Tiger

Conservation status:Endangered
Scientific classification
Kingdom:Animalia
Phylum:Chordata
Class:Mammalia
Order:Carnivora
Family:Felidae
Genus:Panthera
Species:P. tigris

The tiger is a member of the Felidae family; the largest of the four "big cats" in the genus Panthera. Native to much of eastern and southern Asia, the tiger is an apex predator and an obligate carnivore. Reaching up to 4 metres (13 ft) in total length and weighing up to 300 kilograms (660 pounds), the larger tiger subspecies are comparable in size to the biggest extinct felids. Aside from their great bulk and power, their most recognizable feature is the pattern of dark vertical stripes that overlays near-white to reddish-orange fur, with lighter underparts. The most numerous tiger subspecies is the Bengal tiger while the largest subspecies is the Siberian tiger.
Highly adaptable, tigers range from the Siberian taiga, to open grasslands, to tropical mangrove swamps. They are territorial and generally solitary animals, often requiring large contiguous areas of habitat that support their prey demands. This, coupled with the fact that they are endemic to some of the more densely populated places on earth, has caused significant conflicts with humans. Of the nine subspecies of modern tiger, three are extinct and the remaining six are classified as endangered, some critically so. The primary direct causes are habitat destruction and fragmentation, and hunting. Their historical range, which once reached from Mesopotamia and the Caucasus through most of South and East Asia, has been radically reduced. While all surviving species are under formal protection, poaching, habitat destruction and inbreeding depression continue to be threats.
Nonetheless, tigers are among the most recognizable and popular of the world's charismatic megafauna. They have featured prominently in ancient mythology and folklore, and continue to be depicted in modern films and literature. Tigers appear on many flags and coats of arms, as mascots for sporting teams, and as the national animal of several Asian nations.

Naming and etymology
The word "tiger" is taken from the Greek word "tigris", which is possibly derived from a Persian source meaning "arrow", a reference to the animal's speed and also the origin for the name of the River Tigris. In American English, "Tigress" was first recorded in 1611. It was one of the many species originally described, as Felis tigris, by Linnaeus in his 18th century work, Systema Naturae. The generic component of its scientific designation, Panthera tigris, is often presumed to derive from Greek pan- ("all") and theron ("beast"), but this may be a folk etymology. Although it came into English through the classical languages, panthera is probably of East Asian origin, meaning "the yellowish animal," or "whitish-yellow".
A group of tigers is rare (see below), but when seen together is termed a 'streak' or an 'ambush'.
Range of the tiger including the western part 1900 and 1990

Range
In the historical past, tigers were widespread in Asia, from the Caucasus and the Caspian Sea, to Siberia and Indonesia. During the 19th century the striped cats completely vanished from western Asia, and became restricted to isolated pockets in the remaining parts of their range. Today, this fragmented relic range extends from India in the west to China and Southeast Asia in the east. The northern limit is close to the Amur River in south eastern Siberia. The only large island inhabited by tigers today is Sumatra. Tigers vanished from Java and Bali during the 20th century, and in Borneo are known only from fossil remains.

Physical characteristics, taxonomy and evolution
The oldest remains of a tiger-like cat, called Panthera palaeosinensis, have been found in China and Java. This species lived about 2 million years ago, at the beginning of the Pleistocene, and was smaller than a modern tiger. The earliest fossils of true tigers are known from Java, and are between 1.6 and 1.8 million years old. Distinct fossils from the early and middle Pleistocene were also discovered in deposits from China, and Sumatra. A subspecies called the Trinil tiger lived about 1.2 million years ago and is known fossils found at Trinil in Java.
Tigers first reached India and northern Asia in the late Pleistocene, reaching eastern Beringia (but not the American Continent), Japan, and Sakhalin. Fossils found in Japan indicate that the local tigers were, like the surviving island subspecies, smaller than the mainland forms. This may be due to the phenomenon in which body size is related to environmental space or perhaps the availability of prey. Until the Holocene, tigers also lived in Borneo, as well as on the island of Palawan in the Philippines.

Physical characteristics
Tigers are perhaps the most recognisable of all the cats (with the possible exception of the lion). They typically have rusty-reddish to brown-rusty coats, a whitish medial and ventral area, a white "fringe" that surrounds the face, and stripes that vary from brown or gray to pure black. The form and density of stripes differs between subspecies (as well as the ground coloration of the fur; for instance, Siberian tigers are usually paler than other tiger subspecies), but most tigers have over 100 stripes. The pattern of stripes is unique to each animal, and thus could potentially be used to identify individuals, much in the same way as fingerprints are used to identify people. This is not, however, a preferred method of identification, due to the difficulty of recording the stripe pattern of a wild tiger. It seems likely that the function of stripes is camouflage, serving to help tigers conceal themselves amongst the dappled shadows and long grass of their environment as they stalk their prey. The stripe pattern is found on a tiger's skin and if shaved, its distinctive camouflage pattern would be preserved. Like other big cats, tigers have a white spot on the backs of their ears.

Skeleton
Tigers have the additional distinction of being the heaviest cats found in the wild. They also have powerfully built legs and shoulders, with the result that they, like lions, have the ability to pull down prey substantially heavier than themselves. However, the subspecies differ markedly in size, tending to increase proportionally with latitude, as predicted by Bergmann's Rule. Thus, large male Siberian Tigers can reach a total length of 3.5 m "over curves" (3.3 m. "between pegs") and a weight of 306 kilograms, which is considerably larger than the sizes reached by island-dwelling tigers such as the Sumatran, the smallest living subspecies with a body weight of only 75-140 kg. Tigresses are smaller than the males in each subspecies, although the size difference between male and female tigers tends to be more pronounced in the larger subspecies of tiger, with males weighing up to 1.7 times as much as the females. In addition, male tigers have wider forepaw pads than females. This difference is often used by biologists in determining the gender of tigers when observing their tracks. The skull of the tiger is very similar to that of the lion, though the frontal region is usually not as depressed or flattened, with a slightly longer postorbital region. The lion's skull has broader nasal openings. However, due to the amount of skull variation in the two species, usually, only the structure of the lower jaw can be used as a reliable indicator of species.