Until 2012, the animal inhabitants of Maria Island were living without any major predators.

So when 15 Tasmanian devils were released onto south-east Tasmanian island in efforts to protect them from facial tumour disease, that number quickly grew to 100.

The devil’s presence shook things up for the other creatures living on island which were not too familiar with competing for food, nor fearing for their lives.

A foraging experiment showed the possums went back up into the trees instead of spending large amounts of time on the ground searching for food.

The study has revealed the possums learned quickly — it took them less than three years to change their behaviour.

More:

https://www.abc.net.au/news/2019-09-28/possums-versus-devils-on-maria-island-important-predator-study/11542638