Oxford-led study suggests animals evolved 200 million years earlier than thought

An international research team, led by the University of Oxford and including scientists from Yale, UC Berkeley, and ETH Zurich, suggests that animals may have evolved 100 to 200 million years earlier than previously thought. While the oldest undisputed animal fossils date to approximately 574 million years ago during the Ediacaran period, new findings published in Science Advances indicate that animal life could have emerged between 700 and 800 million years ago.

The study challenges the long-held assumption that the absence of animal fossils in certain exceptional deposits, such as the Weng’an Biota in China, serves as a definitive limit for animal existence. Researchers argue that excellent preservation does not guarantee the presence of animal remains, as animals may have inhabited different environments or lacked the specific conditions for fossilization at those times.

To reach these conclusions, scientists utilized molecular clock techniques—measuring genetic mutations to estimate when lineages diverged—and analyzed chemical traces, such as lipid biomarkers associated with sponges. This revised timeline suggests that complex life may have existed even before Earth experienced extreme ice ages, known as the “Snowball Earth” periods.