Animal, Vegetable or Mineral? (IMAGE) Washington University in St. Louis Caption The nature of the acritarchs, spiny fossils found in the Doushantuo formation in southern China, became clear only when scientists understood the chemistry of the waters in which they lived. Even though acritarchs lived in the Edicaran, long after the Great Oxygenation Event, they turned out to be animals that had encysted to escape death by anoxia. Credit Shuhai Xiao/PNAS Usage Restrictions Please credit as shown License Licensed content 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.