The oldest animals are found in the Ediacaran biota, towards the end of the Precambrian, around 610 million years ago. It had long been doubtful whether these included animals, but the discovery of the animal lipid cholesterol in fossils of Dickinsonia establishes that these were indeed animals.

Najstarsze szczątki zwierząt (tzw. fauna ediakarańska) mają ponad 600 milionów lat. Najstarsza niepewna skamieniałość zwierzęcia (gąbka Otavia antiqua) ma ok. 750 milionów lat