Tasmanian Devil by David Owen Read Free Book Online Page B

and grass sags.
    Anatomically the thylacine is dog-like (a good example of convergent evolution), is considerably more streamlined than the squat, stout devil, and properly described as a cursorial predator. Yet dentition studies carried out by Menna Jones confirm that devils and thylacines competed directly, their teeth demonstrating a significant niche overlap. Although the devil is only about half the weight of a thylacine, it is by comparison heavy-bodied and, with its speed over a short distance and powerful bite and forepaw grip, capable of bringing down prey larger than itself. She cites cases of devils attacking adult wombats of up to 30 kilograms. 1 Thylacines, however, show much less tooth breakage than devils, meaning less bone-eating. Thus, while the devil ‘has a highly carnivorous dentition and trophic adaptions for bone consumption . . . The thylacine groups with the canids. Their molar teeth are intermediate in grinding and slicing functions and are quite slender, with no indications of adaption for bone consumption’. 2
    The devil’s comparatively greater tooth and associated jaw muscle strength leads Jones to conclude that ‘the role of top predator in the Tasmanian ecosystem was, at the least, shared equally between thylacines and devils’. 3 Although the concept of ‘sharing and competing’ may seem to be at odds with itself, there are successful examples elsewhere. Jaguars and pumas are roughly the same size as each other, but heavy-bodied jaguars take heavy prey such as peccaries, while the lighter-built pumas prey on smaller animals such as antelope. Jones speculates that the devil may have had a slight edge over the thylacine in taking heavy wombats.
    Taxonomically, devils and thylacines are not that closely related, but their similarities and their greater differences provide insight into how evolutionary fine-tuning allowed them to coexist closely. They have in common distinctive markings: bold stripes, bold patches, which have camouflage, physiological and behavioural functions. Devil markings are important during feeding, the pure white flashes standing out at night in close interactions. The markings of both species are an indication of activity concentrated at dawn and dusk, less often during the day.

    R.F. Ewer, a carnivore specialist in hyaenas and devils, speculated that a prototype/ideal canid would have both white markings and stripes to accentuate behavioural postures. While stripes aid in camouflage and possibly individual identification, white markings ‘may serve to direct bites to relatively non-vulnerable areas’. 4 The thylacine has stripes, the devil has white patches. Where devil agonistic encounters result in bites they are typically on or near the rump where white markings are located (although the white chest-flash seems to play a role in initiating an encounter). Knowledge of devil marking is extremely limited. White flashes range from pronounced to marginal, with an estimated 16 per cent of animals being melanic, that is, all black.
    The thick, largely non-prehensile tails of both species store fat. The devil’s tail is important in physiology, locomotion and social behaviour. During high-speed motion it acts as a counterbalance.
    The jaw gape of both species is wide, at 75–80 degrees, although for different reasons: thylacines used their gape to seize and suffocate or crush prey, while the gape and powerful teeth of the devil enable it to tear and gulp large lumps of food in a competitive manner, as well as to crush bones in order to consume them.
    The animals’ differences are pronounced. The devil’s blackness is a sure asset for a small nocturnal creature; the thylacine’s fawn or tan colouring shows a functional similarity to placental hunters such as wolves and wild dogs which hunt by day. An adult thylacine is about twice the weight and size of a devil. Anatomically it is considerably more streamlined than the