The tiger (Panthera tigris) is a mammal of the Felidae family, the largest of four "big cats" in the Panthera genus. Native to the mainland of Asia, the tiger is an apex predator and the largest feline species in the world, comparable in size to the biggest fossil felids. The Bengal Tiger is the most common subspecies of tiger, constituting approximately 80% of the entire tiger population, and is found in India, Bangladesh, Bhutan, Myanmar and Nepal. It has disappeared from much of its former distribution including the Caucasus, Java and Bali.
The tiger is an endangered species, with the majority of the world's tigers now living in captivity. Several subspecies are extinct and others critically endangered. Tigers have featured in ancient mythologies and folklore, and continue to be depicted in modern films and literature, as well as appearing on flags, coats of arms and as mascots for sporting teams. It is the national animal of India, and some other countries.
Naming and etymology
The word "tiger" is taken from the Greek word "tigris", which itself is derived "possibly from an Iranian source." It is said that "tigris" means arrow, and that the tiger was given this name due to its speed, which was its more famous trait in Ancient times. This would presumably be the origin of the Tigris river name. In American English, "Tigress" was first recorded in 1611. "Tiger's-eye" is a name for a golden-brown striped, chatoyant, fibrous variety of quartz used as a semi-precious gemstone. 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 their ("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".
Taxonomy and evolution
The Tiger is uncommon in the fossil record, which is why its evolution remains partly unclear. The oldest remains of a tiger like cat, called Panthera palaeosinensis have been found in China and Java. This species occurred about 2 million years ago at the beginning of the pleistocene and was smaller than a tiger. Early true tiger fossils stem from Java and are between 1.6 and 1.8 million years old. Distinct fossils from the early and middle Pleistocene were discovered in deposits from China, Sumatra and Java. A subspecies called Trinil tiger (Panthera tigris trinilensis) occurred about 1.2 million years ago and was found at the locality of Trinil, Java, Indonesia. In India, and northern Asia the tiger appears for the first time in the late pleistocene. Fossil tigers were also found in eastern Beringia (but not on the American Continent) and Sachalin island. Tiger fossils of the late Pleistocene have also turned up in Japan. These fossils indicate that the Japanese tiger was not bigger than the island subspecies of tigers of recent ages. This may be due to the phenomenon in which body size is related to environmental space (see island dwarfism), or in the case of a large predator like a tiger, availability of prey. Until the Holocene tigers occurred also in Borneo, where it is not present today.
There are nine recent subspecies of tiger, three of which are extinct, one of which is almost certain to become extinct in the near future, and five of which still occur. Their historical range (severely diminished today) ran through Russia, Siberia, Iran, Afghanistan, India, China and south-east Asia, including the Indonesian islands. These are the surviving subspecies, in descending order of wild population:
The Bengal tiger or the Royal Bengal tiger (Panthera tigris tigris) is found in parts of India, Bangladesh, Nepal, Bhutan and Myanmar. It lives in varied habitats: grasslands, subtropical and tropical rainforests, scrub forests, wet and dry deciduous forests and mangroves. The Indian government's estimated population figure for these tigers is between 3,100 and 4,500, some 3,000 of which are found in India alone. However, many Indian tiger conservationists doubt this number, seeing it as overly optimistic. The number of Bengal tigers in India may be fewer than 2,000, as most of the collected statistics are based on pugmark identification, which often gives a biased result. Even though this is the most 'common' tiger, these tigers are under severe pressure from both habitat destruction and poaching. In 1972, India launched a massive wildlife conservation project, known as Project Tiger, to protect the depleting numbers of tigers in India. The project helped increase the population of these tigers from 1,200 in the 1970s to 3,000 in the 1990s and is considered as one of the most successful wildlife conservation programs. At least one Tiger Reserve (Sariska) has lost its entire tiger population to poaching. Males in the wild usually weigh 205 to 227 kg (450-500 lb), while the average female will weigh about 141 kg. However, the northern Indian and the Nepalese Bengal tigers are supposed to be somewhat bulkier than those found in the south of the Indian Subcontinent, with males averaging around 520 lbs (236 kg).
The Indochinese tiger (Panthera tigris corbetti), also called Corbett's tiger, is found in Cambodia, China, Laos, Myanmar, Thailand, and Vietnam, preferring to exist in forests in mountainous or hilly regions. Estimates of its population vary between 1,200 to 1,800, with only several hundred left in the wild, but it seems likely that the number is in the lower part of the range; it is considered Endangered. The largest current population is in Malaysia, where illegal poaching is strictly controlled, but all existing populations are at extreme risk from habitat fragmentation and inbreeding. In Vietnam, almost three-quarters of the tigers killed provide stock for Chinese pharmacies. Also, the tigers are seen by poor natives as a resource through which they can ease poverty. Indochinese tigers are smaller and darker than Bengal tigers. Males weigh from 150-190 kg (330-420 lb) on average while females are smaller at 110-140 kg (242-308 lb).
