Big cat

The term big cat – which is not a biological classification – is used informally to distinguish the larger felid species from smaller ones. One definition of "big cat" includes the four members of the genus Panthera: the tiger, lion, jaguar, and leopard. Members of this genus are the only cats able to roar. A more expansive definition of "big cat" also includes the cheetah, snow leopard, clouded leopard, and cougar.

Despite enormous differences in size, the various species of cat are quite similar in both structure and behavior, with the exception of the cheetah, which is significantly different from any of the big or small cats. All cats are carnivores and efficient apex predators. Their range includes the Americas, Africa, Asia, and Europe.

Roaring
The ability to roar comes from an elongated and specially adapted larynx and hyoid apparatus. (However, the snow leopard cannot roar, despite having hyoid morphology similar to roaring cats.) When air passes through the larynx on the way from the lungs, the cartilage walls of the larynx vibrate, producing sound. The lion's larynx is longest, giving it the most robust roar.

Threats
The principal threats to big cats varies upon geographical location, but primarily are habitat destruction and poaching. In Africa many big cats are persecuted by pastoralists or government 'problem animal control' officers. Certain protected areas exist that shelter large and exceptionally visible populations of lions, hyenas, leopards and cheetahs, such as Botswana’s Chobe, Kenya’s Masai Mara and Tanzania’s Serengeti. It is rather outside these conservation areas where persecution poses the dominant threat to large carnivores.

In the United States, 19 states have banned ownership of big cats and other dangerous exotic animals as pets, and the Captive Wildlife Safety Act bans the interstate sale and transportation of these animals.

Species
Family Felidae
 * Genus Panthera (roaring or great cats)
 * Tiger, Panthera tigris (Asia)
 * Lion, Panthera leo (Africa, Gir Forest in India; extinct in former range of southeast Europe, Middle East, much of Asia, and North America)
 * Jaguar, Panthera onca (the Americas; from the Southern United States and Mexico to northern Argentina)
 * Leopard, Panthera pardus (Asia and Africa)
 * Genus Acinonyx
 * Cheetah, Acinonyx jubatus (Africa and Iran; extinct in former range of India)
 * Genus Puma
 * Cougar, Puma concolor (North and South America)
 * Genus Uncia
 * Snow Leopard, Uncia uncia (mountains of central and south Asia)
 * Genus Neofelis
 * Clouded Leopard, Neofelis nebulosa (southeast and south Asia)
 * Sunda Clouded Leopard, Neofelis diardi (Borneo and Sumatra)

Evolution
A 2010 study published in Molecular Phylogenetics and Evolution has given insight into the exact evolutionary relationships of the big cats. The study reveals that the snow leopard and the tiger are sister species, while the lion, leopard, and jaguar are more closely related to each other. The tiger and snow leopard diverged from the ancestral big cats approximately 3.9 Ma. The tiger then evolved into a unique species towards the end of the Pliocene epoch, approximately 3.2 Ma. The ancestor of the lion, leopard, and jaguar split from other big cats from 4.3–3.8 Ma. Between 3.6–2.5 Ma the jaguar diverged from the ancestor of lions and leopards. Lions and leopards split from one another approximately 3.1–1.95 Ma.