The researchers, who hail from McMaster University in Hamilton, Ont., the University of Alberta, the American Museum of Natural History and the Yukon government, say in a news release that their analysis reveals mammoths and horses were already in steep decline prior to the climatic instability of the Pleistocene-Holocene transition between 11,000 and 14,000 years ago, during which a number of large species such as mammoths, mastodons and sabre-toothed cats disappeared.
However, the researchers say mammoths and horses didn't immediately disappear as a result of overhunting by humans as previously believed.
Instead, they say the DNA evidence shows both the woolly mammoth and North American horse were around until as recently as 5,000 years ago during the mid-Holocene — the epoch humans currently live in, which began about 11,000 years ago
The study builds on previous research done by McMaster scientists, who in 2020 reported that woolly mammoths and the North American horse were likely in the Yukon about 9,700 years ago
Using tiny soil samples containing billions of microscopic genomic sequences from animal and plant species, as well as DNA capture-enrichment technology developed at McMaster, the researchers were able to reconstruct ancient ecosystems at different points in time during the Pleistocene-Holocene transition
Due in part to a lack of megafaunal "ecological engineers" such as large grazing herds of mammoths, horses and bison, grasslands no longer prosper in northern North America, according to a news release on the study
"The horse that lived in the Yukon 5,000 years ago is directly related to the horse species we have today, Equus caballus
Biologically, this makes the horse a native North American mammal, and it should be treated as such."
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