In the specially protected water area of ​​the Olga Bay of Kronotsky Bay, scientists from the A.N. Severtsov Institute for Ecology and Evolution of the Russian Academy of Sciences have begun the next stage of research on the most ancient baleen whales listed in the Red Books of all levels. Olga Bay in the Kronotsky Reserve has been serving gray whales native to the waters of California and Mexico for many years as a kind of summer restaurant. Here, after wintering off the coast of North America and the birth of offspring, they “halt” during a long migration to feed in shallow water off benthos - organisms that live at the bottom of the coastal zone or above its surface. These are bottom fish species, crustaceans and various mollusks. In the Kronotsky Nature Reserve, where fishing is not carried out and there is no intensive navigation, the whales feel completely safe. Gray whales are one of the main objects of observation for participants in sea excursions and scientific expeditions in the protected bay. In July, here you can see about fifty individuals in one day, watch their fountains. IEE RAS expedition to study gray whales started in early June. Marine biologists conduct photo-ID of animals. This is necessary in order to trace the migration path of "old acquaintances" and to add new encountered individuals to the existing catalogs of gray whales. The data will allow us to learn more about the migration routes and lifestyle of ancient marine mammals and develop recommendations for the conservation of the population. The expedition members shared their first results. "So far, according to photo-identification data, we have 40 whales. And about 10 of them were seen in the summer on Sakhalin in previous years. Many of these whales will also go to Sakhalin. We try to photograph the left and right sides, we also capture the upper back from the drone. Photos allow not only to count all the whales encountered, but also to assess their fatness and the condition of the skin. This work will take a lot of time. If we evaluate the current state of the animals, we see a lot of thin whales. Which, in fact, is normal after a long migration, "said Matvey Mamaev , leader of the expedition, leading engineer of IEE RAS. The researchers noted that while the unpredictable weather in Kamchatka allows them to observe the sea for several hours almost every day, the work is proceeding according to plan. Additional Information: The gray whale is the only species of the gray whale family. Listed in the Red Books of the IUCN, the Russian Federation and the Kamchatka Territory. Gray whales are indigenous to the eastern Pacific. Animals winter in warm lagoons off the coast of the southern United States (California) and Mexico, and possibly Japan and Korea, where mating takes place and offspring are born. In early spring, they go on a long journey to summer feeding grounds - the cold territorial waters of Alaska, Chukotka, Kamchatka, Sakhalin and the Kuril Islands, where they feed on benthos in shallow water (organisms living in the bottom part of the sea or burrowing into the ground). At the end of autumn, they go in the opposite direction alone or in small groups. Thus, gray whales cover from 12 to 19 thousand kilometers per year. Every year, scientists study marine mammals in the waters of the Kronotsky Reserve and the South Kamchatka Reserve. The largest accumulation of animals there is observed from the beginning of June to the end of July and in November on the way back.

An increase in temperature in water bodies can lead to a noticeable change in the life cycle of parasites, according to the research of scientists from the A.N. Severtsov Institute of Ecology and Evolution RAS. Due to global warming, it is possible to change the “parasite-host” chains, which will lead to a restructuring of the entire appearance of freshwater ecosystems. In recent years, there has been growing interest among scientists in how temperature affects the risk of transmission of infections in ecosystems, or, in other words, the interaction of parasites and their hosts. To find out, scientists from the IEE RAS studied how temperature affects the separation of the dispersal stages (larvae/cercariae) of two closely related species of parasitic flatworms (trematodes): Rhipidocotyle campanula and R. fennica. The first intermediate host in these species of trematodes is the mollusk - common toothless (Anodonta anatina), the second roach. And only the final owners - predatory fish - differ. To conduct the experiment, scientists collected mollusks from rivers and distributed them in flow tanks with three temperature regimes. The average temperature in these tanks was 18°C ​​(range 7-24°C), 15°C (7-20°C) and 13°C (6-18°C). The design of the experiment did not assume a constant temperature of the molluscs. On the contrary, it had to fluctuate in accordance with seasonal changes, as in natural ecosystems, to emulate the real world in terms of global warming. The experiment lasted five months. Every two weeks, the scientists checked whether the molluscs secreted parasitic larvae (cercariae) and, if so, how many. “We were interested in how temperature affects the duration of the emission of cercariae by molluscs, the time of its start and end, the total number of isolated cercariae and other indicators. It turned out that these closely related species of trematodes are very different in their temperature preferences. Cercariae of R. campanula began to be released at 9-10°C, and a further increase in temperature only modestly increased their production by the mollusk. At the same time, the proportion of mollusks secreting cercariae was approximately the