• Bats are usually given a wide berth. With the misinformation around COVID-19, they’re seen as carriers that can transmit horrible diseases to us. We just don’t seem to have a lot in common. Except perhaps, for our cities.
  • Research has shown that flying foxes exhibit some remarkable characteristics – allomaternal care or a mid-wife system, homosexuality, and are referenced as symbols of love in historical literature.
  • Bird watching in urban areas has proved to help citizens engage with their neighbourhood green spaces, and the same could be true for bats.
  • Urban planners need to incorporate ecological learning in their strategies to make space for bats in an increasingly transforming urban ecosystem.

Dusk settles over the city.

On cue, the sky brings out its colour palette. As deep oranges and reds take over, the day – with its creatures – shifts. It’s rush hour. Egrets and cormorants fly across, kites circle up and above until they don’t. Crows gather at rooftop tanks, planning little murders.

The skies empty.

In the canopy of the rain tree opposite my house in Mumbai, black upside-down shapes – appearing like large, rectangular fruits – begin to stir. Enormous, leathery wings unfurl among the branches, fanning the wind.

The hitherto quiet tree erupts with chatter – squeaks, and screeches that rapidly rise into a cacophony of noises. One by one, Indian flying foxes (Pteropus medius) fill the sky with their goliath wings, circling the trees around, leaving in groups or alone, some soaring high, some taking well-known routes, until the tree is silent. Sun’s out, the moon’s in. And like clockwork, the night shift begins.

A little over a year ago, I moved into a room that faced a roosting site of Indian flying foxes. It took me a while to notice them, conditioned, as I was to find colour among the leaves – the hues of the coppersmith, or the green of the parakeets. We habitually give bats a wide berth. They’re not conventionally beautiful, they’re associated with vampires and demons in popular culture, they claim the nights while we function through the day and their worldview is literally the polar opposite to ours.

A roosting site, a place where bats settle for rest or sleep, on a tree amidst buildings in Mumbai. Urban green spaces are vital as they host a variety of living organisms. Photo by Sejal Mehta.
A roosting site, a place where bats settle for rest or sleep, on a tree amidst buildings in Mumbai. Urban green spaces are vital as they host a variety of living organisms. Photo by Sejal Mehta.

There are over 1,400 species of bats worldwide. Over a third of bat species assessed by the International Union for Conservation of Nature (IUCN) are considered threatened or data deficient, and well over half of the species have unknown or decreasing population trends.

Predominantly, there are two types of bats – fruit bats and insectivorous. Other groups (by diet) include those that are carnivorous, nectarivorous (that don’t eat fruits but only sip nectar), and blood-feeding vampire bats.

India has a diverse population of bats; at least 128 species belonging to nine families. Out of the 14 fruit bat species in the country, there are five species of flying foxes, and only one of them – the Indian flying fox – is distributed throughout the mainland; the other four are in the Andamans. The Indian flying fox is the largest of all bats in the mainland.

Flying foxes get their name from their long snout and ears, which give them a fox-like appearance. Globally, they are distributed throughout the old world tropics (mainly on the continents of Asia, Australia, and Africa).

Now, with the misinformation on bats in relation to COVID-19, bats are seen as carriers that can transmit horrible diseases to us. We just don’t seem to have a lot in common. Except perhaps, for our cities. It would seem that like most creatures, safety and food would be primary factors in setting up home. Except for Salim Ali’s fruit bat, fruit bats are listed under Schedule V (the vermin category) of the Indian Wildlife Protection Act. Farmers consider them pests especially for commercial fruits like mangoes, guavas, grapes, and sapotas. In urban areas, this conflict does not arise. So, how do these creatures use our cities?

“Many species choose cities and make the most of urban opportunities,” said researcher Rohit Chakravarty. “Flying foxes, pipistrelles, short-nosed fruit bats, greater yellow house bats – all of these are commensal species, although more data is needed on how and if bats and humans benefit by living together in an urban area.”

Commensals are species that benefit from another species without causing either advantage or disadvantage to them.

