Tiger
Panthera Tigris
P. Meier
Description
The tiger (Panthera tigris) evolved alongside other modern felids in the Panthera genus from an ancestral cat species around 10.8 million years ago. Several million years later, it diverged with the other “great roaring cats” of the modern Panthera genus. The oldest known tiger fossils, approximately two million years old, were discovered in China and on Java, Indonesia.
Historically, the tiger ranged widely across southern and eastern Asia. Around 73,000 years ago, the Toba volcanic eruption on Sumatra may have caused a major reduction in its range, a population bottleneck, and a subsequent decline in genetic diversity among survivors. The most recent common ancestor for tiger matrilineal mitochondrial DNA is estimated to have lived between 72,000 and 108,000 years ago.
Traditionally, the modern tiger was considered to comprise six extant and three extinct subspecies. The six-living subspecies, identified by distinctive molecular markers, are:
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Amur tiger (Panthera tigris altaica) – inhabits the Russian Far East and north-eastern China
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South China tiger (Panthera tigris amoyensis) – likely extinct in the wild, now found only in captivity
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Northern Indochinese tiger (Panthera tigris corbetti) – occurs in Indochina north of the Malay Peninsula
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Malayan tiger (Panthera tigris jacksoni) – found on the Malay Peninsula
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Sumatran tiger (Panthera tigris sumatrae) – native to Sumatra
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Bengal tiger (Panthera tigris tigris) – inhabits the Indian subcontinent
The three recognised extinct subspecies, based on morphological differences, are:
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Bali tiger (Panthera tigris balica) – formerly on Bali
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Javan tiger (Panthera tigris sondaica) – formerly on Java
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Caspian tiger (Panthera tigris virgata) – formerly in western Asia, including Afghanistan, Iran, Turkey, and surrounding regions
Recent genetic studies, however, propose only two subspecies:
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Panthera tigris tigris, which includes virgata, altaica, amoyensis, corbetti, and jacksoni, occurring across mainland Asia
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Panthera tigris sondaica, which includes balica and sumatrae, occurring on Sumatra and formerly on Java and Bali
These inconsistencies in subspecies classification largely stem from limited genetic sampling across the tiger’s range. Consequently, the taxonomy of this species is currently under review by the IUCN SSC Cat Specialist Group.
Tiger subspecies sizes
Weight
75 - 325 kg
Body Length
150 - 230 cm
Tail Length
90 - 110 cm
Longevity
12 - 15 years
Litter Size
1 - 5 cubs
S. Clayton
The tiger is the largest living cat species, although size varies among subspecies, and large lions (Panthera leo) can exceed smaller tigers in size. Tigers are the only cats with stripes, featuring a reddish-orange to yellow-ochre coat with black stripes and a white underside. Stripe patterns are unique to each individual, varying in number, width, and whether they split or form spots. Dark lines above the eyes tend to be symmetrical, while facial markings differ. Males have a prominent ruff, particularly pronounced in the Sumatran tiger.
In India, tigers with white coats, ashy-grey or brown stripes, and blue eyes have been recorded in forests of Assam, Odisha, Madhya Pradesh, and Bihar. The last documented white tiger was shot in Bihar in 1958; none have been reported since.
Tigers evolved to hunt large ungulates efficiently, possessing a relatively large skull, formidable canines, and a powerful build.
IUCN SSC Cat Specialist Group 2022. Panthera tigris. The IUCN Red List of Threatened Species. Version 2024-2
Status and Distribution
The tiger is listed as Endangered on the IUCN Red List. In 2009, the in-situ population was estimated at around 3,200 individuals, with likely fewer than 2,500 mature individuals. This represents a dramatic decline from an estimated 100,000 at the start of the 20th century. Many populations are now extremely small and isolated. In 2010, populations from 42 protected sites with evidence of breeding were estimated at only 2,154 individuals. Estimates for tigers outside protected areas remain uncertain.
By 2021, the global population was estimated at 3,726–5,578 individuals (excluding cubs), with an average of approximately 3,140 mature individuals. These figures are based largely on capture–recapture and occupancy methodologies. Tigers are now confined to ten countries: Bangladesh, Bhutan, China, India, Indonesia, Malaysia, Myanmar, Nepal, Russia, and Thailand. Over the past three generations, their range has contracted by more than 50%, resulting in a suspected population reduction of over 50%.
