DNA analysis showed that mammoths disappeared from the American continent thousands of years later than previously thought.
Scientists analyzed ancient DNA from sediments sampled at the Klondike and found that wild horses and woolly mammoths may have become extinct in the region less than six thousand years ago. They emphasized that these animals were reliably present in the region at least until 9700-9200 years ago. In addition, scientists have clarified how the ancient flora in the region changed at the turn of the Pleistocene and Holocene.
Extinction of the megafauna
In the Late Pleistocene and Early Holocene epochs in Northern Eurasia and Beringia, there were two stages of extinction of the megafauna, which includes animals weighing more than 44 kilograms.
The first occurred before and during the maximum of the last glaciation (about 26.5-19 thousand years ago), when, in particular, the straight-tusked forest elephant (Paleoloxodon antiquus), the European hippopotamus (Hippopotamus antiquus), the European water buffalo (Bubalus murrensis), saber-toothed cats Homotherium and Neanderthals.
The second wave occurred between 15,000 and 10,000 years ago, when wild horses (Equidae), woolly rhinos (Coelodonta antiquitatis), and mammoths (Mammuthus primigenius), as well as cave lions (Panthera spelaea), disappeared from most regions.
Mammoth extinction
There is no consensus among scientists about the reasons for the extinction of mammoths. A number of researchers see this as a consequence of the widespread settlement of people of the modern anatomical type (H. sapiens).
In addition, the warming, which began at the turn of the Pleistocene and Holocene, seriously changed the environment, in particular, the territories suitable for the habitation of these animals – the mammoth steppes – were significantly reduced. Thus, the last mammoths lived in small populations in small refugia and became extinct on Wrangel Island about 3700 years ago, and on Taimyr about 3900 years ago. When it comes to the American continent, scientists believed that mammoths disappeared about 9,700 years ago.
Scientists found ancient DNA from a variety of species including mammoths
Tyler Murchie of McMaster University worked with Canadian and US scientists to study sediment samples from four sites in the Klondike, an undeveloped permafrost region in the western and central Yukon, Canada. Paleogeneticists were able to read ancient DNA dating back 30,000–4,000 years ago.
During the study, scientists found DNA from steppe bison (Bison Priscus), woolly mammoths (Mammuthus primigenius), wild horses (Equus sp.) And partridges (Lagopus Lagopus). Less represented were caribou (Rangifer tarandus) and sheep (Ovis sp.).
In addition, the sample included a small amount of DNA from gray wolves (Canis lupus), martens (Martes sp.) And rodents – ground squirrels (Urocitellus sp.), Yellow-cheeked voles (Microtus xanthognathus), and Greenland lemmings (Dicrostonyx groenlandicus).
Mammoth DNA
Scientists noticed that about 20 thousand years ago, the amount of mammoth DNA in the sediments began to decline. According to researchers, most of the megafauna disappeared in the Klondike about 13-10 thousand years ago. However, the latest DNA from horses and mammoths is only about six thousand years old. Although scientists have emphasized that this dating is rather unreliable, horses and mammoths were present in the Klondike at least until 9700-9200 years ago.
A study of the DNA of plants found in the sediments showed that a change in the flora of the region took place between 13,500 and 10,000 years ago. The Pleistocene grasses that were typical of the mammoth steppe were replaced by arboreal taxa – willow (Salix), poplar (Populus), birch (Betula), and spruce (Picea), as well as horsetails (Equisetum), ferns (Gymnocarpium) and peat mosses. (Sphagnum). After the reduction of megafauna in the Klondike, the rodent population increased, which attracted hunters for small animals such as martens.
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Sources:
• Murchie, T. J., Monteath, A. J., Mahony, M. E., Long, G. S., Cocker, S., Sadoway, T., Karpinski, E., Zazula, G., MacPhee, R. D. E., Froese, D., & Poinar, H. N. (2021, December 8). Collapse of the mammoth-steppe in central Yukon as revealed by ancient environmental DNA. Nature News.
• O’Neill, M. (2021, December 9). Ancient DNA discovery reveals woolly mammoths, wild horses survived thousands of years longer than believed. SciTechDaily.
• Schultz, I. (2021, December 8). Ice age mammoth and horse DNA found in soil samples left in freezer. Gizmodo.
• Schuster, R. (2021, December 9). Mammoths survived in Canada until 5,000 years ago. Haaretz.com.
• Wetzel, C. (2021, December 9). Mammoth and horse DNA left in Freezer rewrite ice age extinctions. Smithsonian.com.
