The tiger (Panthera tigris) is the largest species among the Felidae and classified in the genus Panthera. It is most recognizable for its dark vertical stripes on reddish-orange fur with a lighter underside.
It is an apex predator, primarily preying on ungulates such as deer and bovids. It is territorial and generally a solitary but social predator, requiring large contiguous areas of habitat, which support its requirements for prey and rearing of its offspring.
Tiger cubs stay with their mother for about two years, before they become independent and leave their mother’s home range to establish their own.
The tiger once ranged widely from Eastern Anatolia Region in the west to the Amur River basin, and in the south from the foothills of the Himalayas to Bali in the Sunda islands.
Since the early 20th century, tiger populations have lost at least 93% of their historic range and have been extirpated in Western and Central Asia, from the islands of Java and Bali, and in large areas of Southeast and South Asia and China.
Today’s tiger range is fragmented, stretching from Siberian temperate forests to subtropical and tropical forests on the Indian subcontinent and Sumatra.
The tiger is listed as Endangered on the IUCN Red List since 1986. As of 2015, the global wild tiger population was estimated to number between 3,062 and 3,948 mature individuals, down from around 100,000 at the start of the 20th century, with most remaining populations occurring in small pockets isolated from each other.
Major reasons for population decline include habitat destruction, habitat fragmentation and poaching.
This, coupled with the fact that it lives in some of the more densely populated places on Earth, has caused significant conflicts with humans.
The tiger is among the most recognisable and popular of the world’s charismatic megafauna. It featured prominently in ancient mythology and folklore and continues to be depicted in modern films and literature, appearing on many flags, coats of arms and as mascots for sporting teams. The tiger is the national animal of India, Bangladesh, Malaysia and South Korea.
Probable evolution of the tiger
The tiger’s closest living relatives were previously thought to be the Panthera species lion, leopard and jaguar.
Results of genetic analysis indicate that about 2.88 million years ago, the tiger and the snow leopard lineages diverged from the other Panthera species, and that both may be more closely related to each other than to the lion, leopard and jaguar.
P. t. palaeosinensis from the Early Pleistocene of northern China is the most primitive known tiger to date.
Fossil remains of Panthera zdanskyi were excavated in Gansu province of northwestern China.
This species lived at the beginning of the Pleistocene about two million years ago, and is considered to be a sister taxon of the modern tiger. It was about the size of a jaguar and probably had a different coat pattern.
Despite being considered more “primitive”, it was functionally and possibly also ecologically similar to the modern tiger. Northwestern China is thought to be the origin of the tiger lineage.
Tigers grew in size, possibly in response to adaptive radiations of prey species like deer and bovids, which may have occurred in Southeast Asia during the early Pleistocene.
Panthera tigris trinilensis lived about 1.2 million years ago and is known from fossils excavated near Trinil in Java.
The Wanhsien, Ngandong, Trinil and Japanese tigers became extinct in prehistoric times.
Tigers reached India and northern Asia in the late Pleistocene, reaching eastern Beringia, Japan, and Sakhalin. Some fossil skulls are morphologically distinct from lion skulls, which could indicate tiger presence in Alaska during the last glacial period, about 100,000 years ago.
Tiger fossils found in the island of Palawan were smaller than mainland tiger fossils, possibly due to insular dwarfism.
Fossil remains of tigers were also excavated in Sri Lanka, China, Japan, Sarawak dating to the late Pliocene, Pleistocene and Early Holocene.
The Bornean tiger was apparently present in Borneo between the Late Pleistocene and the Holocene, but may have gone extinct in prehistoric times.
The potential tiger range during the Late Pleistocene and Holocene was predicted applying ecological niche modelling based on more than 500 tiger locality records combined with bioclimatic data.
The resulting model shows a contiguous tiger range from southern India to Siberia at the Last Glacial Maximum, indicating an unobstructed gene flow between tiger populations in mainland Asia throughout the Late Pleistocene and Holocene.
The tiger populations on the Sunda Islands and mainland Asia were possibly separated during interglacial periods.
Results of a phylogeographic study indicate that all living tigers had a common ancestor 72,000–108,000 years ago.
The tiger’s full genome sequence was published in 2013. It was found to have similar repeat composition than other cat genomes and an appreciably conserved synteny.
Captive tigers were bred with lions to create hybrids called liger and tigon. They share physical and behavioural qualities of both parent species. Breeding hybrids is now discouraged due to the emphasis on conservation.
The liger is a cross between a male lion and a tigress. Ligers are typically between 10 and 12 ft (3.0 and 3.7 m) in length, and weigh between 800 and 1,000 lb (360 and 450 kg) or more.
Because the lion sire passes on a growth-promoting gene, but the corresponding growth-inhibiting gene from the female tiger is absent, ligers grow far larger than either parent species.
The less common tigon is a cross between a lioness and a male tiger. Because the male tiger does not pass on a growth-promoting gene and the lioness passes on a growth inhibiting gene, tigons are around the same size as their parents.
Some females are fertile and have occasionally given birth to litigons when mated to a male Asiatic lion.