The Malayan tiger (Panthera tigris malayensis), exclusively found in the southern (Malaysian) 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. Recent counts showed there are 600-800 tigers in the wild, making it the third largest tiger population behind the Bengal tiger and the Indochinese tiger. 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. 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, if it is not made extinct. This has led to suggestions that Sumatran tigers should have greater priority for conservation than any other subspecies. Habitat destruction is the main threat to the existing tiger population (logging continues even in the supposedly protected national parks), but 66 tigers were recorded as being shot and killed between 1998 and 2000, or nearly 20% of the total population. The Sumatran tiger is the smallest of all living tiger subspecies. Adult males weigh between 100-130 kg (220-286 lb), females 70-90 kg (154-198 lb). Their small size is an adaptation to the thick, dense forests of the Sumatra island where they reside, as well as the smaller-sized prey. On February 3, 2007 a pregnant Sumatran Tiger was caught by people from Rokan Hilir village at Riau province. Indonesian fauna conservation officials are planning to transfer her to the Bogor Safari Park in Java.
The Amur tiger (Panthera tigris altaica), also known as the Siberian, Manchurian or North China tiger, is confined completely to the Amur region in far eastern Siberia, where it is now protected. The last two censuses (1996 and 2005) found 450-500 Amur tigers within their single and more or less continuous range making it one of the largest undivided tiger populations in the world. Considered the largest subspecies, with an average weight of around 227 kg (500 lb) for males. The Amur tiger is also noted for its thick coat, distinguished by a paler golden hue and a smaller number of stripes. The Amur tiger is the largest and heaviest of all naturally-occurring felines. A six-month old Amur tiger can be as big as a fully grown leopard.
South China tiger
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 species in the world. will almost certainly become extinct. It is one of the smaller tiger subspecies. The length of the South China tiger ranges from 2.2-2.6 m (87-104 in) for both males and females. Males weigh between 127 and 177 kg (280-390 lb) while females weigh between 100 and 118 kg (220-260 lb). From 1983 to 2007, no South China tigers were sighted. In 2007 a farmer spotted a tiger and handed in photographs to the authorities as proof. 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. 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, making extinction a possibility. Currently, there are breeding efforts to reintroduce these tigers to the wild by 2008.
There is a well-known mutation that produces the white tiger (the correct term used is chinchilla albinistic), an animal which is rare in the wild, but widely bred in zoos due to its popularity, and because white tigers have proved helpful in solving the continual problem of inbreeding; many initiatives have taken place in white and orange tiger mating in attempt to remedy the issue. Recordings of white tigers were first made in the early 19th century. They can only occur when both parents carry the rare gene found in White tigers; this gene has been calculated to occur in only one in every 10,000 births. The white tiger is not a separate sub-species, but only a color variation, and this is a common misconception. Another misconception is that White tigers are albinos, despite the fact that pigment is evident in the White tiger's stripes. They are distinct not only because of their white hue; they have distinctive blue eyes and pink noses. There are also unconfirmed reports of a "blue" or slate-colored tiger, and largely or totally black tigers, and these are assumed, if real, to be intermittent mutations rather than distinct species.
The Balinese tiger (Panthera tigris balica) has always been limited to the island of Bali. These tigers were hunted to extinction—the last Balinese tiger is thought to have been killed at Sumbar Kima, West Bali on 27 September 1937; this was an adult female. No Balinese tiger was ever held in captivity. The tiger still plays an important role in Balinese Hindu religion.
The Javan tiger (Panthera tigris sondaica) was limited to the Indonesian island of Java. It now seems likely that this subspecies became extinct in the 1980s, as a result of hunting and habitat destruction, but the extinction of this subspecies was extremely probable from the 1950s onwards (when it is thought that fewer than 25 tigers remained in the wild). The last specimen was sighted in 1979, but there was a re-ignition of reported sightings during the 1990s.
