The great Himalayan leaf bat has finally been confirmed in Bangladesh

DHAKA — Scientists have published the first record of the great Himalayan leaf bat in Bangladesh, throwing another needle into the distribution map of this wide-ranging species in Asia and underscoring the importance of continued biodiversity studies in Bangladesh.

species, Hipposideros armigerwas found in a cave in the Chittagong Hill Tracts of southeastern Bangladesh during field surveys between July and December 2023, according to a newly published study.

“We were delighted to confirm this species in Bangladesh,” said the lead researcher M. Abdul Azizprofessor in the Department of Zoology at Jahangirnagar University.

“This is an exciting time for both local and global bat conservation efforts, as this discovery not only adds to the national fauna, but also provides a deeper understanding of the species’ distribution in South Asia.”

H. armigeramong the largest of the leaf bats, it has a wide distribution, extending from India in the west to China in the east and as far south as Malaysia. Until last year’s discovery, however, its presence in Bangladesh had never been confirmed by scientists.

How it was identified

The species is a high-altitude cave dweller known for its distinctive nose-leaf structure, a crucial part of its echolocation mechanism that helps it navigate in the dark. The cave where Aziz and his team found it is a culturally important one in the region. It has long served as a spiritual retreat for a local Buddhist monk and is now also recognized for hosting a colony of these bats that roost in its cool, dark depths, researchers said.

To confirm bats as a species H. armigerresearchers caught specimens and measured key physical traits such as forearm length, head-body size and ear length, Aziz said. They also took close-up photos of its distinctive nose leaf, a key identifier for the species.

“Hipposideros armiger it stands out from similar bat species with its longer forearms, dark brown fur and a fleshy outgrowth behind the nose blade – features that confirmed its identity,” Aziz said.

The H. armiger the colony they found in the cave is estimated to be around 75-80 individuals. The cave is also home to other species of bats, including horseshoe bats of the genus horseshoe and several as-yet-unidentified insect-eating bats.

Why is this discovery important?

Conservationists say the discovery of the species in Bangladesh is a major milestone in understanding the country’s bat species. A 2022 review listed 31 bat species with confirmed presence in the country. He also noted that while there have been no confirmed reports of H. armiger in the country, his presence here was “highly likely.”

Despite this wealth of bat diversity, little is known about many of the species. More than half are considered “data deficient” on the IUCN Red List, meaning that not enough is known about their population trends and threats to make a conservation assessment. H. armiger it is listed as a species of least concern by the IUCN, given its wide distribution and large population in its range.

“With this discovery, we now have a clearer picture of the diversity of bat species in Bangladesh,” Aziz said. “But much remains to be done to fully understand the distribution and ecological role of bats in the country.”

The Chittagong Hill Tracts, in particular, where the great Himalayan leaf bat was found, are a known hotspot for biodiversity due to their lush forests and dramatic topography. Researchers have long argued that the region remains underexplored and have called for more surveys to uncover the many species still hidden in its caves and forests.

Future conservation challenges

The cave where H. armiger it was found to be protected by local authorities due to its spiritual importance, but increased human activity could pose risks to the bats. Researchers cite increased visitor numbers or human encroachment into the area.

“Although this cave is currently safe, there is always the potential for human disturbance,” Aziz said. “It is essential that we protect these habitats to ensure that the species like them H. armiger can continue to thrive in Bangladesh.”

Bats play a crucial ecological role, controlling insect populations and pollinating plants, making their protection vital to maintaining ecosystem balance. The research team calls for further studies in the Chittagong Hill Tracts and beyond, with the aim of building a more comprehensive inventory of bat species in the country.

As scientists continue to study Bangladesh’s caves, this new discovery serves as a reminder of the importance of conserving the country’s natural habitats and the remarkable species that depend on them.

Banner image: The bats were found in a cave in the Chittagong Hill Tracts of southeastern Bangladesh during field surveys between July and December 2023. Image by M. Aziz.

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Quotes:

Aziz, MA, Marma, AS, Hamza, A., Rahman, MA, Rahman, MA, and Naznin, S. (2024). First record of the Himalayan leaf-nosed bat, Hipposideros armiger (Hipposideridae) from Bangladesh. Mammals, 88 years(5), 451-454. two:10.1515/mammalia-2024-0003

Ul Hasan, MA and Kingston, T. (2022). Bats of Bangladesh – A systematic review of diversity and distribution with recommendations for future research. Diversity, 14(12), 1042. two:10.3390/d14121042