Tübingen / Helsinki (dpa) - Until about 4000 years ago, the Wrangel Island in the Arctic Ocean was home to the last mammoths. The isolation saved them only before death - and then probably sealed the rapid extinction of the whole species, as an international research team found out.
According to the scientists, the mammoths on the island 150 kilometers north of the Siberian coast are not extinct because of long-term climatic changes, but because of a sudden scenario. "Maybe rain has fallen on snow and frozen, so they could not find any food," says paleo-biologist Hervé Bocherens from the Senckenberg Center for Human Evolution and Palaeoenvironment at the University of Tübingen.
It is also conceivable that arriving people on the island had something to do with the extinction of the giant herbivores. According to Bocherens, bone finds suggest that animals and humans could have lived there at the same time. Maybe the quality of the drinking water has also deteriorated.
Mammoths spread out in the northern hemisphere 100,000 years ago during the Ice Age. As a result of global warming 15,000 years ago, their habitats shrank and humans hunted the animals. The giants died for reasons not yet completely clarified - only on the Wrangelinsel survived a colony first. The rising sea level sealed the today belonging to Russia island from the mainland.
4000 years ago - while people in Egypt had already developed socially advanced civilizations and built pyramids - the mammoths on the island also died out. The scientists from the Universities of Helsinki and Tübingen as well as the Russian Academy of Sciences are now researching the causes and presenting their findings in the journal "Quaternary Science Reviews".
For this they examined the atomic species (isotopes) of mammoth bones and teeth. These compared them with those of formerly extinct conspecifics from Alaska and Siberia. In the specimens of the island mammoths, they found no evidence of gradually changing environmental conditions or nutrition.
"On the island, the mammoths were completely isolated and protected from climate change," says Bocherens. There it remained mainly cold and dry, the soil had many grasses to eat. But with no more than 300 animals, the last mammoth horde, according to Bocherens was so small that a sudden event could completely obliterate them - and thus the entire species. Genetic analyzes of the mammoth remains of a Swedish-Russian team on the Wrangel Island had previously been followed by a sudden extinction alluded.
Bocherens also interprets the results as a lesson for the present. According to him, there are now many animal species that live in isolation. They are particularly at risk of extinction by extreme environmental influences or human behavior.
Genetic study of 2010