No subspecies are recognised.

The last recorded killing of a wild Thylacine was in 1930, and the last known Thylacine was captured in 1933 and died in Hobart Zoo in 1936. Despite numerous reports of sightings since then including on mainland Australia (Heberle 2004), and many organised searches in Tasmania by government agencies, conservation NGOs, philanthropists, and others (more search effort than any other extinct mammal (Fisher and Blomberg 2011)), there has been no convincing evidence of its persistence. Brook et al. (2023) used uncertainty modelling of purported sightings to map a regional extirpation pattern, and concluded that it probably persisted until the 1980s, however Mooney (2023) concluded that no sightings since 1936 can be substantiated. All data sets analysed with a conservative probabilistic sighting-record resampling by Brook et al. (2023) concluded that the Thylacine has 100% probability of being extinct in 2023. The statistical approaches of Brook et al. (2023), Carlson et al. (2018) and Fisher & Blomberg (2011, 2012) are robust probabilistic extinction models using sighting data that included uncertainty of records, distribution variables, search effort, and other trait data. There have been at least six classes of quantitative models applied to estimate the probability of extinction and the date of extinction of the thylacine in the peer-reviewed scientific literature (Fisher and Humphries 2024). 1) Stationary Poisson (Solow 1993), 2) Weibull model / Optimal linear estimation (Roberts and Solow 2003), 3) Nonparametric (Solow and Smith 2005), 4) Cox Regression Survival model of threat and effort (Fisher and Blomberg 2012), 5) Bayesian Stationary Poisson model with varying certainty of sightings and independent processes for valid and invalid sightings (Solow and Beet 2014, Carlson et al. 2018), 6) Stationary Poisson with resampling (Brook et al. 2019, Brook et al. 2023). These have used a range of assumptions about the data distribution and certainty, both frequentist and Bayesian approaches, and sets of different sources of data including sighting dates, species traits, measures of effort, distributional data, and observer reliability. Virtually all have concluded that the Thylacine is extinct, and nearly all (and all with physical evidence) have concluded that the extinction date was in the 1930s or 1940s. Additionally, from 2014 to 2020, 3,225 camera trap sites throughout Tasmania leading to photographs on >315,000 camera nights revealed no detections of anything that could be attributed to a Thylacine (C.N. Johnson pers. comm.).

The Thylacine was once found on the island of New Guinea and was widespread on the Australian mainland, but disappeared from everywhere except Tasmania by at least 2000 years ago, probably because of predation by and competition from the Dingo Canis lupus (Johnson 2006). In modern times it was known only in Tasmania, which was isolated from the Australian mainland c. 8,000 – 10,000 years ago, before the arrival of the Dingo on the mainland. It was widespread in Tasmania, but most abundant in open forest and woodland (Guiler 1985, Paddle 2000). It occurred in most habitat types from low (east) to high (north-west) rainfall but at low densities in the south-west where rainfall is very high, soil fertility is very low, and vegetation is hummock grassland (button grass), wet scrub, or wet forest.

This species is presumed to be extinct.

Thylacines occurred in most habitats in Tasmania, but apparently not the dense temperate rainforests of the south-west (Paddle 2000). The skull of the Thylacine is highly convergent with the wolf suggesting similar dietary ecology (Newton 2021), although it probably had a less powerful bite than a wolf (Mooney and Rounsevell 2023). It was likely an endurance runner ('coursing predator') that hunted and scavenged mainly at night, singly or in pairs. Before it was widely persecuted, diurnal observations were also reported (Mooney and Rounsevell 2023). Its main food items were reported to be kangaroos and wallabies. Dens were often located among rocks and in caves, Paddle (1993) describes a 1903 photograph of a den in a shallow cave containing nesting material of ferns. Litters (of up to four young, usually two or three) were also discovered amongst dense vegetation.

There was extensive persecution of the Thylacine because of a perceived threat to sheep, and fear of a large predator (Mooney and Rounsevell 2023). From 1830 (less than three decades after Europeans arrived in Tasmania), companies and individual landowners began offering bounty payments (Mooney and Rounsevell 2023). Its eradication was funded by a Tasmanian government scheme from 1888 to 1909, and a bounty was paid for more than 2,200 Thylacines killed (Heberle et al. 2004, Sleightholme and Campbell 2016). This is a similar number to the estimated Thylacine population of Tasmania at any one time (Mooney and Rounsevell 2023). Collecting by museums and zoos was also a major reason for hunting in the early 20th century. A disease similar to canine distemper could have contributed to extinction (Paddle 2012). However single-species population viability analysis models are unable to account for extinction unless a high human harvest, small starting population size or low maximum population growth rate is assumed, even if disease effects are included from 1906 to 1909. Thylacine extinction in Tasmania is readily recreated using disease-free multi-species models that simulate declines in native prey populations (particularly due to competition with introduced sheep) (Prowse et al. 2013).

In 1936, the Thylacine received legal protection under Tasmanian law (Mooney and Rounsevell 2023). In 1966, a 647,000 ha game reserve was set up in south-western Tasmania, partly to protect any animals possibly remaining in the area. Currently there are no conservation measures pertaining to this species as it is presumed extinct. It is listed on CITES Appendix I. The species is listed as Extinct under Australian environmental law.