Weak Skeletons May Have Spelled the End for Mammoths

New results suggest that weak bones made the beasts more susceptible to human hunters

Science Picture Co./Corbis

The wooly mammoth’s curving tusks and towering skeleton captures people’s imagination, as does the mystery of their extinction: Did human hunters kill the species? Did the end of the Ice Age and a changing climate decimate their food of choice? Now researchers have added a new theory to the list of potential mammoth killers. These titans may have had bones too weak to let them survive.

Sergei Leshchinskiy of Russia’s Tomsk State University analyzed more than 23,500 mammoth bones and teeth from several sites and found bone disease in 90 percent of them, reports Kate Horowitz for Mental Floss. This disease is most likely from nutrient deficiencies.

"Even the bones from baby mammoths were brittle and weak, which suggests their mothers weren’t getting the nutrients they needed," Horowitz writes.

The new theory could tie up all of the stories about potential causes for mammoth demise into one tidy package: A period of changing climate could have leached minerals from the soil, resulting in the osteoporosis and other bone diseases Leshchinskiy found. Weak bones would have made the beasts easier to hunt and kill, leaving mammoths on track for extinction.

In the journal Archeological and Anthropological Sciences, Leshchinskiy writes that the bones he analyzed came from regions called beast solonetz, a Russian term for soils where an abundance of calcium, magnesium, zinc and sodium would have attracted large plant-eating animals. But during the Late Pleistocene, about 126,000 to 5,000 years ago, a more humid and warmer climate in Northern Eurasia provoked floods along the coast and in areas where permafrost melted, drawing those minerals from the soil. 

A period of mineral scarcity could have lasted more than 15,000 years, Leshchinskiy says in a press release. "The woolly rhinoceros and cave bear may have suffered the same fate." The last remaining beast solonetz would have been very attractive to the dying animals and eventually the sites of mass cemeteries.

While the new paper only applies to Eurasia, Leshchinskiy believes that the global changing climate could have had a similar effect around the world. 

The explanation also bolsters the idea that people could have hunted the huge creatures to extinction—the brittle-boned creatures would be more susceptible to hunters. Radiocarbon dates of fossils from North and South American wooly mammonths shows that extinction closely followed the time frame when humans migrated into the Americas. In addition, Leshchinskiy and other experts have found stone implements used to butcher animals at a mammoth mass burial site in the Novosibirsk region of Siberia.

"They came here to effortlessly extract the tusks and skins of dead animals or to hunt weakened individuals, including the youngsters," he told Anna Liesowska of The Siberian Times. "One thing is clear: the people whose implements were found in Volchya Griva witnessed the mass natural mortality of the mammoths.' 

If the new theory proves true, it would mean a somewhat grisly and sad end to an imposing species.

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