Wild Cats of the World

IUCN RED LIST (2015):

Endangered (global)

Critically Endangered(Malayan and Sumatran Tiger)

Head-body length ♀ 146−177cm, ♂ 189−300cm

Tail 72−109cm

Weight ♀ 75−177kg, ♂ 100−261kg

The Tiger is one of the ‘big cats’ in the genus Panthera and thought to be most closely related to the Snow Leopard with a common ancestor more than two million years ago, though the relative position of these two species within Panthera is uncertain. The Tiger is traditionally classified into eight subspecies, three of which are extinct (Javan P. t. sondaica, Bali P. t. balica and Caspian P. t. virgata). A fourth, the South China Tiger (P. t. amoyensis), is almost certainly extinct in the wild with no unequivocal evidence since the 1970s. Approximately 60−70 are maintained in captivity in China, though most have evidence of hybridisation with other subspecies. Recent molecular analyses support the division of extant tiger populations into four classically described subspecies with possibly a fifth: Amur Tiger P. t. altaica (Russian Far East, marginally east China); Indochinese Tiger P. t. corbetti (Indochina); Bengal Tiger P. t. tigris (Indian subcontinent); Sumatran Tiger P. t. sumatrae (Sumatra) and, controversially, Malayan Tiger P. t. jacksoni (Malayan Peninsula). Importantly, the molecular differences between Tiger subspecies are modest; they intergrade at the putative boundaries and arose very recently, likely well within the last 100,000 years. The Sumatran Tiger is clearly sufficiently genetically isolated to be accorded its own subspecific status. The support for the Malayan Tiger as a distinct subspecies is least convincing. It has slight genetic differences from the Indochinese Tiger and does not differ in morphology (cranial and pelage characteristics). Similarly, samples from the now extinct Caspian Tiger show very few genetic differences to the Amur Tiger. Continental Tiger populations were probably largely continuous until relatively recently, and some authorities argue that all mainland populations should be treated as the same, single subspecies with distinct but slight differences between populations that should be treated as ‘evolutionary significant units’ rather than subspecies. The oldest Tiger fossils, about two million years old, are from northern China and Java.

The Tiger is the world’s largest cat by a small margin. The Lion is comparable in all measurements and Lions have longer skulls on average, but the largest Tigers have slightly longer and heavier bodies than the largest Lions. It is important to note that there are few reliable body measurements of wild Tigers, and that figures from captivity and of sport-hunted animals (from the early 20th century) are often inflated. The Tiger is a massive, powerfully built cat with a deep chest, muscular forequarters and heavily built limbs. Body size varies across the range, roughly decreasing in a cline from north to south, and correlated with prey availability. Tigers from the Indian subcontinent and Russian Far East are largest, and Sumatran Tigers (and extinct island populations from Java and Bali) are the smallest. Wild male Sumatran Tigers weigh up to 140kg while the largest wild male on record, from Nepal, weighed 261kg (up to 325kg is recorded from captivity).

The Tiger’s ground colour varies from pale yellow to rich red with white or cream underparts. Tigers are generally darker and more richly striped in tropical South-east Asia and paler, more lightly striped in temperate areas. The fur on the cheeks forms a long facial ruff that is most developed in males of Amur and Sumatran Tigers. Amur Tigers (and the now extinct Caspian form) develop a long, dense winter coat which has a washed-out appearance compared to summer pelage. White Tigers are not albino and arise from a recessive mutation that produces blue eyes and chocolate-coloured stripes on a white background. There is only one record from the wild (Madhya Pradesh, India) since 1951, a male cub from which all captive white Tigers are descended (and are extremely inbred as a result). An intermediate form called ‘golden tabby’ or ‘strawberry’ is known only from captivity. Complete melanism is unknown, though individuals occasionally appear with pseudomelanism (or abundism), in which the stripes are very wide and merged, producing an almost entirely black appearance.

Similar species The Tiger is the only striped cat and is unmistakable. Local nomenclature may cause confusion as variants of the name for Tiger are often employed for other cats.

The Tiger is now restricted to, at most 10 per cent of its historical range with an extremely patchy distribution largely restricted to isolated populations in forest fragments. In South Asia, it occurs mainly in protected areas in India (chiefly south-western, central and north-eastern India); in a narrow band along the southern lowlands and slopes of the Himalayas from Uttarakhand, India, through Nepal and Bhutan to Arunachal Pradesh, India; and a population in the Sundarbans of Bangladesh and India. The only definite populations remaining in Indochina occur in western Thailand bordering Burma (Huai Kha Khaeng/Thung Yai Naresuan, Kaeng Krachan/Kui Buri) and Peninsular Malaysia (Endau Rompin, Taman Negara National Park, Belum-Temengor Forest). Tigers may still occur more widely in extensive forest tracts along the Thai-Burma border, and in western and northern Burma, though there are few recent records and no evidence of reproduction. In Sumatra, Tigers occur patchily along the Bukit Barisan mountain range running the length of the island and in one population in central Sumatra. The largest contiguous Tiger population is in the Russian Far East and marginally into adjacent areas of eastern China; in contrast to the rest of the range, most of this population occurs outside protected areas. The Tiger is now functionally or entirely extinct in China (except for the Amur population), Cambodia, Lao PDR, North Korea and Vietnam. It is extinct in Bali (1940s), central Asia (1968) and Java (1980s). Tigers are naturally absent from Sri Lanka and Borneo.

