The iconic woolly mammoth (Mammuthus primigenius) became extinct on mainland Asia and North America around 11,500 years ago. However, relict populations survived on at least two islands for millennia after these mainland extinctions. The last known population survived on Wrangel Island, off the coast of Siberia, until around 4,000 years ago, coinciding with the arrival of humans. Another late-surviving population endured on the Bering Sea island of St. Paul until at least 6,500 years ago. There is no evidence for human occupation of this island prior to the 18thCentury CE, and the St. Paul mammoth extinction was therefore likely driven solely by non-anthropogenic factors. To explore potential extinction drivers, it is crucial to first understand the precise timing of the extinction. The limited record of mammoth fossils on St. Paul does not provide the temporal resolution to determine a precise timing. Instead, we used a multiproxy approach to compliment the paleontological data, which included isolating ancient mammoth DNA from a dated crater lake sediment record on St. Paul Island. The steady accumulation of lake sediments through time, combined with fine-scale sampling of the sediment sequence, make this sedimentary ancient DNA based approach ideal for precisely constraining the timing of mammoth disappearance from St. Paul Island.
Results/Conclusions
Our sedimentary ancient DNA results clearly show that woolly mammoth disappears from the lake sediment record at 5,600 years ago, around a millennium later than the youngest published radiocarbon date from a mammoth fossil. This result is highly congruent with other paleofaunal proxies, which include spore abundances of coprophilous fungi in the sediment and radiocarbon dates of newly discovered mammoth fossils from St. Paul. Altogether, our results provide a robust and precise timing of extinction for the late-surviving mammoth population of St. Paul Island, which will be critical for determining extinction drivers.