Kalong Facts and Threats: The Malayan Flying Fox Under Siege

Estimated reading time: 11 minutes

In this article, learn about the kalong, also known as the Malayan flying fox, large flying fox, Malaysian flying fox, or giant fruit bat – ethereal creatures of the tropical Asian night. Famous for their massive 1.7 metre wingspans, they are the largest bats in the world and glide silently through moonlit forests.

Their fox-like almond-shaped eyes and expressive faces are framed by glossy black fur and golden-russet collars. These features give Kalongs a warm and almost mythical aura. Meanwhile their immense wings are awe-inspiring to see in flight.

These nocturnal giants are the architects of tropical forests, scattering seeds and pollinating flowers as they travel across vast landscapes. Sadly, kalongs are under siege, hunted mercilessly and displaced by mangroves, lowland forests, and coastal trees that vanish for timber, shrimp farms, and especially palm oil plantations. This article explores what a kalong is, Malayan flying fox habitat, behaviour, diet, reproduction, and the threats pushing this giant fruit bat deeper into danger across South and Southeast Asia. In conclusion, protect the guardians of the night before it is too late. #BoycottPalmOil #Boycott4Wildlife

Malayan Flying Fox Pteropus vampyrus

IUCN Red List Status: Endangered

Location: The Malayan Flying Fox is found across South and Southeast Asia, including India, Sri Lanka, Myanmar, Thailand, Cambodia, Laos, Vietnam, Malaysia, Indonesia, and the Philippines.

Appearance and behaviour

The Malayan Flying Fox is a marvel of the natural world, both striking and otherworldly. Their velvety fur ranges from glossy black to a rich reddish-gold that glows in the dappled sunlight of their treetop roosts. Their expansive wings, often veined and translucent, are masterpieces of natural engineering, allowing them to soar effortlessly, sometimes for over 50 km in a single night. Weighing between 0.65 and 1.1 kilograms, they are among the largest bat species in the world.

Their glossy, woolly fur varies between individuals and ages, with mature males often sporting thicker, slightly stiffer coats. Colouration ranges from mahogany-red and orange-ochre on the head to chocolate-brown and silver tinges on their undersides. Their golden or orange mantles form a regal collar. By contrast, immature bats are duller, with greyish-brown hues that brighten as they age. They have no tail, and their fox-like faces, complete with pointed ears, add to their unique charm.

The Malayan Flying Fox’s haunting, intelligent eyes seem to observe the world with a quiet wisdom, reflecting their keen reliance on sight over echolocation. In their colonies—sometimes numbering tens of thousands—they are lively, social creatures.

Their wing membranes, mostly hairless, are rounded at the tips. As a result, they can manoeuvre very well when flying. Furthermore, Malayan Flying Foxes display a fascinating array of behaviours. At roost, they hang upside down, often fanning themselves with their wings to stay cool in tropical heat. They groom one another, squabble over perches with flurries of deep growls and impressive wing displays. Despite this, they cradle their young tenderly in their wings.

By carrying seeds far and wide, they regenerate ecosystems across Southeast Asia’s fragile tropical ecosystems, ensuring the survival of countless other plants and animal species.

Threats

Deforestation and habitat loss

The Malayan Flying Fox faces relentless habitat destruction. Particularly, Mangroves, lowland forests, and coastal trees, which they rely on for roosting and foraging, are being cleared for agriculture, particularly timber and palm oil plantations. In East Kalimantan, mangrove habitats have been replaced by shrimp farms, leaving once-thriving colonies displaced and fragmented.

Hunting and human persecution

These bats are hunted across their range for bushmeat, traditional medicine, and sport. In some areas, thousands are killed in a single night. Hunters target roost sites, causing devastating ripple effects on entire colonies. Farmers, frustrated by perceived crop damage, trap and poison them, unaware of their critical ecological role.

Climate change-induced extreme weather

Climate change has intensified weather systems. Rising sea levels and intensifying typhoons ravage the mangroves and coastal forests these bats call home. Heatwaves have caused mass deaths from heatstroke. Meanwhile, the increasing frequency of extreme weather events further strains already vulnerable populations of Kalongs.