same in all temperature regimes. R. fennica turned out to be much more thermophilic. The temperature optimum for the isolation of cercariae for this trematode was above 15°C, and the dependence of the number of produced cercariae on temperature was much stronger. Moreover, the proportion of mollusks producing cercariae of this parasite increased with temperature”, says Mikhail Gopko, one of the authors of the study. The scientists came to the conclusion that at typical northern latitude summer temperatures, many individuals of R. fennica do not have time to accumulate enough degree-days to continue their life cycle. In this case, it turns out that an increase in average annual temperatures can bring much more benefit to R. fennica than to R. campanula. At high temperatures, the beginning and end of the production period of cercariae is shifted closer to the beginning of the season. At similar temperatures, mollusks produced fewer cercariae in autumn than in winter. “In other words, temperature is temperature, and “fatigue” of the host organism imposes natural restrictions on the ability of the parasite to force its reproduction,” adds Ekaterina Mironova, co-author of the article. Scientists came to the conclusion that due to global warming, the balance in the R. fennica - roach - R. campanula system may shift towards the predominance of a more heat-loving parasite species. Thus, an increase in temperature in water bodies can lead to a noticeable change in the periodization of the life cycle of parasites. Ultimately, given the incredible abundance of host-parasite systems, this has the potential to change the entire face of freshwater ecosystems. In their next study, the scientists plan to explore how these changes will be synchronized with changes in the life cycle of the parasite's next host, the fish. What will happen with changes in the "parasite-host" systems? Answered by Mikhail Gopko There are at least two realistic scenarios for the development of relationships between parasites and their hosts under global warming. According to the first of them, with an increase in temperature, parasites will gain an advantage over their hosts. Parasites have a faster rate of evolution, which is important in changing conditions, and they also have higher productivity at moderately elevated ambient temperatures. For aquatic organisms, such as fish, the situation is further complicated by the fact that at high temperatures their immune system begins to fail, making it easier for infections to enter the host organism. It is possible that all the benefits that parasites get from warming will be only temporary - most experiments on the effects of warming on parasites are short-lived. In addition, parasites may even benefit from the desynchronization of the life cycles of the parasite and the host. Let's say that warming will lead to the fact that the parasites will be ready to infect the host earlier in the season, but no one guarantees that the host will be already “ready” for this, say, not yet migrating to a suitable part of the reservoir. The second scenario can lead to very strong changes in ecosystems. The fact is that parasites play an unusually important and specific role in communities. This is a kind of glue that unites various trophic levels. When a cheetah rushes across the savannah, chasing a Thompson's gazelle, or a gluttonous gull tries to grab a gaping fry from the surface of the water, the false impression can be created that everything that happens is solely the work of a predator and its prey. In fact, the parasites that weaken each side sometimes play an even more significant role. The desynchronization of the life cycles of parasites and their hosts can lead to a "domino effect", disrupting trophic interactions between predators and their prey. A new study by scientists supports the second point of view. However, the applicability of its results to all "parasite-host" systems is out of the question. In addition, there is no information about how quickly changes in ecosystems will occur and whether nature will be able to adapt to them. As Mikhail Gopko notes, the impact of global warming on host- parasite systems and ecosystems will be generally stronger as we approach the poles and the equator, but in temperate latitudes, everything will likely be more moderate. The article “Contrasting temperature responses in seasonal timing of cercariae shedding by Rhipidocotyle trematodes” was published in the journal Parasitology. Dependence of the average (for all mollusks that produced cercariae on the day ofobservation) number of cercariae produced on temperature for R. fennica (A, B) and R.campanula (C, D). On the right, partial regression plots (added variable plot) taking intoaccount seasonality. Note the outliers in the "underbelly" of graph A. This is the production ofcercariae during the autumn months, when the emission volume was lower at the sametemperatures. Adding a seasonality factor (the number of days since the start of theexperiment) “corrects” the dependence, and the points fit very neatly on the regression line(plot C). For R. campanula (bottom row), the situation is similar. The work was published in the journal Parasitology Related materials: МетеоВести: "Climate change could disrupt freshwater food chains" ТАСС Наука: "Climate change may disrupt food chains in fresh waters"

