Panthera tigris (Linnaeus, 1758)

Don E. Wilson & Russell A. Mittermeier, 2009, Felidae, Handbook of the Mammals of the World – Volume 1 Carnivores, Barcelona: Lynx Edicions, pp. 54-168 : 128-130

4.

Tiger

Panthera tigris

French: Tigre / German: Tiger / Spanish: Tigre

Other common names: Bagh, Sher, Harimau

Taxonomy. Felis tigris Linnaeus, 1758 ,

Bengal, India.

Recent analyses of morphological and genetic variation in Tigers suggests little evidence for subspecies differentiation. Eight subspecies are recognized historically, but three races are extinct: balica (Schwarz, 1912) from Bali, sondaica (Temminck, 1844) from Java, and virgata (Illiger, 1815) from the river valleys of the Takla Makan, western slopes of the Tian Shan Mountains, Amu Darya and Syr Darya river valleys, shores of the Caspian Sea, Elburz Mountains, and Tigris and Euphrates river valleys. A new subspecies from Peninsular Malaysia (jacksoni) has been recently proposed, butit has never been described properly and its taxonomic validity is still being discussed. Five extant subspecies recognized.

Subspecies and Distribution.

P. t. tigris Linnaeus, 1758 — Indian subcontinent.

P. t. altaica Temminck, 1844 — Russian Far East, N Korean Peninsula and NE China.

P. t. amoyensis Hilzheimer, 1905 — SC China (could be extinct in the wild).

P. t. corbetti Mazak, 1968 — S China (Yunnan), S to Indochinese region, and S to the Malay Peninsula.

P. t. sumatrae Pocock, 1929 — Sumatra.

Descriptive notes. Head-body 146-290 cm, tail 72-109 cm; weight 75-325 kg, with considerable regional variation in size. Adult males from Sumatra may weigh 100-140 kg, females 75-110 kg. On average, adult males from Nepal are 100 kg heavier and females 50 kg heavier than their counterparts in Sumatra. Few documented weights exceeding 300 kg, and total length (nose to tip oftail) of three meters or more appear to be exceptional individuals. Background coat color varies from a dark red to a pale yellow and variation also seen in darkness of stripes and stripe pattern. General trend is for Tigers from South-east Asia to have darker ground color and more stripes, while Tigers from northern areas are paler and have fewerstripes. Fur is short in most parts of its range, but winter pelage of Tigers from Russian Far East is thick and long, adding to appearance of great size. Tigers from India are highly variable in coat color and pattern of markings. Markings on head and flanks are individually unique. No melanistic skins or museum specimens exist, but there are three records of black Tigers from the same general area of north-east India and Bangladesh. The last record of white Tigers in India was a male cub captured in the forests of Rewa, Madhya Pradesh, in 1951. All the white Tigers in captivity are descendants of this male; they are not albinos but the result of a mutation that occurred about 100 years ago. Tigers are the largest of the living felids, embodying power and grace. Head is large and foreshortened, increasing the bite force on the large canine teeth. Neck is short, thick, and shoulders and forearms are massive, with long, retractile claws on the broad forepaws. Morphology is specialized for single-handed capture and killing of large prey. Stand about one meter high at the shoulder; hindquarters are slightly lower. Body is long and lithe and the tail is typically less than half the head-body length.

Habitat. Tigers are found in a great variety of habitat types. In Turkmenistan, Uzbekistan, and Tajikistan the Tiger was found in the drainage basins ofrivers and lakes, where they hunted in the “tugai,” which consists of thickets of low-stature trees (turanga, tamarisk), shrubs, and dense reed beds. In Kazakhstan Tigers sometimes ascended into montane forests in the summer in pursuit of Wild Boar, attaining heights of 2500 m. There are also records of Tigers in the Himalayas at altitudes of almost 4000 m, although in most areas the cats remain well below 2000 m. In China they occupied grass thickets, montane sub-tropical evergreen forests, and mixed forests dominated by oak and poplars. Tigers in the Russian Far East live in low mountainous terrain dominated by nut pine, birch, oaks, fir, and spruce. Winterin this region is harsh, with deep snow and temperatures dropping to —34°C. In Sumatra and Malaysia Tigers are found in lowland humid tropical rainforest, where precipitation exceeds 2000 mm annually. In the outwash areas south of the Himalayas Tigers inhabit the “terai”, a belt of floodplain habitat dominated by marshes, swamps, oxbow lakes, and tall, dense grasslands intermixed with riverine forest. Sal forest, a climax form of moist deciduous forest, occurs on the slopes of the adjacenthills. In India Tigers inhabit the tropical, wet evergreen, and semi-evergreen forests of Assam, the mangrove swamps of West Bengal and neighboring Bangladesh, the vast expanses of dry deciduous forest in the central plateau, the tropical moist and dry deciduous forests of the Western Ghats, and the thorn forests of Rajasthan and Gujarat. In Ranthambhore National Park, Rajasthan, Tigers also use the ancient temples and fortresses as places to lie up during the day.

