A faint skittering of tracks preserved in the fossilized sediment of an ancient shallow sea has allowed University of Alberta scientists to push back the date of the earliest known animal.

In a paper published today in a scientific journal, they say the creature wasn't much -- a slug-like little beastie just a few millimetres long.

It crawled around looking for tasty algae to eat 585 million years ago -- 30 million years earlier than any previously known animal was able to move on its own.

Not only does the animal set a new record, it helps confirm two theories of the Earth's ancient past.

Geobiologist Kurt Konhauser says the animal appears to have developed exactly when genetic modelling theories suggest it ought to have.

He adds it makes sense that a silt-loving animal should have developed right after an ancient glacial period would have created vast amounts of silt.