September 7, 1936, was the last time a Tasmanian tiger was seen alive, the thylacine (Thylacinus cynocephalus) living in captivity at Hobart Zoo died that day, dropping its species from the taxonomic catalog of living species. At the time, the Tasmanian tiger was declared extinct in captivity and later in the wild, but new research suggests that it is possible that the species survived into the 1980s or even later.
The Disappearance of the Tasmanian Tiger
The declaration of extinction is a very strong statute, which implicitly brings the death of a genome from the face of the Earth. However, it is not as simple as it sounds, i.e., biologists cannot know precisely the exact moment when the last specimens of a species stop breathing. Instead, they have to do a combination of in-depth research, statistics, and a lot of guesswork.
It is precisely the lack of sightings in situ that mostly sustains the extinction of a species. This was the case in the 1930s with the Tasmanian tiger when sightings in the wild of the ‘marsupial wolves’ declined considerably until the Australian species ended up in oblivion.
Evidence-based on the lack of verifiable observations, as well as tracks and remains, led the International Union for Conservation of Nature to close the Tasmanian tiger case. It was declared extinct in captivity in 1936, but it was not until 1986 that the IUCN finally lost all hope in the case and closed its investigations into it.
Is It Really Extinct?
Australian institutions are interested in knowing the story of the disappearance of one of their most iconic native species in history. That’s why new research from the University of Tasmania suggests that the Tasmanian tiger may have gone extinct decades later than previously thought, and they even believe there is a remote possibility that families of thylacines are still living wild, hidden in the corners of the wilderness.
Researchers at the University of Tasmania developed a new method to visualize the spatiotemporal dynamics of the species in the 20th century. They assembled an exhaustive collection of 1,237 reports of possible sightings that included hunters, trappers, wildlife professionals, and local people. The clearest difference from previous research is that this one includes reports not only from formal investigations but from a wider range of people.
Through extensive research, they were able to determine that the Tasmanian tiger probably did not go extinct until four decades after the last captive sighting date, meaning that the species would have gone extinct around 1970.
However, uncertainty modeling of the entire sighting record, where each observation was assigned a probability, and then the entire dataset was subjected to sensitivity analysis, suggests that the extinction could have occurred as recently as the late 1980s and early 2000s. The modeling also shows a small possibility that the species persists in the more remote wilderness areas of southwestern Tasmania, although this has no in situ support so the extinct species status has not changed.
In summary, there is a remote possibility that the Tasmanian tiger continues to live in remote areas of southwestern Tasmania, although this would not change the extinction designation unless in situ research proves this.
Story written in Spanish by Alejandra Martínez in Ecoosfera
