An international team of scientists investigated the crustaceans found in the skull of the mummy of the Siberian mammoth Yuki. An analysis of their species composition showed that the last refuge of the ancient animal (the reservoir in which its body lay before freezing into the permafrost ice) was inhabited by taxa not typical for the region. The discovery posed new questions and hypotheses about the nature of northern Siberia during the Pleistocene for researchers. The work was published in Scientific Reports.
Mammoths existed on Earth 4 thousand years ago, but their mass extinction began at the border of the Pleistocene and Holocene. These animals are larger than their elephant relatives living today. Their body was covered with hair, their ears and legs were relatively short, and their heads were large - these are adaptations for life in cold conditions. Long, curved tusks protruded forward.
The last representatives of the genus - woolly mammoths - lived mainly in Siberia and in the northern part of America. Their remains are often found in permafrost; corpses with preserved skin, wool, meat and even internal organs are of particular value. Their study allows us to reconstruct the nature of distant times and understand how life developed on the planet. This is what paleoecology is doing.
The methods of this science are becoming more and more complex. Scientists are examining every available material, from the soil and rocks surrounding the remains to the contents of the intestines. The former allow you to recreate the paleoenvironment of the animal, and the latter - “snapshots” of the last days of its life.
However, this is not always possible. This happened, for example, in the case of the woolly mammoth Yuki, discovered on the shore of the Laptev Sea in 2010. The animal was named in honor of the Yukagir community, whose members found it in the exposed permafrost of the bank of the Kondratyevo River in the Ust-Yansky Ulus of the Republic of Sakha (Yakutia). The mummy has perfectly preserved the reddish hair characteristic of the young and even soft tissues. At the same time, the sedimentary rocks surrounding the corpse turned out to be highly eroded and therefore unsuitable for analysis. Also, the Yukaghirs cleaned the mammoth well and some research, for example, analysis of the remains in the wool, is impossible.
Researchers at the Severtsov Institute of Ecology and Evolution of the Russian Academy of Sciences, together with their colleagues, obtained a sample of frozen precipitation from Yuka's skull. It contains the remains of ancient crustaceans and shells of diatoms that lived in the reservoir, where the baby mammoth was at the time and after death. There he slowly plunged into the permafrost. The remains of the algae were not in the best condition, and therefore, with their help, it was not possible to draw accurate conclusions about what kind of reservoir it was. Crustaceans belonged mainly to taxa common in the region, but some of them are typical for arid regions of Eurasia, for example, Kazakhstan and Mongolia. Their preferred conditions correspond to small freshwater ponds and small lakes with stagnant water - it is probably in such a reservoir that the mammoth Yuka died.
“Our find testifies in favor of the fact that freshwater communities of reservoirs of Pleistocene Beringia have no modern analogues, in which they are similar to the so-called“mammoth fauna”, which was characterized by a completely unthinkable combination of animals - mammoths, reindeer, saigas, lions, etc. rhinos. The "mammoth fauna" lived in other non-analogous communities - tundra steppes (cold dry herbaceous plains with high productivity, which is currently not seen beyond the tundra). The fact that crustaceans, completely uncharacteristic for the modern fauna of the region, were found in the sample indicates their extinction at the border of the Pleistocene and Holocene, and this may be a manifestation of a deep crisis in freshwater ecosystems of that time. The study of this phenomenon is an absolutely new task of paleoecology, which is being solved within the framework of our project of the Russian Foundation for Basic Research ", - concludes Alexey Kotov, Doctor of Biological Sciences, Professor of the Russian Academy of Sciences, Corresponding Member of the Russian Academy of Sciences, leading researcher at the A. N. Severtsov RAS.
The work was carried out jointly with colleagues from Lomonosov Moscow State University, University of Kansas (USA), Queen Mary University of London (Great Britain) and the Academy of Sciences of the Republic of Sakha (Yakutia).