Food and Feeding. The list of prey species found as kills or in Tiger scats (feces) is extensive, but across its vast geographic range the Tiger's diet consists largely of deer and pigs. Over a b4year period in Sikhote-Alin, Russia, Red Deer ( Cervus elaphus) and Wild Boar were the dominant prey, representing 437 of 522 kills (84%). Minor prey included Moose ( Alces alces), Siberian Roe Deer ( Capreolus pygargus), and Sika Deer ( Cervus nippon), Siberian Musk Deer (Moschus moschiferus), and Long-tailed Goral ( Naemorhedus caudatus). Surprisingly, the kill records included a small number of adult Brown and Asiatic Black Bears. There is little information available on the food habits of Tigers in South-east Asia, but in a sample (n = 38) of Tiger scats from Huai Kha Khaeng Wildlife Sanctuary, Thailand, muntjac were the dominant prey (42%). Sambar Deer (7%) and Wild Boar (9%) occurred relatively infrequently in scats, whereas smaller prey such as porcupines, Hog Badgers, primates, and lizards collectively occurred in 28% of scats. The diet of Tigers in Royal Bardia National Park, Nepal, was reconstructed from an analysis of 215 scats collected over a 5year period. Three species, Chital ( Axis axis), Wild Boar, and Hog Deer ( Axis porcinus), contributed more than 90% of the biomass consumed. Several other species, including langur monkeys, Nilgai ( Boselaphus tragocamelus), Barasingha ( Rucervus duvaucelii), and porcupine occurred infrequently in scats. Larger ungulates such as the Nilgai and Barasingha were not killed preferentially, probably due to their low densities. Wild Boar were taken out of proportion to their availability, although Tiger predation was heaviest on the incredibly abundant (over 200/km?) Chital. Based on an analysis of 472 scats, Tigers in Nagarhole National Park, India, preyed selectively on the largest prey available, the Gaur ( Bos frontal) and Sambar, whereas smaller prey such as Chital, Red Muntjac ( Muntiacus muntjak), and Wild Boar were underrepresented in the diet. These five prey species together provided about 96% of the biomass consumed by Tigers. Among the larger prey species, Tiger predation was biased towards adult male Sambar, Chital, and Wild Boar, and young Gaur. Minor prey identified in scats included Indian Spotted Chevrotain (Moschiola), hare, porcupine, Dhole, and primates. Based on the scat data, the average weight of prey taken by Tigers in Nagarhole was 91 kg. In contrast, the average weight based solely on kills was 400 kg; however, because large kills are more likely to be found, this method grossly overestimates the average weight of prey taken. It does indicate, however, that Tigers are capable of taking extremely large prey, including adult male Gaur that may weigh 1000 kg. Tigers are solitary, stalk-and-ambush hunters and they actively search for prey. Habitat features that attract ungulates, such as water holes and the edges of small clearings, are favorite hunting spots. Stalking cover is important: a Tiger will attempt to get as close as possible to its prey before making a final rush, relying on quickly overtaking prey rather than pursuit for long distances. The tiger catches hold of the prey with its claws and holds and kills its prey with a bite from the large canine teeth. Small prey, or those weighing half that of the Tiger, are typically killed with a bite to the nape, with the canines separating the vertebrae and breaking the spinal cord. Large prey are most often killed with a throat bite, leading to strangulation or neck breakage due to twisting on impact. Except for adult Gaur, Tigers in Nagarhole killed their prey where cover density was significantly higher than that of leopard kills. Adult Gaur were killed in areas with significantly less cover, suggesting that attacks on Gaur in dense cover were extremely risky. Tigers in Nagarahole also took advantage of the cover of darkness; about 27% of kills were made between 06:00-09:00 h and the remainder were made between 18:00-06:00 h. Large kills such as Gaur may be too heavy to be moved, but if there is insufficient cover at the kill site the Tiger will drag its kill to an area where it feels secure before beginning to feed. Drag distances may be a few meters or several kilometers, and individual temperament may also influence this behavior. Feeding usually begins on the hindquarters or rump and once the body cavity is opened the stomach is removed and set aside. The carcass is then dragged a short distance before feeding resumes. Tigers use their carnassial or blade-like cheek teeth to slice off large hunks of meat and the rough tongue is used to rasp flesh from bones. The amount of meat consumed can be substantial: one adult male Tiger in Chitwan ate 32 kg in a single night and there are other reports of Tigers consuming 20% of their body weight in a night’s feeding. Tigresses in Chitwan spent an average of three days with each kill and during that time consumed 46 kg of meat. However, even large kills may notlast long if several Tigers are feeding on the carcass. For example,a tigress in Chitwan and her two large young fed on an adult Sambar for two days, consuming 102 kg of meat or about 17 kg per Tiger per day. Tigers often rest near the carcass, feeding intermittently, but if the Tiger leaves it will typically cover the remains, raking leaves, grass, dirt, or even rocks over the carcass. There is little information on kill rates, but tigresses in Chitwan without dependent young killed a large prey animal about every eight or nine days, which translates to 40 to 46 kills per year. Females with dependent young have to kill more often or kill larger prey to meet the nutritional demands of growing offspring.

