Environment

Amid COVID-19, let’s not forget how bats help our environment

Yellow house bat

Yellow house bat   | Photo Credit: Rohan Chakravarty (Green Humour)

They are pollinators, seed dispensers, pest controllers and do a lot for the spaces we inhabit. Unfortunately, most of us are unaware of it

Let us get two things straight.

One: So far, there is no evidence that bats are carriers of SARS-CoV-2, the virus that causes COVID-19. Because, “The current pandemic virus, SARS-CoV-2 has not been identified in any bat species, to date.”

Two: Of the thousands of bat species around the world, only one — the intermediate horseshoe bat — is linked to COVID-19, that too indirectly. And the chances of you finding a horseshoe bat in your urban or rural household are supremely slim, for these bats do not venture near human habitations.

According to scientists, the journey of the virus from this bat to humans was a convoluted one, with genetic drifts and the possible interaction of other creatures in between. A journey they are still trying to trace. “We do not know the natural host of the virus. It is therefore unlikely at the moment that bats pose any threats to humans with regards to SARS-CoV-2.”

Fruit bat pup

Fruit bat pup   | Photo Credit: Devna Arora

Both the statements quoted above are by Aaron Irving, a senior research fellow working on bat diseases at the DUKE-NUS Medical School in Singapore. He adds, via email, “The intermediate horseshoe bat is linked to a bat CoV (coronavirus) called RaTG13 that is 96.2% the same as SARS-CoV-2. There is some genetic distance between this virus and SARS-CoV-2, so even then this bat species is not directly linked to COVID-19 (but it is linked more closely than other bat species).”

Aaron is not the only one constantly having to come to the defence of bats ever since the pandemic began. “I definitely have a bat right now, in my own house, hiding somewhere in a pipeline or a crack in a wall,” says Rohit Chakravarty, sounding unconcerned about it. The chiropterologist, pursuing his PhD at Leibniz Institute for Zoo and Wildlife Research, Berlin, has been spending the COVID-19 lockdown in his hometown Nagpur, making similar statements in defence of bats on podcasts, phone interviews and emails. Like Aaron and Rohit, conservationists and chiropterologists across the continent and beyond are finding themselves having to battle a flood of fear and misinformation.

Like elves in the night
  • Bats like the short-nosed fruit bat and Leschenault’s rousette don’t feed off or damage the mahua (iluppai tree).
  • In fact, they pollinate its flowers and disperse its seeds.
  • The flowers, which are dull in colour, bloom at night and emit a strong scent, seem poised to attract nocturnal creatures like bats

Says Rohit, “There are 1,400 species of bats around the world, and 128 in India. The most common ones that people see in India are the large Common Indian flying fox, the short-nosed fruit bat (half the size of flying fox), and pipistrelles which are very small, five to six-gram bats. In fact, my brother’s dog found a pipistrelle in our house just the other day.”

Most of these bats feed on fruit, while the pipistrelle eats flies, mosquitos and moths. “So we have nothing to fear from any of these,” he reiterates, though he does suggest people avoid bat colonies because of the chance of fungal infections “just like you would get from pigeon faeces, or from the droppings of other animals.”

Indian flying fox with fruit

Indian flying fox with fruit   | Photo Credit: Rajesh Puttaswamaiah

Integral to Nature

Chiropterologists are used to busting urban legends and prejudice against bats, but the surge of it amid the COVID-19 outbreak has been so strong that they felt the need for direct action. In April, as many as 64 conservationists, chiropterologists, and even experts in transdisciplinary health sciences from across South Asia put out a joint statement to expressly state that, among other things, “The exact origin of SARS-CoV-2 or its precursor is not known. It is premature and unfair to blame bats or any other animal for the pandemic.”

The statement came after a study by the Indian Council of Medical Research found cases of bat coronaviruses in two Indian bat species. The detailed report did state that this BtCoV is very distantly related to SARS-CoV-2. But, unsurprisingly, a hurried reading and much panic ensued. Moreover, “less than 5% of the screened samples contained this BtCoV,” points out the South Asian Scientists and Conservationists’ statement.

Much ado, for a reason

If you are wondering why you should care, it is because many aspects of our environment — from rice plantations to mangroves to even the mahua tree — are dependent on bats. They are pollinators, seed dispersers and pest controllers that do a lot for the spaces we inhabit, but unfortunately most of us do not know it.

Sights and sounds
  • Bats are not blind, they just prefer echolocation to sight because it is easier and faster in the darkness.
  • Echolocation is the process of using ultrasound and its echoes (instead of rays of light) to gauge where objects are placed and of what size they are.
  • Bats use it to navigate their routes, find foods such as insects, and even objects as fine as the human hair.

In fact, most of us hardly even noticed bats before this lockdown, when we spent more time on our terraces and balconies, looking at the late-night skies. But lately, suddenly, bats seem to be everywhere. “I wouldn’t say that bat numbers have increased at all; I think that people are noticing them more because of the lockdown. When people claim that they have never seen bats around their homes before, that cannot be true. Bats are everywhere. In fact, this is the time when the population of bats like the flying fox — the big fruit bats that you see on trees — actually drops, because they are very susceptible to getting dehydrated. In summer, when temperatures cross 44 or 43 degrees Celsius, they just start dying off. They cannot take the heat,” explains Rohit.

And no, despite all the urban myths you have heard, they are not going to claw at your eyes or get entangled in your hair.

“Most of the urban populace takes some time to cross the barrier from superstition to Science,” says Rohit, adding, “The people of Northeast India, and the tribes in the Andamans, are extremely aware of bats. They don’t know the scientific names of species, but they know a lot about bats’ natural history. For example, my field assistant Saw Isaac, when I was in the Andamans in late 2013, knew exactly where to look for bats. Whenever we walked through the forest, he would look into tree holes and look for incisions in bamboos, where bats roost.”

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Printable version | May 31, 2020 9:47:06 AM | https://www.thehindu.com/sci-tech/energy-and-environment/amid-covid-19-lets-not-forget-how-bats-help-our-environment/article31566072.ece

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