The Caspian tiger or Persian Tiger (Panthera tigris virgata) appears to have become extinct in the late 1950s, with the last reliable sighting in 1968, though it is thought that such a tiger was last shot dead in the south-eastern-most part of Turkey in 1970. Historically it ranged through Afghanistan, Iran, Iraq, Pakistan, the former Soviet Union, and Turkey. The Caspian tiger was a large subspecies and reached nearly the dimensions of the Bengal Tiger. The heaviest confirmed weight of a male was 240 kg. The ground color was comparable to that of the Indian subspecies, but differed especially in the tight, narrow striping pattern. The stripes were rather dark grey or brown than black. Especially during the winter, the fur was relatively long. The Caspian tiger was one of two subspecies of tiger (along with the Bengal) that was used by the Romans to battle gladiators and other animals, including the Barbary Lion. The Romans traveled far to capture exotic beasts for the arena. There are still occasional reported sightings of the Caspian Tiger in the wild.
Hybridization among the big cats, including the tiger, was first conceptualized in the 19th century when zoos were particularly interested in the pursuit of finding oddities to display for financial gain.
Lions have also been known to breed with tigers (most often the Amur and Bengal subspecies) to create hybrids called ligers and tigons. The liger is a cross between a male lion and a tigress. Because the lion sire passes on a growth-promoting gene, but the corresponding growth-inhibiting gene from the female lion is absent, ligers grow far larger than either parent. They share physical and behavioral 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 if they grow one their manes will be modest: around 50% of a pure lion mane. Ligers are typically between 10 to 12 feet in length, and can be between 800 and 1,000 pounds or more. The less common tigon is a cross between the lioness and the male tiger. 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.
Biology and behavior
Tigers are the heaviest cats found in the wild, but the subspecies differ strongly in size, tending to increase proportionally with latitude, as predicted by Bergmann's Rule. Large male Siberian Tigers (Panthera tigris altaica) can reach a total length of 3.5 m and a weight of 306 kg. Apart from those exceptional large individuals, male Siberian tigers usually have a head and body length of 190-220 cm and an average weight of 227 kg (The tail of a tiger is 60-110 cm long.) The heaviest siberian tiger 384 kg, but according to Mazak these giants are not confirmed via reliable references. Females are smaller, those of the Siberian or Indian subspecies weigh only between 100 and 181 kg. Isle tigers like the Sumatran subspecies (P. t. sumatrae) are much smaller than mainland tigers and weigh usually only 100-140 kg in males and 75-110 kg in females. The extinct Bali Tiger (P. t. balica) was even smaller with a weight of 90-100 kg in males and 65-80 kg in females.
Tigers have rusty-reddish to brown-rusty coats, a fair (whitish) medial and ventral area and stripes that vary from brown or hay to pure black. The form and density of stripes differs between 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 hide these animals from their prey. The stripe pattern is found on a tiger's skin and if shaved, its distinctive camouflage pattern would be preserved.
Like most cats, tigers are believed to have some degree of color vision.
Adult tigers are fiercely territorial. The size of a tiger's home range mainly depends on prey abundance, and, in the case of male tigers, on access to females. A tigress may have a territory of 20 km² while the territories of males are much larger, covering 60-100 km². While females can at times be aggressive towards other females, their territories can overlap and they do tolerate each other. Males, however, are usually intolerant of other males within their territory. Because of their aggressive nature, territorial disputes can be violent, and may end in the death of one of the males. To identify his territory, the male marks trees by spraying urine and anal gland secretions on trees as well as by marking trails with scat. Males show a grimacing face, called the Flehmen response, when identifying a female's reproductive condition by sniffing their urine markings.
Male tigers can mingle easily with females in their territories and will even share kills. George Schaller observed a male tiger share a kill with two females and four cubs. Females are often reluctant to let males near their cubs, but Schaller saw that these females made no effort to protect or keep their cubs from the male. This suggests that the male might have been the father of the cubs. In contrast to male lions, male tigers will allow the females and cubs to feed on the kill first. Females will also share kills, even more so than the males. They are also much more tolerant of sharing kills with individuals of the same sex.
Tigers have been studied in the wild using a variety of techniques. The populations of tigers were estimated in the past using plaster casts of their pugmarks. In recent times, camera trapping has been used instead. Newer techniques based on DNA from their scat are also being evaluated. Radio collaring has also been a popular approach to tracking them for study in the wild.
Hunting and diet
In the wild, tigers mostly feed on larger and medium sized animals. Sambar, gaur, water buffalo, chital, wild boar and nilgai are the tiger's favored prey in India. In Siberia the main prey species are Mandchurian elk, wild boar, sika deer, roe deer and musk deer. In Sumatra rusa deer, wild boar and Malayan tapir are preyed on. In the former Caspian tiger's range saiga, camels, Caucasian Wisent, yak and wild horses were preyed. Like many predators, they are opportunistic and will eat much smaller prey such as as monkeys, peacocks, hares and fish.