Under the IUCN Green Status of Species, the tiger is assessed as Critically Depleted, with a Species Recovery Score of 14%. This reflects severe historical and ongoing threats, population declines, range contractions, and local extinctions. Tigers are regionally extinct in nine spatial units, considered Vulnerable in five, Endangered in two, and Critically Endangered in eight. Conservation Legacy is assessed as High: without past conservation efforts, tigers would be far closer to extinction. These initiatives have likely prevented further steep declines and range loss, averting regional extinction in six spatial units.
However, Conservation Dependence and Conservation Gain are both assessed as Low. This reflects the tiger’s slow life history – a 10-year timeframe is too short for large-scale recovery – yet the species remains heavily reliant on ongoing protection. Even small improvements in status represent significant gains given its current Critically Depleted condition. Over the coming decade, conservation is expected to prevent further declines, stimulate limited range expansion, and improve status in several spatial units. Without conservation, tigers would likely face regional extinction in four additional units, with all remaining units worsening to Regionally Endangered or Critically Endangered. Planned actions could maintain or improve status in all units.
Looking ahead 100 years, tigers could recover significantly, as indicated by their Medium Recovery Potential, and return to all spatial units if all plausible conservation actions are implemented effectively. Under this scenario, nine units could reach a Viable state, and baseline densities and ecological functioning could be restored in at least parts of five units. However, the species faces ongoing and emerging threats, including habitat loss, fragmentation, human population growth, prey depletion, climate change, disease outbreaks, and political instability. These pressures jeopardise survival and limit recovery prospects. Nonetheless, sustained and intensified conservation could mitigate these threats, enabling long-term survival and substantial recovery.
M. Pittet
Tiger density varies considerably. In India’s Kaziranga and Corbett National Parks, where prey is abundant, densities of 15–19 animals per 100 km² have been recorded. In contrast, in Russia’s Sikhote Alin Mountains, where prey availability is low, densities of 0.13–0.45 animals per 100 km² have been estimated. Generally, tiger densities are higher in alluvial floodplains and tropical deciduous forests than in tropical moist evergreen forests of South and Southeast Asia or the temperate habitats of Far East Asia.
Historically, the tiger’s range extended across Asia, from eastern Turkey and the southern Caspian Sea to the Sea of Okhotsk in Russia. Today, less than 7% of its original range remains. Breeding subpopulations are confirmed in Bangladesh, Bhutan, China, India, Indonesia, Malaysia, Myanmar, Nepal, Russia, and Thailand. Tigers have disappeared from Afghanistan, Georgia, Bali, Java, Iran, Iraq, Kazakhstan, Kyrgyzstan, Pakistan, Singapore, South Korea, Tajikistan, Turkey, Turkmenistan, and Uzbekistan.
Over the last century, tigers vanished from Singapore (1930s), Bali (1940s), Java and Hong Kong (1960s), Central Asia (1970s), most of temperate China (1980s), tropical China (1990s), and more recently from Vietnam, Lao PDR, and Cambodia (2000s). Between 2001 and 2020, tiger range decreased by 7%, from 1,049,430 km² to 978,293 km². In the latest assessment, 71 Tiger Conservation Landscapes (TCLs) were identified, of which only 21% are legally protected and just 9% fall under IUCN Categories I and II (strictly protected). Management remains poor due to regulatory, budgetary, and enforcement constraints, and hunting continues to pose a major threat.
In 2010, Walston et al. identified 42 source sites across the tiger range. These were defined as locations with confirmed tiger presence, evidence of breeding, population estimates exceeding 25 breeding females, legal protection, and sites embedded in larger landscapes capable of supporting over 50 breeding females. Since then, tigers have been extirpated from the only source site in Lao PDR, and several sites were found to host fewer tigers than previously thought. Conversely, some additional source sites meeting the criteria have been documented, particularly in South Asia. Globally, it is likely that over 60% of tiger populations occur within protected areas.
Ecology and Behaviour
The tiger is a solitary animal. Females establish and maintain individual territories, while males may disperse over long distances, with their territories often overlapping those of one to three females. Home ranges can be extensive: females must vigorously defend the resources within their range, whereas males roam widely in search of mates and compete for access to them. The size of a home range varies according to prey density. Females require areas suitable for raising cubs, while males maintain larger ranges to maximise access to females.
