The snow leopard (Panthera uncia), also known as the ounce, is a felid in the genus Panthera native to the mountain ranges of Central and South Asia. It is listed as Vulnerable on the IUCN Red List because the global population is estimated to number fewer than 10,000 mature individuals and is expected to decline about 10% by 2040. It is threatened by poaching and habitat destruction following infrastructural developments. It inhabits alpine and subalpine zones at elevations of 3,000–4,500 m (9,800–14,800 ft), ranging from eastern Afghanistan, the Himalayas and the Tibetan Plateau to southern Siberia, Mongolia and western China. In the northern part of its range, it also lives at lower elevations.

Taxonomically, the snow leopard was long classified in the monotypic genus Uncia. Since phylogenetic studies revealed the relationships among Panthera species, it has been considered a member of that genus. Two subspecies were described based on morphological differences, but genetic differences between the two have not been confirmed. It is therefore regarded as a monotypic species.

The snow leopard was long classified in the monotypic genus Uncia. It was subordinated to the genus Panthera based on results of phylogenetic studies.

Until spring 2017, there was no evidence available for the recognition of subspecies. Results of a phylogeographic analysis indicate that three subspecies should be recognised:

• P. u. uncia in the range countries of the Pamir Mountains

• P. u. irbis in Mongolia, and

• P. u. uncioides in the Himalayas and Qinghai.

This view has been both contested and supported by different researchers.

Additionally, an extinct subspecies Panthera uncia pyrenaica was described in 2022 based on material found in France.

Based on phylogenetic analysis of DNA sequence sampled across the living Felidae, the snow leopard forms a sister group with the tiger (P. tigris). Genetic divergence time of this group is estimated at 4.62 to 1.82 million years ago. The snow leopard and the tiger probably diverged between 3.7 to 2.7 million years ago.[12] Panthera originates most likely in northern Central Asia. Panthera blytheae excavated in western Tibet's Ngari Prefecture is the oldest known Panthera species and exhibits skull characteristics similar to the snow leopard.

The mitochondrial genomes of the snow leopard, the leopard and the lion (P. leo) are more similar to each other than their nuclear genomes, indicating that their ancestors hybridised at some point in their evolution.

The snow leopard's fur is whitish to grey with black spots on head and neck, with larger rosettes on the back, flanks and bushy tail. The belly is whitish. Its eyes are pale green or grey in color. Its muzzle is short and its forehead domed. Its nasal cavities are large. The fur is thick with hairs between 5 and 12 cm (2.0 and 4.7 in) long. Its body is stocky, short-legged, and slightly smaller than the other cats of the genus Panthera, reaching a shoulder height of 56 cm (22 in), and ranging in head to body size from 75 to 150 cm (30 to 59 in). Its tail is 80 to 105 cm (31 to 41 in) long. It weighs between 22 and 55 kg (49 and 121 lb), with an occasional large male reaching 75 kg (165 lb), and small female of under 25 kg (55 lb). Its canine teeth are 28.6 mm (1.13 in) long and are more slender than those of the other Panthera species. In relation to the length of its skull and width of its palate, it has large nasal openings, which allow for increasing the volume of air inhaled with each breath, and at the same time for warming and humidifying cold dry air. It is not especially adapted to high-altitude hypoxia.

The snow leopard shows several adaptations for living in a cold, mountainous environment. Its small rounded ears help to minimize heat loss. Its broad paws well distribute the body weight for walking on snow, and have fur on their undersides to increase the grip on steep and unstable surfaces; it also helps to minimize heat loss. Its long and flexible tail helps to maintain balance in the rocky terrain. The tail is very thick due to fat storage, and is covered in a thick layer of fur, which allows the cat to use it like a blanket to protect its face when asleep.

The snow leopard differs from the other Panthera species by a shorter muzzle, an elevated forehead, a vertical chin and a less developed posterior process of the lower jaw. It cannot roar despite its partly ossified hyoid bone, as its 9 mm (0.35 in) short vocal folds provide little resistance to airflow.

The snow leopard is distributed from the west of Lake Baikal through southern Siberia, in the Kunlun Mountains, Altai Mountains, Sayan and Tannu-Ola Mountains, in the Tian Shan, through Tajikistan, Kyrgyzstan, Uzbekistan and Kazakhstan to the Hindu Kush in eastern Afghanistan, Karakoram in northern Pakistan, in the Pamir Mountains, the Tibetan Plateau and in the high elevations of the Himalayas in India, Nepal and Bhutan. In Mongolia, it inhabits the Mongolian and Gobi Altai Mountains and the Khangai Mountains. In Tibet, it occurs up to the Altyn-Tagh in the north. It inhabits alpine and subalpine zones at elevations from 3,000 to 4,500 m (9,800 to 14,800 ft), but also lives at lower elevations in the northern part of its range. Potential snow leopard habitat in the Indian Himalayas is estimated at less than 90,000 km2 (35,000 sq mi) in Jammu and Kashmir, Ladakh, Uttarakhand, Himachal Pradesh, Sikkim and Arunachal Pradesh, of which about 34,000 km2 (13,000 sq mi) is considered good habitat, and 14.4% is protected. In the beginning of the 1990s, the Indian snow leopard population was estimated at 200–600 individuals living across about 25 protected areas.

In summer, the snow leopard usually lives above the tree line on alpine meadows and in rocky regions at elevations from 2,700 to 6,000 m (8,900 to 19,700 ft). In winter, it descends to elevations around 1,200 to 2,000 m (3,900 to 6,600 ft). It prefers rocky, broken terrain, and can move in 85 cm (33 in) deep snow, but prefers to use existing trails made by other animals.

Snow Leopard (Panthera uncia) - Hemis National Park, Ladakh India