Looking through ancient animal waste isn’t a glamorous job, but it can tell us a lot about the Earth’s history. After examining the poop of ancient creatures that roamed Australia until they went extinct around 45,000 years ago, scientists believe they have found what caused the demise of Australian megafauna: humans.
A team of researchers from Monash University in Victoria, Australia and the University of Colorado Boulder analyzed a sediment core taken from the Indian Ocean. The core, collected just off the coast of southwest Australia, contains layers of material that help to lay out ancient chronological events for scientists. The oldest layer of the sediment core dates back more than 150,000 years.
CU Boulder Professor Gifford Miller said in the core, the team found fungal spores from plant-eating mammal dung. The spores were abundant in the layers dating from 150,000 years ago to around 45,000 years ago. After that, they suddenly dropped off.
The ancient creatures in question would have included 1,000-pound kangaroos, giant wombats, and 25-foot-long lizards, among other humongous beings. Scientists believe that humans played a part in the animals’ extinction because more than 85% of these Australian mega-beasts went extinct just after the arrival of humans on the planet.
Miller doesn’t believe that the species went extinct due to humans engaging in a full-out assault on them. Rather, he believes that the Australian megafauna fell victim to “imperceptible overkill.” Australian researchers studied this concept in 2006 when they discovered that even low-intensity hunting could have been enough to devastate the Australian megafauna population. Killing as little as one juvenile mammal per person per decade, for example, would have been enough to drive the species into extinction within a few hundred years.
The study was published in the journal Nature Communications.
By Dawn Henderson, Earth.com Staff Writer
Source: Gifford Miller, University of Colorado