Activity patterns. Radio-tracking studies indicate that Tigers are essentially crepuscular and nocturnal. Activity patterns appear to be driven primarily by activity patterns of the prey.

Movements, Home range and Social organization. In Nagarhole National Park, India, the rates of movements of radio-collared Tigers were lower during the daytime (mean = 0-07 km/h) than at night (mean = 0-21 km/h). Radio-collared tigresses in Chitwan National Park, Nepal, traveled about 0-7 km/h (range 0-2-1-2 km/h); estimates of the distances traveled in a night by females varied from 3-8 to 9-6 km. These estimates are based on straight-line distances between hourly nighttime locations, so the actual distances traveled would be somewhat greater. On some occasions tigresses crossed their ranges in a single night, while at other times they remained in a portion ofit for several days. However, except when they had a kill or young, tigresses in Chitwan normally choose a different rest site each day. Adult females typically occupy relatively small, mutually exclusive territories. The ranges of adult males may also be exclusive, but each male attempts to include as many female ranges as possible within his range, and thus male ranges can vary enormously in size. In Chitwan National Park, Nepal, the average home range size of resident females was 23 km? (range 13-51 km?); overlap of neighboring ranges varied from 3-7-7-1%. These territories function to ensure that females have exclusive access to food, cover, and other resources needed for survival and the successful rearing of young. Females who did not hold territories did not breed. Site fidelity was strong; females spent their entire reproductive lives in these territories, although some females shifted so that part of their range was acquired by their daughters. The tendency for daughters to try to settle next to their mothers resulted in clusters of females that were on average as closely related as lionesses in a pride. Breeding territories of males were established by direct takeovers and sometimes expanded after fights with neighboring males. The average home range size of resident males in Chitwan was 68 km? (range 24 to 151 km?*). Males who did not hold territories did not breed. Turnover rates of territorial males were high. The average reproductive life was 2-8 years, but ranged from seven months to 6-3 years. The ranges of resident males overlapped the ranges of two to seven resident females. The home range size of Tigers, especially females,is positively correlated with the abundance of prey, and consequently the density of adult Tigers living in an area is also related to prey biomass density. In the temperate forests of the Russian Far East, Tiger density is estimated at 0-5-1-4/ 100 km?, but prey biomass density is low (400 kg /km? in Sikhote-Alin) and range size of tigresses (200-400 km?) are an order of magnitude larger than those in Chitwan. Prey biomass density in Chitwan is about 2000 kg /km® and Tiger density on the alluvial floodplain is about 8/ 100 km ®. The highest Tiger density reported, 16-8/ 100 km?, is from Kaziranga National Park in north-east India. Kaziranga is an alluvial floodplain grassland that supports one of the highest densities of large prey on the subcontinent. Common ungulate prey in Kaziranga include wild Water Buffalo ( Bovidae ), Barasingha, Hog Deer, Red Muntjac ( Cervidae ), Wild Boar, and Gaur ( Bovidae ). High Tiger density (14-7/ 100 km ²) is also reported from the moist deciduous forests of Nagarhole National Park in south India, where prey biomass densities are estimated at 7500 kg /km². The lowest Tiger densities are reported from the lowland tropical rain forests of Peninsular Malaysia, Sumatra, and Laos, where prey densities are typically less than 500 kg /km².