In regions with abundant prey throughout the year, such as Nepal’s Chitwan National Park, studies have recorded female home ranges averaging 10–39 km² and male ranges of around 30–105 km². In the Russian Far East, where prey is unevenly distributed and moves seasonally, female ranges can extend to 100–400 km², and male ranges may reach as much as 1,379 km². In the Sundarbans of Bangladesh, female home ranges have been found to range from 12.3 to 14.2 km². Tiger densities also vary with prey availability, from as high as 15–19 tigers per 100 km² in prey-rich areas such as India’s Kaziranga and Corbett National Parks, to as low as 0.13–0.45 tigers per 100 km² in prey-scarce regions like Russia’s Sikhote Alin Mountains.
The tiger is an obligate terrestrial carnivore. It primarily ambushes its prey but also actively searches for it. After making a kill, it often drags the carcass to nearby cover, hides any uneaten parts, and typically returns later to feed on them.
The reproductive season varies by region. Studies indicate that breeding can occur year-round: from December to February in Manchuria, from November to April in India, and with a birth peak between May and July in Nepal. Oestrus lasts about seven days, with cycles ranging from 15 to 20 days in Rajasthan, although other studies report cycles of 34–61 or 46–52 days. If a litter is lost, oestrus may recur within a few weeks (mean 17 days, range 10–39). Gestation lasts approximately 103 days. The interval between births averages 20–24 months but can extend to 36 months; however, if a litter is lost within the first two weeks, the interval may be as short as eight months. Cubs become independent at 18–28 months.
In Chitwan, first-year cub mortality was about 34%, with 73% involving the loss of the entire litter due to factors such as fire, floods, and infanticide. Second-year mortality was 17%, of which only 29% involved complete litter loss. Overall, infanticide was the leading cause of cub deaths. Research suggests that populations decline when mortality among breeding females exceeds 15%.
Data collected over nearly two decades by a long-term monitoring project in Chitwan National Park show that the average reproductive lifespan of tigers is 6.1 years for females and 2.8 years for males. Females typically reproduce for the first time at 3.4 years, while males do so at an average of 4.8 years (range 3.4–6.8). The last recorded reproduction occurred at 14 years. On average, females produce 4.54 offspring that survive to dispersal, with about 2.0 eventually joining the breeding population. For males, an average of 5.83 offspring survive to dispersal, with 1.99 recruited into the breeding population.
Prey
The tiger’s primary prey consists of large ungulates such as chital (Axis axis), gaur (Bos gaurus), sambar (Cervus unicolor), wild pig (Sus scrofa), and muntjac (Muntiacus muntjak). It also hunts red deer (Cervus elaphus), roe deer (Capreolus capreolus), peafowl (Pavo cristatus), and musk deer (Moschus spp.). Wild pigs and various deer species generally make up a significant portion of its diet, although tigers occasionally kill livestock and smaller prey such as hares.
The tiger’s diet is highly diverse across its range. In India, it includes chital, sambar, nilgai (Boselaphus tragocamelus), chinkara (Gazella bennettii), wild pig, and common langur (Semnopithecus entellus). In Cambodia, major prey species comprise barking deer (Muntiacus vaginalis), wild boar, sambar, gaur, and banteng (Bos javanicus). Tigers typically require around 50–60 large prey animals per year.
When populations of large prey decline, tigers hunt opportunistically, targeting smaller animals such as birds, fish, rodents, amphibians, and mammals (e.g., porcupines or primates). They are capable of killing prey much larger than themselves, including large bovids such as water buffalo (Bubalus bubalis), and, on rare occasions, animals such as the Asian elephant (Elephas maximus) or Indian rhinoceros (Rhinoceros unicornis). Nevertheless, their preferred prey generally falls within the same weight range as the tiger itself.
M.Pittet
Main Threats
Illegal hunting and poaching remain among the greatest threats to tigers. Historically, they were hunted for sport and trophies, and both legal and illegal hunting persisted through the 19th and much of the 20th century, often as retaliation for human–tiger conflict. Although tigers are now legally protected and international trade is banned, illegal trade continues in areas with weak enforcement, such as northern Myanmar near the Chinese border.
Tigers are killed for skins, bones, meat, and other body parts, particularly for use in Traditional Chinese Medicine. Enforcement is difficult, and cultural practices sustain demand. Skins, claws, and canines can fetch USD 10,000–70,000 and are sometimes displayed as status symbols. Bones, meat, organs, whiskers, urine, and faeces are also believed to have medicinal properties.
