Grim Discovery of Dead Bats Spark Concern in Recent Ecological Mystery

In the quiet corridors of Nanyang Technological University (NTU) in Singapore, a troubling phenomenon has emerged. Since August 2024, dozens of Javan pipistrelles, one of the smallest bat species in the city-state, have been found grounded or dead on campus grounds. Lifeless bodies, some with wings splayed out and others curled up in distress, paint a grim picture of an ecological mystery. In January 2025 alone, 15 groundings and seven deaths were recorded, part of a larger tally of 45 such incidents at NTU over the past seven months. As students and researchers scramble to uncover the cause, concerns are mounting over the survival of this tiny insect-eating bat and its role in Singapore’s delicate ecosystem.

The Javan pipistrelle (Pipistrellus javanicus), no larger than a human thumb, is a common sight in urban and natural landscapes across Singapore. It roosts in trees and building structures, playing a vital role in controlling mosquito and night-flying insect populations. Yet, at NTU, something is preventing these bats from taking flight. Grounded bats, often exhausted, injured, or too young to launch themselves from the ground, face grave risks—being crushed underfoot in busy campus pathways or succumbing to starvation if unable to return to the air.

The National Parks Board (NParks) notes that while bat groundings occur elsewhere in Singapore, no other location has seen such a concentrated cluster of incidents. This has spurred action from NTU’s student community, with environmental and wildlife interest group EarthLink initiating rescue efforts in 2024. Karina Lim, EarthLink’s director at the time and now a senior wildlife coordinator at the rescue group Acres, recalls the early days of finding grounded bats near NTU’s Hall of Residence 9. “We initially suspected pesticide fogging might be the cause, but checks showed no such activity in the area during those weeks,” she explains. Another theory pointed to nearby construction for the Jurong Region MRT line, which some students speculated could disrupt the bats’ sonar navigation. However, without concrete evidence, this remains a hypothesis.

Driven by concern, two NTU students—first-year undergraduate Emma Chao and third-year PhD candidate Nicole Dorville from the Asian School of the Environment—launched the NTU Grounded Bat Surveys in January 2025. Supported by NParks, which provided training on safe handling of the animals, their initiative marks Singapore’s first dedicated study into bat groundings. Now involving 19 contributors from diverse academic backgrounds, including biological sciences and business, the group aims to pinpoint hotspots on campus and identify threats to these nocturnal mammals. “We’re passionate about bats and want to understand why this is happening so we can improve the situation,” says Ms Chao.

Several theories have emerged from their early observations. Ms Chao suggests that over-reproduction during mating season could be a factor, with mother bats abandoning pups due to insufficient resources. Natural causes, such as exhaustion or inexperience among younger bats, may also play a role. Yet, the fact that only Javan pipistrelles are affected at NTU raises questions. Across Singapore, other species like the whiskered myotis and lesser Asiatic yellow house bat have been reported grounded—176 cases in 2024 alone, with higher concentrations in areas like Punggol and Yishun. But NTU’s unique situation suggests a localised issue, possibly tied to campus-specific environmental changes.

The broader context of habitat fragmentation adds another layer of complexity. As Singapore continues to develop, urban expansion chips away at natural spaces, leaving bats with fewer places to roost. “Development means greater habitat fragmentation, and bats need new spaces to live in,” Ms Lim warns. When residents request the removal of bats from homes or public areas, it often fails to address the root problem. NParks advises a more compassionate approach: if a bat enters a home, turn off lights and fans, open windows, and allow it to exit on its own. If it remains, contacting Acres’ Wildlife Rescue Hotline is recommended.

The ecological importance of the Javan pipistrelle cannot be overstated. As a natural pest controller, it helps manage insect populations, benefiting both urban and rural environments. Losing this species to unexplained groundings could have ripple effects on Singapore’s biodiversity. Ms Lim, who first learned of the issue through a community wildlife group on Telegram in 2022, has been instrumental in rallying student efforts. Between September 2022 and January 2023, she and fellow EarthLink members rescued 37 bats, a mission now expanded by the NTU Grounded Bat Surveys team.

For now, the mystery persists. NParks confirms that no infectious zoonotic diseases, including rabies, have been detected among Singapore’s bat population since monitoring began in 2011. This rules out health-related causes, shifting focus to environmental or behavioural factors. As research continues, the call for coexistence grows louder. “What we need to do now is learn to modify our environments, or better yet, learn to coexist with them,” Ms Lim urges.

At NTU, the sight of a tiny Javan pipistrelle struggling on the ground serves as a poignant reminder of the delicate balance between urban life and wildlife. While student-led initiatives offer hope, the path to safeguarding these bats remains unclear. Until answers are found, each grounding is a small but urgent call to protect Singapore’s often-overlooked nocturnal guardians.