The A.N. Severtsov Institute of Ecology and Evolution RAS became the winner of the competition "State support for scientific research conducted under the guidance of leading scientists in Russian educational institutions of higher education, scientific institutions and state scientific centers of the Russian Federation" (9th stage). The application was supported by the leading international scientist Enric Gisbert Casas, whose main place of work is the Institut de Recerca i Tecnologia Agroalimentaries (IRTA), Spain. From the Russian side, the main executors of the grant included researchers from the IEE RAS Mikhail Gopko, Eduard Galoyan, Anna Vasilyeva, Evgeny Esin. From the Institute of Systematics and Ecology of Animals of the Siberian Branch of the Russian Academy of Sciences, researchers Evgeny Simonov, Elena Kashinskaya, Pavel Vlasenko and Mikhail Solovyov take part in the work. The project "Evolution of the functioning of the digestive system of ectothermic vertebrates as a mechanism for mastering a contrasting habitat" is aimed at solving one of the fundamental problems of biology - determining the patterns of evolutionary transformations of the digestive tract of animals for the successful transformation of matter and energy in aquatic and terrestrial ecosystems. In the course of this project, a modern laboratory of evolutionary trophology will be created on the basis of the IEE RAS. The laboratory will study specialized groups of fish, amphibians and reptiles, characterized by contrasting food adaptations and living in various natural conditions from the Arctic to the tropics. In addition to the tasks of a fundamental nature, approaches will be found to the development of specialized feeds and additives that will improve the efficiency of raising animals in aquaculture. Related materials: News: "В ИПЭЭ РАН будет создана лаборатория эволюционной трофологии"

On June 22, 2022 Konstantin Bronislavovich Gongalsky, Deputy Director of the IEE RAS, Doctor of Biological Sciences, Head of the Laboratory for the Study of Ecological Soil Functions, received the diploma of a Professor of the Russian Academy of Sciences. The award ceremony took place in the Presidential Hall of the Russian Academy of Sciences. Congratulations to Konstantin Bronislavovich on a well-deserved title! Author of the photo: Andrey Luft, "Scientific Russia".

For the first time in Russia, a skin mite Promyialges italicus from the Epidermoptidae family was discovered by researchers. This will enable a deeper study of its distribution and faunal composition. The study is conducted by the staff of the A.N. Severtsov Institute of Ecology and Evolution RAS. Feather mites of the Epdermoptidae family are persistent ectoparasites whose developmental stages are entirely on the skin of host birds. Some of their representatives, belonging to the subfamily Epidermoptinae and all genera of the subfamily Myialginae, have biological connections with bloodsucking flies Hippoboscidae, which parasitize birds, and less often with the lice Phthiraptera. Fertilized female ticks use flies and lice to disperse and infect other hosts. Attaching to these parasitic insects, female ticks either use them only for transfer to a new host individual, laying eggs on the cuticle around the attachment site in the process of moving, or additionally feed on the hemolymph (blood) of insects, biting through the cuticle of the abdomen. The species Promyialges italicus was first described only in 2019 in Italy, and so far little has been studied. Now it was first discovered in our country on the wings of a fly from a domestic pigeon that died from psittacosis. “The faunistic composition of ticks from this group in Russia is poorly understood, despite their veterinary significance. Neither is the exact species composition nor the distribution of representatives of this family. This article is only part of the preparatory stage for other studies of both ticks and flies with which these ticks are associated,” said Alexandra Yatsuk, junior researcher at the Laboratory of Soil Zoology and General Entomology, IEE RAS. The article published in the journal Acarologia. Photo: skin mite Promyialges italicus Materials: МК: "В Москве найден новый вид клещей, живущих на голубях" Вести Московского региона: "В Москве нашли новый вид клещей, живущих на голубях"

High school students, focused on profile education in biology, visited the laboratories at the A.N. Severtsov Institute of Ecology and Evolution RAS and listened to the speeches of researchers. The history of our Institute and the main directions of research were relayed by Doctor of Biological Sciences, Deputy Director for Research, prof. RAS Konstantin Gongalsky. After that, Senior Researcher Daniil Korobushkin, Ph.D., gave a lecture “Science and travel, or how to travel while doing science”. He told the students about how to properly pack for the expedition. The future biologists had the opportunity not only to listen to the scientists, but also to observe their work. They visited the Aquarium of the Institute, where researcher Sergey Simanovsky, Ph.D., demonstrated the fish being kept there and described what scientific experiments their data was used for. Sergey also demonstrated the experiment with disposable masks and napkins being put into the water to test the rate of their biodegradation. After a period, fish are put into this water to see how microplastics will affect them. In another laboratory, Yuri Kaverkin and Oleg Nikolaev showed the children lizards and geckos. They talked about the incredible ability of geckos to stay on smooth surfaces, the unusual sounds they make, and the fact that these animals eat their skin after shedding it off. The scientists showed some individuals and explained to the children what scientific work is currently taking place in this laboratory. The employees of the Institute are happy to share their experience with novice biologists and inspire them for a great scientific future.

