Good feed converters - and yet extinct
The extinction of mammoths and wild horses at the end of the Ice Age is a classic paleo crime novel. Numerous conflicting theories have faced each other for years. With new research results, the Enlightenment is now within reach. When the first settlers arrived in North America from Asia around 12,000 years ago, many Ice Age mammals such as the giant beaver (Castoroides spec.) were already extinct. Mammoth (Mammuthus primigenius), bison (Bison priscus) and elk (Cervus canadensis), on the other hand, still roamed the vast landscape. The migrants from Siberia met their animal contemporaries at the transition from the cold Ice Age to the warmer climate of the Holocene - a phase in which living conditions changed drastically. But while humans, buffalo and deer survived this transition to this day, the shaggy mammoths only roamed Alaska and northern Canada for about 1000 years.
Did humans perhaps have a hand in the death of the imposing ice giants or did other causes put an end to them? And the situation is even trickier for wild horses (Equus ferus): they may have disappeared just as humans arrived in North America.
According to Andrew Solow of the Marine Policy Center in Woods Hole, Massachussetts, Ice Age hunters could well be to blame . He examined the dates of recent bone fossil finds using a statistical calculation that had not previously been applied to these dates. In his opinion, the previous dates do not necessarily reflect the time when the last wild horses really died. For example, there could be even younger wild horse fossils that archaeologists just haven't found yet.
Solow thus supports the so-called overkill theory, which assumes that humans have killed wild horses and mammoths in North America. The skilful hunters from Siberia were so superior to the unprepared animals that they were wiped out within a few hundred years. A second opinion is that the immigrants may have also had an insidious disease in their luggage, to which the large mammals fell victim due to a lack of immunity.
Dale Guthrie of the University of Alaska vigorously contradicts these theories: If mammoths and humans coexisted for over a millennium, there could be no talk of a devastating campaign by humans against the mammoth. Guthrie also rejects the assumption that an imported disease killed the large mammals. There would have to be demographic gaps in the fossil finds, but that is not the case.
Guthrie and his colleagues base their findings on a large number of dated bone finds - including 600 new C-14 dates - from mammoths, horses and other large mammals, the ages of which they had compared with archaeological finds and pollen analyses. Curiously, they found a particularly large number of bones from bison and elk near the camp sites, which are still alive today. But if wild horses and mammoths were popular targets for Ice Age hunters, the absence of their remains would be more than surprising, says Guthrie.
Mammoths and horses coped much worse with the changed conditions in the Holocene than bison, elk or even moose
(Dale Guthrie) In his opinion, however, the wild horses had to contend with the enormous changes in their living conditions long before the first people migrated across the Bering Strait. The wide steppes where the herbivores originally found their food grew more and more bushy, and with the warmer climate extensive forests developed. Wild horses, like mammoths, are better feeders than bison or elk, but they specialize in grasses. In the late Pleistocene, horses and mammoths were still able to survive, but the Holocene forage plants were unfavorable or - like the birch - even poisonous for them. The horses therefore became smaller from generation to generation and, according to Guthrie, were long past their prime and doomed to extinction when man arrived. Just like the mammoth, which was also unable to defy ecological change in the long term.
"Even if humans might have contributed to the extinction of the mammoth and horse: Both coped with the changed conditions in the Holocene much worse than bison, elk or even the elk", Guthrie concludes from his findings.
The brief transition from the Pleistocene to the Holocene produced vegetation that was lush grazing ground for all large mammals
(Dale Guthrie) However, the pollen analyzes contained a small surprise: "The brief transitional phase from the Pleistocene to the Holocene produced vegetation that was initially lush grazing ground for all large mammals," says Guthrie. In this 1000-year-old land of milk and honey there was enough for everyone - including the original inhabitants of Canada. This abundance may even have sparked the first heyday of their culture.