Some mites are known to live exclusively in moist grasslands and pastures, where they break down vegetable matter (including livestock excrement) to provide a rich food source.
Studying ancient civilizations can be difficult when they have left no detailed written records behind. But researchers say they now have a new tool for examining the fortunes of animal-based populations.
Scientists are now able to follow the progress of ancient civilizations by studying fossil mites that were found in the dung of their livestock. A group of scientists from America, France and Britain have been studying llama dung mite fossils to track the rise and fall of the Inca empire. Llama dung mites are tiny -- not much more than a millimetre across, and they are related to domestic dust mites often found in carpets or mattresses.
The team found a dramatic increase in the number of fossil mites as the Inca empire expanded from the Cuzco area in the early 1400s. A sudden drop in numbers corresponded with the collapse of the human population after the arrival of the Spanish conquistadors.
"It couldn't have been better if we'd made it up," said Mick Frogley, of Sussex University, UK. "It was that good."
The Inca were a test case that provided information for how to use these tiny fossils to follow the social trajectory of other, lesser-known animal-based civilizations, such as the Viking occupation of Greenland.
"A lot less is known about their economic and social structures and why these other cultures disappeared from the archaeological record. The technique could help find some answers."
The study results are published in the Journal of Archaeological Science.