A new study in eastern Sikkim has recorded a gaur at 3,542 metres, the highest verified photographic sighting of the species globally.
A tiger was photographed at 3,966 metres, among the highest documented elevations for the species in the Himalayas.
Camera-trap surveys documented 30 mammal species, including five new elevational range records and six first confirmed photographic records for eastern Sikkim.
Researchers say suitable high-altitude habitats, previously unexplored areas and improved monitoring could explain the findings.
Climate change may also be influencing wildlife distribution, but scientists say long-term monitoring is needed to establish whether animals are moving uphill.
How high into the Himalayas do India's wild animals venture? A new camera-trap study in eastern Sikkim has recorded a gaur at 3,542 metres — the highest verified photographic sighting of the species globally — and a tiger at 3,966 metres, among the highest elevations documented for the big cat in the region.
The sightings, among several new high-altitude wildlife records from Sikkim, are prompting scientists to investigate whether these animals have long inhabited the region's remote mountain forests or are moving uphill as environmental conditions change.
The gaur sighting is the highest verified photographic record for the species globally, while the tiger was photographed at one of the highest documented elevations for the species in the Himalayas, according to researchers from the Wildlife Institute of India (WII) who were part of the analysis.
The findings, published in the Journal of Threatened Taxa, identified five new elevational range records and six first confirmed photographic records for mammals in eastern Sikkim.
Conducted between February 2023 and May 2026, the survey covered altitudes ranging from 1,800 to 4,200 metres. Researchers deployed 64 camera-trap stations over 20,411 trap nights across three protected areas — Kyongnosla Alpine Sanctuary, Pangolakha Wildlife Sanctuary and Fambonglho Wildlife Sanctuary — and adjoining unprotected forests.
The cameras documented 30 mammal species, including several found at elevations higher than previously recorded in the region.
The gaur (Bos gaurus), the world's largest wild cattle species, was photographed at 3,542 metres in Pangolakha Wildlife Sanctuary, substantially exceeding its previously documented upper elevation of about 2,800 metres.
A tiger (Panthera tigris) was recorded at 3,966 metres in the Kyongnosla region.
Other notable sightings included sambar at 3,050 metres, red panda and golden jackal at 4,100 metres, clouded leopard at 3,189 metres and spotted linsang at 2,939 metres.
Researchers also photographed crab-eating mongoose at 2,368 metres, common palm civet at 2,939 metres and mithun at 2,936 metres.
Pooja Pant, lead author of the study, said similar high-altitude mammal records had been documented elsewhere in the Indian Himalayas.
“Our camera-trap surveys helped us document several mammal species at elevations higher than previously reported in eastern Sikkim,” she said.
The researchers said several factors could explain the findings, including suitable habitats at higher elevations, improved wildlife monitoring and changing environmental conditions.
Unlike the central and western Himalayas, the eastern Himalayas have a relatively high treeline because of greater monsoon rainfall and lower latitude. Forest cover in eastern Sikkim extends to approximately 4,000 metres, potentially providing suitable habitat for species such as gaur and tiger.
“Our observation may therefore reflect both the long-standing availability of high-elevation forest and more recent environmental changes,” the authors said.
S Sathyakumar, former senior scientist at WII and corresponding author of the study, said the findings highlighted how little was known about wildlife distribution in previously underexplored mountain habitats.
He said systematic camera-trap surveys had made it possible to document mammals at elevations where their presence had not previously been confirmed.
Pant said the findings could reflect broader patterns across the Himalayas, rather than changes restricted to Sikkim.
“Several factors may contribute to these patterns, including improved wildlife monitoring, availability of suitable habitats, changing climatic conditions and vegetation patterns,” she said.
The researchers cautioned that the new records did not necessarily mean animals had recently moved uphill. Some species may have occupied these habitats for years but escaped detection because earlier surveys were limited by difficult terrain and inadequate monitoring.
Climate change could also be contributing to shifts in wildlife distribution as rising temperatures alter vegetation and habitat conditions. However, the study said there was insufficient evidence to determine whether the sightings reflected ecological changes or simply better monitoring.
The researchers called for long-term surveys to establish whether Himalayan mammals are moving to higher elevations and assess the consequences for conservation. They warned that changes in species distribution could increase competition, disrupt predator-prey relationships and potentially intensify human-wildlife conflict.