How did mammoths move

Numerous species of mammals became extinct in North America towards the end of the last Ice Age. A study now supports the thesis that Stone Age hunters and not climate change are responsible for the disappearance of these species.

12,000 years ago, North America rivaled East Africa in terms of the diversity of large mammals. The rich fauna included the mammoth, the giant sloth and the mastodon, which, at 2.80 meters high and 4.5 meters long, was smaller but longer than today's elephant. But the wildlife spectacle ended abruptly towards the end of the last Ice Age. The first species disappeared 11,200 years ago; 400 years later, 33 species of mammals were extinct, including all species weighing more than 1,000 kilograms.

Drier and colder

What happened? The animal world has had to deal with two changes. On the one hand, the climatic capers at the end of the Ice Age made species difficult. There is evidence that drought hit the continent 11,000 years ago. It was also getting colder again. Food was becoming scarce and competition was fierce. On the other hand, the first archaeological evidence of the presence of humans in the areas south of what is now Canada can be found for the time 11,500 years ago. These belong to the Clovis culture, which is characterized above all by professionally machined projectile points made of stone. With the new, far-reaching and powerful weapons, even large animals such as the mammoth and the mastodon could theoretically be hunted.

However, science is far from unanimous about which of the two factors gave the large animals the fatal blow. Biologists in particular believe that humans were the cause of the disaster. They point out that many mammal species, due to their size or the lack of enemies, probably had no escape behavior and could be easily and quickly exterminated. The very rapid colonization of the continent by humans prevented the species from adapting - be it evolutionary or through a learning process - to the new situation, in contrast to Africa, where the rhino and elephant were slowly able to get used to the presence of humans.

However, other scientists doubt human responsibility. They point out that it must have been much easier and safer for the hunters to kill small animals. At the latest when the big animals had become rare, it was no longer worthwhile to go hunting for big game. It is much more likely that humans have fed on plants and small animals. Even the indigenous peoples living today, with the exception of the Inuit, who catch whales, rarely hunt big game. However, Gary Haynes of the University of Nevada's Anthropology Department found these arguments unconvincing. His research in recent years suggests that the hunters of the Clovis culture are actually responsible for the extinction of large mammals in North America.

Haynes points out that the decline of the mammoth and mastodon occurred at the same time as the spread and establishment of the Clovis culture. The abrupt climatic changes at the end of the last ice age, however - according to Haynes - were nothing new for the fauna: every previous ice age ended with similar climatic capers; and each time the mammals had survived the stress caused by it without any problems. The drought 11,000 years ago was also not felt to the same extent everywhere in North America. There were enough areas of retreat on the continent. Haynes also points out that the mammoth and the mastodon had different food requirements. They therefore did not suffer to the same extent from climate change. The mammoth, which mainly fed on grass, should also have benefited from a cooling because the tree line retreated to the south. Yet it died out.

Haynes is convinced that the Stone Age people not only occasionally hunted the large mammals, but also specialized in hunting big game. Archaeologists have found mostly mammoth and mastodon bones around the storage areas of the Stone Age people. Nuts, seeds, or bones from smaller animals such as rabbits are rare. Now, mammoth bones can also come from animals that have died naturally. However, this does not seem to be the case here. In Zimbabwe, Haynes compared collections of bones from elephants that either died as a result of a drought or were killed by humans. Depending on the type of death, there was a different distribution pattern of the bones. Haynes has applied his results to bone clusters in mammoths in North America and comes to the conclusion that many of the mammoths must have been killed by humans.

Advantages of hunting mammoths

Hunting mammoths had many advantages, according to Haynes: It was probably just as dangerous to kill a mammoth as it was to kill a bison. But the 4,000 kilogram mammoths produced four times more meat. Because it was still very cold 11,000 years ago, the meat was slow to spoil. If mammoth and mastodon behaved similarly to today's elephants, they were also easy to find - even when they were already very rare. Elephants mainly move on well-trodden paths through the landscape. Many of these trails lead to water holes or mineral leaks. It would therefore have been easier to find the location of a mammoth than that of a deer. In addition, the increasingly drier and colder climate restricted the habitat for numerous animal species. These withdrew to certain regions. The retreat areas were probably also known to the hunters and were used as fertile hunting grounds.

But why did another 31 species become extinct? Haynes also provides an answer to this question: Mammoth and mastodon were probably the first species to disappear from the landscape. It was the two heaviest animals that exerted the greatest influence on the vegetation. Her disappearance must have started a chain reaction. Like today's elephants in Africa, the large animals of that time kept trees and bushes in check and thus kept the landscape open. This was dominated by a highly productive mosaic of grassland and groups of trees. However, when the landscapers were eradicated, the environment changed fundamentally. Trees and bushes spread, and old mammoth paths, which were also used by other animal species, disappeared. Haynes believes that habitat has become scarce for many animal species and that as a result, they also became extinct.

Haynes is convinced that without the arrival of humans, mammoths, giant sloths and mastodons would still live in North America. However, Russian scientists have found that the decline of the mammoths in Asia 6,000 years ago is simultaneously associated with climatic warming and the associated advance of the forest line to the north. It is therefore quite possible that the fur-covered pachyderms of North America would have died out a few thousand years later without human intervention.

Gregor Klaus