Ancient-DNA analysis of 521 woolly mammoths finds a striking sex-bias difference: natural deposits were 66% male, while human-associated bone piles were 70% female. The contrast suggests Ice Age hunters preferentially killed females—likely because females traveled in herds with young—raising the possibility that selective hunting of breeding females accelerated mammoth declines. The study also documents the first XX/X0 mosaicism seen in an extinct species and builds on recent genomic advances in mammoth research.
Ancient DNA Suggests Ice Age Hunters Targeted Female Woolly Mammoths
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New genetic analysis of woolly mammoth remains indicates that Ice Age hunters in parts of Europe and North America selectively killed females, with potential consequences for mammoth populations and human survival strategies.
Published in Current Biology, the study compared DNA from 521 woolly mammoths: 421 individuals recovered from natural-deposition contexts across Europe and North America and 100 specimens from 11 large bone-accumulation sites associated with human activity and dated to roughly 20,000–30,000 years ago.
Clear Difference In Sex Ratios
The two assemblages showed a striking contrast in sex composition. Mammoths from natural deposits were 66% male, whereas remains from human-associated sites were 70% female. Because the pattern at human-linked sites diverges so markedly from natural deposits, the results strengthen the interpretation that many large mammoth bone piles were created by human hunting rather than by natural causes alone.
Why Females?
Researchers suggest several possible explanations. Female mammoths likely moved in matriarchal herds with juveniles, which would have made them easier to locate, follow, and trap than adult males, which often lived more solitary lives. However, co-author Hannah Moots of the Center for Palaeogenetics cautions that the reality may be more complex than simply targeting smaller animals: social behavior, seasonality, and hunting strategies could all have influenced which individuals were taken.
"By scaling up sample sizes, ancient DNA can go beyond evolutionary history to teach us about animal behavior and human culture tens of thousands of years ago," said Love Dalén, an evolutionary geneticist at Stockholm University and a co-author of the study.
Ecological And Cultural Consequences
Selective removal of breeding females can accelerate population decline, limit recovery, and push a species closer to extinction, especially during periods of environmental stress. Because Ice Age communities depended on mammoths for meat, hides, shelter, and ivory, intensified hunting of females could have reduced long-term access to those resources and inadvertently undermined human resilience.
Paleoecologist Audrey Rowe of the University of Alaska Fairbanks told New Scientist that the findings "raise a new line of evidence that humans contributed to the extinction of mammoths," noting that prehistoric hunters likely did not anticipate the long-term depletion of the populations they relied on.
Additional Findings And Context
Beyond the hunting-pattern evidence, the study reports the first documented case of XX/X0 mosaicism (a Turner-like chromosomal condition) in an extinct species. The research also builds on recent advances in mammoth genomics: in 2024, scientists reconstructed the 3D architecture of DNA from preserved mammoth skin in Siberia, improving understanding of gene regulation and offering methods that could inform conservation genetics for living species.
This work demonstrates how expanding ancient-DNA datasets lets researchers address behavioral and cultural questions that bone morphology alone cannot resolve, shedding new light on the complex interactions between humans and megafauna during the Ice Age.
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