“I’ve never seen these in forests or away from human settlements. They actively choose to live among people but we don’t know why,” said Chakravarty. “Insectivorous bats feed on pest insects while fruit bats eat fruits and disperse their seeds (in strictly urban areas, seed dispersal by fruit bats may not be very beneficial because the seeds land on concrete where they can’t germinate).”

But there are other benefits – they’re marvellous subjects to observe.

Built for… anything

Over the year, I have been gobsmacked at how their bodies are designed to navigate spaces. Baheerathan Murugavel, who has been researching behavioural aspects of flying foxes for the past six years said, “Bats suspend their entire body weight from their toes and claws. They use a tendon-locking mechanism just like birds of prey, as long as they are hanging. The lock releases once the bat takes flight enabling them to “uncling” and take off. There is no muscle energy required for this process, it’s all in the hook of the claw; this is why you see bats hanging on branches even after they’re dead.”

That explains how they hold on like pendulums as Mumbai’s legendary monsoon beats down on them. Their wings switch roles according to the season – in the monsoon, they bring out their waterproofing tools, by secreting oily sebum from sebaceous glands. This forms a protective layer that acts like a raincoat against the watery onslaught. In the summer, these bats fan their wings to keep cool (this activity is the most common to spot) and in winter, the same wings trap heat tightly around the body.

Bats are the only mammals with true flight and flying foxes of the genus Pteropus comprise some of the largest of all bats, providing an easy opportunity for us to include them in our idea of watching nature, and understand that they’re not actively trying to kill us. In that, to also acknowledge that not all bats are the same.

An Indian flying fox feeds on a fruit on the streets of Mumbai. They are the largest of all bats in mainland India and have historically coexisted in human-dominated areas. Photo by Sarang Naik.

Different species, different habits

“The RatG13 virus – somewhat similar to the COVID-19 virus – was isolated from one out of the 1421 species of bats but hatred spread against all species just like with the current outbreak,” said Murugavel. “There are only three species of vampire bats in the world and all of them are in parts of Central/South America and no, they do not attack humans for their blood. Each species has its own story to tell.”

Indeed. Although nocturnal, since they forage in the night, my neighbours have obliterated the daytime slumber myth. Flying foxes are the only bats that spend their daytime fully exposed to daylight, said Murugavel. “This could mean exposure to disturbance and attacks by daytime predators, rendering it vital to keep awake during the day. This is still speculation, there’s much research left to do to fully understand this.”

As it is with their calls. Flying foxes are loud. Imagine a concert crowd welcoming its favourite artist. Now imagine living next to that crowd. If they’re awake, they’re chattering. “Insectivorous bats are actually much louder, thankfully we can’t hear them because they call in the ultrasound. Echolocating bats typically call at about 70-80 decibels, which sounds like a firecracker,” said Chakravarty. But flying foxes (almost all fruit bats) are non-echolocating and predominantly rely on their eyes and sense of smell for navigation and food. And while research on the vocalisations of a different cave-dwelling fruit bat species confirms their ability to learn dialects from their roost mates, flying foxes appear to use vocalisations for mother-pup interactions and to navigate the roost life, so to speak. Their language is yet unknown.

Of new mothers, mid-wives and pup crèches

Bats move upright only during delivery (and excretion). Mothers fly with their new-born pups for the first few weeks, even until they’re one-third of their body weight, after which they park them at different places before foraging forays. They return to pick them up in the mornings, from a baby bat crèche so to speak.

A tree with numerous flying foxes – like most sites you’ll see – is likely to be a colony, which remains loyal to a site for years. “While it is still uncertain if they’re related, some preliminary evidence suggests there is a rank hierarchy in the males,” said Murugavel.

But it’s the revelation of allomaternal care or in simple terms “mid-wives” in the bat world that has me doing mental cartwheels. “It has been observed that experienced, ‘helper’ females of the Rodrigues flying fox, endemic to the eponymous island in the Indian ocean, help new mothers give birth, even imitating vaginal cramps in front of the delivering female to assist her in a smooth birth,” Murugavel said.