Breeding. In subtropical and tropical areas Tigers mate and give birth at any time of the year, but in temperate areas such as the Russian Far East, young are more likely to be born in the spring. Estrus is preceded by an increase in scent marking, which probably ensures that a male is present when the female is sexually receptive. In captivity, the average length of estrus is five days. In the wild pairs were seldom found together for more than two days, although prolonged associations may be related to inexperience. Courtship in Tigers is risky and familiarity appears to be an important prelude to mating. Once the female is ready to mate copulations occur frequently (e.g.17-52 times/day). Females are thought to be induced ovulators; that is, they require a certain number of copulations within a limited time period to stimulate ovulation. Conception rates are low, about 20 to 40%, and if conception does not occur the female will come into heat again in about a month. Following a gestation of about 103 days the female gives birth to one to seven young. In Nepal, mean litter size for 49 litters was 2:98 (range 2-5); litters were born in all months except February. Birth dens have been found in impenetrable thickets, shallow depressions in dense grass areas, rock crevices, and caves. Kittens are born with eyes closed, helpless, weighing 785 to 1610 g, but they quadruple their birth weight in a month. During the first month of the cubs’ lives the tigress spends most of her time at the den and her home range contracts to a small area focused on the den site. Her home range gradually expands as the young become mobile at two to three months of age. At four months of age a Tiger cub is the size of a setter dog. By six months the cubs are weaned, but lack the ability to kill for themselves. The permanent canines appear between twelve and 18 months of age, and this marks a period of rapid weight gain as the young are now physically equipped to make their own kills. They must, however,still refine their hunting techniques and learn to kill efficiently. Male cubs learn to kill on their own and become independent sooner than their female siblings, and by 15 months of age they may begin spending some time away from their mother. By 18-20 months young Tigers are typically independent of their mothers but continue to hunt in their natal range. Dispersal occurs when young are 18-28 months old and it seems to be keyed to the arrival of a new litter. In Chitwan the interbirth interval varied from 20 to 24 months (mean 21-6 months). The average dispersal distance for ten subadult males in Chitwan was 33 km (range 9-5-65 km), but the average for four females was only 9-7 km (range 0-2-33 km). However, only four of the ten males managed to establish breeding territories whereas all four females did. Mean age offirst reproduction for females was 3-4 years, and for males it was 4-8 years (range 3-4-6-8 years). Average reproductive life span of females was 6-1 years, but two females in the park had reproductive life spans of 10-5 and 12-5 years, and during this time reared four and five litters, respectively. These females were exceptional: the mean lifetime reproduction of females was 4-54 young surviving to dispersal age and 2-0 that survived to breed. One extraordinary male, who managed to maintain exclusive access to seven females for four years, sired 27 offspring that survived to dispersal age. Most males were far less successful; the mean lifetime reproduction of males was 5-83 young surviving to dispersal age and 1-99 young that survived to breed.

Status and Conservation. CITES Appendix I. Three subspecies (Amur, South China, and Sumatran Tiger) classified as Critically Endangered on The IUCN Red List. Otherwise classified as Endangered. Large range reduction (41% overthe last decade), and an estimated global population of 3402-5140 adult Tigers in the wild, with perhaps half of these residing in India. However a recent tiger census carried out in 2007 stated that the wild tiger population in India has come down to approximately 1411. Another 700-1400 Indo-Chinese Tigerslive in Myanmar, Thailand, Laos, Cambodia, Vietnam, China, and Peninsular Malaysia. There are about 500 Tigers restricted to some forest tracts on Sumatra. Another 400 or so Siberian Tigers live in the Russian Far East, with a few in neighboring China. The Chinese Tiger has almost been extirpated, and no definite evidence of continued persistence exists. The Bali, Javan, and Caspian races are extinct. Tiger populations have declined over many parts of Asia because ofillegal hunting, commercial trade in Tiger bone and derivatives, a declining prey base, and loss and degradation of habitat. Saving the Tiger has become an enormous and complex undertaking, involving efforts by federal, national, and state governments, large corporations, parks and wildlife departments, and non-government organizations. The problem is being attacked on many fronts, including threats of sanctions against countries that do not control trade in Tiger parts, establishing protected reserves, training and deployment of anti-poaching teams, identification of critical conservation units, working with traditional Chinese medical practitioners to find alternatives to Tiger parts, public education campaigns deploring the use Tiger parts, habitat restoration projects, economic incentives to locals, development of suitable survey and monitoring methods, and initiation of baseline ecological research projects. Some of these initiatives have led to recoveries of Tiger populations within a decade in many reserves in India and Nepal, but with expanding human populations in the region the pressures on the natural systems are only going to increase. Fortunately, Tigers are a resilient species and demographic modeling suggests that even relatively small Tiger populations with 6-12 breeding females may be viable over a 100year timeframe. Even small reserves, 300-3000 km?, can potentially support viable Tiger populations if the prey base is intact. However, managing and protecting these areas will require more resources and it will also be important to know which management practices work and which do not.

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Figures

On following pages: 4. Tiger (Panthera tigris).

Subspecies and Distribution. P. t. tigris Linnaeus, 1758 — Indian subcontinent. P. t. altaica Temminck, 1844 — Russian Far East, N Korean Peninsula and NE China . P. t. amoyensis Hilzheimer, 1905 — SC China (could be extinct in the wild). P. t. corbetti Mazak, 1968 — S China (Yunnan), S to Indochinese region, and S to the Malay Peninsula. P. t. sumatrae Pocock, 1929 — Sumatra.