Tigers occur in a variety of tropical, subtropical and temperate forests, forest-grassland mosaics and associated dense cover such as terai (dense floodplain grasslands), thickets, scrub and marshes. They reach highest densities on the Indian subcontinent in dry and mesic forests, and terai. The Sundarbans population (Bangladesh–India) lives in low-lying freshwater swamp-forest and salt-tolerant mangrove forests inundated by tidal seawater. The Amur Tiger inhabits mountainous terrain with temperate forest of Korean Pine, birch, fir, oak and spruce with deep winter snowfall and temperatures reaching -40°C. They traverse but do not permanently occupy human-modified habitats such as agriculture, palm plantations and monocultures. Tigers occur from sea level typically to 2,000m, and are recorded from montane forest with deep snow up to 4,201m in the Himalayas.

A rare photograph of a wild female Amur Tiger, taken in Lazovskiy Zapovednik (strictly protected area) on the Russian coast of the Sea of Japan at the southern tip of the subspecies’ present range. Genetic analysis of extinct Caspian Tiger samples from central Asia show minimal differences from Amur Tigers and they probably comprised a single population perhaps as recently as the last 200 years.

The Tiger is an immensely powerful predator adapted to overpower prey as large as or larger than itself. A healthy adult Tiger can kill almost anything it encounters with the exception of adult rhinos and Asian Elephants, but the diet is dominated by various medium-sized and large deer species and wild boar. Tigers typically focus on two to five species of locally common ungulates weighing 60−250kg, particularly Sambar, Red Deer, Chital, Hog Deer, muntjacs and Wild Boar. They are capable of killing adult Gaur and Asiatic Water Buffalo exceeding 1,000kg, though most kills of these species are juveniles and subadults. Regional dietary patterns are best known from the Indian subcontinent and the Russian Far East where Tigers are best studied. The staple of Tigers in India and Nepal is Chital, Sambar and Wild Boar, as well as Barking Deer (Indian Muntjac) and Hog Deer depending on local abundance. Barasingha, Chousingha, Chinkara Gazelle, Blackbuck, Nilgai, Himalayan Goral and Nilgiri Tahr are also recorded. Tigers in Nagarahole-Bandipur reserves in India’s Western Ghats prey heavily on Gaur as well as Sambar. Amur Tigers in the Russian Far East rely chiefly on Red Deer and Wild Boar (84 per cent of 552 documented kills of wild prey; 64 per cent of 729 kills, including domestic animals) with Siberian Roe Deer and Sika Deer common in the diet in some areas. Siberian Musk Deer, Moose and Long-tailed Goral are recorded incidentally. Tiger diet is least known from South-east Asia but based on a small number of records, Barking Deer, Wild Boar and Sambar are most important in Thailand and Way Kambas National Park, Sumatra. Tigers in Way Kambas National Park also frequently killed Southern Pig-tailed Macaques. The diet in South-east Asian lowland forest is thought to include a greater diversity of smaller prey given the low productivity of the habitat. Banteng and Malayan Tapir are recorded as rare prey in Malaysia and Thailand.

Smaller prey taken relatively often by Tigers includes primates (especially Grey Langurs; Rhesus Monkeys are consumed quite often in the Sundarbans), Indian Crested Porcupines, hares, small carnivores (including records of Yellow-throated Marten, Greater Hog Badger, Eurasian Badger, Golden Jackal, Red Fox, Raccoon Dog, civets and mongooses) and birds such as peafowl. Herptiles, fish and crabs are eaten, though the contribution to intake is trivial. Tigers, including females, are recorded killing very large Mugger Crocodiles up to 4m long and poisonous snakes; an adult male Tiger found dead had eaten a King Cobra and an Indian Cobra (Sundarbans Tiger Reserve, India). Tigers kill other felids and large carnivores including Jungle Cats, Fishing Cats (Sundarbans Tiger Reserve, India), Asiatic Golden Cats (Chitwan National Park, Nepal), Eurasian Lynx (Russian Far East), Leopards, Dholes, Grey Wolves, Asiatic Black Bears, Sloth Bears and Brown Bears (including adults killed in winter dens, Russian Far East). Carnivore carcasses are often abandoned without having been eaten, though bears are usually partially or entirely consumed. Cannibalism occurs rarely, generally of cubs killed by infanticidal males and occasionally of adults killed in territorial clashes. Tigers prey on livestock, mainly when unattended in forest. Together with wild Sambars, domestic cattle, yaks and horses comprised 93.3 per cent of Tiger diet during one study in mountainous habitat with very low densities of wild prey where livestock roams freely (Jigme Singye Wangchuck National Park, Bhutan). Tigers were not recorded killing domestic dogs during this study, but Amur tigers regularly kill dogs (87 of 177 recorded kills of domestic animals), particularly when dogs are accompanying hunters in the forest and during severe winters that force Tigers into villages seeking prey. Tigers probably kill more people than any other large carnivore, in part because human population density in Asia is so high and people utilise Tiger habitat intensively. Habitual ‘man-eaters’ that focus on humans as prey are very rare.

