A newly discovered fossil the size of a grain of rice indicates that primitive animals appeared as early as 600 million years, according to a recent report by a research group from the Nanjing Institute of Geology and Paleontology under the Chinese Academy of Sciences. A credible discovery, it is the oldest animal body fossil discovered to date. Also published in the US Proceedings of the National Academy of Sciences, the discovery will clear up doubt in the field of archaeology as to whether animals had appeared on the planet 600 million years ago.