Sounds of the Midnight Jungle

loading Sunda colugo.

A recent discovery on Penang Hill has scientists and primatologists squeaking with excitement.

Priscillia Miard.

When a team of scientists went hiking at night along The Habitat Penang Hill's trail to survey for bats, they sensed something very different on their ultrasound microphones. They picked up an unusual call – one unlike anything they were familiar with.

Searching for more clues, they tracked the sound to a Sunda colugo (Galeopterus variegatus) clinging on a tree trunk just a few metres away. The Sunda colugo, a nocturnal mammal which glides between trees, is in fact widespread in Malaysia but poorly studied or understood. Till very recently it was assumed that the colugo only communicated using audible sounds, but further ultrasound colugo recordings by the same team in the Penang Botanic Gardens confirmed that the arboreal mammal did indeed use ultrasound.

According to Priscillia Miard, a young primatologist and a PhD candidate studying nocturnal mammals at Universiti Sains Malaysia (USM), the ultrasound colugo calls recorded on Penang Hill were indeed impressive because such behaviour has never been recorded from the animal before. Unlike bats, tarsiers and slow lorises which also communicate using ultrasound, colugo calls are characterised by a distinct wavy pattern of multiple peaks for each pulse.

"What are you looking at?"

Miard was part of the 117-member team of international scientists and students who scoured the lush forests of Penang Hill to study its biodiversity during the 2017 Penang Hill BioBlitz, and made the exciting find. The surveys were organized by The Habitat Penang Hill, The Habitat Foundation, Penang Hill Corporation and key government agencies with the participation of scientists mainly from USM and the California Academy of Sciences.

She is currently spearheading a study on ultrasound use by colugos with a research grant from The Habitat Foundation. Concurrently, she also runs her own community outreach programme called the “Night Spotting Project”, where she ropes in the public to join her on night walks to spot and tally nocturnal mammals. One of the key areas she focuses on through the programme is raising awareness among people, especially farmers, about the importance of colugos to the ecosystem and their crops.

This finding on colugo ultrasound communication was recently published in an international scientific journal, Bioacoustics, and Miard is optimistic about the discovery as it will open the door for future studies on the social behaviour of nocturnal mammals. “On one occasion when we recorded colugo ultrasound, we could see only two individuals but could count at least 11 different individuals in the area making ultrasound,” she says. This also seems to show that these creatures, which were once believed to be solitary, actually live in groups.

Miard and her team are exploring the purpose of these ultrasound calls. From preliminary observations, it seems that the calls are produced only when human presence in the vicinity is detected by the colugos. This suggests that it could be a danger or alarm call, but there may be instances where these calls function potentially as territorial vocalisations or contact calls, she adds. With a better grasp of social behaviour, population size and distribution, primatologists like Miard can use this information to identify important habitats for protection.

Miard conducting a night walk with members of the public at The Habitat Penang Hill. As part of her community outreach programme, the Night Spotting Project, she seeks to raise awareness about nocturnal mammals.

Part of the 117-member team of international scientists and students who participated in the 2017 Penang Hill BioBlitz.

View of the 230m-long Langur Way Canopy Walk.

More importantly, this discovery shows the importance of Penang Hill, not just as a green lung and a water catchment area, but also as a regional biodiversity hub, possessing rich flora and fauna where local and international scientists can come to conduct ecological studies. And this goes in line with the current bid to nominate Penang Hill as a Unesco Man and the Biosphere Reserve. The Biosphere initiative, helmed by the Penang state government in collaboration with the Ministry of Natural Resources and Environment (NRE), seeks to recognise Penang Hill not just as a diverse and unique ecosystem, but also as one that has a rich human landscape, coexisting with nature.

It is also a culmination of the vision of the Cockrell family, who established The Habitat, to enable people to connect with the forests of Penang Hill and to generate support for biodiversity and environmental conservation causes through The Habitat Foundation. The 2017 Penang Hill Bioblitz was one of the first steps in that direction. It enabled a comprehensive whole forest biodiversity survey, where creatures from the bottom to the top were surveyed and documented. Over 1,700 species of flora and fauna were listed over this period; so far, four species are considered new to science, and many more discoveries are expected to emerge in the coming months as scientists confirm taxonomic findings in their respective labs.

On top of that, Penang Hill is easily accessible to scientists and researchers who can bring in new technology, aiding research into animal behaviour and paving the way for more discoveries. This can then deepen our understanding of forest ecology and lead to more targeted conservation efforts.

During the 2017 BioBlitz, students had the opportunity to learn alongside world-renowned scientists and researchers.

Work is currently underway to prepare a dossier for the Biosphere listing. Once successfully designated, Penang Hill will join 670 other reserves around the world and function to conserve biodiversity, promote sustainability and act as a place to conduct research and monitoring. Public engagement is an important component of the nomination and the biodiversity assessment has been followed by dialogues and meeting with local stakeholders to promote a clear understanding of what the Biosphere entails and elaborate the means through which local people can be actively involved.

It is hoped that this listing will pave the way for Penang Hill to be established as an internationally recognised centre of research into rainforest diversity and ecology, as well as raise awareness among locals about the need to conserve our natural heritage.

Rexy Prakash Chacko is an electronic engineer by profession and a nature lover by passion. While he spends his weekdays earning a living at the Bayan Lepas Free Trade Zone, his weekends are spent reflecting and recharging on the green hills of Penang.



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