Of Caves and Cavernicoles: A Memoir of the World in Darkness
I was standing alone near a rock formation (Shivling) in the middle chamber of the famous Kotumsar cave of Chhatisgarh. As I switched off my flashlight, dense darkness enveloped me, and all I could sense was the ground under my feet. Except for an acute awareness of my own self, nothing else existed in those moments. A few bats briefly shuffled in their roosting colony on the chamber’s roof. Once the flutter of their wings stopped, a deep silence crawled over. A drop of water trickled down into the pool, and the plink vanished forever in the prevailing silence.
Entry of Kotumsar cave- by Jayant Biswas
In my meditative state, I thought of the myth of three times – past, present and future – existing in physical form inside the cave of Patal Bhuvneshwar, Uttarakhand. The Chand dynasty of Kumaon started maintaining it as a pilgrimage site from the 12th Century onwards, as legend holds that it was visited by the Pandavas and Adi Shankaracharya. According to mythology, the cave’s dripstone structures depict different gods, four Yugas (ages) and three Kaalas (times).
Hipposideros spp colony in Buddheshwar cave, Pithoragarh- by Shivam Shrotriya
A friend had once told me about bats and snakes living in surrounding caves of Palat Bhuvneshwar cave in Pithoragarh during a casual chat. The conversation quickly sparked a more fascinating topic – can some animals sustain themselves entirely inside caves? I was thoroughly intrigued, and set out to look for more information. Searching scientific literature on caves, I encountered significant work from Europe and the Americas. A few studies from south-east Asia also popped up. But to my disappointment, India had very little representation in cave research. Whatever I could find was about caves in Meghalaya and Chhatisgarh, and mostly linked to one scientist – Dr Jayant Biswas. I shot him an email inquiring if he still worked on caves and if I could bug him to learn more – he replied warmly, answering my queries and inviting me to visit him.
Three months later, in October 2008, I was at Kotumsar cave with Dr. Biswas. Little did I know at this time that I would be so inspired by this visit that I would eventually take up cave research for my MSc dissertation under his guidance! We entered the cave through a 15 meter deep vertical fissure followed by about a 500 meter long horizontal tunnel. Colourful dripstone structures such as stalagmite, stalactite and flanks pervaded the roof and walls of the cave.
Dandak cave- by Jayant Biswas
The environment of the cave is extreme, and the species trapped inside it often develop unique adaptive characteristics. The common loach Indoreonectes evezardi (syn. Nemachelius evezardi) is a ray-finned fish endemic to the streams of Central India and the Western Ghats. However, the population living inside Kotumsar cave has turned blind and albino in response to the subterranean environment. Another intriguing species of Kotumsar – the cave cricket, Kempiola shankari, has developed elongated tentacles for enhanced sensory perception in the dark.
Caves are distinctly unique systems isolated from the outside environment and deprived of sunlight. Perpetual darkness, scanty and sporadic food supply, and almost constant temperature, humidity and air composition differentiate caves as a specialised ecological niche. Food resources in caves are either carried by bats and other animals, or flow in with wind and water. No two caves are similar in structure, geology and environment. Each cave, therefore, can hold the biological community best suited for its capacities.
On comparing Kotumsar cave with Dandak, another pilgrimage site in Kanker Valley National Park, Chhatisgarh, I found that cave ecosystems were predominantly shaped by their architecture and geology. Availability of sunlight, fluctuations in internal climate and water-holding capacity of the overload were additional deciding factors.
Dandak has a horizontal opening with an airflow system via chimneys and blow-holes. A minimal rocky overload makes it comparatively dry. Dandak gets most of its nutrients through sporadically visiting (trogloxene) mammalian species such as small Indian civet Viverricula indica, Indian crested porcupine Hystrix indica, and bats. By contrast, Kotumsar opens downward, allowing a sudden influx of detritus during rains, and has a wet substrate. Organic matter and bat excrement create an opportunity for the evolution of obligatory cave species (troglobite) and populations (eutroglophiles) such as pillbug Armadillium spp, guano moth Kangerosithyris kotomsarensis, cave snail Opeas spp, and the blind cavefish.
Water pool inside Kotumsar cave, encompassing blind fish- by Jayant Biswas
During my research, I also monitored populations of rufous horseshoe bat Rhinolophus rouxii and ashy roundleaf bat Hipposideros cineraceus in both the caves. The peak tourism season in these caves coincided with the bats’ gestation period, reducing their populations. Often, religious association of the caves brings in threats and challenges for their conservation. Appropiate efforts are therefore urgently required to conserve the caves as both unique wildlife habitats, as well repositories of geo-historical information.
A decade after my research, cave science continues to be uncharted territory, and new facts and species are constantly being discovered in caves across the world. Scientists discovered two new species of tube-nosed bats Murina spp in the caves of Meghalaya in 2012. The current geological age that began 4,200 years ago was named the Meghalayan in 2018 since its first evidence came from Mawmluh cave. The world’s largest and yet unnamed cavefish with partial blindness was discovered in Um Ladaw cave, Meghalaya in 2019. Currently, the National Cave Research and Protection Organization (https://caves.res.in/) is the best resource for beginners in India. In the future, Having a database of Indian caves and their scientific explorations would hugely benefit future explorers.
Pitch darkness, absolute silence and a mysterious serenity make every cave visit a metaphysical experience. Standing in Kotumsar cave with the blind fish that had returned to their primitive characteristics through retrogressive evolution on the one hand, and the cave crickets that developed advanced characteristics compared to its relatives outside on the other, revealed to me the elasticity of cave time. The alternate evolution of cavernicoles brings together characters from different evolutionary times. Indeed, the past, present and future reside here together.
