My eyes gleamed when I heard that and rushed for the bats which were hanging in cloth bags. I gently rubbed my fingers on the outside of all the bags and picked the one with the smallest bat. I delicately removed the bat, holding it with just the tips of my first three fingers. This was no ordinary bat. Its head was flat as if slammed with a shoe! It had suction pads on its thumb and toes to help it cling and sleep inside thin, hollow bamboo culms. The bat in my hand was an evolutionary marvel. The Lesser Bamboo Bat (Tylonycteris pachypus) marked the beginning of a successful night. After it eight other species flew into our nets in quick succession. Borneo was beginning to justify itself as a naturalist’s dream destination.
In August 2015, I was in Sarawak to attend the 3rd Southeast Asian Bat Conference organized by Universiti Malaysia (UNIMAS), Sarawak and Southeast Asian Bat Conservation Research Unit (SEABCRU). After four intense days of talks, discussions and workshops with the most renowned bat biologists of the world, we were off to a bat lover’s ultimate pilgrimage – Gunung Mulu National Park.
Southeast Asia is one the hottest biodiversity hotspots in the world and Borneo – the third largest island in the world – is the jewel in its crown. The World Wide Fund for Nature (WWF) estimates that more than 220 species of mammals, 420 species of birds, 200 reptiles and amphibians and close to 400 species of fish are found in Borneo. A part of this staggering diversity comprises iconic, threatened species like Bornean Orangutan, Bornean Pygmy Elephant, Proboscis Monkey and Hose’s Palm Civet which are found nowhere else on earth. Eight species of hornbills occur here and on their account, the state of Sarawak in Malayasian Borneo derives its apt title – Bumi Kenyalang – The Land of the Hornbills. However, unbeknown to many, the major contributors to the mammalian diversity of this incredible island are bats. With roughly 90 species, bats make up about 40% of all the mammals found in Borneo. Once you set foot on Gunung Mulu National Park, you know why.
Gunung Mulu National Park and a UNESCO World Heritage Site is the most spectacular landscape that I have seen. 20 million years ago, this stunning forest was an underwater mountain. Five million years ago, tectonic activity brought the mountain above water and what one sees today is lush-green rainforest criss-crossed by rain-fed rivers through which emerge jagged limestone mountains that give Mulu its unique pre-historic ambience. When rainwater touches upon limestone it dissolves the rock to form caves. On account of the undulating limestone hills and the heavy rainfall that Mulu receives, it has countless cave systems. Such is the vastness of this pristine and rugged limestone forest that it took 15 months and 115 scientists of the Royal Geographic Society, UK to map its topography in 1977-78!
We arrived in Mulu in the afternoon on 18 August 2015. Our plan was to assist the team of student-researchers from UNIMAS in their study on bats of Mulu. On our arrival, Ellen McArthur, a masters’ student who was working on the bats of Mulu greeted us with the delightful news that she had found something special for us during her routine morning reconnaissance. I whiled away my time watching birds and a hungry Prevost’s Squirrel gorging on leaves at the canopy until it was time to go bat hunting with Ellen. Ellen led us to the nature trail and after barely walking a kilometer she stopped abruptly in front of a wild turmeric plant. Neatly hidden inside a young, rolled-up leaf of the turmeric was a tiny bat. It was a bat high up on my wishlist – the Hardwicke’s Woolly Bat (Kerivoula hardwickii). This is a diminutive bat, hardly weighing 3-4 g. Its body is densely covered with sooty-black woolly hair. What makes this bat sui generis is its recently-discovered symbiotic association with a carnivorous pitcher plant. In the nutrient-poor peat swamp forests of Borneo, the pitcher plant Nepenthes hemesleyana has evolved to attract these bats into its pitcher. However, the plant does not eat the bat; it provides lodging and the bat pays its rent by feeding the plant with its nitrogen-rich droppings! Hardwicke’s Woolly Bats are also the supreme sopranos of the animal world. Their ultrasonic calls start at 250 kHz – that’s 12 times higher than what we can hear!