Russian scientists as part of an international team studied the effect of serotonin on the formation of adrenal glands in rodents. It turned out that with an increase in its level during a certain period of pregnancy, fewer cells that produce adrenaline and norepinephrine are formed in the adrenal glands of the young. This change makes rodents less aggressive and anxious, but more friendly and inquisitive - it is these individuals that provide range expansion and migration in the wild. A similar mechanism for regulating the size of the adrenal glands has also been identified in human development. The results of the study, supported by a grant from the Russian Science Foundation (RSF), were published in the journal Nature Communications. The behavior of vertebrates, including humans, is determined not only by brain activity: for quick decision-making in critical situations, the work of the endocrine system is also of great importance. One of its glands are the adrenal glands - paired organs above the upper part of the kidneys. In response to stressful factors, such as danger or physical exertion, the cells of their internal so-called brain substances release adrenaline and noradrenaline into the blood. It is on the activity of the chromaffin cells of the adrenal medulla that the body's ability to quickly navigate the situation and implement the "fight or flight" defense strategy depends. In the process of differentiation from their precursors, chromaffin cells form receptor proteins on the surface for the “happiness hormone” serotonin, but it still remained a mystery what follows the activation of these receptors. The international team, which included Russian scientists, unveiled this pattern. The researchers injected pregnant rodents with a precursor of serotonin, which is converted to serotonin in the mother's body and in the placenta. They did this at the stage of embryo development, when the differentiation of chromaffin cells occurs. The authors then studied the tissues of the adrenal glands of the offspring. In this they were helped by the most modern methods of transcriptomics of individual cells, that is, studies of the activity (expression) of genes, and various biochemical and histological approaches. The researchers also conducted experiments with genetically modified lines of animals that were unable to produce serotonin, and with the help of pharmacological preparations they changed the activity of the corresponding receptors. Finally, the authors studied the behavior of the young of females with an increased content of the “hormone of happiness” in the body and examined samples of the adrenal glands of wild Siberian voles, which are characterized by waves of migration. It turned out that an increase in the level of serotonin during the critical period of pregnancy and activation of receptors in the precursors of chromaffin cells leads to a decrease in the size of the entire adrenal medulla. Normally, such a negative feedback mechanism does not allow young cells to divide excessively, and protects the body from the occurrence of a number of malignant tumors. The size of the adrenal medulla, which is laid during the development of the embryo, remains in the rodent for the rest of its life, and fewer cells secrete fewer hormones, which significantly affects behavior. Animals with less brain matter are less aggressive and anxious, but more inquisitive and friendly. Studies have shown that in wild populations of voles, it is these animals that ensure the migration of the species, the change of its range and the development of new territories. The level of serotonin in the placenta is very variable and sensitive to the external conditions in which the pregnant mother is. Physical activity, moderate stress caused by social contacts or lack of food lead to its increase, thus “signaling” to the unborn descendant about the conditions that they will meet after birth: there are many relatives around, competition is great and already his generation will have to master new places. “The serotonin-mediated mechanism we have discovered that regulates the number of adrenal chromaffin cells reveals one of the possible ways of epigenetic, that is, due to external factors, transmission of information from mother to the young. It provides a kind of prenatal programming of long-term changes in the behavior of offspring, which explains the emergence of various types of response to stress during development,” says one of the co-authors of the study, Victoria Melnikova. “Further studies will establish how the contribution of the epigenetic effect of serotonin to the variability of chromaffin organs in wild and domesticated animals is compared to genetic factors. The detection of serotonin receptors on progenitor cells will allow in the future to develop new drug therapy strategies for certain types of malignant tumors”, says Elena Voronezhskaya, one of the authors of the article and head of the project on a grant from the Russian Science Foundation. The study was conducted by the staff of the N.K. Koltsov Institute of Developmental Biology RAS (Moscow), together with colleagues from the National Medical Research Center for Endocrinology of the Ministry of Health of Russia (Moscow), the V.V. Zakusov Research Institute of Pharmacology (Moscow), Institute of Cytology RAS (St. Petersburg), Institute of Translational Biomedicine (St. Petersburg), I.M. Sechenov First Moscow State Medical University (Moscow), A.N. Severtsov Institute of Ecology and Evolution RAS (Moscow), Karolinska Institute (Sweden), Medical University of Vienna (Austria) and international research institutes in Germany, the Czech Republic, Italy and France.

