A black and white film from 1935 shows the last known thylacine, a captive animal at Beaumaris Zoo in Hobart, pacing uncertainly in his small enclosure, as a man in a trilby hat bangs on the wire mesh.
The thylacine died a year later, and although unverified wild sightings persisted for decades, the species is now considered well and truly extinct.
- What happened to the remains of the last known thylacine?
- The thylacine became extinct in the 1960s… or did it?
The thylacine, also known as the Tasmanian tiger, was once the world’s largest marsupial predator. With the head of a wolf, the stripes of a tiger and the stiff tail of a kangaroo, it was an odd and imposing animal.
Unusually for a marsupial, both sexes had a pouch – backwards facing - which the females used to carry their joeys, and the males used to protect their reproductive organs.
The animal’s troubles started in the early 19th century, when European settlers said it was killing their sheep. A bounty was placed on the animal’s head, and thylacines were slaughtered in their thousands.
Its de-extinction was first mooted over 20 years ago, when Australian scientists recovered fragments of DNA from a preserved museum specimen. Then, in 2017, Andrew Pask from the University of Melbourne and colleagues successfully decoded the animal’s full genetic sequence.
Building on this, researchers from Colossal Biosciences have since completed high quality genomes of additional thylacines, as well other carnivorous marsupials, including the little fat-tailed dunnart, which is the thylacine’s closest living relative. The team is now editing the ‘genetic essence’ of thylacine into marsupial cells, which they will then use to generate embryos and then joeys.
On the one hand, this could be easier than making a mammoth, because marsupials have short gestations and give birth to lentil-sized babies. So, although the fat-tailed dunnart is only the size of a mouse, it could still possibly work as a surrogate. But after the joey is born, what then? Colossal Biosciences are designing what they call an ‘exo-pouch’ to solve the problem, but this is still very much in development.
None of these steps are trivial, but perhaps the most difficult part will come when the first joey hops out of its exo-pouch. In popular culture, the thylacine was skulking and solitary, but people who saw it, back in the 19th century, described it as a social animal.
Joeys stayed in their mother’s pouch until they were nearly full grown, and then remained with their parents until the next generation arrived. During this time, the family unit lived and hunted co-operatively. Genetics will have influenced this behaviour, but undoubtedly, some was learned. So, who knows how the first de-extinct thylacines will fare?
Released back into their native Tasmania, where it’s said there is plenty of space, the hope is that the animals would be beneficial for the ecosystem. When an apex predator disappears, a process called trophic downgrading ensues. There are ripple effects down the food chain. This happened after the thylacine went extinct.
Invasive species, such as rabbits and ferrets, infiltrated the landscape, and the Tasmanian devil – a scavenger, by nature – became the island’s top predator. De-extinct thylacines could help to bring balance to the ecosystem. By feasting on invasive species, they could help keep their numbers under control. Tasmanian devils are suffering from an infectious facial tumour disease. By predating sick individuals, thylacines could help keep the disease in check.
Only, no one studied the thylacine’s ecology whilst the species was still alive, so no one can be 100% sure.
Perhaps the biggest problem to the thylacine’s potential return, however, is one of acceptance. It’s one thing to bring back a herbivorous mammal like the mammoth, but an apex predator? People were trigger-happy and nervous the first time around, so some major PR may be needed to get local Tasmanians on board.
