Researchers are counting fossilized dung-eating mites in the sediments of an Andean lake to get an idea of the size of llama herds in the surroundings, and thus “reconstruct the fluctuating fortunes of local (human) populations for an era from which no written records exist.” It turns out that “mite numbers rise and fall in concert with well-documented socio-economic changes in the postconquest period.” The paper is in the Journal of Archaeological Science, but you can read a summary here.