Study into Tasmanian devil DNA reveals its long struggle to survive

IT’S cold comfort, but an ice age that happened 20,000 years ago is believed to be killing Tasmanian devils, not a massacre as previously thought.

Heavy snowfall at Barrington Tops with Tasmanian Devils. Courtesy of Twitter @Tim_Beshara

AN ice age is killing our Tasmanian devils, but our actions certainly aren’t helping. New research has revealed the marsupial’s long struggle for survival and why its existence is teetering on the brink.

An effort to understand the origins of a deadly cancer afflicting the last surviving populations of the famous Tasmanian devil published by the University of Tasmania this week has found that fierce little beasts have suffered two serious population declines in the past 50,000 years.

The analysis of genetic data shows the isolated islanders were hit hard by the last ice age some 20,000 years ago, along with the devastating impact on Tasmania’s climate by a major el Nino weather imbalance some 4000 years ago.

An the brink ... Tasmanian devils are suffering a plague of bite-transmitted tumours because of their low genetic diversity. Source: AP

The facial tumours now cutting a swathe through devil populations is most likely caused by the inbreeding of survivors.

“Low genetic diversity is a major extinction risk,” co-investigator Assoc Prof Jeremy Austin from the University of Adelaide said.

“Our new research shows that devils didn’t lose genetic diversity rapidly in the last 200 years as a result of human activities. Instead they have survived for thousands of years with low diversity.”

Bounty hunting by European settlers cut a swathe through devil populations which were once common throughout Australia but are now limited to Tasmania

But Devil Facial Tumour Disease (DFTD) has further massacred devil numbers by up to 80 per cent since it was first noticed by scientists in 1996.

Uncertain future ... A 5 month old Tasmanian devil joey called 'Bear', at the Australian Reptile Park, Somersby, NSW. Source: News Corp.

Now, the DNA revelations of devil inbreeding has raised serious concern for the species’ survival.

“Our results show extensive population declines across Tasmania occurred at the same time as environmental changes around the last glacial maximum and following unstable climate related to increased ‘El Niño — Southern Oscillation’ activity,” Lead author, PhD student Anna Brüniche-Olsen, said.

The findings warn that the devil population will come under yet further pressure as Tasmania’s climate continues to become hotter and more arid.

The study, article, published in the journal Biology Letters, Extensive population decline in the Tasmanian devil predates European settlement and Devil Facial Tumour Disease statistically processed the DNA data of more than 300 devils to infer the history of the species in Tasmania.