By Rohit Chakravarty
“The bat is more than just an animal. He is a vision to the mind. From man’s earliest times the bat has been woven into a tapestry of fable and fact. But fancy has distorted him to grotesque proportions… He has become more of a thing than an idea.”
This quote is from the opening of Silently, By Night (1964), a now out-of-print book by American writer Russell Peterson. My aunt’s father, an avid reader and book collector, discovered it at a roadside bookstall. After his passing, around the same time, I developed an interest in bats, and my aunt gave me the book. The opening paragraph has stayed with me ever since, perfectly capturing the complexity of a bat’s existence, both in pristine nature and the Anthropocene.
While my family celebrates my dad’s birthday in the sweltering 440C heat in Nagpur, I find myself freezing in the Kedarnath Wildlife Sanctuary at 3,000 m., where it’s a biting 40°C cooler. My field assistants, Shamshad and Prabhat, and I are quietly huddled in a rhododendron forest, waiting for bats to get caught in our mist net. Nearby, a pair of Long-billed Thrushes is settling in for the night by the brook.
A male leaf-nosed bat Hipposideros sp. captured mid flight in a cave on the outskirts of Visakhapatnam, Andhra Pradesh. Photo: Anjani Kumar/Sanctuary Photolibrary.
In the first two hours, we catch two stunning bats – my favourites: the Kashmir long-eared bat Plecotus wardi and the bronze sprite Arielulus circumdatus. The former has ears almost as long as its body, while the latter sports copper-red fur, mottled with black – Shamshad likens it to a bat that’s dyed itself in mehndi (henna).
The night’s excitement is just beginning. We soon catch a third, an unknown species – a handsome bat with silky dark brown fur on top and soft, cottony yellow fur below. Its ear structure suggests it’s from the Eptesicus genus (now Cnephaeus). Determining the species proves tricky. After returning from the field, I write to Dr. Manuel Ruedi, my collaborator and bat expert. He’s stunned – perhaps even a little jealous he confesses – because the bat matches only one known species: the Sombre bat Cnephaeus tatei, previously recorded from a single specimen in North Bengal in 1972. Forty-five years later, we have rediscovered it, over a thousand kilometres from its last known location!
This rediscovery is part of a broader trend: in the past decade, passionate bat researchers have uncovered five new species to science, two of which were in the past three years: the Meghalaya thick-thumbed
bat Glischropus meghalayanus and Srini’s long-fingered bat Miniopterus srinii.
But you don’t need to venture into remote regions to find fascinating bats. India is home to 134 bat species, including 16 endemics, making bats the most diverse group of mammals in the country. The Indian flying fox Pteropus medius, with a wingspan of 1.2 m., is the most widespread and easily recognisable bat. Watching them fan themselves in the heat and descend to drink water from a lake is a spectacle. Unlike more agile bats, they gently dip themselves into the water, then fly to a perch to lap it off their chest.
The greater short-nosed fruit bat Cynopterus sphinx is a quarter the size of the flying fox, and a common city dweller. These bats are known for their unique tent-making behaviour – males bite off palm leaves to create shelters for themselves and their harem of females. At night, you can spot them around fruiting Singapore cherry trees along even the busiest urban streets.
Among insectivorous bats, the Indian pygmy bat Pipistrellus tenuis is the smallest, weighing just over four grams. These tiny bats are often the first to emerge at dusk, hunting insects attracted to street lights. A larger cousin, Kelaart’s pipistrelle Pipistrellus ceylonicus, is also common. A colony roosts in my own home in Nagpur, and last October, the juveniles took their first exploratory flights. My brother had a blast chasing and releasing them
back outside.
In the dry regions of north and peninsular India, mouse-tailed bats are often found in old forts and monuments. Their long, whip-like tails – covered with bristle-like hairs – serve as a sensory tool, helping them navigate and retreat into crevices when disturbed. These tails also help maintain stability in flight.
