The tiger (Panthera tigris) is a large cat and a member of the genus Panthera native to Asia. It has a powerful, muscular body with a large head and paws, a long tail and orange fur that fades to white in parts, with black, mostly vertical stripes. It is traditionally classified into nine subspecies, though some recognise only two subspecies, the mainland Asian tiger and the Sunda Islands tiger.
Throughout its range, it inhabits mainly forests, from coniferous and temperate broadleaf and mixed forests in the Russian Far East and Northeast China to tropical and subtropical moist broadleaf forests on the Indian subcontinent and Southeast Asia. The tiger is an apex predator and preys mainly on hooved mammals, which it takes by ambush. It lives a mostly solitary life and occupies home ranges, defending these from individuals of the same sex. The range of a male tiger overlaps with that of multiple females with whom he mates. Females give birth to usually two or three cubs that stay with their mother for about two years. When becoming independent, they leave their mother's home range and establish their own.
Since the early 20th century, tiger populations have lost at least 93% of their historic range and are locally extinct in West and Central Asia, in large areas of China and on the islands of Java and Bali. Today, the tiger's range is severely fragmented. It is listed as Endangered on the IUCN Red List of Threatened Species, as its range is thought to have declined by 53% to 68% since the late 1990s. Major threats to tigers are habitat destruction and fragmentation due to deforestation, poaching for fur and the illegal trade of body parts for medicinal purposes. Tigers are also victims of human–wildlife conflict as they attack and prey on livestock in areas where natural prey is scarce. The tiger is legally protected in all range countries. National conservation measures consist of action plans, anti-poaching patrols and schemes for monitoring tiger populations. In several range countries, wildlife corridors have been established and tiger reintroduction is planned.
The tiger is among the most popular of the world's charismatic megafauna. It has been kept in captivity since ancient times and has been trained to perform in circuses and other entertainment shows. The tiger featured prominently in the ancient mythology and folklore of cultures throughout its historic range and has continued to appear in culture worldwide.
The Old English tigras derives from Old French tigre, from Latin tigris, which was a borrowing from tigris (Ancient Greek: τίγρις).
Since ancient times, the word tigris has been suggested to originate from the Armenian or Persian word for 'arrow', which may also be the origin of the name for the river Tigris. However, today, the names are thought to be homonyms, and the connection between the tiger and the river is doubted.
In 1758, Carl Linnaeus described the tiger in his work Systema Naturae and gave it the scientific name Felis tigris, as the genus Felis was being used for all cats at the time. His scientific description was based on descriptions by earlier naturalists such as Conrad Gessner and Ulisse Aldrovandi. In 1929, Reginald Innes Pocock placed the species in the genus Panthera using the scientific name Panthera tigris.
Nine recent (Holocene) tiger subspecies have been proposed between the early 19th and early 21st centuries, namely the Bengal, Malayan, Indochinese, South China, Siberian, Caspian, Javan, Bali and Sumatran tigers. The validity of several tiger subspecies was questioned in 1999 as most putative subspecies were distinguished on the basis of fur length and colouration, striping patterns and body size of specimens in natural history museum collections that are not necessarily representative for the entire population. It was proposed to recognise only two tiger subspecies as valid, namely P. t. tigris in mainland Asia and the smaller P. t. sondaica in the Greater Sunda Islands.
This two-subspecies proposal was reaffirmed in 2015 through a comprehensive analysis of morphological, ecological and mitochondrial DNA (mtDNA) traits of all putative tiger subspecies.
In 2017, the Cat Classification Task Force of the IUCN Cat Specialist Group revised felid taxonomy in accordance with the 2015 two-subspecies proposal and recognised only P. t. tigris and P. t. sondaica. Results of a 2018 whole-genome sequencing study of 32 samples from the six living putative subspecies—the Bengal, Malayan, Indochinese, South China, Siberian and Sumatran tiger—found them to be distinct and separate evolutionary branches. These results were corroborated in 2021 and 2023. A 2023 study found validity for all nine recent subspecies. The Cat Specialist Group states that "Given the varied interpretations of data, the [subspecific] taxonomy of this species is currently under review by the IUCN SSC Cat Specialist Group."
The following tables are based on the classification of the tiger as of 2005, and also reflect the classification recognised by the Cat Classification Task Force in 2017.
The tiger shares the genus Panthera with the lion, leopard, jaguar and snow leopard. Results of genetic analyses indicate that the tiger and snow leopard are sister species whose lineages split from each other between 2.70 and 3.70 million years ago. The tiger's whole genome sequencing shows repeated sequences that parallel those in other cat genomes.
The fossil species Panthera palaeosinensis of early Pleistocene northern China was described as a possible tiger ancestor when it was discovered in 1924, but modern cladistics places it as basal to modern Panthera. Panthera zdanskyi lived around the same time and place and was suggested to be a sister species of the modern tiger when it was examined in 2014. However, as of 2023, at least two subsequent studies considered P. zdanskyi likely to be a synonym of P. palaeosinensis, noting that its proposed differences from that species fell within the range of individual variation. The earliest appearance of the modern tiger species in the fossil record are jaw fragments from Lantian County in China that are dated to the early Pleistocene.
Middle to late Pleistocene tiger fossils have been found throughout China, Sumatra and Java. Prehistoric subspecies include Panthera tigris trinilensis and P. t. soloensis of Java and Sumatra and P. t. acutidens of China; late Pleistocene and early Holocene tiger fossils have also been found in Borneo and Palawan, Philippines. Putative tiger fossils reported from the late Pleistocene in Japan represent the cave lion Panthera spelaea, as indicated by mitochondrial and nuclear genome analysis.
Results of a phylogeographic study indicate that all living tigers have a common ancestor that lived between 108,000 and 72,000 years ago. Genetic studies suggest that the tiger population contracted around 115,000 years ago due to glaciation. Modern tiger populations originated from a refugium in Indochina and spread across Asia after the Last Glacial Maximum. As they colonised northeastern China, the ancestors of the South China tiger intermixed with a relict tiger population.
Tigers can interbreed with other Panthera cats and have done so in captivity. The liger is the offspring of a female tiger and a male lion and the tigon the offspring of a male tiger and a female lion. The lion sire passes on a growth-promoting gene, but the corresponding growth-inhibiting gene from the female tiger is absent, so that ligers grow far larger than either parent species. By contrast, the male tiger does not pass on a growth-promoting gene while the lioness passes on a growth inhibiting gene; hence, tigons are around the same size as their parents. Since they often develop life-threatening birth defects and can easily become obese, breeding these hybrids is regarded as unethical.
The tiger has a typical felid morphology, with a muscular body, shortened legs, strong forelimbs with wide front paws, a large head and a tail that is about half the length of the rest of its body. It has five digits, including a dewclaw, on the front feet and four on the back, all of which have retractile claws that are compact and curved, and can reach 10 cm (3.9 in) long. The ears are rounded and the eyes have a round pupil. The snout ends in a triangular, pink tip with small black dots, the number of which increase with age.