They’re called “tigers” because of their distinctive stripes, and “wolves” because of their alleged ferocity – “alleged” because there hasn’t been a confirmed sighting of a Thylacine in the wild for nearly a century. A new study of the eating habits of Thylacinus cynocephalus may give it a new nickname that better fits the much beloved yet still officially extinct creature – Tasmanian jackal.
“The thylacine (Thylacinus cynocephalus), the iconic recently extinct marsupial, is considered a classic example of convergent evolution with the distantly related placental wolf or dog, though almost nothing is actually known regarding its ecology. This lack of data leads to questions regarding the degree of convergence with, and the similarity of, the functional ecology of the thylacine and the wolf/dog.”
In the study published in the journal BMC Ecology and Evolution, Douglass S. Rovinsky, co-author and associate research scientist at Australia’s Monash University, points out that while the thylacine evolved at the same time and pace (convergently) as distantly related, non-marsupial wolves and dogs, any comparisons between the species are severely hindered by the lack of knowledge about the thylacine and the environment it lived and evolved in. Rovinsky and Monash colleagues Alistair Evans and Justin W. Adams started with Rovinsky’s previous research on the unusual skull shape of the thylacine in comparison with wolves and wild dogs and expanded it to 56 different species across 12 families of marsupial and placental faunivorous mammals. (“Faunivorous” is any animal that eats other animals.)
“Using hand-held 3D scanners, we scanned hundreds of skulls from 56 different species of carnivorous mammals, with specimens obtained from more than a dozen museums around the world. This enabled us to build a skull “shapespace” to then see where the thylacine would fit among the others.”
As they explain in The Conversation, the researchers found strong evidence of convergent evolution … but not with wolves or dogs. The thylacine’s skull shape was closer to that of the African jackals and South American foxes, which are actually canids similar to jackals. Those two species eat animals much smaller than themselves, so the researchers looked at the Australian environment for similar creatures and decided the preferred food of thylacines was pademelons, bettongs, bandicoots and young wallabies. That separates thylacines even further from wolves, which have no problem eating animals much larger than themselves. Does that mean we should start calling them Tasmanian jackals?
“Interestingly, however, one of the most striking findings was that the thylacine did not actually overlap with any of the other predators, canid or otherwise. While it was similar to some canids, it was not identical. This highlights that even our more precise analysis may paint the thylacine with too broad a brush.”
Rovinsky then describes the painfully obvious reason for the demise of the thylacine – it was hunted to extinction because it reminded European settlers of the wolf, who then assumed it was as dangerous to their livestock as wolves.
“This reaction, like most based on first glance, was devastatingly wrong.”
Unfortunately, because they’re gone, we can’t determine what was right – what the thylacine was really like before the arrival of Europeans. Its convergent evolution with jackals only gives a partial picture. Yes, there’s still a remote chance a few will be found in Tasmania, but they won’t be able to fill in the blanks because they live in a completely different environment.
It’s no wonder so many people feel guilty about its likely extinction and hold out hope its DNA might bring it back. If you don’t, Rovinsky gives us one more reason.
“When we lost the thylacine, we lost something truly unique for its time.”