The thylacine was the largest known carnivorous marsupial of modern times. It is commonly known as the Tasmanian tiger (because of its striped back) or the Tasmanian wolf. Native to continental Australia, Tasmania and New Guinea, it is thought to have become extinct in the 20th century. It was the last extant member of its family, Thylacinidae, although several related species have been found in the fossil record dating back to the early Miocene.The thylacine had become extremely rare or extinct on the Australian mainland before European settlement of the continent, but it survived on the island of Tasmania along with several other endemic species, including the Tasmanian devil. Intensive hunting encouraged by bounties is generally blamed for its extinction, but other contributing factors may have been disease, the introduction of dogs, and human encroachment into its habitat. Despite its official classification as extinct, sightings are still reported, though none has been conclusively proven.
Like the tigers and wolves of the Northern Hemisphere, from which it obtained two of its common names, the thylacine was an apex predator. As a marsupial, it was not closely related to these placental mammals, but because of convergent evolution it displayed the same general form and adaptations. Its closest living relative is thought to be either the Tasmanian devil or numbat. The thylacine was one of only two marsupials to have a pouch in both sexes (the other being the water opossum). The male thylacine had a pouch that acted as a protective sheath, covering the male's external reproductive organs while he ran through thick brush. It has been described as a formidable predator because of its ability to survive and hunt prey in extremely sparsely populated areas.
The modern thylacine first appeared about 4 million years ago. Species of the family Thylacinidae date back to the beginning of the Miocene; since the early 1990s, at least seven fossil species have been uncovered at Riversleigh, part of Lawn Hill National Park in northwest Queensland.[9][10] Dickson's Thylacine (Nimbacinus dicksoni) is the oldest of the seven discovered fossil species, dating back to 23 million years ago. This thylacinid was much smaller than its more recent relatives. The largest species, the powerful thylacine (Thylacinus potens) which grew to the size of a wolf, was the only species to survive into the late MioceneIn late Pleistocene and early Holocene times, the modern thylacine was widespread (although never numerous) throughout Australia and New Guinea.
An 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. Since the thylacine filled the same ecological niche in Australia as the dog family did elsewhere it developed many of the same features. Despite this, it is unrelated to any of the Northern Hemisphere predators.
Descriptions of the thylacine vary, as evidence is restricted to preserved joey specimens, fossil records, skins and skeletal remains, black and white photographs and film of the animal in captivity, and accounts from the field.
The thylacine resembled a large, short-haired dog with a stiff tail which smoothly extended from the body in a way similar to that of a kangaroo. Many European settlers drew direct comparisons with the hyena, because of its unusual stance and general demeanour. Its yellow-brown coat featured 13 to 21 distinctive dark stripes across its back, rump and the base of its tail, which earned the animal the nickname, "Tiger". The stripes were more marked in younger specimens, fading as the animal got older.One of the stripes extended down the outside of the rear thigh. Its body hair was dense and soft, up to 15 mm (0.6 in) in length; in juveniles the tip of the tail had a crest. Its rounded, erect ears were about 8 cm (3.1 in) long and covered with short fur. Colouration varied from light fawn to a dark brown; the belly was cream-coloured.
The mature thylacine ranged from 100 to 130 cm (39 to 51 in) long, plus a tail of around 50 to 65 cm (20 to 26 in).The largest measured specimen was 290 cm (9.5 ft) from nose to tail. Adults stood about 60 cm (24 in) at the shoulder and weighed 20 to 30 kg (40 to 70 lb).There was slight sexual dimorphism with the males being larger than females on average.
The female thylacine had a pouch with four teats, but unlike many other marsupials, the pouch opened to the rear of its body. Males had a scrotal pouch, unique amongst the Australian marsupials, into which they could withdraw their scrotal sac
The thylacine was able to open its jaws to an unusual extent: up to 120 degrees. This capability can be seen in part in David Fleay's short black-and-white film sequence of a captive thylacine from 1933. The jaws were muscular but weak and had 46 teeth.
The thylacine's footprint is easy to distinguish from those of native and introduced species.
Thylacine footprints could be distinguished from other native or introduced animals; unlike foxes, cats, dogs, wombats or Tasmanian devils, thylacines had a very large rear pad and four obvious front pads, arranged in almost a straight line. The hindfeet were similar to the forefeet but had four digits rather than five. Their claws were non-retractable.
The early scientific studies suggested it possessed an acute sense of smell which enabled it to track prey,but analysis of its brain structure revealed that its olfactory bulbs were not well developed. It is likely to have relied on sight and sound when hunting instead. Some observers described it having a strong and distinctive smell, others described a faint, clean, animal odour, and some no odour at all. It is possible that the thylacine, like its relative, the Tasmanian devil, gave off an odour when agitated.
The thylacine was noted as having a stiff and somewhat awkward gait, making it unable to run at high speed. It could also perform a bipedal hop, in a fashion similar to a kangaroo—demonstrated at various times by captive specimens.Guiler speculates that this was used as an accelerated form of motion when the animal became alarmed. The animal was also able to balance on its hind legs and stand upright for brief periods.
Observers of the animal in the wild and in captivity noted that it would growl and hiss when agitated, often accompanied by a threat-yawn. 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. It also had a long whining cry, probably for identification at distance, and a low snuffling noise used for communication between family members.
The thylacine was exclusively carnivorous. Its stomach was muscular with an ability to distend to allow the animal to eat large amounts of food at one time, probably an adaptation to compensate for long periods when hunting was unsuccessful and food scarce.Analysis of the skeletal frame and observations of it in captivity suggest that it preferred to single out a target animal and pursue that animal until it was exhausted. Some studies conclude that the animal may have hunted in small family groups, with the main group herding prey in the general direction of an individual waiting in ambush. Trappers reported it as an ambush predator.
Little is known of the thylacine's diet and feeding behaviour. Prey is believed to have included kangaroos, wallabies and wombats, birds and small animals such as potoroos and possums. One prey animal may have been the once common Tasmanian emu. The emu was a large, flightless bird which shared the habitat of the thylacine and was hunted to extinction around 1850, possibly coinciding with the decline in thylacine numbers. Both dingoes and foxes have been noted to hunt the emu on the mainland. European settlers believed the thylacine to prey upon farmers' sheep and poultry.Throughout the twentieth 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 in a shepherd's hut. In captivity, thylacines were fed a wide variety of foods, including dead rabbits and wallabies as well as beef, mutton, horse, and occasionally poultry. Tasmania's leading naturalist Michael Sharland published an article in 1957 stating that a captive thylacine refused to eat either dead wallaby flesh or to kill and eat a live wallaby offered to it, but "ultimately it was persuaded to eat by having the smell of blood from a freshly killed wallaby put before its nose."
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