The snow leopard (Panthera uncia) is a large feline unique to the Qinghai-Tibet Plateau and its surrounding areas. How this apex predator gradually adapted to the extreme environments remains unexplored due to the scanty fossil record in Tibet. In new research, scientists examined five outside-Tibet records of the snow leopard lineage. Their results suggest that the snow leopard dispersed out of the Tibetan Plateau multiple times during the Quaternary period. The anatomy of the modern snow leopard shows adaptations to the steep slope and cold/high-altitude environment. The new results suggest that the snow leopard experienced a gradual strengthening of such adaptation, especially since the Middle Pleistocene (0.8 million years ago).

The snow leopard is one of the iconic animals of the Tibetan Plateau and distributes also in the ranged mountainous regions of central Asia as the Mongolian Plateau.

It has distinctive features, e.g., long and dense pelage, long tail, short face, steep and wide forehead, large cheek teeth etc., that clearly distinguish it from the other members of the genus Panthera.

The snow leopard typically inhabits within high alpine regions, above 3,000 m, or above the tree line, but may also occur at much lower elevations below 1,000 m in some areas of Siberia.

The status of the snow leopard in IUCN’s Red List is Vulnerable, with 4,000 individuals. However, under global warming, its distribution is expected to be substantially affected, as moving northward or upward to a higher altitude.

“While the distinctive characteristics of the snow leopard have long been acknowledged, the correlation between these traits and its adaptation to the Tibetan Plateau environment, as well as their evolutionary history, remains largely unexplored,” said Dr. Qigao Jiangzuo, a researcher at the Institute of Vertebrate Paleontology and Paleoanthropology of the Chinese Academy of Sciences and Peking University, and colleagues.

“This gap in understanding is primarily due to the scarcity of snow leopard fossils in the Tibetan Plateau and its surrounding regions.”

In the study, the researchers described snow leopard fossils from five sites: Longdan in Gansu, China; Arago in France; Zhoukoudian locality 3 in Beijing, China; Manga Larga in Portugal; and Niuyan Cave in Mentougou, Beijing, China.

Except for the fossil from Niuyan Cave, which can be classified as a modern snow leopard, the others show significant differences compared to existing snow leopards.

The scientists concluded that the snow leopards found outside the Qinghai-Tibet Plateau are not an independent lineage but rather comprise small offshoots from the main snow leopard branch.

It is likely that these offshoots represent multiple dispersals of snow leopards out of Tibet at different times.

To study the evolution of important morphological features, the authors conducted a systematic analysis of the functional morphology of modern snow leopards using anatomy, geometric morphometrics, and finite element analysis.

Their findings indicate that snow leopards have large eye sockets and highly developed binocular vision, suggesting they possess advanced stereoscopic vision that allows them to quickly focus on prey in complex terrain.

“Snow leopards have a short snout and a steeply angled jaw, with canines that feature a nearly round cross-section,” the researchers said.

“This structure enables them to exert powerful forces to subdue strong prey, although it may also compromise flexibility.”

“Furthermore, snow leopards’ well-developed frontal sinus system warms inhaled air and enhances respiratory efficiency, making them animals well-adapted to cold, low-oxygen environments.”

“Moreover, snow leopards possess a pronounced tympanic bulla, which increases their sensitivity to infrasonic waves, allowing them to detect prey sounds from greater distances in open areas.”

“Their large cheek teeth (i.e., premolars and molars) also enable them to consume most meat from prey before it freezes in the cold environment.”

“In addition, these teeth improve snow leopards’ ability to chew already frozen carcasses.”

“While the scapulae and pelvis of snow leopards are relatively small, their distal limb bones are elongated.”

“This indicates that their forelimbs have less muscular power but greater flexibility in movement, making them suited for running and jumping in mountainous regions.”

“Most of these features represent adaptations to mountainous environments and to their primary prey, the Caprinae (sheep and related species), which tend to have slower speeds but short, robust limbs and strong horns for resistance.”

“Only a small portion of snow leopard adaptations pertains to high-altitude, low-oxygen conditions.”

The scientists also studied the functional morphology of fossil snow leopards by correlating various morphological features with their functions.

