The marsupials of the Australian region descend from a single microbiotherian population that happened to be on the Antarctican/Australian part of Gondwana when the supercontinent split up. This population experienced an adaptive radiation, resulting in the kangaroos, bandicoots and the other mammals Australia is famous for. Of those, the Tasmanian Devil (Sarcophilus harrisii) is the topic today. As you can see from the diagram above (Nilsson et al., 2010), the Devil’s line (Dasyuromorpha) is one of the earliest-branching, diverging even before reaching Australia, making it doubly important for the study of evolution.
The Tasmanian Devil is a carnivorous marsupial, the largest in the world, found on Tasmania and to a lesser degree on Australia (where the dingo appears to have outcompeted and driven it out). It is unique in at least the mammalian world by running against the trend and having forelimbs almost more powerful than the rear limbs (in mammals, if there is any power difference, the trend is almost unanimously to powerful back legs, cf. kangaroo, gazelle). They also have one of the fastest rates of body mass evolution, 10 times faster than the rest of the mammals (although this may be an artefact of the model used; Cooper & Purvis, 2010). Along with the quolls, they are the only surviving close relatives of the Tasmanian Wolf (the thylacines, which you can ironically see on Tasmania’s coat of arms), a species that was hunted to extinction.
As of 2008, it has been on the IUCN’s Endangered list due to its population being decimated by a contagious cancer, devil facial-tumour disease (see Murgia et al., 2006). Between 1997 and 2008, this disease caused the Devil population to decline by 64%. The cause of the cancer is, as far as I know, still speculated at, but the general consensus is that it is due to human influences: habitat destruction and human encroachment has introduced carcinogens into the environment at a rate faster than the organisms could develop defensive mechanisms. Regardless of the origin, the situation is a disaster and the Tasmanian Devil is on a quick road to extinction.
Such situations have happened before: the western gorilla went to critically endangered due to Ebola virus. What kept the western gorilla live was conservation efforts that delivered vaccines to them.
If you want to help the Tasmanian Devil, money is the only way. To that end, a group of writers (including a friend of mine, hence the post) has compiled this anthology: “Extinct doesn’t mean forever“. The profits from this anthology from 1-15 July will go to Tasmanian Devil conservation efforts. Get the book, spread the word and help save the Devil! Mother Nature will thank you.
Cooper N & Purvis A. 2010. Body Size Evolution in Mammals: Complexity in Tempo and Mode. The American Naturalist 175, 727-738.
Murgia C, Pritchard JK, Kim, SY, Fassati A & Weiss, RA. 2006. Clonal origin and evolution of a transmissible cancer. Cell 126, 477–487.
Nilsson MA, Churakov G, Sommer M, Tran NV, Zemann A, Brosius J & Schmitz J. 2010. Tracking Marsupial Evolution Using Archaic Genomic Retroposon Insertions. PLoS Biology 8, e1000436.