window of growth in the mother's pouch. This study revealed new information on the biology of the thylacine, including the growth of its limbs and when it developed its 'dog-like' appearance. It was found that two of the thylacine young in the Tasmanian Museum and Art Gallery (TMAG) were misidentified and of another species, reducing the number of known pouch young specimens to 11 worldwide. 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. Feeding and diet The thylacine was an apex predator, though exactly how large its prey animals could be is disputed. 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. It tended to retreat to the hills and forest for shelter during the day and hunted in the open heath at night. Early observers noted that the animal was typically shy and secretive, with awareness of the presence of humans and generally avoiding contact, though it occasionally showed inquisitive traits. At the time, much stigma existed in regard to its "fierce" nature; this is likely to be due to its perceived threat to agriculture. The thylacine was exclusively carnivorous. In captivity, thylacines had a clear preference for birds (particularly chickens). In the wild, large ground-dwelling birds (such as Tasmanian nativehens) may have been their primary prey, since they are documented to have hunted a wide range of them, and its comparatively moderate bite force was more suited to hollow avian bones. During its peak occupation of the mainland, such prey would have been bountiful, and studies of their Pleistocene habitat points to a more suitable diet consisting of a range of megapodes (such as the Giant malleefowl) ratites (such as the emu), and possibly dromornithids (most of which became extinct prior to European settlement). At the time of European settlement, the Tasmanian emu, a subspecies believed to be smaller than mainland emus, was common and widespread and Thylacines were known to prey on them and share the same habitat. Many early depictions of them hunting included emu. The large, flightless bird was hunted to extinction by humans within 30 years of European settlement. The extinction correlates with a rapid decline in thylacine numbers. Cassowary species