India is also home to four species of carnivorous bats. The greater and lesser false vampires Lyroderma lyra and Megaderma spasma have a winged bunny appearance, and feast on a variety of prey, including lizards, mice, birds, and even fish. The great evening bat Ia io, mostly found in Meghalaya, switches from an insectivorous diet to feeding on birds during migration periods. Another rare carnivorous bat, the Rickett’s big-footed bat Myotis pilosus, uses its long legs to rake the water’s surface in search of small fish.
Bat researchers and tourists watching Mexican free-tailed bats Tadarida brasiliensis at Bracken cave, Texas, USA as they emerge at dusk. Bracken cave is home to more than 15 million bats. Photo: Rohit Chakravarty.
Himalayan bats, in contrast to their plains-dwelling cousins, have thick, woolly coats to keep warm. The tube-nosed bat, which I have studied in Uttarakhand, has dense fur that makes it resemble a miniature flying Yeti. One of my interns called them the “Anil Kapoors of the bat world”, a comparison that immediately struck a chord with my Bollywood-loving heart!
This is just a glimpse of the remarkable diversity of bats in India. With so many unique species, I’d need more than one list to fully capture their wonder.
Around 65 million years ago, as dinosaurs went extinct, bats took to the skies, evolving potentially from a tree-shrew-like ancestor. This was a time of opportunity: flowering plants thrived, and insects began to diversify. Over millions of years, as these creatures leapt from tree-tops chasing flying insects, they developed wings and began resembling modern bats. Today, bats are found on every continent except at the poles, and in the Pacific island nations, they are the only native terrestrial mammals. With 1,484 species across 21 families, bats form the second-largest order of mammals, surpassed only by rodents. When we talk about families, some bats are as different from each other as cats are from dogs.
Naturally, such a staggering diversity results in a smorgasbord of shapes and sizes in the bat world. The tiniest bat – also the tiniest mammal – in the world is the bumblebee bat Craseonycteris thonglongyai from Thailand and Myanmar, weighing in at two grams, lighter than a one-rupee coin! On the other extreme is the giant golden-crowned flying fox Acerodon jubatus with a wingspan of 1.5 to 1.8 m. and weighing up to a kilogramme, heavier and larger than an average Black Kite. The bat’s face has sparked imaginations over generations, appealing to everyone with interests ranging from Victorian art to sci-fi fans. Many bats have mouse-like features, which is why many European languages associate them with mice. For example, the German word fledermaus means fluttering mouse, and similar terms appear in Dutch (vleermuis) and Swedish (fladdermus). Spanish offers the elegant murciélago, meaning blind mouse, while French takes a more playful turn with chauve-souris, or bald mouse.
Beyond the ‘mouse-like’ bats, Old World fruit bats have dog-like faces, earning many of them the name flying fox owing to their large size. Bats from the false vampire family (Megadermatidae) and New World leaf-nosed bats (Phyllostomidae) sport large, rounded ears and beady eyes – imagine a bat dressed as a rabbit for a school costume contest!
The oddities don’t stop here. The male hammer-headed bat Hypsignathus monstrosus has swollen cheeks and a nose that gives it a hippopotamus look. This bizarre feature helps males produce loud honking sounds to attract females. The tube-lipped nectar bat Anoura fistulata from the Andean cloud forests boasts the longest tongue (relative to body size) in mammals – so long that it reaches down to the bat’s chest when folded. The seven species of Barbastelles Barbastella spp. in Eurasia have pug-like noses and almost forward-facing ears.
No discussion of odd bat faces is complete without the wrinkle-faced bat Centurio senex from the Neotropics, whose exaggerated facial wrinkles make it look like a hundred-year-old man. Finally, not all bats are dull in colour – some are strikingly vibrant. The pure white Honduran white bat Ectophylla alba, the black-and-white badger bat Glauconycteris superba, the hoary bat Lasiurus cinereus, which resembles a donut topped with powdered sugar, and the orange-and-black painted bat Kerivoula picta break the mold.
