The big cats are the larger member of the biological family. Felidae. A member of this family is called a felid. The most familiar felid is the domestic cat, which is considered a small cat. The big cats are tiger, lion, jaguar, leopard, cougar, and cheetah. All of them are strict carnivores and efficient apex predators. They are found in the Americas, Africa, Asia, and Europe. of the world's 37 species of cats, eight reigns as the big cats. Almost all big cats, except the snow leopard and the cheetah, can produce loud roars. The leopard is the most widespread of all big cats.

The male Siberian Tiger (also called the Amur Tiger) is the largest cat in the world, with a length of about 3.2 m, excluding the tail. The tail length in fully grown males is about 1m. The power and strength of the animal are such that it is able to prey on guar bulls, which can weigh as much as 1,000 kg. The lion is the second largest big cat with some males exceeding 250 kg in weight. The head-to-tail length of a male tiger is 1.7-2.5 m, while the tail is approximately 1m.

"Jaguar" is a Native American word that means "he who kills with one leap". Jaguars are found in the Americas, living in wet lowland areas, and swampy grasslands near rivers or lakes. They are the third largest of the cat family. The length varies from roughly 160 to 180 cm from head to tail, and the tail can then add a further 75 cm. Jaguars are often confused with leopards, but a jaguar is a larger, more solid animal with a broad head and shorter legs and tail. A jaguar's spots are also different. On its sides and back, a jaguar's spots are each a circle of spots around a central spot, while the spots on the legs, head, and underside are a solid black.

The big cats are able to roar because of their elongated and specially adapted larynx and hyoid apparatus, a unique part of the throat. When air passes through the larynx on the way from the lungs, the cartilage walls of the larynx vibrate, thus producing the characteristic roaring sound. The lion's larynx is the longest, giving it the most robust roar. An adult lion's roar can be heard for up to five miles (eight kilometers). As far as cougar, cheetah, and snow leopard are concerned, they do not roar, as their larynx creates more of a combination of hiss/snarl sound without the bass tone of a real roar.

The fastest of the big cats is the cheetah, which is also the fastest land animal. The adult male grows up to 7 feet (2.15m) long, weighing up to 55 kg. Cheetahs are shy and not very sociable with each other. With a slender body, long legs, and a long tail that lets it make very abrupt turns, the cheetah can reach speeds of up to 70 mph (113 kmh).

The cougar is a solitary cat, native to the Americas. It is also called puma, mountain lion, mountain cat, or panther, depending on the region. Although large, the cougar is most closely related to smaller felines and is genetically closer to the domestic cat than to true lions.

Male lions are characterized by their manes. They are unusually social, compared to other cats. They live in groups called pride; a single pride can have up to 25 lions, consisting of related females and offspring and a smaller number of adult males. Groups of females typically hunt together, preying mostly on large ungulates.

Leopards were once found across Eastern and Southern Asia and Africa, but their range of distribution has decreased radically due to hunting and loss of habitat. They are now chiefly found in sub-Saharan Africa, although there are scattered populations in India, Sri Lanka, Malaysia, Indonesia, and China.