By H.H. Mohrmen
Meghalaya is renowned not only for its breathtaking landscapes but also for its extraordinary underground world. Its heavy rainfall and vast limestone deposits have, over millions of years, created one of the largest and most spectacular cave systems in India, earning it the title of the “Caving Capital of India.” These caves are home to a remarkable diversity of rare and endemic species, including Neolissochilus pnar, the world’s largest known subterranean fish. Together, they make Meghalaya a globally important centre for cave biodiversity and scientific research.
These cave systems have become a source of pride for the state, as the study and exploration of caves in Meghalaya have attracted scientists, geologists, and cave explorers from around the world.
Formation of Caves in Meghalaya
Most caves in Meghalaya are formed through a natural process known as karst formation. Karst topography develops when rainwater, which is slightly acidic, dissolves soluble rocks such as limestone over thousands of years. This process creates underground channels, tunnels, chambers, sinkholes, and caves. Most of these caves are limestone caves, and they occur in areas that have large deposits of limestone.
Meghalaya’s heavy rainfall accelerates this process. Water seeps through cracks in limestone rocks, gradually widening them into large underground passages. Over time, these passages become extensive cave systems. While most caves in Meghalaya are limestone caves, some are formed in sandstone, which is rare and scientifically important. While one can find many sandstone caves in the state, the most remarkable example is Krem Puri, which is recognised as the longest sandstone cave in the world, stretching over 25 kilometres.
Exploration of Caves in Meghalaya
Although local communities have known about many caves for centuries, scientific exploration began only in the late twentieth century. In 1992, a small team of European cave explorers visited Meghalaya and recognised the enormous potential for cave exploration in the Khasi, Jaiñtia, and Garo Hills.
In 1994, they partnered with the Meghalaya Adventurers’ Association, led by Brian D. Kharpran Daly and Donbok Syiemlieh. This partnership launched the project known as Caving in the Abode of the Clouds, which has continued for more than three decades. Through this collaboration, approximately 1,700 caves have been recorded in Meghalaya, and over 1,000 have been explored or partially mapped. These discoveries have placed Meghalaya on the global map of cave exploration.
These many expeditions have also helped establish the fact that most of the longest and deepest caves in the Indian subcontinent are found in Meghalaya.
Importance of Caves
The caves of Meghalaya are important for several reasons. They preserve evidence of Earth’s geological history and help scientists understand climate change and environmental changes over thousands of years. They are home to many rare and endangered species, some of which are endemic to the region and therefore contribute significantly to biodiversity conservation. Caves also attract tourists, researchers, and adventurers, which support the local economy and create employment opportunities. Additionally, the caves are an important part of Meghalaya’s natural heritage and must be protected for future generations.
Dr. Khlur Baiaineh Mukhim, one of the experts in the study of cave fishes in East Jaiñtia Hills, said, “Caves like Krem Liatprah Um-im-labit are a factory of time-taking speciation, where new species are being formed over millions of years. If the Shillong Plateau (including both Jaiñtia and Garo Hills) was raised some 50 million years ago from the Tethys Sea, nature could have taken at least 5–10 million years to create such extensive caves of great magnificence that are often visited with a sense of respect, wonder, and awe! These are humongous natural assets (belonging to our past ancestors, to us today, and to many future generations of our children, grandchildren, and their children) that have to be responsibly respected.”
The Meghalayan Age
In 2018, the International Commission on Stratigraphy officially named the present geological age the Meghalayan Age. This was based on scientific evidence collected from a stalagmite found in Mawmluh Cave. This discovery gave Meghalaya international recognition and highlighted the scientific importance of its caves.
Biodiversity in
Meghalaya’s Caves
Although caves appear dark and lifeless, they support a rich and unique ecosystem. Many animals have adapted to survive in these dark and isolated environments. The caves of Meghalaya provide shelter to more than eleven species of bats. These include the Greater Large-eared Horseshoe Bat, Pomona Leaf-nosed Bat, and Eastern Bent-winged Bat. One of the rarest species found here is Wroughton’s Free-tailed Bat, and Meghalaya is believed to hold more than half of the world’s known population of this species.
