The tiger (Panthera tigris) is the largest
cat species, reaching a total body length of up to 3.3 metres (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 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).
[4] In zoos, tigers have lived for 20 to 26 years, which also seems to be their longevity in the wild.
[5] 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 as
endangered by
IUCN. The global population in the wild is estimated to number between 3,062 to 3,948 individuals, down from around 100,000 at the start of the 20th century,
[6] with most remaining populations occurring in small pockets that are isolated from each other. Major reasons for population decline include
habitat destruction,
habitat fragmentation and
poaching.
[1] 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.
[7]
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.
[8] The
Bengal tiger is the
national animal of Bangladesh and India.
[9][10]
Contents
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hide]
Taxonomy and etymology
In 1758,
Linnaeus first described the species in his work
Systema Naturae under the
scientific name Felis tigris.
[3] In 1929, the British taxonomist
Reginald Innes Pocock subordinated the species under the genus
Panthera using the scientific name Panthera tigris.
[11]
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.
[12]
The word "tiger" is retraceable to the Latin word tigris meaning a spotted tigerhound of Actaeon.
[13] The Greek word tigris is possibly derived from a
Persian source.
[14]
Range of the tiger in 1900 and 1990
Characteristics 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 (Panthera tigris trinilensis) lived about 1.2 million years ago and is known from fossils found at
Trinil in
Java.
[15]
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 (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.
[16]
Characteristics
"Tiger tail" redirects here. It is not to be confused with
Tiger Tale,
Tiger Trail, or
Tigertail.
Tigers have muscular bodies with particularly powerful forelimbs and large heads. The pelage coloration varies between shades of orange or brown with white
ventral areas and distinctive black stripes. The face has 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.
[4] These spots, called
ocelli, play an important role in intraspecific communication.
[17]
The pattern of stripes is unique to each animal, these unique markings can be used by researchers to identify individuals (both in the wild and captivity), much in the same way that
fingerprints are used to identify humans. 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 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.
[18] 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).
[18] 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).
[19] Body size of different populations seems to be correlated with climate
Bergmann's Ruleand can be explained from the point of view of
thermoregulation.
[4] 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 reach 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).
[20][21] At the shoulder, tigers may variously stand 0.7 to 1.22 m (2.3 to 4.0 ft) tall.
[5] The accepted 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 by the fact that it had eaten a
water buffalo the previous night.
[22][23]
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.
[24] In addition, male tigers have wider forepaw pads than females. Biologists use this difference to determine gender based on tiger tracks.
[25] 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.
[26]
Subspecies
There are nine
subspecies of tiger, three of which are
extinct. Their historical range in
Bangladesh,
Siberia,
Iran,
Afghanistan,
India,
China, and
southeast Asia, including three
Indonesian islands is severely diminished today. The surviving subspecies, in descending order of wild population, are:
- The Bengal tiger (Panthera tigris tigris), also called the Indian tiger, lives in India, Nepal, Bhutan and Bangladesh, and is the most common subspecies with populations estimated at less than 2,500 adult individuals. In 2011 the total population of adult tigers is estimated at 1,5201,909 in India, 440 in Bangladesh, 155 in Nepal and 75 in Bhutan.[27] It lives in alluvial grasslands, subtropical and tropical rainforests, scrub forests, wet and dry deciduous forests, and mangroves. Male Bengal tigers had a total length, including the tail, of 270 to 310 cm (110 to 120 in), while females range from 240 to 265 cm (94 to 104 in). The weight of males range from 175 to 260 kg (390 to 570 lb), while that of the females range from 100 to 181 kg (220 to 400 lb).[4][28] In northern India and Nepal, tigers tend to be of larger size. Males often average 235 kilograms (520 lb), while females average 141 kilograms (310 lb).[29] In 1972, Project Tiger was founded in India aiming at ensuring a viable population of tigers in the country and preserving areas of biological importance as a natural heritage for the people.[30] But the illicit demand for bones and body parts from wild tigers for use in Traditional Chinese medicine is the reason for the unrelenting poaching pressure on tigers on the Indian subcontinent.[31] Between 1994 and 2009, the Wildlife Protection Society of India has documented 893 cases of tigers killed in India, which is just a fraction of the actual poaching and illegal trade in tiger parts during those years.[32] An area of special conservation interest lies in the Terai Arc Landscape in the Himalayan foothills of northern India and southern Nepal, where 11 protected areas comprising dry forest foothills and tall grass savannas harbor tigers in a 49,000 square kilometres (19,000 sq mi) landscape. The goals are to manage tigers as a single metapopulation, the dispersal of which between core refuges can help maintain genetic, demographic, and ecological integrity, and to ensure that species and habitat conservation becomes mainstreamed into the rural development agenda. In Nepal, a community-based tourism model has been developed with a strong emphasis on sharing benefits with local people and on the regeneration of degraded forests. The approach has been successful in reducing poaching, restoring habitats, and creating a local constituency for conservation.[33]
- The Indochinese tiger (Panthera tigris corbetti), also called Corbett's tiger, is found in Cambodia, China, Laos, Burma, Thailand, and Vietnam. These tigers are smaller and darker than Bengal tigers: Males weigh from 150190 kg (330420 lb) while females are smaller at 110140 kg (240310 lb). Their preferred habitat is forests in mountainous or hilly regions. According to government estimates of national tiger populations, the subspecies numbers around a total of 350 individuals.[34] All existing populations are at extreme risk from poaching, prey depletion as a result of poaching of primary prey species such as deer and wild pigs, habitat fragmentation and inbreeding. In Vietnam, almost three-quarters of the tigers killed provide stock for Chinese pharmacies.
- The Malayan tiger (Panthera tigris jacksoni), exclusively found in the southern part of the Malay Peninsula, was not considered a subspecies in its own right until 2004. The new classification came about after a study by Luo et al. from the Laboratory of Genomic Diversity Study, part of the National Cancer Institute of the United States. According to official government figures, the population in the wild may number around 500 individuals, but is under considerable poaching pressure. The Malayan tiger is the smallest of the mainland tiger subspecies, and the second smallest living subspecies, with males averaging about 120 kg (260 lb) and females about 100 kg (220 lb) in weight. The Malayan tiger is a national icon in Malaysia, appearing on its coat of arms and in logos of Malaysian institutions, such as Maybank.
- The Sumatran tiger (Panthera tigris sumatrae) is found only on the Indonesian island of Sumatra, and is critically endangered.[35] It is the smallest of all living tiger subspecies, with adult males weighing between 100140 kg (220310 lb) and females 75110 kg (170240 lb).[36] Their small size is an adaptation to the thick, dense forests of the island of Sumatra where they reside, as well as the smaller-sized prey. The wild population is estimated at between 400 and 500, seen chiefly in the island's national parks. Recent genetic testing has revealed the presence of unique genetic markers, indicating that it may develop into a separate species,[specify] if it does not go extinct.[37] This has led to suggestions that Sumatran tigers should have greater priority for conservation than any other subspecies. While habitat destruction is the main threat to existing tiger population (logging continues even in the supposedly protected national parks), 66 tigers were recorded as being shot and killed between 1998 and 2000, or nearly 20% of the total population.