On account of their small size and mouse-like appearance, many people mistakenly assume bats produce lots of babies and have short lifespans. In reality, most bat species give birth to only one pup every year, and rarely, twins. Like humans, bats have just one pair of teats (unlike mice, which have about five pairs), meaning they can’t nurse more than two pups at once.
After mating, mothers carry their pregnancy for six to nine weeks – nearly as long as a dog. After birth, they fly with pups that can weigh a third of their own body weight. The pups cling to their mother by biting her nipples or false nipples, the latter of which are soft skin projections on her flanks. It is safe to say that mother bats are made of steel!
Many bat species have short lifespans; for example, the noctule bat has an average lifespan of three to four years. However, there are many others that are incredibly long-lived. The Indian flying fox Pteropus giganteus, the most familiar species in India, has lived up to 34 years in captivity. The record holder though is a Brandt’s bat Myotis brandtii from Siberia, weighing only 10 grams (the size of a travel toothpaste!), that lived for 41 years! Compare this to a 200 kg. tiger that barely makes it to 15 years.
Greater false vampire bats Lyroderma lyra roosting in a temple in Vidarbha, Maharashtra. These bats are one of the few carnivorous bats found in India. Photo: Rohit Chakravarty.
In addition to their extraordinary life span, bats also have extreme viral tolerance. Most mammalian immune systems go into overdrive when infected by certain pathogens. Bats, however, have specific DNA and cell repair mechanisms that mount a very controlled response to infections, ensuring the pathogen is neither killed nor allowed to make them ill.
One of bats’ most famous superpowers is their ability to navigate using ultrasound. Here’s how it works: as bats fly, they emit loud, high-frequency sounds (as loud as a firecracker) and wait for the returning echoes. Sounds that hit solid objects return strong echoes, while those that hit soft, permeable surfaces, such as animal skin return weaker ones. In milliseconds, bats calculate how much sound was emitted and how much was reflected to identify obstacles, predators, prey, or even other bats.
The discovery of this ability is equally fascinating. In 1793, Italian priest and physiologist Lazzaro Spallanzani, curious about how animals with small eyes could navigate in the dark, conducted experiments with wild bats. He placed them in a dark maze, and they navigated without any issues. When he blindfolded them, they still managed the maze. But when he plugged their ears, the bats became disoriented. This was a groundbreaking discovery for its time: the idea that an animal could use sound to navigate was unheard of. It took 150 years for Prof. Donald Griffin, an American zoologist, to record ultrasonic bat calls and coin the term echolocation. Today, researchers and nature enthusiasts use pocket-sized bat detectors to record these calls and identify bat species.
In the forests of Malaysia, Indonesia and Philippines lives the Dayak fruit bat Dyacopterus spadiceus. This bat challenges patriarchy in a way no other mammal does. It is possibly the only male mammal that is known to lactate to feed its pups! The reasons behind this are unknown but two possibilities stand out. One, male lactation may help reduce some burden on the female. Another hypothesis is that the plants they consume are rife with phytoestrogens that induce milk production. On the other end of the world, in Central and South America, vampire bats drink the blood of birds and ungulates by making pin pricks and secreting an anticoagulant (much like a leech). As you can imagine, blood meals are hard to come by, and starvation is a common problem in vampire bat colonies. To fix this problem, these bats regurgitate blood to feed starving individuals. Blood-sharing depends on trust, reliability, and reciprocity. Over time, members of a colony learn to recognise friends and reliable blood donors.
Bats have surprisingly steamy sex lives. Two familiar species, the Indian flying fox Pteropus medius and the short-nosed fruit bat Cynopterus sphinx, are among the few mammals known to engage in oral sex,; this behaviour is observed in all directions – male to female, female to male, and male to male. Bats also exhibit fascinating behaviours during childbirth. In a captive colony of the endangered Rodrigues’ fruit bat Pteropus rodricensis in Mauritius, researchers observed one female acting as a midwife to assist a delivering roost-mate. Over three hours, the midwife groomed the mother’s vaginal region, helped her maintain the correct birthing position, and physically assisted in maneuvering the pup into position to nurse.
