Hidden wonders

From tiny pipistrelles to large flying foxes, India’s bat population is diverse. Here we feature one of the rarest large bat (Megachiroptera) species in the world endemic to the Indian Territory—the Salim Ali’s fruit bat (Latidens salimalii).

What are fruit bats?

Look out at the sky during the dusk wherever you are,  and you are likely to see large dark creatures flying across the sky. Of course, they are not birds, nor do they mean any harm; and all that they are seeking are plants: bananas, kokum (mangosteen), kapok, Bakul, haldu and kadamb trees for their nectar-rich flowers, and figs for their large, nutritious fruits. These large creatures lubberly flying across the evening sky are a type of fruit bats commonly called ‘flying foxes’. These are just one species of the globally known 166. While the flying foxes are the largest of the fruit bats and may have wingspans of more than a metre in length, there are also some smaller members in this group who scourge for fruits and nectar as much as their larger cousins. Strictly nocturnal as all bats are, fruit bats too spend their daytime resting, hanging upside -down from trees, crevices or caves, and their camps (colonies) may be hundreds of members strong!

Large in size, weak in their legs, a furry body, long fingers covered by an overarching thin membranous skin (which enables their flight), fruit bats might come across as helpless, odd creatures and not surprisingly, they have dominated our imagination for a long time. Their elongated mouths (snouts) and long protruding tongues help them access their food sources to the fullest. They move from a point on the tree to another with a unique upside-down crawl.

Given their excessive dependence of flowers and fruits, it is but obvious that fruit bats play a crucial role in pollinating and large-scale dispersal of seeds, thereby helping regeneration of forest ecosystems and affecting some 500 species of plants and trees.

For many readers, it may be surprising to know that of the many species of mammals found across the world, bats constitute one of the major taxa. In peninsular India alone, they make up for more than a quarter of the mammalian species. Despite this fact, it’s a paradox that these flying mammals are among the least known and often despised species. Much of the acrimony towards these maligned creatures is perhaps owed to their unaesthetic appearances and uncanny habits. Moreover, being nocturnal, they are not as well appreciated as other animals. To add to their woes, bats have always been depicted as vampires or evil creatures in novels and movies the world over.

Bats are broadly classified into two groups, megabats (Megachiroptera) and microbats (Microchiroptera). Megabats are usually large and live primarily in tropical regions. The megabats (fruit and pollen eating or nectar-feeding bats) have well-developed eyes and nose and hence use their eyesight and sense of smell to locate fruits and flowers. The microbats (insectivorous bats) are usually smaller than megabats and have small eyes but large ears. They primarily eat insects, lizards, rodents, fish and birds by tracking them through echolocation. Microbats constitute 70% of bat species while megabats constitute most of the remaining 30% species.

These creatures play a very important role in the ecology through pollination, seed dispersal and insect control. Their faecal droppings are known as “Guano”, which are highly rich in phosphorous and calcium apart from fungi and bacteria, making it one of the best organic fertilisers. However, in spite of their benefits, the fruit-eating bats are ill-reputed since they raid orchards and fruit yards occasionally and hence are labelled as vermin.

Right off the bat

In our quest to understand more about these creatures, we set out exploring many species in their natural environment in the last few years. While we surveyed and understood many kinds of bats primarily in the south Karnataka region, one species that caught our interest more than the rest was Salim Ali’s fruit bat (Latidens salimalii). Having started our study of natural history through birding, the name “Salim Ali” for a bat sounded curious. Furthermore, we wanted to understand why only this species of fruit bats enjoy legal protection in India while the others don’t.

During our study, we had the opportunity to interact with various experts on bats across India, including bat scientists Dr Sripati Khandula, from Madurai Kamraj University and Dr Balaji Chattopadhyay from National Centre for Biological Sciences (NCBS) along with Vinoth Kumar, the researcher from Madurai Kamraj University. Eventually, it led us to a trip down to Kardana Estate in Meghamalai Wildlife Sanctuary, which is one of the most well-known and oldest localities housing the Salim Ali’s fruit bats.

