In Korea, premium Korean beef, known as hanwoo, consumed for grilling is nearly half cows and half castrated bulls. Intact bulls have tough meat and are used for processing or soup. In the wild, cows would likely have been the top choice. Even mammoths, the prime food source of the Ice Age, appear to have been preferred as females.
An international team led by David Díez del Molino, a zoology professor at Stockholm University in Sweden, said on the 30th (local time) in the journal Current Biology that "an analysis of more than 500 woolly mammoth bones from Eurasia and North America dated 20,000 to 30,000 years ago shows that Ice Age humans hunted females intensively." The paper lists 52 co-authors from 14 countries in Europe and North America.
◇ Males often died naturally while traveling alone
The team decoded the genetic sequences of 448 woolly mammoths unearthed in Eurasia and North America. They also integrated previously analyzed DNA data from 73 individuals to determine the sex of a total of 521. They distinguished males and females based on sex chromosomes preserved in the fossils. Like modern elephants and humans, mammoth females had XX chromosomes and males had XY.
One hundred specimens came from sites near human settlements, and 421 came from natural sites. Analysis showed that at natural sites, male mammoths accounted for 280 individuals, or 66.5% of the samples. At natural sites, mammoth bones, tusks, and teeth were scattered rather than clustered. The team noted that when remains were more than 100 meters apart or came from different stratigraphic layers spanning tens of thousands of years, it was unlikely they were from the same individual or from a human-made accumulation.
Díez del Molino said, "If male mammoths, like today's male elephants, moved alone and took more risks, they would have been more easily trapped in natural hazards such as sinkholes, landslides, or tar pits," adding, "The same trend is observed in male bison and brown bears."
A prime example of a natural trap is the La Brea Tar Pits in Los Angeles. Hydrocarbon seepage from underground pooled on the surface to form sticky natural asphalt pits. For tens of thousands of years, animals mistook them for water or grass and became trapped, making this a world-renowned fossil preservation site where large numbers of perfectly preserved ancient fossils have been excavated.
◇ Females became prey along with their young
By contrast, at sites associated with human activity, 70% of the mammoths found were female. Of 100 specimens, 70 were females. This means people at the time focused on females. The team said females were likely easier prey than males, which were larger and more aggressive, because females were smaller and moved more slowly as they traveled with their young.
Woolly mammoths are often unearthed with dozens to as many as hundreds of remains clustered together. Most of these sites are near places where humans lit fires and cooked. Mammoth bones also show butchering marks such as scraping with stone tools. Some mammoths were found with broken bones from accidents and with spear tips embedded. These are signs that hunters drove mammoths into pits or over cliffs and speared them.
Díez del Molino said, "For decades there has been debate over whether large accumulations of mammoth bones formed naturally or resulted from human hunting," adding, "By comparing the genetic sex ratios of mammoths found in natural contexts with those found in archaeological contexts, we can now infer that human activity was the main cause of the bone accumulations."
The team also identified a mammoth showing XX/X0 mosaicism, a condition in which only one sex chromosome is present in some cells and which in humans causes Turner syndrome. When a woman lacks an X chromosome, short stature, ovarian insufficiency, and delayed puberty can appear. This is the first time a sex chromosome mutation has been found in an extinct animal. It has been documented in modern livestock but not yet in elephants.
◇ From Neanderthals onward, bone-processing factories were set up
Love Dalén, a co-corresponding author and professor at Stockholm University, said, "This study demonstrates the power of ancient DNA research in answering long-standing archaeological questions," adding, "Expanding sample sizes in ancient DNA research can go beyond showing animal evolution to provide insights into animal behavior and human culture from tens of thousands of years ago."
Humans have long followed and hunted mammoths. Neanderthals, who went extinct 40,000 years ago, set up camps to follow mammoth herds, hunt them, and process the yields even before Homo sapiens, the direct ancestors of modern humans, arrived in Eurasia. A Leiden University team in the Netherlands said last year that Neanderthals, 125,000 years ago in what is now eastern Germany, left evidence of large-scale processing of animal bones.
The team excavated more than 100,000 bone fragments from 172 large animals, including extinct mammoths, elephants, and cattle. The bones were broken into small pieces, and traces of fire, such as charcoal and scorched granite, were found nearby. The team inferred this as evidence of boiling bones to extract fat. Animal fat does not spoil easily, can be stored for a long time, and is convenient to carry. This suggests they did not just eat the meat right after hunting mammoths but also engaged in a kind of food processing.
The current study's authors also inferred that Ice Age humans hunted mammoths in the same way. Hannah Moots, the paper's first author at the Center for Palaeogenetics in Sweden, said, "Elephant herds move in predictable ways along seasonal migration routes, while males move more randomly," adding, "Ice Age hunters likely tried to position themselves in places where they could be confident mammoth herds would pass."
References
Current Biology (2026), DOI: https://doi.org/10.1016/j.cub.2026.07.023
Science Advances (2025), DOI: https://doi.org/10.1126/sciadv.adv1257