Wild Snow Leopard caught on Camera trap - Ladakh, Northern India

A wild snow leopard, caught on a Snow Leopard Trust / NCF India research camera in Ladakh, Northern India.

The snow leopard (Panthera uncia or Uncia uncia) is a moderately large cat native to the mountain ranges of Central Asia. The classification of this species has been subject to change, and as of 2000, it is still classified as Uncia uncia by MSW3. and CITES Appendix I.However, with more recent genetic studies, the snow leopard is now generally considered as Panthera uncia and classified as such by IUCN. Classically, two subspecies have been attributed, but genetic differences between the two have not been settled. The snow leopard is listed on the IUCN Red List of Threatened Species as globally Endangered (EN).
Snow leopards occupy alpine and subalpine areas generally 3,350 to 6,700 metres (10,990 to 22,000 ft) above sea level in Central Asia. McCarthy and Chapron (2003) compiled national snow leopard population estimates, updating the work of Fox (1994). Many of the estimates are acknowledged to be rough and out of date, but the total estimated population is 4,150--7,350. However, the global snow leopard effective population size (those likely to reproduce) is suspected to be fewer than 2,500 (50% of the total population, or 2,040--3,295).

Snow leopards are slightly smaller than the other big cats but, like them, exhibit a range of sizes, generally weighing between 27 and 55 kg (60 and 120 lb), with an occasional large male reaching 75 kg (170 lb) and small female of under 25 kg (55 lb). They have a relatively short body, measuring in length from the head to the base of the tail 75 to 130 cm (30 to 50 in). However, the tail is quite long, at 80 to 100 cm (31 to 39 in), with only the domestic-cat-sized marbled cat being relatively longer-tailed. They are stocky and short-legged big cats, standing about 60 cm (24 in) at the shoulder.
Snow leopards have long, thick fur, and their base colour varies from smoky gray to yellowish tan, with whitish underparts. They have dark grey to black open rosettes on their bodies, with small spots of the same color on their heads and larger spots on their legs and tails. Unusually among cats, their eyes are pale green or grey in colour.
Snow leopards show several adaptations for living in a cold, mountainous environment. Their bodies are stocky, their fur is thick, and their ears are small and rounded, all of which help to minimize heat loss. Their paws are wide, which distributes their weight better for walking on snow, and have fur on their undersides to increase their grip on steep and unstable surfaces; it also helps to minimize heat loss. Snow leopards' tails are long and flexible, helping them to maintain their balance, which is very important in the rocky terrain they inhabit. Their tails are also very thick due to storage of fat and are very thickly covered with fur which allows them to be used like a blanket to protect their faces when asleep.
The snow leopard has a short muzzle and domed forehead, containing unusually large nasal cavities that help the animal breathe the thin, cold air of their mountainous environment.
The snow leopard cannot roar, despite possessing partial ossification of the hyoid bone. This partial ossification was previously thought to be essential for allowing the big cats to roar, but new studies show the ability to roar is due to other morphological features, especially of the larynx, which are absent in the snow leopard. Snow leopard vocalizations include hisses, chuffing, mews, growls, and wailing.

Both the Latinised genus name, Uncia, and the occasional English name "ounce" are derived from the Old French once, originally used for the European lynx. "Once" itself is believed to have arisen by back-formation from an earlier word "lonce" -- the "L" of "lonce" was construed as an abbreviated "le" ("the"), leaving "once" to be perceived as the animal's name. This, like the English version "ounce", became used for other lynx-sized cats, and eventually for the snow leopard.
The snow leopard is also known in its native lands as wāwrīn pṛāng (Pashto: واورين پړانګ‎), shan (Ladakhi), irves (Mongolian: ирвэс), bars or barys (Kazakh: барыс [ˈbɑrəs]), ilbirs (Kyrgyz: Илбирс ), barfānī chītā (Urdu: برفانی چیتا) and him tendua (Sanskrit, Hindi: हिम तेन्दुआ).
According to the American Heritage Dictionary, the origin of the word panthera is unknown. A folk etymology derives the word from the Greek πάν pan- ("all") and thēr ("beast of prey") because they can hunt and kill almost anything. It has also been proposed that it comes ultimately into Greek from a Sanskrit word meaning "the yellowish animal" or "whitish-yellow". The Greek word πάνθηρ, pánthēr, referred to all spotted Felidae generically.

The snow leopard was first described by Schreber in 1775 on the basis of an illustration. Schreber assumed that the cat ranges in Barbary, Persia, East India and China.