- The Siberian tiger (Panthera tigris altaica), also known as the Amur tiger, inhabits the Amur-Ussuri region of Primorsky Krai and Khabarovsk Krai in far eastern Siberia.[38] It ranks among the biggest felids that have ever existed with a head and body length of 160180 cm (6371 in) for females and 190230 cm (7591 in) for males, plus a tail of about 60110 cm (2443 in) and an average weight of around 227 kg (500 lb) for males. Siberian tigers have thick coats and a paler golden hue and fewer stripes.[4] The heaviest wild Siberian tiger weighed 384 kg (850 lb) but according to Mazák this record is not reliable.[5] In 2005, there were 331393 adult-subadult Siberian tigers in the region, with a breeding adult population of about 250 individuals. The population has been stable for more than a decade, but partial surveys conducted after 2005 indicate that the Russian tiger population is declining.[39] At the turn of the century, the phylogenetic relationships of tiger subspecies was re-assessed, and a remarkable similarity between the Siberian and Caspian tiger observed indicating that the Siberian tiger population is the genetically closest living relative of the extinct Caspian tiger, and strongly implying a very recent common ancestry for the two groups.[40]
- The South China tiger (Panthera tigris amoyensis), also known as the Amoy or Xiamen tiger, is the most critically endangered subspecies of tiger and is listed as one of the 10 most endangered animals in the world.[41] One of the smaller tiger subspecies, the length of the South China tiger ranges from 2.22.6 m (87100 in) for both males and females. Males weigh between 127 and 177 kg (280 and 390 lb) while females weigh between 100 and 118 kg (220 and 260 lb). From 1983 to 2007, no South China tigers were sighted.[42] In 2007 a farmer spotted a tiger and handed in photographs to the authorities as proof.[42][43] The photographs in question, however, were later exposed as fake, copied from a Chinese calendar and digitally altered, and the "sighting" turned into a massive scandal.[44][45][46] In 1977, the Chinese government passed a law banning the killing of wild tigers, but this may have been too late to save the subspecies, since it is possibly already extinct in the wild. There are currently 59 known captive South China tigers, all within China, but these are known to be descended from only six animals. Thus, the genetic diversity required to maintain the subspecies may no longer exist.[citation needed] Currently, there are breeding efforts to reintroduce these tigers to the wild.[citation needed]
- The Bali tiger (Panthera tigris balica) was limited to the Indonesian island of Bali, and was the smallest subspecies with a weight of 90100 kg (200220 lb) in males and 6580 kg (140180 lb) in females.[5] Bali tigers were hunted to extinctionthe last Bali tiger, an adult female, is thought to have been killed at Sumbar Kima, West Bali on 27 September 1937. There is no Bali tiger in captivity. The tiger still plays an important role in Balinese Hinduism.
- The Caspian tiger (Panthera tigris virgata), also known as the Hyrcanian tiger or Turan tiger was found in the sparse forest habitats and riverine corridors west and south of the Caspian Sea and west through Central Asia into the Takla-Makan desert of Xinjiang, and has been recorded in the wild until the early 1970s.[47] The Amur tiger is the genetically closest living relative of the Caspian tiger.[40]
- The Javan tiger (Panthera tigris sondaica) was limited to the island of Java, and has been recorded until the mid-1970s.[48] Javan tigers were larger than Bali tigers; males weighed 100140 kg (220310 lb) and females 75115 kg (170250 lb).[49] After 1979, there were no more confirmed sightings in the region of Mount Betiri.[50] An expedition to Mount Halimun Salak National Park in 1990 did not yield any definite, direct evidence for the continued existence of tigers.[51]
Hybrids
Further information:
Panthera hybrid,
Liger and
Tiglon
Hybridisation among the big cats, including the tiger, was first conceptualised in the 19th century, when zoos were particularly interested in the pursuit of finding oddities to display for financial gain.
[52] Lions have been known to
breed with tigers (most often the
Amur and
Bengal subspecies) to create
hybrids called
ligers and
tigons.
[53] Such hybrids were once commonly bred in zoos, but this is now discouraged due to the emphasis on conserving species and subspecies. Hybrids are still bred in private menageries and in zoos in
China.
The liger is a cross between a male lion and a tigress.
[54] Because the lion sire passes on a growth-promoting gene, but the corresponding growth-inhibiting gene from the
female tiger is absent, ligers grow far larger than either parent. They share physical and behavioural qualities of both parent species (spots and stripes on a sandy background).
Male ligers are sterile, but female ligers are often fertile. Males have about a 50% chance of having a mane, but, even if they do, their manes will be only around half the size of that of a pure lion. Ligers are typically between 10 to 12 feet in length, and can be between 800 and 1,000 pounds or more.
[54]
The less common tigon is a cross between the lioness and the male tiger.
[55]
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