Demand for tiger bones has impacted other species, including lions (Panthera leo), jaguars (Panthera onca), leopards (Panthera pardus), and clouded leopards (Neofelis nebulosa and Neofelis diardi). Tiger farming and the capture of wild tigers for breeding further threaten populations. For example, tiger farms in China produce tiger bone wine, often illegally. This trade remains a major driver of decline.
Habitat loss and degradation pose another serious threat, caused by infrastructure development, human settlements, logging, and land conversion for agriculture or plantations such as oil palm and rubber. Habitat degradation also increases human access, facilitating poaching. Tigers have lost over 93% of their historical range, and Asia’s rapid development places remaining habitats under severe pressure.
Many populations are now isolated, with some so small that genetic inbreeding is a concern. Disrupted connectivity can lead to local or functional extinction. Prey species also face heavy pressure from hunting, habitat loss, and competition with humans and livestock, reducing prey density and impacting tiger survival.
Human–tiger conflict adds further risk. Tigers may kill livestock or, rarely, people, leading to retaliatory killings by firearms, poison, or traps. Such conflicts have historically contributed to tiger extirpation from western Asia, Java, Singapore, and parts of China and Russia. In some cases, tigers are relocated or placed in captive breeding facilities after attacks, complicating conservation efforts.
Disease is another poorly understood threat. Canine distemper virus has caused tiger deaths in Russia’s Sikhote-Alin Zapovednik, while outbreaks such as African swine fever reduce prey availability.
Combined threats—habitat loss, prey depletion, hunting, and disease—likely caused the extinction of the Bali (P. t. balica), Javan (P. t. sondaica), and Caspian (P. t. virgata) tigers. Today, illegal trade, prey loss, and habitat degradation continue to drive declines, even in suitable habitats.
Conservation Effort and Protection Status
The tiger is listed in Appendix I of CITES and is legally protected across most of its range, with commercial trade prohibited. Hunting is banned in Bangladesh, Bhutan, Cambodia, China, India, Indonesia, Lao PDR, Malaysia, Myanmar, Nepal, Russia, Thailand, and Vietnam, though information for North Korea is unavailable.
Conservation efforts have been implemented at local, national, and international levels. One of the earliest and most notable programmes was Project Tiger, launched in India in 1973, which led to the creation of numerous tiger reserves. Other range countries have since introduced similar initiatives with varying success.
In 2010, leaders of 13 tiger range states, alongside NGOs and donors, signed the St. Petersburg Declaration under the Global Tiger Recovery Programme. Its goal was to stabilise and double the global wild tiger population to at least 6,000 individuals by 2022. Key actions included:
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Protecting and managing tiger habitats
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Combating poaching and illegal trade
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Enhancing transboundary cooperation
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Involving local communities in conservation
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Improving management effectiveness
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Restoring tigers to former ranges
Long-term success depends on recognising threats such as habitat loss, human–wildlife conflict, and illegal trade. Conserving large, connected habitats and linking core populations to maintain gene flow is critical. Studies suggest reserves could support more than double the current population, but this requires strong national and international commitment.
Currently, core protected areas cover only about 6% of the tiger’s range. Priorities include safeguarding breeding populations, establishing wildlife corridors, improving protected area management, and engaging local communities. Reducing human-caused mortality, conserving prey, and managing conflict are essential for survival.
Additional support is needed to address broader threats, including habitat loss, illegal activities, pollution, and disease. Strengthening laws, mobilising resources, and raising public awareness are vital for recovery.
The loss of tigers from much of their historical range also offers opportunities for reintroduction. Plans are underway to restore tigers to former range countries, including Kazakhstan and Cambodia.
The fact that tigers no longer are present in much of their historical range presents opportunities for range expansion and targeted tiger reintroductions and translocations in the future. There now are plans to reintroduce tigers into former range countries including Kazakhstan and Cambodia.
P. Meier
Habitat
Tigers inhabit a wide range of environments, including tropical and subtropical forests, evergreen and deciduous forests, mangrove swamps, grasslands, and temperate forests. They are highly adaptable and can survive in habitats ranging from the humid tropics to snowy regions of the Russian Far East. However, they require sufficient cover, access to water, and an adequate prey base.
K. Modi