They also may kill such formidable predators as dholes, leopards, and pythons. Tigers have been known to kill even crocodiles on occasion, although predation is rare and the predators typically avoid one another. Siberian tigers and brown bears are a serious threat to each other and usually avoid confrotation; however, tigers will kill bear cubs and even some adults on occasion. Bears (Asiatic black bears and brown bears) make up 5-8% of the tigers diet in the Russian Far East. Sloth bears are quite aggressive and will sometimes drive tigers away from their kills although the opposite happens as well and in some cases tigers even prey on sloth bears.
Adult elephants are too dangerous to tigers to serve as common prey, but conflicts between elephants and tigers do sometimes take place. A case where a tiger killed an adult female Indian rhino has been observed. Young elephant and rhino calves are occasionally taken.
Tigers sometimes prey on domestic animals such as dogs, cows, horses and donkeys. These individuals are termed cattle-lifters or cattle-killers in contrast to typical game-killers. Especially old and injured tigers have been known to attack humans and are then termed as man-eaters, which often leads to them being captured, shot or poisoned. Man-eaters have been a recurrent problem for India, especially in Kumaon and Garhwal in the early part of the twentieth century, notable accounts of the hunting of which have been written by Jim Corbett. The Sundarbans mangrove swamps of Bengal, where some healthy tigers have been known to hunt humans, have had a higher incidence of man-eaters.
Tigers hunt alone and prefer medium to large sized herbivores. They ambush their prey as other cats do, overpowering them from any angle, using their body size and strength to knock large prey off balance. Even with their great masses, tigers can reach speeds of about 49-65 km/h (35-40 mph). Tigers prefer to bite the throats of large prey and use their muscled forelimbs to hold onto the prey, bringing it to the ground. The tiger remains latched onto the neck until its prey dies. With small prey, the tiger bites the nape, often breaking the spinal cord, piercing the windpipe, or severing the jugular vein or carotid artery. The prey is killed instantly.
In the wild, tigers can leap as high as 5 m (16 ft) and as far as 9-10 m (30-33 ft), making them one of the highest-jumping mammals (just slightly behind cougars in jumping ability).
They have been reported to carry domestic livestock weighing 50 kg (110 lb) while easily jumping over fences 2 m (6 ft 6 in) high. Their heavily muscled forelimbs are used to hold tightly onto the prey and to avoid being dislodged, especially by large prey such as gaurs. Gaurs and water buffalos weighing over a ton have been killed by tigers weighing about a sixth as much. The combination of claws and power behind a tiger's paws enables it to kill an adult human with one swipe.
A female is only receptive for a few days and mating is frequent during that time period. A pair will copulate frequently and noisily, like other cats. The gestation period is 16 weeks and 3-4 cubs of about 1 kg (2 lb) each are born. The females rear them alone. Wandering male tigers may kill cubs to make the female receptive. At 8 weeks, the cubs are ready to follow their mother out of the den. The cubs become independent around 18 months of age, but it is not until they are around 2-2½ years old that they leave their mother. The cubs reach sexual maturity by 3-4 years of age. The female tigers generally own territory near their mother, while males tend to wander in search of territory, which they acquire by fighting and eliminating another male. Over the course of her life, a female tiger will give birth to an approximately equal number of male and female cubs. Tigers breed well in captivity, and the captive population in the United States may rival the wild population of the world.
Tigers are found in a variety of habitats, including both tropical and evergreen forests, woodlands, grasslands, rocky country, swamps, and savannas. The Caspian tiger was also found in steppes and mountainous areas. Compared to the lion, the tiger prefers more dense vegetation, for which its camouflage is ideally suited, and where a single predator is not at a disadvantage compared to a pride. Among the big cats, only the tiger and jaguar are strong swimmers; tigers are often found bathing in ponds, lakes, and rivers.
A tiger marks its territory with a strong mix of urine and other bodily fluids marked on trees, bushes, rocks, and soil, as well as by scratches made on trees. This territory can vary from only a few square miles in area, to over fifty square miles. It is a common trend of these territories that a males will encompass ground taken by a female. Tigers defend their territory fiercely and actively; out of all of the big cats, the tiger has killed the most humans, and much of the time, these humans are killed because they ventured into an area that is part of a tiger's territory.
Humans are the tiger's most significant predator, as tigers are often poached illegally for their fur. Many Indian tigers' parts found their way to Tibet, where they were widely used for making traditional costumes.