A colony of Indian flying fox. Flying foxes are the only bats that spend their daytime fully exposed to daylight, making them easier to observe along with biodiversity such as birds. Photo by Harshjeet Singh Bal/Flickr.
A colony of Indian flying fox. Flying foxes are the only bats that spend their daytime fully exposed to daylight, making them easier to observe along with biodiversity such as birds. Photo by Harshjeet Singh Bal/Flickr.

Symbol of love, not of evil

Women supporting women aside, this seemingly outlandish animal is more relatable than we would have thought. More inclusive, even. According to this recent paper, apart from a small number of primate species, the Indian flying fox appears to be unique in the animal world in practicing oral sex as well as homosexual acts, “the utility of which appear to have generated considerable discussion with no understanding yet as to why bats might engage in such sexual behaviour (Kunz & Hosken 2009).”

Love forms a large part of their narrative. They appear in multiple references in Tamil Sangam literature (~2000 years old) as symbols of love, not evil or scary. One poem (from a book named Nattrinai), describes the sorrow of a woman who misses her husband. She observes the flight of bats leaving their roost, drawing comparisons to her husband’s unfulfilled promise to return home.

These fascinating animals live around us. While scientists continue their research on them, citizens could probably include them in our observations of the cities we inhabit, just like we do with birds and marine creatures. It might remind us that we’ve lived with them disease-free for longer than we’ve been afraid of them infecting us. Chakravarty added, “The best way to deal with them is to let them be, avoid eating fallen fruits with bite marks (contact with the saliva of any animal can cause infections) and keep our pets and ourselves away from their faeces.”

Bird watching in urban areas has proved to help citizens engage with their neighbourhood green spaces, and the same could be true for bats. Shweta Wagh, Assistant Professor at Kamla Raheja Vidyanidhi Institute for Architecture and Environmental Studies and co-founder at Collective for Spatial Alternatives, said, “New constructions or infrastructure projects are increasingly transforming diverse urban neighbourhoods that have been historically conducive to wildlife. Historic buildings and older building societies with plenty of indigenous, old-growth trees and groves ensured that various creatures, including bats, bees, and birds could share that space.”

“While development control regulations for new constructions often make it mandatory to plant a minimum number of trees, this does not factor in the kind of trees that have ecological value or support wildlife. For example, ecologically important trees including fishtail palms, ficus species like peepul or banyan, etc. that facilitate food and pollination are often chopped down to plant a small patch of supari trees, which will not perform those supportive roles. Urban planners need to incorporate ecological learning in their strategies,” Wagh expanded.

Indian flying fox feed on fruits and nectar and are declared as vermin under the Wildlife Protection Act. Protecting existing urban green spaces is important to conserve these animals. Photo by Manojiritty/Wikimedia Commons.

In the last year, I have watched these flying foxes share this urban space: a rain tree at a busy hospital intersection with buildings all around and wires (which they sometimes choose over trees to hang from) crisscrossing above the canopies. It’s made me curious about rain trees and realised they don’t roost where they eat, but love chickoo trees to have dinner at. Due to my increased immobility from lockdown, I know when they leave the roost, when they return in the morning, at what time the sun illuminates their rust to golden. I have read about roosting sites being chopped down out of fear, and worry about their incessant chatter; it might give someone one more reason to drive them away. They’re familiar to me now, neighbours almost.

As Murugavel said, “From an urban ecology perspective, they are an indication of how the sparse natural vegetation still feeds and sustains such large plant-dependent wildlife. I would see them as a constant reminder that we are just a single node in a big ecological network that comprises all forms of organisms coexisting together on this planet.”

Going forward, recognising how different species use urban areas might be the only way to sustainable cities.

As for these giants of the sky, they stick to their corners, their females support females, they’re sexually experimental and inspire regional poetry.

What’s not to love?

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Banner image: An Indian flying fox, one of the 14 fruit bat species in India, takes off from its roost in Mumbai. Photo by Sejal Mehta.

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