They discovered that early snow leopards, including the Early Pleistocene Panthera aff. pyrenaica from Longdan and the Early Middle Pleistocene Panthera pyrenaica from France, had mandibles that were already steeply angled but had not yet shortened.

Additionally, their cheek teeth had not increased in size. This suggests an initial adaptation to Caprinae prey; however, no significant specializations for cold environments were apparent at this stage.

Later fossils, such as the Late Middle Pleistocene Panthera aff. uncia from Zhoukoudian locality 3 and the Late Pleistocene Panthera uncia lusitana, were found to be very similar to modern snow leopards, displaying comparable adaptations.

However, certain features, including the development of the ectotympanic chamber and the extent of forehead expansion, were generally less pronounced in the European Panthera uncia lusitana compared to contemporary snow leopards.

“Bayesian analyses of morphological evolution rates indicate that snow leopards began to change rapidly in the Middle Pleistocene,” the authors said.

“This timeframe coincides with the emergence of large ice sheets on the Qinghai-Tibet Plateau.”

“Since the Middle Pleistocene, global climate variability has increased, resulting in more severe and prolonged glacial periods.”

“These conditions allowed snow leopards to expand their range beyond the Qinghai-Tibet Plateau.”

“Notably, the Middle Pleistocene also marks the period when many members of the Caprinae subfamily began to migrate from the Qinghai-Tibet Plateau into North China and Europe, paralleling the movement of snow leopards from the plateau.”

To determine if fossil snow leopards had similar ecological adaptations to modern snow leopards, the researchers analyzed the relationship between the distribution of modern snow leopards and climate data.

They employed a random forest approach, training a model known as species distribution modeling to predict how snow leopards might adapt based on climate conditions.

Subsequently, they applied climate data from the Last Glacial Maximum to evaluate the potential maximum distribution of modern snow leopards during that time period.

“The results indicate that the potential suitable distribution for snow leopards during the Last Glacial Maximum was significantly larger than it is today,” the scientists said.

“However, regions such as Europe and Beijing were outside the areas deemed suitable for their distribution.”

“This suggests that fossil snow leopards may have developed ecological adaptations distinct from those of modern snow leopards.”

“Consequently, the distribution of fossil snow leopards can’t be entirely predicted using modern snow leopard models.”

“Additionally, it is important to note that while these fossil sites are generally located at relatively low elevations (below 500 m), they were situated in mountainous environments and typically contained Caprinae fossils.”

“The only exception is the site in Portugal, which lacks faunal records. This observation suggests that mountainous terrain and the availability of related prey may have been more critical for snow leopards than the high-altitude, low-oxygen conditions.”

“Niuyan Cave is the only known site in the world containing both snow leopard and leopard fossils.”

“Since we know that snow leopards today occasionally share habitats in transitional zones near the forest line, the Niuyan Cave discovery suggests that similar environmental conditions may have existed there when the fossils were deposited.”

“By integrating paleobiology, molecular biology, finite element analysis, and species distribution modeling, we were able to trace the evolutionary history and functional morphological adaptations of the snow leopard, a key target of ecological conservation on the Qinghai-Tibet Plateau.”

“Our findings reveal the evolutionary path of snow leopards, suggesting that mountainous terrain may have played a more critical role in their survival than climate factors alone.”

These insights are important to ongoing snow leopard conservation efforts and also prove the usefulness of preservation paleontology.

“The analyses we have carried out lead us to conclude that surely the high altitude and snow would not have been the limiting factor for the distribution of the species, but rather the presence of open and steep spaces,” said Dr. Joan Madurell Malapeira, a researcher at the Università di Firenze and the Universitat Autònoma de Barcelona.

“In other words, the snow leopard has always been adapted to live in the mountains, but not necessarily at high altitudes and with snow.”

“And this, in a context of climate change like the current one, is encouraging to ensure their survival.”

The team’s paper was published in the journal Science Advances.

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Qigao Jiangzuo et al. 2025. Insights on the evolution and adaptation toward high-altitude and cold environments in the snow leopard lineage. Science Advances 11 (3); doi: 10.1126/sciadv.adp5243