Fossilized feces from the Pleistocene epoch have divulged the mitochondrial DNA of a woolly rhinoceros, whose genome had never previously been assembled. The ancient poop was not excreted by an ancient rhino but by a hyena—an animal that evidently ate the massive herbivore before it, too, died sometime in the Middle Paleolithic.
The team inspected two coprolites from different caves in Germany, and one hyena coprolite excavated in the 1930s. The samples yielded hyena and rhino DNA—enough of the latter to assemble a genome, despite degradation. The team’s research was published last week in The Royal Society journal Biology Letters.
“We see that the woolly rhinos displayed different mitochondrial lineages across their range,” said Peter Seeber, a molecular biologist at the University of Konstanz and the study’s lead author, in an email to Gizmodo. “This points to a possible complex history of population subdivision across its existence as a species, and the study shows that we can uncover this history using ancient DNA with relative ease.”
Coprolites are rich with information about long-dead things. In 2019, a team in Texas reported a 1,500-year-old piece of human poop containing evidence that its, uh, producer ate an entire rattlesnake, complete with a fang. 14,000-year-old coprolites found in Oregon between 2002 and 2010 turned out to be human, according to a 2020 paper, offering hints about early modern humans’ presence in North America. And as reported by Gizmodo earlier this year, some coprolites have bite marks on them, perhaps because other ancient critters mistook the feces for food.
All DNA recovered from the recently analyzed coprolites belonged to the extant spotted hyena (Crocuta crocuta) and the extinct woolly rhinoceros (Coelodonta antiquitatis). It was not clear from the excretory remains whether the rhinoceros had been preyed on by the hyenas or merely scavenger. Despite the degradation of the DNA, the team concluded that the European woolly rhinoceros was genetically distinct from the Siberian rhinoceros.
“Our results come from only one near-complete mitogenome and another very fragmented one, thus they are only a first glimpse, and more data is needed for solid conclusions,” Seeber said. “But it shows that we will be able to trace the history of the species using a wide range of samples and not only using classical bone finds.”
So move over, boring bone DNA. Fossilized fecal matter contains its own treasures, thanks to modern ways of extricating it.