When the Tasmanian devil is away, the possum will play.
This could be the case for a long time, if not remain permanent, due to the facial cancer disease that has caused approximately 90 percent of the devils to disappear from eastern Tasmania, in the Australian wild.
University of Tasmania Zoologist Tracey Hollings highlights that possums still maintain vigilant behavior despite the fact that predation risk has become much lower.
"They are probably not looking around as much or spending as much energy with those anti-predator behaviors that they would in areas of high devil density," Hollings explains.
Possums used to protect themselves from the marsupial predators by staying above-ground on trees. The devils, however, are now functionally extinct, and possums have become freer to stay longer on the ground; this means more time for the possums to feed.
To further study the possum's changed behavior, Hollings and her colleagues set out an experiment at 30 sites on Tasmania's north side, and six sites on Maria Island which is off the coast of Tasmania. Devils have long been gone from Maria Island as far back as 10,000 years ago. Possums, on the other hand, were introduced 50 years ago.
The researchers surveyed the areas where there were more possums active on the ground - areas where there were least number of devils due to the disease.
To check how comfortable the possums were climbing down the trees and onto the ground, the researchers they would pour rocks and 100 sultanas into a container and leave it under a tree, overnight. They would count how much sultanas were left the following morning. The less sultanas there were left on the container, the more comfortable the possum has become, the researchers concluded.
In the areas that Hollings's team surveyed, where there have been less devils, they found that there were more possums staying longer on the ground. However, even with the devils diminishing, Hollings notes that possums should still be in the lookout for other predators like cats and the spotted-tailed quoll.
Other studies are also being conducted to find a cure to the devil disease. For the time being, while the devils are away, the possums will definitely play.