
Arunachal Pradesh stands as the exclusive refuge for the Namdapha flying squirrel (Biswamoyopterus biswasi), a critically endangered mammal that embodies both scientific intrigue and conservation urgency. Endemic to India, this elusive species has garnered international attention for its mysterious status, ingenious adaptations, and the near-mythical aura surrounding its existence.
Discovery, Rarity, and Scientific Mystery
First described in 1981 after a lone specimen was collected in Changlang district’s Namdapha National Park near the Myanmar border, the Namdapha flying squirrel has not witnessed a confirmed sighting since, despite decades of concerted searches and field expeditions. This “ghost of the forest,” as naturalists often call it, epitomizes the challenges in detecting arboreal nocturnal mammals with inherently small populations and extreme habitat specialization. The initial discovery honored Indian zoologist Biswamoy Biswas and defined a new genus, Biswamoyopterus, which now includes two other rare flying squirrel species identified in Laos and China. Taxonomic uncertainties persist, with some experts suggesting all three might be variations of a single species, but detailed evolutionary studies remain limited.


Distinctive Features and Ingenious Adaptations
Medium-sized among Asian flying squirrels, the Namdapha flying squirrel displays grizzled reddish-brown fur, a striking white underbelly, and an unmistakable ear tuft — traits that separate it from more common red giant flying squirrels nearby. Its head-body length nears 40 cm, complemented by a slightly longer bushy tail. Most distinct is its patagium, a skin membrane stretching from neck to tail, which forms an advanced gliding apparatus capable of spanning up to 150 meters across dense forest canopies. As a strictly nocturnal and arboreal resident, the squirrel has large eyes optimized for night vision, aiding its navigation and foraging in the treetop dark.
Ecological Context: Habitat and Lifestyle
The Namdapha flying squirrel is strictly endemic to the Namdapha Tiger Reserve—an expanse spanning ~1,900 square kilometers of tropical wet evergreen forests, montane woods, and alpine meadows, forming one of India’s most biodiverse landscapes. Within this haven, the species favors tall Mesua ferrea jungles on hill slopes near the Dihing River’s catchment in the Patkai range. Its daily rhythm revolves around sleeping inside hollow tree cavities by day and emerging at night to forage on a diet rich in fruits, nuts, seeds, fungi, flowers, and tree sap.
Conservation Status: Critical Endangerment and Data Deficiency
Rated Critically Endangered by the IUCN Red List, Biswamoyopterus biswasi faces near-immediate risk of extinction. Its very survival is threatened by rampant habitat loss—illegal logging, agricultural expansion, infrastructure development, and forest fragmentation all encroach upon the contiguous canopy essential for its gliding behavior. While Schedule I of India’s Wildlife Protection Amendment Act (2022) affords the highest legal safeguards, practical enforcement remains sporadic and challenging. Conservation is further complicated by a lack of data; with only one confirmed specimen and mostly anecdotal reports since, researchers have little information about population size, reproductive biology, or precise ecological needs. Global initiatives such as the Search for Lost Species have spotlighted the Namdapha flying squirrel, placing it among the world’s most wanted lost species—a vivid symbol of both fragility and resilience.
Recent Developments and Hope
In the wake of more than 40 years without a confirmed sighting, recent unverified photographs and anecdotal sightings from Namdapha National Park have sparked renewed optimism. Ongoing DNA studies and intensified fieldwork aim to confirm the species’ presence and guide future conservation action. Efforts are underway to integrate local community involvement, scientific research, and ecosystem restoration, recognizing that protecting the Namdapha flying squirrel means safeguarding one of India’s richest biodiversity hotspots.
Global Significance and Conservation Imperatives
The Namdapha flying squirrel’s plight highlights the broader dilemma of “data-deficient species” in conservation biology-species so rare and evasive that scientists cannot reliably determine trends or needs, calling for holistic protection of entire ecosystems. As Northeast India faces mounting development pressures, the survival of creatures like Biswamoyopterus biswasi serves as a powerful reminder of the urgent need for habitat preservation, scientific study, and global commitment to conserving Earth’s rarest mammals.
For Arunachal Pradesh and the world, the Namdapha flying squirrel remains a silent glider-its presence both a symbol of nature’s mysteries and a clarion call for conservation action in the 21st century