Animals that live in caves are called troglofauna (from the Greek trogle, meaning “hole”). They are divided into three groups based on their dependence on caves. The first group is called trogloxenes. These animals use caves temporarily for shelter or breeding but do not spend their entire lives there. Bats are a common example.
The second group is troglophiles. These animals prefer living in caves but can also survive outside them. Examples include certain frogs, spiders, and insects. The third group is troglobites, which are true cave animals. They are fully adapted to cave life and cannot survive outside caves. They often have pale bodies, reduced eyes or no eyes, and enhanced senses of touch and smell.
Neolissochilus pnar and Other Cave Fish
The caves also contain rare fish species adapted to life in darkness. Among these rare species are Schistura larketensis, Schistura papulifera, and Neolissochilus pnar, discovered in East Jaiñtia Hills. These animals have reduced eyesight or no eyesight at all, as vision is not necessary in total darkness.Scientific information about Neolissochilus pnar was first published in Vertebrate Zoology 73:141–152 on February 6, 2023. The paper was co-authored by Neelesh Dahanukar, Department of Life Sciences, School of Natural Sciences, Shiv Nadar Institution of Eminence, Delhi-NCR, India; Remya L. Sundar and Rajeev Raghavan, Department of Fisheries Resource Management, Kerala University of Fisheries and Ocean Studies (KUFOS), Kochi, India; Duwaki Rangad, Department of Zoology, St. Edmund’s College, Laitumkhrah, Shillong, India; and Graham Proudlove, Department of Entomology, The Manchester Museum, University of Manchester, Manchester, United Kingdom.
The world’s largest subterranean fish was discovered in 2019 and was tentatively identified as a troglomorphic form of the golden mahseer, Tor putitora. Detailed analyses of its morphometric and meristic data, together with results from molecular analyses, revealed that it is a new species of the genus Neolissochilus, the sister taxon of Tor. The study formally described the new species as Neolissochilus pnar, honouring the tribal communities of East Jaiñtia Hills in Meghalaya, Northeast India, where it was discovered. Neolissochilus pnar possesses a number of characters unique among species of Neolissochilus, with the exception of the similarly subterranean N. subterraneus from Thailand. The unique characters that distinguish N. pnar from all epigean congeners include highly reduced eye size or the complete absence of externally visible eyes, complete lack of pigmentation, long maxillary barbels, long pectoral-fin rays, and a distinct scalation pattern.
The Endemic Fish Gets National Recognition
In the February 23, 2020, episode of Mann Ki Baat, Prime Minister Narendra Modi of India shared fascinating facts about a rare fish species discovered by biologists in a cave in Meghalaya and remarked that it is the largest among the cave-dwelling species existing in deep underground caves where even light cannot reach. This recognition led the ministry to support the protection and conservation of this very unique fish species.
Later, the Central Government, through the Ministry of Fisheries, sanctioned Rs 1 crore to the department of Fisheries, Government of Meghalaya for the protection and conservation of Neolissochilus pnar in its only known habitat in East Jaiñtia Hills. With the funds now available, it is hoped that the government, through the Fisheries Department and with the support of the Meghalaya Adventurers’ Association, will be able to protect this endemic species.
Threats to the Caves
Despite their importance, Meghalaya’s caves face several threats. Limestone mining and quarrying can damage or destroy cave systems. Pollution from human activities can harm delicate cave ecosystems. Unregulated tourism can also damage cave formations and disturb wildlife. Deforestation around cave areas affects water flow and increases erosion, further threatening these fragile environments. Therefore, conservation and responsible tourism, instead of promoting the cement industry, are essential to protect Meghalaya’s caves.
Conclusion
The caves of Meghalaya are among the state’s greatest natural treasures. They tell the story of the Earth’s geological past, support unique forms of life, and contribute to the cultural and environmental heritage of the region. Protecting these caves is the responsibility of every citizen so that future generations may continue to learn from and appreciate this remarkable natural heritage. Hopefully, the government will accord due recognition to these natural phenomena and ban mining and any activities that could put the caves in danger.