Human-wildlife conflict

As forests vanish, these gentle giants are forced into closer proximity to humans. Misguided fears have linked these bats to disease outbreaks, such as COVID-19. This has escalated culling and persecution activities in many countries, compounding the threats they already face.

Habitat and geographic range

The Kalong spans South and Southeast Asia, inhabiting countries like India, Malaysia, Indonesia, and the Philippines. Their range includes mangroves, lowland rainforests, and coastal forests. Roosting in tall trees, they depend on large, intact forest canopies for shelter and sustenance.

Diet

Malaysian Kalongs are frugivores and nectarivores, with their diet focused on fruits, flowers, and nectar. They are particularly fond of figs, bananas, mangoes, and durian flowers, consuming the pulp of the fruit and licking nectar from blossoms without damaging them. They also feed on rambutan and langsat fruits.

At night, these bats fly up to 50 kilometres from their roosts to forage, guided by their exceptional eyesight. Upon landing on fruiting trees, they often choose the tips of branches, hanging upside down to feed. Their feeding aggregations are noisy and energetic, with flocks forming smaller family or feeding groups at foraging sites.

This diet makes them crucial for pollination and seed dispersal, ensuring the regeneration of tropical ecosystems across their range.

Mating and reproduction

Malayan Flying Foxes are polygynous, with dominant males maintaining harems of up to 10 females. Courtship displays involve wing flutters and vocalisations. Females give birth to a single pup after a gestation of up to 190 days, usually timed with the abundance of fruiting trees.

Kalong mating typically occurs in the autumn, with females giving birth to a single pup after a gestation of approximately six months. Gestation peaks vary by region: in Peninsular Malaysia, births are most common between November and January; in the Philippines, they occur in April and May.

Newborns cling tightly to their mothers as they forage, learning to navigate the vast night skies. Weaning occurs at around three months, but the bond between mother and pup often lasts much longer, a testament to the deep care these animals show their young. Pups remain dependent on their mothers until they develop the strength to join nightly foraging flights.

Their slow reproduction rate—female bats usually produce just one pup annually—makes the species especially vulnerable to population declines caused by hunting and habitat destruction.

FAQs

Take Action!

The Malayan Flying Fox is a keystone species, essential for the health of tropical forests. Protect them by boycotting products linked to deforestation and advocating for stronger protections: #BoycottPalmOil #Boycott4Wildlife.

Support the Malayan Flying Fox by going vegan and boycotting palm oil in the supermarket, it’s the #Boycott4Wildlife

Support the conservation of this species

This animal has no protections in place. Read about other forgotten species here. Create art to support this forgotten animal or raise awareness about them by sharing this post and using the #Boycottpalmoil #Boycott4Wildlife hashtags on social media. Also you can boycott palm oil in the supermarket.

Further Information

Cambridge University Press. (2021). Intensive hunting of Large Flying Foxes in Central Kalimantan, Indonesian Borneo. Retrieved from https://www.cambridge.org/core/journals/oryx/article/intensive-hunting-of-large-flying-foxes

Critter Science. (n.d.). The Giant Malayan Flying Fox. Retrieved from https://critter.science/the-giant-malayan-flying-fox/

Hengjan, Y., et al. (2017). Daytime behaviour of Pteropus vampyrus in a natural habitat: The driver of viral transmission. Journal of Veterinary Medical Science, 79(6), 1125–1133. https://doi.org/10.1292/jvms.16-0643

Mildenstein, T., Abdul Aziz, S., Paguntalan, L., Jakosalem, P.G., Mohd-Azlan, J., Tagtag, A., Bansa, L., Reintar, A.R., Struebig, M., Fredriksson, G., Lee, B., Thong, V.D. & Sheherazade. 2022. Pteropus vampyrus. The IUCN Red List of Threatened Species 2022: e.T18766A22088824. https://dx.doi.org/10.2305/IUCN.UK.2022-2.RLTS.T18766A22088824.en. Accessed on 27 January 2025.

---

---