The skull of the thylacine exhibits a far greater degree of sexual dimorphism than is the case with any other marsupial species.  The male thylacine has a proportionally larger skull with a longer face than that of the female.  The female's skull by comparison is smaller, with a shorter muzzle, less expanded zygomata, and smaller but proportionally larger teeth.  There are a number of important structural differences between the skull of a thylacine and that of its placental counterparts.  The dental formula of the thylacine is: I1-4/1-3; C1/1 ; P1-3/1-3; M1-4/1-4 = 46, compared to that of the wolf: I1-3/1-3; C1/1; P1-4/1-4; M1-3/1-2 = 42 (dental abbreviations: I (incisors), C (canines), P (premolars), M (molars). The teeth of the thylacine appear to be homologous to the placental milk teeth; the only

. . A thylacine by L. Medland at the London Zoo, 1906. Another photo of this individual is shown here. marsupial tooth replaced in life being the third premolar.  In the thylacine, both the upper and lower molars are adapted to function as carnassials.  In placental carnivores, it is the last upper premolar and the first lower molar so modified, the remaining molars being adapted for crushing.

The thylacine is unique in having the largest gape of any mammal.  This is often quoted as being in the order of 180º, apparently influenced by old photographs and films which depict the animal yawning.  However, this would be anatomically impossible, since a gape greater than 90º would result in dislocation of the jaw.

.     The thylacine is digitigrade, and like dogs and cats, walks on its toes.  A major difference between the feet of the thylacine and those of a canid, is that there is no webbing present between the thylacine's toes.  In canids, the webbing serves to hold the digits together when the animal is running.  Thylacines also have proportionately longer rear limbs as compared to canids, giving them a rear-to-front sloping back, and a loping gait.     The shape of the thylacine's hindquarters is very distinctive.  The tail is not abruptly separated from the body as would be the case with a dog, but tapers gradually, rather like that of a kangaroo or wallaby. . A female thylacine in the sanatorium (quarantine) at London Zoo, photographed by F. W. Bond.  Courtesy: Zoological Society of London.  This thylacine was purchased from Mrs. Roberts at the Beaumaris Zoo (SB), and arrived in London on the 12th March 1909.  It was resident at the zoo until its death on the 5th June 1914. Other photographs of this individual: 1, 2, 3, 4.

    No audio recordings of thylacine vocalisation exist.  Our knowledge of the sounds it makes is based solely on the historical accounts of trappers, zoo staff, and naturalists. It appears that thylacine vocalisation serves both as a structured warning to any potential aggressor, as well as a means of social interaction between family members.  Five distinct vocalisations have been identified: a coughing bark, a snuffle, a hiss, an undulating cry, and a growl.