Hunting is mainly nocturno-crepuscular and terrestrial. Tigers are recorded climbing to 7.5m but they are too heavy to hunt arboreally except for occasional cases of prey snatched from lower branches. Tigers search for prey as they walk, readily using forest roads, logging tracks, animal trails and watercourses. Depending on prey availability, Tigers cover large distances while hunting: 3−10km in prey-abundant areas to more than 20km a night where prey occurs in low densities (Russian Far East). They intersperse mobile hunting with waiting or resting where prey congregates, for example near water sources or salt licks and at the edges of meadows and open areas. The Tiger stalks prey in typical felid fashion before an explosive rush, usually from within 25m of the target. Tigers usually abandon pursuit if a kill is not made after 150−200m; most successful hunts are shorter. Tigers kill most prey by asphyxiation with a throat bite or by covering the nostrils and mouth with a clamping muzzle bite, the latter used most often for very large prey such as adult Gaur. They kill very large crocodiles by biting the spine where it meets the base of the skull. Small prey is bitten at the nape or skull.

Estimates of hunting success by Tigers are poorly known. Based on snow-tracking (which provides limited but accurate data), Amur Tigers hunting Red Deer and Wild Boar in winter were successful 38 per cent and 54 per cent of the time respectively. Success outside winter and elsewhere in the range is expected to be significantly lower. GPS-collared Amur Tigers made a kill (mainly of ungulates) on average every 6.5 days, eating close to 9kg of meat per day. Tigers killed slightly more often, killed more large prey and ate slightly more during winter compared to summer. Unless disturbed, Tigers remain with their kills until finished, spending up to five to six days feeding from large carcasses. Tigers scavenge and readily appropriate the kills of other carnivores including from other Tigers, Leopards, Dholes and Golden Jackals.

The Tiger is solitary and generally territorial. Adults socialise chiefly for breeding, but males in high-density populations frequently spend time with familiar females and cubs, including sharing kills. Males are very tolerant of cubs belonging to known females (presumably as the males are likely to be the cubs’ sires). Males have large ranges that overlap the smaller ranges of one or more females (for example, two to seven females, in Chitwan National Park, Nepal). Adults establish exclusive territories where possible but complete exclusivity is rare except in small core areas within the range. Territorial overlap is least in high-density populations with abundant prey and small home ranges (for example, in India and Nepal), and greatest where prey is dispersed and ranges are very large (for example, in Russia). Both sexes demarcate territory and advertise their presence by depositing scent-marks via cheek-rubbing and spraying vegetation, and by depositing scats and scraping the ground with the hindfeet. Territorial fights are rare but are sometimes fatal when they occur, more often in males and more likely to occur during social disruption, such as when a resident dies or an immigrant male moves in. Adult females generally live out their lives in one area while male territorial tenure is typically shorter, on average 2.8 years (ranging from seven months to 6.5 years) in Chitwan National Park, Nepal.

Recorded territory size varies from 10km² (female, Chitwan National Park, Nepal) to more than 1,000km² (male, Russian Far East). Home range size by radio-telemetry has been established only for populations in India, Nepal and Russia. Range size for Tigers in very productive terai and forest in Nepal and India is 10−51km² (females) and 24−243km² (males), compared to 224−414km² (females) and 800−1,000km² (males) in Russia. Densities of Tiger populations, even in high-quality habitat, are often depressed due to human hunting of prey (even if Tigers are not hunted). In lowland tropical forest at sites where poaching is prevalent, density estimates include 0.2–2.6 tigers per 100km² (Malaysia, Burma, Sumatra and formerly Laos). In relatively well- to very well-protected lowland forest, density increases to 3.5 Tigers per 100km² (Huai Kha Khaeng, Thailand) and as high as six Tigers per 100km² (southern Tambling Wildlife Nature Conservation, Sumatra). Amur Tigers in temperate forest in the Russian Far East occur at densities of 0.3−1 Tigers per 100km², depending on the level of protection. Tigers reach their highest densities in very productive habitats under strong protection, 8.5−16.8 per 100km² (deciduous forests, alluvial floodplains and terai, India).

