[6] The Tasmanian emu had not progressed to the point where it could be considered a distinct species and even its status as a distinct subspecies is not universally accepted, as it agreed with the mainland birds in measurements and the external characters used to distinguish it – a whitish instead of a black foreneck and throat and an unfeathered neck – apparently are also present, albeit rare, in some mainland birds.

There are suggestions the bird was slightly smaller than the mainland emu, but in conflict, other evidence (including descriptions of Pleistocene remains) indicates that both are similar in size.

[8] The Sydney Gazette in 1803 painted an image of the Van Diemen's Land landscape, when it reported the arrival of Lieutenant Bowen on the Lady Nelson: 'close to the Settlement are abundance of Emues, large Kangaroos, and Swans'.

[10][full citation needed] In 1808 George Harris the surveyor travelled from Hobart Town to Launceston, and wrote that his party walked 'thro the finest country in the world ... the quantities of kangaroos, emus and wild ducks we saw ... [was] incredible'.

[12][full citation needed] In 1831, Robinson described an Aboriginal dwelling, stating that the ground in front of this habitation was thickly strewed with the feathers of the emu, and the bones of the stately bird ... covered the ground, which the natives had broken to pieces to obtain the marrow to anoint their head and body.

[6] At a ceremony at Cape Grim on 14 April 1834, Aboriginal people danced and characterised emus by stretching out one arm to emulate the long neck of the bird.

The depiction of the emu in 'native drawings' is noted in the narrative of the overland journey of Sir John and Lady Franklin from Hobart to Macquarie Harbour in 1842.

[17] In 1838, John Gould after his voyage to Van Diemen's Land claimed that 'it would require a month search, in the most remote parts of the island, before one could see any'.

[20][full citation needed] An article in the Hobart Town Courier in 1832 deplored the loss of the emu, comparing it to that of the dodo, 'and we mention it particularly upon the present occasion, in order to impress upon our local government the propriety of taking some steps to prevent similar annihilation of that apparently no less valuable bird our native Emu.

[21][full citation needed] This plea for preservation was echoed by Ronald Campbell Gunn who in 1836 reflected on an unsuccessful attempt to entice Lieutenant-Governor Arthur to respond to the plight of the Tasmanian emu, pointing out that 'Emus are now extremely rare – and in a few years will be quite gone'.

Other than humans, the only other species to hunt the emu was the thylacine, which was an endurance hunter with a tendency to track and tire its prey.

[11] In addition, the practice of setting fire to grassland and shrubland to aid in claiming land for agriculture deprived the birds of habitat.

The subspecies became extinct around 1850, but this date is not very precise: mainland birds were introduced after diemenensis' disappearance (and possibly even when the last birds of the Tasmanian subspecies were still around, therefore hybridising them out of existence), but the history of emu introductions on Tasmania is not sufficiently documented to allow a more precise dating of the disappearance of diemenensis.

[28] The extinction theory is based on historical documents that reference Tasmanian Aboriginal people talking about goanna eggs being eaten by rats.

Knox & Walters (1994)[30] detail both the eggs and the skins of the Tasmanian emu specimens held by London's Natural History Museum.

The journal reported that 'Happily, those Emu specimens were not mounted and had been removed for safety, along with a lot of other valuable ratite material, to the museum premises at Tring, Hertfordshire'.