This Kardana estate lies within the Meghamalai wildlife Sanctuary along the Western Ghats and has both coffee and tea plantations, apart from other spices like black pepper and cardamom. The cave which hosts these bats lie within the ambit of this estate and the owners and staff have been protecting the cave. while in the past the estate workers were known to catch and consume these bats for their belief in their medicinal properties; ever since the staff has been educated in sessions conducted by various scientists and researchers, they have stopped the practice.

The cave which houses these endemic bats is in a valley sandwiched by two mountain ranges. A multitude of small streams cuts across the terrain forming breathtaking waterfalls along the path during the rains. The small streams amalgamate to form a bigger stream making its way into the valley, while the cave itself is concealed neatly by its pristine forest surroundings

The undulating terrain makes the cave virtually inaccessible, while the cave itself is not formed from a monolithic rock, but as a result of several rock-formations. Consequently, it is not tightly concealed and has openings through which natural light seeps in and into its inter-connected smaller caves. A small stream falls right into the cave and flows within before rejoining the mainstream. Salim Ali’s fruit bat prefers to roost in caves which have a high moisture content, are close to water (perennial) bodies and have cooler temperatures; hence protecting their natural habitat is crucial for their long-term survival. The cave houses around 150-200 bats in average, which indicates a reduction in numbers as compared to data obtained a decade back.

Characteristics and behaviour

On first look, these bats are often confused with Fulvous fruit bats which are similar in appearance. They are medium-sized fruit bats and as with most bats are sombre in hue, covered mostly in grey with some brownish tinges on wings and greyish-brown underparts. These frugivorous bats feed on berries and fruits. It is believed that these bats favour figs among other fruits and some of the trees include Ficus racemosa, Ficus beddomei, Elaeocarpus serratus. Compared to other fruit bats, the Salim Ali’s fruit bats prefer higher altitudes and broad-leaved moist evergreen forest biotype. Since they rely heavily on wild fruits, they play a key role in seed dispersal of various trees in a forest ecosystem. As a result, bats are integral to the regeneration of this moist evergreen biotype.

These bats usually have multiple roost sites, some being used only during the night while foraging, and others as both day and night roost. During the visit we observed these bats flying close to the gushing waterfall or through the slowly flowing water to absorb moisture and keep their body cool. Once their body was wet enough they would perch and clean themselves.

Battle for bats

While several species from other genera receive some form of protection from governing bodies, bats are among the neglected ones. Being labelled as vermin is perhaps one of the reasons for the step-motherly treatment towards these wonderful denizens of the natural world. Only two bats viz. Wroughton’s Free-tailed Bat (Otomops wroughtoni) categorised as critically endangered and the Salim Ali’s fruit bat (Latidens salimalii) categorised as endangered under IUCN red list, enjoy the protected status under the Schedule I of the Indian Wildlife (Protection) Act 1972, as per amendment in 2006

Bats, in general, are slaughtered and consumed for their alleged medicinal properties and Salim Ali’s fruit bats too face the same danger until the local community is educated about their conservation value.

We believe these bats could be existing in more locations across central and northern Western Ghats. Identification of more such locations is planned for not only accessing their status and distribution but also to ensure enough measures are taken to protect them. Two decades ago, Salim Ali’s fruit bats were known to exist only at one or two locations, primarily in the Kardana Estate and Highway Mountains. However, in-depth research and wider surveys in the last decade have resulted in identifying seven more roosting sites in the southern Western Ghats. Habitat loss and availability of suitable roosting sites are cited to hamper the population growth of these bats. These new locations helped scientists assess their latest population and distribution which contributed to their status being upgraded from “Critically endangered” to “endangered” in the IUCN Red list in 2004.

 

This is a joint article by Chaitra Ramaiah and Rajesh Puttaswamaiah originally published in April 2014 Issue of Saevus Magazine

Chaitra Ramaiah and Rajesh Puttaswamaiah are naturalists by passion and work in the software industry. Their notable documentation includes the breeding behaviour of Yellow-Throated Bulbuls and the commensalism behaviour between Short-Toed Snake Eagle and Indian Silver Bills during nesting season.

Read also: An enigma in white 

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