January 2013, Kolar, Karnataka: I was pursuing my master’s in wildlife biology at the National Centre for Biological Sciences, Bengaluru. Enthusiastically, one morning, armed with vague descriptions and GPS coordinates of two caves and precisely two words of Kannada – guhe (caves) and bavuli (bats), my batchmate Rohit Jha and I set out for Kolar, about two hours from the city. These were no ordinary caves. In 1994, German bat taxonomist Dr. Dieter Kock and Indian virologist Dr. H.R. Bhat discovered a new species of bat called the Kolar leaf-nosed bat. In the two decades that followed, no new information was added about these bats. Did the bat still occur near Kolar or had we lost it in oblivion? After an entire day of walking through the countryside and enquiring with locals, an hour before dusk we were pointed to a cave that perfectly matched Kock and Bhat’s description and we saw some leaf-nosed bats flying inside. Unfortunately, it’s not easy to identify the species of leaf-nosed bats. The fact that the cave was very narrow made it harder to take good photographs. Alarmingly, the cave is on a hill that was almost completely ravaged by granite mining. Even if the Kolar leaf-nosed bat exists here, its future looks bleak.
In August 2013, Rohit Jha and I published an article in Sanctuary Asia to raise awareness about the Kolar bat. Thanks to the efforts of Dr. Chelmala Srinivasulu, Dr. Bhargavi Srinivasulu, and their team from Osmania University, the Kolar bat was rediscovered, sparking initiatives to protect its habitat and designating the hillock as a Community Conserved Area. Today, Rajesh Puttaswamaiah, founder of Bat Conservation India Trust (BCIT), is leading research and conservation efforts to develop a comprehensive plan for the species’ protection.
The Kolar leaf-nosed bat stands as a rare success story in Indian bat conservation, but many other species are not as fortunate. For instance, the Nicobar flying fox Pteropus faunulus, endemic to the Central Nicobar Islands, has not had a study since 2003. Despite being endangered and having a restricted range, no significant conservation action has been taken to protect it – other than its recent inclusion in Schedule 1 of the Wildlife (Protection) Act, 1972. Other species urgently requiring research and conservation include Sálim Ali’s fruit bat Latidens salimalii, the Nicobar leaf-nosed bat Hipposideros nicobarulae, and the Andaman horseshoe bat Rhinolophus cognatus, which are endemic to the southern Western Ghats, Central and Great Nicobar, and Andaman Islands, respectively.
It’s not just rare or threatened species – common Indian bats likely face severe, yet unquantified, threats. For instance, wind energy is known to cause mass bat mortality during spring and autumn in Europe and North America, with tens of thousands of bats killed annually in wind farms. However, there is little scientific research on the impact of wind energy on Indian bat populations, even as India plans to double its wind energy capacity by 2030.
Similarly, urbanisation is rapidly emerging as a major socio-ecological challenge. While deforestation and habitat conversion to urban areas affect bat species globally, we lack a comprehensive understanding of which Indian species can adapt to or withstand urbanisation. Recently, the painted bat has also fallen victim to wildlife trade in the form of framed souvenirs. Along with habitat modification, one of the most pervasive challenges bats face globally is their poor public image – an issue further fueled by frequent zoonotic disease outbreaks wrongly attributed to bats. This not only diminishes global support for bat conservation but also makes them unwelcome in areas where they could thrive.
A probable species of fulvous fruit bat Rousettus leschenaultii licks nectar from a banana flower in Uttar Dharamtul, Morigaon, Assam. Photo: Gaurab Talukdar/Sanctuary Photolibrary.
Monuments, forts, and old temples – important cultural heritage sites – are bat havens. For example, Golconda Fort in Hyderabad and several monuments of Delhi house some of the largest urban
bat colonies, with populations reaching up to 10,000 individuals. Despite this, authorities often try to chase them away. In light of these threats, my team and I have launched studies to raise awareness and take action to protect common bats before they become endangered.
