 of these assessed for conservation status. Of these, 137 are categorised as threatened – 14 critically endangered, 74 endangered, and 49 vulnerable.
“This,” Biju explains, “means 31 per cent of India’s amphibian species are at risk. Additionally, 31 species are classified as near-threatened, bringing the total proportion of species at risk of extinction to nearly 40 per cent.”
Zooming in on Kerala
One of the world’s most threatened frog categories is ‘Micrixalidae’, the Indian Dancing Frog family. Endemic to the Western Ghats, this family includes 24 species, 17 of which are found in Kerala. Nine are endemic to the state. “Alarmingly, all nine species are threatened, with eight classified as endangered and one as vulnerable,” Biju notes.
“If we enumerate the IUCN Red List species of Kerala, three species are critically endangered, 46 endangered, and 28 vulnerable, bringing the total number of threatened species to 77.”
That brings us to the question: why are we losing the world’s frogs now? According to the Second Global Amphibian Assessment (2023), climate change is the primary threat, affecting 39 per cent of species. This number is expected to rise as more data on species’ responses to climate change become available.
“Climate change is particularly concerning for amphibians because they are highly sensitive to changes in their environment,” says Biju.
“Growth and breeding conditions of frogs are directly linked to weather patterns, and irregularities such as erratic rainfall can be devastating.”
Globally, he adds, the fungal disease chytridiomycosis has caused devastation in Africa, Australia, and South America. “Fortunately, its impact in India has so far been limited. But that doesn’t mean we can rule the threat out,” says Biju.
“As of now, habitat destruction and degradation are the primary drivers of amphibian decline in India, caused largely by agriculture and cropland expansion for timber and large-scale cultivation of crops such as coffee, tea, and spices.”
Echoing concerns about climate change, Sandeep Das, a Science and Engineering Research Board postdoctoral fellow at the University of Calicut, highlights the example of the Indian Purple Frog (Nasikabatrachus sahyadrensis).
“These frogs, which are endemic to the Western Ghats, have a unique evolutionary history and were rediscovered in 2003 in Idukki district after being undetected for nearly 125 years,” he says.
“Their breeding occurs only during the monsoon season, over a span of two to three weeks, in seasonal streams. However, irregular rainfall patterns — such as delayed or excessive rain — can kill their eggs and tadpoles. Over the past three years, there was a loss of about 70 per cent of Purple Frog eggs in breeding sites we monitor.”
The growing network of roads is another issue. “Roadkill affects frogs as well, not just larger animals. These hapless little ones often go unnoticed. Big species might draw attention when accidents occur, but how often do we pause to consider the toll on frogs?” asks Sandeep.
The way forward
According to Biju, current wildlife conservation efforts prioritise larger, more charismatic animals such as tigers and elephants, often at the expense of lesser-known species.
“I am not against the conservation of larger animals. It is certainly crucial, but our conservation priorities need to evolve. Our administration must diversify its focus and not channel all resources toward just a few species,” he says.
“Conservation is not about focusing on a few species. It’s about preserving life on Earth as a whole. If we are to survive, we must survive together. Every organism matters.”
A fundamental step in improving frog conservation efforts is thorough documentation of biodiversity, Biju adds. “It’s a fact that the Western Ghats still does not have a complete inventory of its animal and plant species,” he notes.
While amphibian conservation remains “under-funded and under-prioritised”, there has been “some progress”. In 2018, for instance, Delhi University launched a project named ‘Lost Amphibians of India’, and there have been discussions around creating a frog sanctuary.
“The project is still on, but there has been no significant action on the ground,” says Biju, adding that enhanced public awareness can be a catalyst.
In Kerala, he adds, many frog species remain undiscovered and unnamed. “Further research is essential to understand their diversity and specific habitat needs. The Kerala forest department can play a key role here,” he says.
“As a first step, areas rich in amphibian life, many of which lie outside protected zones but within reserve forests, must be safeguarded from disturbances.”
Why are frogs important
Frogs play a crucial role as environmental indicators. Their permeable skin makes them highly sensitive to environmental changes. “A decline in frog populations or changes in their breeding patterns signal shifts in their habitat, often affecting other species that share these environments, particularly wetlands and water bodies,” explains Ashish Thomas, a Delhi University professor who did his doctorate on the Indian Purple Frog.
In simple words, any change to the frog population will disrupt the food chain of that region. And this can have ripple effects that would eventually affect humans. Moreover, earlier, waterbodies were commonly found near cultivated fields, encouraging frog populations. Known as “farmers’ friends”, frogs serve as natural pest control.
A single frog can consume hundreds of insects in a day. “A healthy frog population can help reduce dependence on chemical pesticides,” he adds. Additionally, the chemical secretions in frogs’ skin (bioactive peptides) have antiviral and antibacterial properties, Ashish notes. “Reseachers have also shown that they are effective against cancer cells.”
The Kerala scene
Critically endangered
Cave Dancing Frog (Micrixalus spelunca)
Franky’s Narrow-mouthed Frog (Mysticellus franki)
Mark’s Bush Frog (Raorchestes marki)
Endangered
Beautiful Dancing Frog (Micrixalus adonis)
Malabar Night Frog (Nyctibatrachus major)
Golden-back Frog Indosylvirana aurantiaca
Biju’s Tree Frog (Beddomixalus bijui)
Jayaram’s Shrub Frog (Raorchestes jayarami)
Resplendent Shrub Frog (Raorchestes resplendens)
Travancore Shrub Frog (Raorchestes travancoricus)
Vulnerable
Galaxy frog (Melanobatrachus indicus)
Indian Purple Frog (Nasikabatrachus sahyadrensis)
Yellow-eyed reed frog (Raorchestes chalazodes)