Leopards (Panthera pardus) are one of the four 'big cats' of the genus Panthera. They range in size from one to almost two meters long, and weigh between 30 and 70 kg. The leopard is a sexually dimorphic species, with females being typically around two-thirds the size of males. Most leopards are light tan or fawn with black spots, but their coat color is highly variable. The spots tend to be smaller on the head, and larger with pale centers on the body.

Despite its size, this largely nocturnal and arboreal predator is difficult to see in the wild. The best location to see leopards in Africa is in the Sabi Sand Private Game Reserve in South Africa, where leopards are habituated to safari vehicles and are seen on a daily basis at very close range. In Asia, perhaps the best site is the Yala National Park in Sri Lanka, which has the world's highest density of wild leopards, but even here sightings are by no means guaranteed because more than half the park is closed off to the public, allowing the animals to thrive. The recently reopened Wilpattu National Park (also in Sri Lanka), is another good destination for leopard watching.

As well as spotted leopards and black leopards there are several other rare mutations. One of the most interesting is the King Leopard. Other color forms include red (erythristic) leopards with chocolate brown markings on a reddish background; buff leopards with orange rosettes on a cream background; pale cream leopards with pale markings and blue eyes, leopards without any distinct rosettes and leopards with striped underparts. The typical Indian leopard, as already mentioned, has the rosettes large and extending over most of the fore quarters. In the African leopard, on the other hand, the rosettes are everywhere smaller and more crowded, and on the shoulders and head break up into small solid spots. In ordinary leopards there are no black dots within the light area enclosed by the rosettes, but in some skins from Siam such dots are present, and thus serve to connect the leopard with the jaguar, in which they are normal.

Leopards are highly successful predators that hunt a wider variety of African prey than do other big cats from Africa, often feeding on insects, rodents, fish (as do domestic cats, animals with similar hunting techniques) as well as such larger game as antelope. Like domestic cats, but unlike the other great cats, they are known to jump from perches onto prey animals. Large size with the efficiency of the smaller cats makes them extremely dangerous to humans and dogs. Dogs in leopard country should be caged for protection from leopards. In much of its range in Africa leopards compete with animals such as the Spotted Hyena, wild dogs and the lion for prey, and it is not uncommon for them to be chased away from their own kills by other top predators.

Like domestic cats, leopards usually hunt at night or at dawn or dusk. They will stalk their prey before making a short run to catch it. They kill mostly by suffocation, by holding onto the animal's throat, though with smaller animals they may break the neck. Some leopards will carry their prey up a tree to avoid losing it to lions and hyenas. They have been observed carrying prey up to three times their own body weight into trees, demonstrating their great strength and power. Opportunistic hunters, leopards will hunt at any time of day or night if they come across suitable prey. Quite often they can make more than one kill in a day, in which case they cache the first kill while stalking their next victim.

The big cats, especially the spotted cats, are easy to confuse for those who see them in captivity or in photographs. The leopard is closely related to, and appears very similar to, the jaguar; it is less often confused with the cheetah. The ranges, habitats, and activities of the three cats make them easy to distinguish in the wild.

Prior to the human-induced changes of the last few hundred years, Leopards were the most widely distributed of all felids other than the domestic cat: they were found through most of Africa (with the exception of the Sahara Desert), as well as parts of Asia Minor and the Middle East, India, Pakistan, China, Siberia, much of mainland South-East Asia, and the islands of Java, Zanzibar, and Sri Lanka.

The leopard is doing surprisingly well for a large predator. It is estimated that there are as many as 500,000 leopards in Sub-Saharan Africa alone. But like many other big cats, leopards are increasingly under threat of habitat loss and are facing increased hunting pressure. Because of their stealthy habits and camouflage, they can go undetected even in close proximity to human settlements. Despite the leopard's abilities, it is no match for habitat destruction and poachers, and several subspecies are endangered, namely, the Amur, Anatolian, Barbary, North Chinese, and South Arabian leopards.