The larger question remains: why should bats be conserved? While the moral argument – that all living beings have the right to exist – is important, bat extinctions could have dramatic consequences for human societies. Fruit-eating bats play a crucial role in pollinating food and cash crops such as bananas, durians, and agave. In fact, agave nectar is used to produce tequila, and conservation groups are advocating for bat-friendly farming practices to ensure the sustainable production of tequila and mezcal. Additionally, nectarivorous long-tongued bats Macroglossus spp. pollinate mangroves, which act as natural barriers against cyclones and storm surges. Insectivorous bats, on the other hand, are powerful predators that provide immense pest control services. Estimates suggest that bats save cocoa farmers in Indonesia around $800 million and corn farmers in the U.S. about $1 billion annually.
A recent study published in Science by environmental economist Dr. Eyal Frank boldly underscores the incredible value of bats to humankind. In 2006, a fungus, Pseudogymnoascus destructans, was accidentally introduced to the Eastern United States and Canada. This fungus infects bats hibernating in caves, appearing as a white mould on the sleeping bats’ faces. The fungus causes frequent arousals in hibernating bats leading to depletion of their fat reserves and, and consequently, death owing to starvation. This disease, called White Nose Syndrome (WNS), has since spread further west and killed millions of bats across North America. However, not all counties in the US are affected by WNS. Frank gathered data on pesticide use and subsequent infant mortality from counties affected by WNS and those without WNS as a natural experiment. After analysing a bunch of variables, his results were startling. In counties severely affected by WNS, farmers used more pesticides potentially leading to higher infant mortality.
Recognising the threats that bats face in India, and how little we know about many of our species, the Nature Conservation Foundation (NCF) and Bat Conservation International (BCI) partnered in 2023 to launch the State of India’s Bats Project (SoIBats). This project is a collaboration among 39 researchers representing 26 institutions dedicated to preparing a roadmap for guiding bat research and conservation in India in the coming years.
Broadly, participating researchers are compiling the steps needed to improve research on the ecology of bats, enhance monitoring of threatened bat populations and species, initiate partnerships between governmental and non-governmental bodies to strengthen bat conservation, and – most importantly – to identify measures to make people value the beneficial role of bats in the ecosystem, and for humankind. The report, which is expected in late 2025, is sure to make an indelible mark on India’s bat research and conservation landscape.
A Tickell’s bat Hesperoptenus tickelli photographed in Meghalaya bares its tiny perfect teeth. This species is one of the few brightly coloured bats found in India. Photo: Rohit Chakravarty.
August 2022, Austin, United States: I’m in Austin for a bat conference. It’s nearly dusk at the Congress Avenue Bridge in the downtown area. The bridge, a viewing platform, and a park by the Colorado river are brimming with people from all walks of life. An open-deck boat parks itself under the bridge and kayakers wait nearby. All eyes are peeled at the bridge. Suddenly, a cheer goes up – imagine Rajnikanth making an on-screen appearance in a movie theatre. The first group of Mexican free-tailed bats Tadarida brasiliensis has emerged. I can’t imagine that this city was once on the brink of exterminating its most beloved residents.
In 1980, the bridge that I stood upon had just been renovated with narrow beams under its span. Expectant female bats returned after wintering in Mexico and Central America and found these gaps conducive for roosting and raising their pups. In the next six years, there were far too many bats to be ignored. At that time, bats were so unpopular in the US that their approval ratings hovered between rattlesnakes and cockroaches. Citizens filed petitions to rid their city of the bats. It was then that Dr. Merlin Tuttle, a passionate bat researcher, photographer and conservationist, actively campaigned to educate the public about the usefulness of bats in the city and the world’s ecosystem. The outcome of this campaign – Tuttle’s legacy – is what I’m witnessing today.
I look back on that moment as a dream that I carry for the whole world: that every place moves on from hating bats to celebrating their existence.
Rohit Chakravarthy He works with the Nature Conservation Foundation and Bat Conservation International, leading conservation and research projects on bats across India. Over the past decade, he has studied bats in different parts of the country, mainly the Andaman Islands and the Himalayas of Uttarakhand.