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.

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.

Intensive hunting on Tasmania is generally blamed for its extinction, but other contributing factors were disease, the introduction of and competition with dingoes, human encroachment into its habitat and climate change.

Recognition that the Australian marsupials were fundamentally different from the known mammal genera led to the establishment of the modern classification scheme, and in 1796, Geoffroy Saint-Hilaire created the genus Dasyurus, where he placed the thylacine in 1810.

[30] A classic example of convergent evolution, the thylacine showed many similarities to the members of the dog family, Canidae, of the Northern Hemisphere: sharp teeth, powerful jaws, raised heels, and the same general body form.

Descriptions of the thylacine come from preserved specimens, fossil records, skins and skeletal remains, and black and white photographs and film of the animal both in captivity and from the field.

[42] The early scientific studies suggested it possessed an acute sense of smell which enabled it to track prey,[43] but analysis of its brain structure revealed that its olfactory bulbs were not well developed.

During hunting, it would emit a series of rapidly repeated guttural cough-like barks (described as "yip-yap", "cay-yip" or "hop-hop-hop"), probably for communication between the family pack members.

[56] The northernmost record of the species is from the Kiowa rock shelter in Chimbu Province in the highlands of Papua New Guinea, dating to the Early Holocene, around 10,000–8,500 years Before Present.

[58] In Tasmania, they preferred the woodlands of the midlands and coastal heath, which eventually became the primary focus of British settlers seeking grazing land for their livestock.

[65] One of four specimens kept at Museum Victoria has been serially sectioned, allowing an in-depth investigation of its internal tissues and providing some insights into thylacine pouch young development, biology, immunology and ecology.

It was a nocturnal and crepuscular hunter, spending the daylight hours in small caves or hollow tree trunks in a nest of twigs, bark, or fern fronds.

Early observers noted that the animal was typically shy and secretive, with awareness of the presence of humans and generally avoiding contact, although it occasionally showed inquisitive traits.

[74] Throughout the 20th century, the thylacine was often characterised as primarily a blood drinker; according to Robert Paddle, the story's popularity seems to have originated from a single second-hand account heard by Geoffrey Smith (1881–1916)[75][76] in a shepherd's hut.

[81][34] A 2005 study showed that the thylacine had a high bite force quotient of 166, which was similar to that of most quolls, indicating that it may have been able to hunt larger prey relative to its body size.

[79] It has been suggested on the basis of the canine teeth and limb bones that the thylacine was a solitary pounce-pursuit predator that hunted smaller prey with trophic niches similar to relatively smaller canids like the coyote, and that it was not as specialised as large canids, hyaenids and felids of today: its canine lacked the adaptation for producing slashing or deep penetrating bites, and its anatomy was not suited for running fast in high speed.

[40] In captivity, thylacines were fed a wide variety of foods, including dead rabbits and wallabies as well as beef, mutton, horse and, occasionally, poultry.

"[89] Australia lost more than 90% of its megafauna around 50–40,000 years ago as part of the Quaternary extinction event, with the notable exceptions of several kangaroo and wombat species, emus, cassowaries, large goannas, and the thylacine.

[90] A 2010 paper examining this issue showed that humans were likely to be one of the major factors in the extinction of many species in Australia although the authors of the research warned that one-factor explanations might be over-simplistic.

The results indicated that the last of the thylacines in Tasmania had limited genetic diversity due to their complete geographic isolation from mainland Australia.

Since no definitive proof of the thylacine's existence in the wild had been obtained for more than 50 years, it met that official criterion and was declared extinct by the International Union for Conservation of Nature in 1982[2] and by the Tasmanian government in 1986.

[129][130] In March 2005, Australian news magazine The Bulletin, as part of its 125th anniversary celebrations, offered a $1.25 million reward for the safe capture of a live thylacine.

[131][139] In August 2022, it was announced that the University of Melbourne would partner with Texas-based biotechnology company Colossal Biosciences to attempt to re-create the thylacine using its closest living relative, the fat-tailed dunnart, and return it to Tasmania.

[146] A draft whole genome sequencing of the thylacine was produced by Feigin et al. (2017) using the DNA extracted from an ethanol-preserved pouch of a young specimen provided by Museums Victoria.

[147] Researchers used the genome to study aspects of the thylacine's evolution and natural history, including the genetic basis of its convergence with canids, clarifying its evolutionary relationships with other marsupials and examining changes in its population size over time.

[160] The best known illustrations of Thylacinus cynocephalus were those in John Gould's The Mammals of Australia (1845–1863), often copied since its publication and the most frequently reproduced,[161] and given further exposure by Cascade Brewery's appropriation for its label in 1987.

[162] The government of Tasmania published a monochromatic reproduction of the same image in 1934,[163] the author Louisa Anne Meredith also copied it for Tasmanian Friends and Foes (1881).

[174] Various Aboriginal Tasmanian names for the thylacine have been recorded, such as coorinna, kanunnah, cab-berr-one-nen-er, loarinna, laoonana, can-nen-ner and lagunta,[175][176] while kaparunina is used in Palawa kani.

[177][178] One Nuenonne myth recorded by Jackson Cotton tells of a thylacine pup saving Palana, a spirit boy, from an attack by a giant kangaroo.

[180] An early European record tells how Aboriginals believed bad weather was caused by a Thylacine carcass being left exposed on the ground, instead of being covered by a small shelter.