The thylacine (; binomial name Thylacinus cynocephalus), also commonly known as the Tasmanian tiger or Tasmanian wolf, was a species of carnivorous marsupial that was native to the Australian mainland and the islands of Tasmania and New Guinea until it went extinct. The thylacine died out in New Guinea and mainland Australia around 3,600–3,200 years ago, prior to the arrival of Europeans, possibly because of the introduction of the dingo, whose earliest record dates to around the same time, but which never reached Tasmania. Prior to European settlement, around 5,000 remained in the wild on the island of Tasmania. Beginning in the nineteenth century, they were perceived as a threat to the livestock of farmers and bounty hunting was introduced. The last known of its species died in 1936 at Hobart Zoo in Tasmania. The thylacine is widespread in popular culture and is a cultural icon in Australia.
The thylacine was known as the Tasmanian tiger because of the dark transverse stripes that radiated from the top of its back, and it was called the Tasmanian wolf because it resembled a medium- to large-sized canid. The name thylacine is derived from thýlakos meaning 'pouch' and -ine meaning 'pertaining to', and refers to the marsupial pouch. Both sexes had a pouch. The females used theirs for rearing young, and the males used theirs as a protective sheath, covering the external reproductive organs. The animal had a stiff tail and could open its jaws to an unusual extent. Recent studies and anecdotal evidence on its predatory behaviour suggest that the thylacine was a solitary ambush predator specialised in hunting small- to medium-sized prey. Accounts suggest that, in the wild, it fed on small birds and mammals. It was the only member of the genus Thylacinus and family Thylacinidae to have survived until modern times. Its closest living relatives are the other members of Dasyuromorphia, including the Tasmanian devil, from which it is estimated to have split 42–36 million years ago.