At the Kalachakra Tibetan Buddhist festival in south India in January 2006 the Dalai Lama preached a ruling against using, selling, or buying wild animals, their products, or derivatives. The result when Tibetan pilgrims returned to Tibet afterwards was much destruction by Tibetans of their wild animal skins including tiger and leopard skins used as ornamental garments. It has yet to be seen whether this will result in a long-term slump in the demand for poached tiger and leopard skins.
Their bones and nearly all body parts are used in traditional Chinese medicine for a range of purported uses including pain killers and aphrodisiacs. The use of tiger parts in pharmaceutical drugs in China is already banned. China has even made some offenses in connection with Tiger poaching punishable by death. Though it has been made illegal, China's wealthy businessmen are known to eat Tiger penis as they feel it is an aphrodisiac. Poaching for fur and destruction of habitat have greatly reduced tiger populations in the wild. A century ago, it is estimated there were over 100,000 tigers in the world but the population has dwindled to between 7,000 and 5,000 tigers. Some estimates suggest the population is even lower, with some at less than 2,500 mature breeding individuals, with no subpopulation containing more than 250 mature breeding individuals. The threat of extinction is mitigated somewhat by the presence of some 20,000 tigers currently in captivity, although parts of the captive population (eg. the 4-5,000 animals in China's commercial tiger farms) is of very low genetic diversity and can be of little use in keeping the species alive.
World's Favorite Animal
In a poll conducted by Animal Planet, the Tiger was voted World's Favorite Animal, narrowly beating the man's best friend, the dog. More than 50000 viewers from 73 countries voted in the poll. The tiger received 21 percent of the vote, the dog 20, the dolphin 13, the horse 10, the lion 9, the snake 8, followed by the elephant, the chimp, the orangutan and the whale. Tigers obtained 10 904 votes, just 17 votes more than dogs.
Animal behaviorist Candy d'Sa, who worked with Animal Planet on the list, said: "We can relate to the tiger, as it is fierce and commanding on the outside, but noble and discerning on the inside".
Callum Rankine, international species officer at the World Wildlife Federation conservation charity, said the result gave him hope. "If people are voting tigers as their favorite animal, it means they recognize their importance, and hopefully the need to ensure their survival," he said.
Traditional Asian medicine
Many people in China have a belief that tiger parts have medicinal properties, and tiger parts are used in some traditional Chinese medicines. There is no scientific evidence to support this belief. Although all trade in tiger parts is illegal under CITES and a domestic trade ban has been in place in China since 1993 there are still a number of tiger farms in the country specializing in breeding the cats for profit from meat and other tiger products. It is estimated that between 4000 and 5000 captive-bred, semi-tame animals live in these farms today.
The American Zoo and Aquarium Association estimates that up to 12,000 tigers are being kept as private pets in the USA, which is significantly more than the world's entire wild population. 4000 are believed to be in captivity in Texas alone.
A well known pop culture reference to the keeping of tigers as pets can be found in the Brian De Palma remake of Scarface starring Al Pacino. Pacino's character, Tony Montana, aspires to obtaining all the exterior trappings of the American Dream, which in the character's opinion included the ownership of a pet tiger, in this case kept on chain on his property.
Part of the reason for America's enormous tiger population relates to legislation. Only nineteen states have banned private ownership of tigers, fifteen require only a license, and sixteen states have no regulations at all.
The success of breeding programs at American zoos and circuses led to an overabundance of cubs in the 1980s and 90s, which drove down prices for the animals. The SPCA estimate there are now 500 lions, tigers and other big cats in private ownership just in the Houston area.
The tiger as a national animal
The Tiger is the national animal of:
- Bangladesh (Royal Bengal Tiger)
- India (Royal Bengal Tiger)
- Malaysia (Malayan Tiger)
- Nepal (Royal Bengal Tiger)
- North Korea (Siberian Tiger)
- South Korea (Siberian Tiger)
- Former Nazi Germany along with the black eagle (currently it is the black eagle (Bundesadler) (official) and leopard (unofficial)
- Former USSR (Siberian Tiger) (currently it is the Bear and golden bicephalic eagle)
- Kingdom: Animalia
- Phylum: Chordata
- Class: Mammalia
- Order: Carnivora
- Family: Felidae
- Genus: Panthera
- Species: P. tigris
Panthera tigris (Linnaeus, 1758)
- Felis tigris Linnaeus, 1758
- Tigris striatus Severtzov, 1858
- Tigris regalis Gray, 1867
Historical distribution of tigers (pale yellow) and 2006 (green).