Tigers are largely aseasonal in their tropical and subtropical ranges, but Amur Tigers show greater seasonal patterns. More than 50 per cent of Amur Tiger cubs are born in late summer (August–October) and winter births are rare. Oestrus lasts two to five days and gestation lasts 95−107 days, averaging 103−105. Litter size is two to five cubs, averaging 2.3−3 (for populations in India, Nepal and Russia). Weaning is around three to five months. Inter-litter interval ranges from 21.6 to 33 months. Cubs reach independence at 17−24 months. Female offspring usually inherit part of their mother’s range or settle close by whereas males disperse more widely. Dispersal distances at Chitwan average 9.7km for females (maximum 33km) and 33km for males (maximum 65km). Based on the genetic relatedness of Tigers in Pench Tiger Reserve, India, most females settle within their natal range, with a maximum dispersal distance of 26km; males related to resident females did not occur within 26km, indicating they dispersed further away. Dispersal distances are large for Amur Tigers with some male dispersers reported hundreds of kilometres outside of known Tiger range.

Sexually maturity is 2.5−3 years for both sexes, but breeding in the wild is typically later, ranging from 3.4 to 4.5 years for females, and 3.4 years at the earliest for males (averaging 4.8 years, Chitwan). Females in Chitwan during a period of strong protection and population stability produced litters on average for 6.1 years with a maximum of 12.5 years. Over the course of their lifetime, these females produced on average a total of 4.5 cubs that survived to disperse and only two that survived to breed. Reproduction by females is possible until at least age 15.5.

Mortality 34 per cent (Chitwan National Park) to 41−47 per cent (Russian Far East) of cubs die in the first year, most related to anthropogenic causes and infanticide. Females sometimes defend cubs against infanticidal males. There are two credible records of a female Tiger killing an adult male Tiger while defending cubs, apparently surprising the male in both cases. Estimates of annual adult mortality include 23 per cent (both sexes combined, Nagarahole National Park, India) and 19 per cent (females, Russia) to 37 per cent (males, Russia). Humans are the main cause of death for most populations, though natural causes including disease and intraspecific fights can be important. Adult Tigers have few natural predators. There are rare records of large packs of Dholes killing Tigers, perhaps unhealthy or injured individuals; in one eyewitness account, 22 Dholes killed a male Tiger in a prolonged clash in which at least 12 of the dogs were killed. An adult female Tiger was killed by a 4m Saltwater Crocodile in the Indian Sundarbans, apparently while swimming a river. Tigers occasionally die from injuries inflicted by dangerous prey, including verified cases by Water Buffalo, Gaur and Wild Boar. Accidents (for example, a male fell through a frozen river in Russia) are uncommon. Canine distemper has been confirmed in Tigers from Russia and India, though the potential impact on population dynamics is still unclear.

STATUS AND THREATS

The Tiger is the most endangered large cat, having suffered a calamitous decline in the 20th century that continues in much of its range today. The Tiger once ranged widely across Asia, from eastern Turkey through central Asia, and in a massive unbroken swathe from the Afghanistan-Pakistan border through South and South-east Asia to Bali in the east, and the Russian Far East. Since the 1940s, Tigers have disappeared from south-western and central Asia, from Bali and Java, and from most of their range in South-east and eastern Asia. Tigers now occur with certainty in only 4.2 per cent of their historical range, and may occur in a further 5.9 per cent of historical range (that is, where suitable habitat occurs but there is no recent information). There are known breeding populations only in eight range countries (Bangladesh, Bhutan, India, Sumatra/Indonesia, Malaysia, Nepal, Thailand and Russia). The species is likely extinct or at best limited to a few individuals with no recent evidence of breeding in Cambodia, Lao PDR and Vietnam. It is extinct in China except for around a dozen individuals in a transboundary population with Russia. An estimated 70 per cent of all remaining wild Tigers (and probably close to 100 per cent of breeding females) occur in 42 populations, each centred on a protected area that collectively comprise around 100,000km2, which is less than 0.5 per cent of the historical range. Most of these populations are in India (18), Sumatra (eight) and the Russian Far East (six). Combined with loss of habitat to forestry, commercial palm plantations and agriculture, Tigers are particularly threatened by intense illegal hunting to supply the traditional Chinese medicinal trade. This is compounded by widespread hunting of their prey to feed a massive demand for bushmeat especially in South-east Asia. Given a respite from human hunting, Tiger populations recover quickly; unfortunately, there are now few areas where this is taking place.

CITES Appendix I. Red List: Endangered (global), Critically Endangered (China, Russia, Sumatra).