The following evening I had a date with a glorious phenomenon in nature; one that I had, hitherto, only seen on television. At 3.30 pm, a crowd assembled at the ‘Bat Observatory’ outside Deer Cave. Deer Cave—the largest cave chamber in the world—is home to an estimated three million Wrinkle-lipped Bats (Chaerephon plicatus). As dusk approached, the anticipation was building up at the observatory. I saw a handsome Bat Hawk perched on a vantage point, its eyes fixed at the cave. Suddenly there was a cheer from the audience; the bats had begun to emerge en masse. One after the other, groups of bats flew out of the cave in perfect synchrony like a flock of starlings. Each group formed a different pattern in the sky – ribbons, waves, ‘S’ and even a moustache! It was time for the Bat Hawk to get active and it launched its first successful strike in the middle of the bat group. At the mouth of the cave, I also briefly saw a large eagle, probably a Wallace’s Hawk Eagle trying to intercept emerging bats. I had watched this phenomenon in the television many years ago (even before I got interested in bats) but to see the drama unfold before my eyes was a dream-come-true.
On our last night in Mulu we beefed up our efforts to catch bats. A mistnet (a thin nylon net used to catch birds and bats for research) was spread on a bridge over a river. An ingenious trap called ‘harp trap’ was set up at a forest trail. This trap has metal frames with fine plastic strings stretched to full tension and placed in parallel rows as in a harp (hence the name). The frame sits on four legs and a collection bag is placed at its base to allow a safe landing for bats that hit the strings. The bats are then picked up from the bag to be identified. Harp traps are particularly effective for strict forest-dwelling bats that often detect mistnets through their ultrasound. One of us was also deployed with a hand-held hoop net to catch bats flying in the open air. Ours was a truly global bat trapping team with representation from 9 countries! We caught a lot of interesting species that night. Our mistnets were full of Wrinkle-lipped Bats that love feeding over wide rivers. They are the most gentle and docile of all bats that I have handled. A not-so-docile bat was the one caught in the hoop net by my Hungarian friend, Tamas Görföl – a Diadem’s Leaf-nosed Bat (Hipposideros diadema). This is a large bat that typically hawks insects in forest clearings. Its body is a rich beige or orange with characteristic white patches on the flanks. At the harp trap we caught the Cantor’s (H. galeritus) and Fawn Leaf-nosed Bats (H. cervinus) and my favourite, the Large-eared Horseshoe bat (Rhinolophus philippinensis). This is a species of dense forests. It has large leaf-shaped ears and a peculiar nose that emerges like a unicorn’s horn. Back at the base, another team had caught a pretty Spotted-winged Fruit Bat (Balionycteris maculata) – a small and timid black bat with chicken pox-like spots on its wings. The best, however, was saved for the last, the miniscule Least Woolly Bat (Kerivoula minuta) which is so tiny that when Tigga Kingston—a leading bat biologist—passed it on to me, she said, “Be careful, you’ll have to hold it like a grain of salt!” A strict inhabitant of primary forests, habitat destruction, unfortunately, has put the Least Woolly Bat in the threatened category.
On the flight back to Kuching, I was reflecting on the immensely thrilling and educative days spent in Mulu. My thoughts were distracted by the sight of a bald patch in the middle of verdant rainforest. There are several threats that bats face globally. Deforestation impacts forest-dwelling bats while granite mining affects cave-roosting species. Recent studies claim that windmills kill more bats annually than anything else and more research is likely to come up with grimmer results. Our own personal attitudes that stem from superstitious beliefs and myths do not allow us to appreciate the crucial role that bats play in the ecosystem. In Southeast Asia, hunting and destruction of vast swathes of prime rainforest are the single biggest threat to bats. In recent years, ever-increasing logging and oil palm plantations have ravaged the magnificent Southeast Asian rainforests with catastrophic impacts on Orangutans, elephants, bats and even its indigenous tribes. It would be mankind’s greatest disaster if a 140 million year old rainforest were to be imperiled by our lifestyle choices and political negligence.
Note: An edited version of this article was published in Sanctuary Asia in August 2017.