In the south of China by the Yangtza Gorges, along the Yangtza river, international scientist have discovered what they claim to be the earliest animal fossil footprint ever recorded. The tracks are roughly 551 million years old, which would place them in the Ediacaran Period (635-541 million years ago), making these the first prints ever found from this period of time. Compare these to the prints found in Fraserburg in the Karoo, they are significantly older by 299 million years (the Fraserburg prints being 252 mllion years old).
The Ediacaran Period creatures are mostly biota, of which the fossil records them 575-542 million years ago in age. They are macroscopic fossils of complex multicellular soft-bodied organisms. Some paleontologist believe these creatures are the forerunners to the modern day animals we know today, while others see these creatures as a completely extinct kingdom in its own right. Most of these biota were measured less than 10cm in size, while a select few grew to over a meter in length.
The nature of the trackways of these fossils found provide a connection to burrowing, suggesting that whatever creature made these tracks might have had a habit of digging into microbial mats and sediment. They could even be possibly looking for oxygen or food.
However, without a complete fossil record, all this is just speculation at this point. Unfortunately the body of this animal has never been found, and might never be found. Fossils from this period has frustrated scientist to the point of them actually reverse engineering them in order to understand these animals and their composition.
Source: Popular Mechanics USA