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The Mouse-tailed Bat lives in Delhi's ruins!

A survivalist: Mouse-tailed Bats Photo credit: Rohit Chakravarty  

From Count Dracula’s ability to command bats to the mythical association of vampires and bats being blood-suckers, the winged creatures have been feared across centuries. In truth, there are only a few bats (Vampire Bats) from the subfamily Desmodontinae that drink blood. Also, it’s possible that the bat as a bad omen is Western in origin.

Rohit Chakravarty — a close friend, bat-researcher, and Ph.D. student at the Leibniz Institute for Zoo and Wildlife Research, Berlin — studies bats in the Himalayas. He says that in some parts of India, bats are considered a good omen. In Rajasthan, the faeces of Mouse-tailed bats and Tomb bats were traditionally used to fertilize Mathania chillies that are used to make Rajasthan's signature dish, Laal Maans.

There is so much more to them than we understand, and their nocturnal behaviour adds to the mystery. While there are a few mammals like flying squirrels that glide or parachute, bats are the only mammals capable of a true flight, i.e. they can fly freely.

True to its name, Mouse-tailed Bats (from the Rhinopomatidae family) have mouse-like tails, long and slender in appearance. They often roost in ruins, caves, and forts. Considering the rich architectural heritage of Delhi-NCR, we find them in the ruins of Hauz Khas, Lodhi Gardens, Nizamuddin and several other areas that play host to their colonies.

The overall dry and hot climate of the city seems ideal for them to thrive as well. In general, they prefer arid and semi-arid regions in Southern Asia and Northern Africa.

According to bat researchers, bats may very well be one of the most vocal mammals, but these sounds are not audible to the human ear, apart from some screeches that are in the pitch range audible to us. Like most bats, they also make use of echolocation to hunt as well as avoid obstacles while flying.

Echolocation is a technique used by bats, shrews and several marine mammals, where they produce high-frequency sounds that bounce back to these bats in case of obstacles. These sounds also help them gauge the size of the object.

One thing the movies did get right was the typical behaviour in most bat species of hanging upside-down while roosting. Mouse-tailed Bats echolocate mostly nasally through their small triangular leaf-shaped nose called nose-leaf. Their bodies are covered with soft fur and are greyish to dark brown in colour.

Mouse-tailed Bats are primarily insectivores that remain active throughout the year but in winter, when insect availability is low, they often remain in torpor, a state of mental and physical inactivity. After the monsoon season, they start accumulating fat in their bodies to help them survive through dire winter.

In general, we find both the Greater Mouse-tailed Bat and the Lesser Mouse-tailed Bat in the city. There are subtle differences in size: the Lesser are smaller, and have a relatively longer tail in comparison to the Greater.

Mouse-tailed Bats Photo: Rohit Chakravarty

Mouse-tailed Bats Photo: Rohit Chakravarty  

In addition, the Lesser Mouse-tailed Bat has a distinct grey belly and tends to have more delicate feet than its larger cousin, according to the book Indian Mammals by Vivek Menon. They do share some common traits like roosting in colonies (can vary from a few individuals to thousands of them) and are typically characterised by a strong, pungent odour.

They are shy and elusive and have learnt to live with humans near their houses and still manage to go unnoticed for years. Besides the fact that they mean no harm, Mouse-tailed Bats feed on insects (beetles, moths) in flight, thus controlling their population.

According to references of credible scientists cited in the book Bats of the Indian Subcontinent by Paul J J Bates and David L Harrison, these bats have tongues highly adapted for insect feeding and can thus play an important role in curbing the population of insects that are harmful for crops.

Chakravarty says, “Bat researchers, all over the world, have repeatedly reaffirmed that COVID-19 doesn't spread from bats. A virus similar to the SARS-CoV-2 has been isolated from a species of bat (out of 1,400 species in the world!) and that virus does not infect humans to cause COVID-19. Recently, 150 Mouse-tailed Bats were killed in Rajasthan out of fear that they spread COVID-19.” These are important for the local economy and culture, he says.

The writer is the founder of NINOX - Owl About Nature, a nature-awareness initiative. He is the Delhi-NCR reviewer for Ebird, a Cornell University initiative, monitoring rare sightings of birds. He formerly led a programme of WWF India.


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Printable version | Aug 5, 2021 8:28:07 AM | https://www.thehindu.com/sci-tech/energy-and-environment/the-mouse-tailed-bat-lives-in-delhis-ruins/article31857645.ece

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