Nature’s unsung heroes

Did you know that our country has 130 species of bats, out of which, 66 are found in Meghalaya, including the critically endangered species, Wroughton’s free-tailed bat?

Dr. Uttam Saikia, scientist and bat specialist, with the Zoological Survey of Shillong, shares his insight on this much feared and maligned species.

By day the bat is cousin to the mouse.

He likes the attic of an aging house.

His fingers make a hat about his head.

His pulse beat is so slow we think him dead.

He loops in crazy figures half the night

Among the trees that face the corner light.

But when he brushes up against a screen,

We are afraid of what our eyes have seen:

For something is amiss or out of place

The above poem by famous American poet Theodore Roethke succinctly summarizes the imagination of the common man about bats. Amongst the most ubiquitous and numerous mammals, bats comprise over 1400 species worldwide. They can be found anywhere in the world, except the Polar region and certain oceanic islands. Among mammals, they are unique, having the capacity of true flight (others like flying squirrels, flying lemurs are actually gliders). Another surprising character trait that bats exhibit is that most species (excluding fruit eating larger bats) hunt or orient by using pulses of very high frequency sound waves, a technique known as echolocation. Echolocation works on the same principle as SONAR which is used to detect underwater objects by ships. As discussed in the following sections, bats are also one of the most beneficial groups of mammals, crucial for maintaining the health of our ecosystem and human health. Unfortunately, our perspective of them is marred with superstitious beliefs. Let’s try to dispel some of these myths.

India has, not less than 130 species of bats and Meghalaya holds a special place in this regard, out of these, 66 are found here, and constitute less than 1% of the total geographic area of the country. One of the primary determinants of this huge bat diversity is the availability of roosting sites in the form of caves and caverns that the state hosts in abundance.

Bat species of Meghalaya

Zoologists have grouped bats into several families – out of the nine bat families found in India, eight come from Meghalaya. All the relatively larger and fruit eating bats are grouped under the family Pteropodidae, of which, species like the Indian Flying Fox, Fulvous Fruit Bat, Short-nosed Fruit Bat and Dawn Bat are commonly found in the state. These bats feed on plant matters like fruits, buds and nectar. Fruit bats can be identified by their large eyes which aid in night navigation. Another group of bats called “false vampire bats” occur in Meghalaya which are curiously carnivorous in habit, preying on frogs, rodents, lizards etc. Normally seen in groups in abandoned houses, sheds etc, these bats can be identified from their large jointed ears and typical facial features i.e., having an erect conical nose leaf. Unlike the true vampire bats of South America, they do not feed on the animals.

A very significant population of a critically endangered bat species called Wroughton’s free-tailed bat belong to a group called “free-tailed bats”. They are striking looking – glossy dark brown with greyish one cave in Karnataka was thought to hold the entire population of this highly protected species. But now, a few caves in the Jaintia Hills are reported to hold breeding colonies of this species which in itself, is a matter of pride to the state.

Two very distinctive groups of bats called horseshoe and leaf-nosed bats occur in plentiful in the caves of Meghalaya. These bats can be told apart by horseshoe-shaped or leaf-like facial structures, that probably aid in echolocation. At least fifteen species of horseshoe and leaf-nosed bats are known to occur in the state. The most common and diverse group of bats in the state are known as “evening bats” with at least twenty-six species. They can be found in all sorts of habitats like caves, in anthropogenic environment, in primary forests etc.

The most frequently occurring among these bats around our village dwellings are called Pipistrelles which are invariably found in the thatch roof of houses, bamboo poles or any cramped space in the roof. However, some of the evening bats have specialized roosting preference like the bamboo bats, that only roost inside bamboo internodes. Development of disk like pads in the feet, skeletal modifications like flattened skull etc., aid in their peculiar living habit. An interesting disk-footed bat from the periphery of Nongkhyllem Wildlife Sanctuary have recently been reported; not earlier known to occur in South Asia. There are some evening bat species which typically occur in forests, like the Tube-nosed bats. These small yet colourful bats have very distinctive protruding nostrils and two new species were discovered from Meghalaya.

Know your Facts

The environment around us is maintained through an intricate balance of functioning of all living organisms, however small. Bats are no exception and their role in maintaining the health of the ecosystem cannot be overemphasized. There is no dearth of scientific evidence in this regard. Insect eating bats are mainly responsible for controlling bursting population of insects; many of which are responsible for crop damage. Many are vectors of human diseases too. Although economic quantification of bat’s services to human economy has never been attempted in India, the figures are staggering for a few studies abroad; recent evidences are emerging. These show that common bats like Pipistrelles are responsible for the control of some major pests of crops like cotton, wheat etc.

Another often underestimated, yet extremely significant service rendered by bats are in pollination and seed dispersal of many ecologically significant plants. Till now, over 500 plant species are known to be pollinated by bats. Many are economically important trees like agave, banana, guava, mango, and silk cotton. Through seed dispersal, bats help in the regeneration of forest. Likewise, bats are also important for human health. Contrary to the hype linking bats to all sorts of infectious diseases, including the current Covid pandemic, they are in fact crucial agents for controlling vector borne diseases. Without bats silently eating mosquitos, the menace of malaria and dengue would have been far greater. No doubt, bats do harbour many kinds of viruses, but so do other animal groups which has not been investigated in detail. Many of the bat borne viruses are innocuous and do not possess any human health hazard.

The only diseases that have definitely been attributed to bats are human Rabies and Nipah. Although known in Europe and America, there is no documented bat transmitted human rabies cases in South Asia so far. An overwhelming majority of human rabies cases in the world are transmitted by dogs. And unlike a rabid dog, a rabid bat will never attack humans. Nipah is a fatal viral encephalopathy that caused a recent outbreak in Kerala in 2018. Fruit bats like flying fox are known reservoir of this virus which is often transmitted to people via consumption of date palm sap contaminated with virus. That said, only a little minority of these bats might carry this virus, otherwise instances of people getting these diseases would have been numerous since flying foxes are a very common bat throughout India.

Can we protect them?

Bats are considered as one of the most threatened mammalian groups on Earth. They are existentially threatened by all sorts of human action – loss of roosting places, loss of feeding grounds, persecution and mass killings out of ignorance. From Manipur recently, came reports of thousands of bats being culled by locals to make a cave site, tourist friendly. Tragically, except for two species, bats are not legally protected by laws in India.

In Meghalaya, especially in the Jaintia Hills, hunting bats for bushmeat is a common practice which has decimated large bat populations in many of the well-known bat caves. It must be stressed that the positive role of bats far outweigh any negative roles that they might play. We must not harm them under false beliefs. A very positive development in this regard is the notification of a forest patch in Pynurkba in Jaintia Hills as Community Forest, exclusively for the protection of endangered Wroughton’s free-tailed bats.

The effort of the officials from Meghalaya Forest department and village community is praiseworthy for making this happen – possibly the second protected area in India dedicated for bat conservation.

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