Tiger

The tiger (Panthera tigris) is the largest cat species, reaching a total body length of up to 3.3 m (11 ft) and weighing up to 306 kg (670 lb). It is the third largest land carnivore (behind only the polar bear and the brown bear). Its most recognizable feature is a pattern of dark vertical stripes on reddish-orange fur with a lighter underside. It has exceptionally stout teeth, and the canines are the longest among living felids with a crown height of as much as 74.5 mm (2.93 in) or even 90 mm (3.5 in). In zoos, tigers have lived for 20 to 26 years, which also seems to be their longevity in the wild.They are territorial and generally solitary but social animals, often requiring large contiguous areas of habitat that support their prey requirements. This, coupled with the fact that they are indigenous to some of the more densely populated places on Earth, has caused significant conflicts with humans.

Tigers once ranged widely across Asia, from Turkey in the west to the eastern coast of Russia. Over the past 100 years, they have lost 93% of their historic range, and have been extirpated from southwest and central Asia, from the islands of Java and Bali, and from large areas of Southeast and Eastern Asia. Today, they range from the Siberian taiga to open grasslands and tropical mangrove swamps. The remaining six tiger subspecies have been classified asendangered by IUCN. The global population in the wild is estimated to number between 3,062 and 3,948 individuals, down from around 100,000 at the start of the 20th century, with most remaining populations occurring in small pockets isolated from each other. Major reasons for population decline include habitat destruction, habitat fragmentation and poaching. The extent of area occupied by tigers is estimated at less than 1,184,911 km² (457,497 sq mi), a 41% decline from the area estimated in the mid-1990s.

Tigers are among the most recognisable 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, coats of arms, and as mascots for sporting teams. The Bengal tigeris the national animal of both India and Bangladesh.

In 1758, Linnaeus first described the species in his work Systema Naturae under the scientific name Felis tigris. In 1929, the British taxonomist Reginald Innes Pocock subordinated the species under the genus Panthera using the scientific name Panthera tigris.

The word Panthera is probably of Oriental origin and retraceable to the Ancient Greek word panther, the Latin word panthera, the Old French word pantere, most likely meaning "the yellowish animal", or from pandarah meaning whitish-yellow. The derivation from Greek pan- ("all") and ther ("beast") may be folk etymology that led to many curious fables.

The word "tiger" is traceable to the Latin word tigris, meaning "a spotted tigerhound of Actaeon". The Greek word tigris is possibly derived from a Persian source.

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 in China and Sumatra. A subspecies called the Trinil tiger (Panthera tigris trinilensis) lived about 1.2 million years ago and is known from 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 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 (see insular dwarfism), 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

Tigers have muscular bodies with particularly powerful forelimbs and large heads. The pelage coloration varies between shades of orange or brown with whiteventral areas and distinctive black stripes. Their faces have long whiskers, which are especially long in males. The pupils are circular with yellow irises. The small, rounded ears have black markings on the back, surrounding a white spot. These spots, called ocelli, play an important role in intraspecific communication.

The pattern of stripes is unique to each animal, and these unique markings can be used by researchers to identify individuals (both in the wild and captivity), in much the same way as fingerprints are used to identify humans. The function of stripes is likely camouflage, serving to help tigers conceal themselves amongst the dappled shadows and long grass of their environments as they stalk their prey. The stripe pattern is also found on the skin of the tiger. If a tiger were to be shaved, its distinctive camouflage pattern would be preserved.

Tigers are the most variable in size of all big cats, even more so than leopards and much more so than lions. The Bengal, Caspian and Siberian tiger subspecies represent the largest living felids, and rank among the biggest felids that ever existed. An average adult male tiger from Northern India or Siberia outweighs an average adult male lion by around 45.5 kg (100 lb). Females vary in length from 200 to 275 cm (79 to 108 in), weigh 65 to 167 kg (140 to 370 lb) with a greatest length of skull ranging from 268 to 318 mm (10.6 to 12.5 in). Males vary in size from 250 to 390 cm (98 to 150 in), weigh 90 to 306 kg (200 to 670 lb) with a greatest length of skull ranging from 316 to 383 mm (12.4 to 15.1 in). Body size of different populations seems to be correlated with climate—Bergmann's rule—and can be explained by thermoregulation. Large male Siberian tigers can reach a total length of more than 3.5 m (11.5 ft) "over curves", 3.3 m (10.8 ft) "between pegs" and a weight of 306 kg (670 lb). This is considerably larger than the size reached by the smallest living tiger subspecies, the Sumatran tiger, which reaches a body weight of 75 to 140 kg (170 to 310 lb). Of the total length of a tiger, the tail comprises 0.6 to 1.1 m (2.0 to 3.6 ft). At the shoulder, tigers may variously stand 0.7 to 1.22 m (2.3 to 4.0 ft) tall. The current record weight, per the Guinness Book of World Records, for a wild tiger was 389 kg (860 lb) for a Bengal tiger shot in 1967, though its weight may have been boosted because it had eaten a water buffalothe previous night.

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 tiger subspecies, with males weighing up to 1.7 times more than the females. In addition, male tigers have wider forepaw pads than females. Biologists use this difference in tracks to determine gender. 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 skull of a lion 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.