Australian Rabbits (image) Duke University Caption Rabbits crowded around a watering hole in southern Australia in 1938. This invasive species started with 24 individuals, reaching a population of 600 million by 1950 in part because of a phenomenon known as the Allee effect. A Duke University team has experimentally tested the concept in engineered bacteria. Credit Commonwealth of Australia (National Archives of Australia) 2013 Usage Restrictions None Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.