1st year undergraduates of the Institute of Animal Science and Biology, studying under the program "Resources of Vertebrate Animals (Protection, Reproduction, Rational Use)", completed an internship at the scientific and experimental base "Chernogolovka" of the A.N. Severtsov Institute of Ecology and Evolution RAS. Future biologists acquired practical experience of field zoological research and were introduced to the fauna of the Moscow region. Practical training was preceded by theoretical training - undergraduates were presented with a series of lectures on the behavior and behavioral ecology of mammals, biology of reproduction of vertebrates, methods and technologies for keeping and breeding rare species of mammals. The lectures were conducted by experienced staff of the A.N. Severtsov Institute of Ecology and Evolution RAS. Under the guidance of teachers of the K.A. Timiryazev RGAU-MSHA the students conducted daily route counts of animals in the vicinity of the scientific and experimental base and on its territory. In practice, undergraduates studied representatives of the fauna of amphibians, reptiles, birds and mammals. They learned the main methods of taking morphometric indicators on the example of amphibians of 4 families. The students were given the opportunity to study a unique collection of vertebrates, which includes more than 2,000 individuals. Among them are predatory, insectivorous, rodents, lagomorphs and bats. As Professor of the Department of Zoology Lyubov Malovichko noted, the students did an excellent job with all the tasks set, and the acquired the necessary skills for their further scientific and labor activities.

The researchers described the species composition of crustaceans inhabiting the reservoirs of the Putorana Plateau, a unique mountain range in Central Siberia that is difficult to study. The authors determined the patterns of their distribution, and discovered 23 new taxa for the region, and 4 new for science. The results of the work, supported by a grant from the Russian Science Foundation (RSF) and published in the journal Diversity, will be invaluable for preserving the region’s unusually rich fauna for the Arctic, which is so vulnerable to human influence and global climate change. The Arctic ecosystems are characterized by a relatively poor species diversity - the conditions are harsh, and therefore only the strongest and fittest, more precisely, the most specialized, can survive. This makes organisms very sensitive to global warming and the impact of human activity, since even a slight change in the usual environmental conditions can disrupt vital metabolic processes. “Unfortunately, many Arctic regions are difficult to access, and therefore we know very little about the species inhabiting them. This is especially true for aquatic animals: a small puddle in a cave or a stream high in the mountains may be the only habitat for representatives of some taxon. It is here that we constantly find new species or even groups higher in the systematic hierarchy. Some of them may be relics - a kind of "time travelers" preserved from ancient times. By studying them, we can learn a lot about the origin and evolution of various organisms,” says Elena Chertoprud, candidate of biological sciences, researcher at the IEE RAS and the Faculty of Biology of Moscow State University. In their new work, researchers from the A.N. Severtsov IEE RAS (Moscow), M.V. Lomonosov Moscow State University (Moscow), Kazan Federal University (Kazan), the Institute of Biology of the Komi Scientific Center of the Ural Branch of the Russian Academy of Sciences (Syktyvkar) and the All-Russian Research Institute of Fisheries and Oceanography (Moscow) focused on studying the water bodies of the Putorana Plateau. This mountain range of volcanic origin is located beyond the Arctic Circle, and most of it is characterized by a harsh, sharply continental climate. However, due to the peculiarities of the relief in some lake valleys, conditions are much more favorable, including for the aquatic animals inhabiting them. The authors studied 30 reservoirs of various sizes and origins on the Putorana Plateau. Among them were low-flowing lakes, preserved due to runoff or formed during the expansion of the stream and channel; oxbow lakes with a permanent or dry summer connection with the riverbed; swampy lakes; endorheic lakes, including mountain lakes, lying in relief depressions. With the help of a plankton net, hydrobiologists caught representatives of zooplankton moving in the water column, and in bottom sediments - meiobenthic organisms inhabiting the soil. Scientists managed to collect 36 species of Cladocera (the so-called water fleas or cladocerans) and 24 species of Copepoda (copepods). Interestingly, 23 of the discovered taxa are new to the region, and four are new to science. The species richness of Copepoda turned out to be higher in the central part and on the western slopes of the plateau compared to the foothills, while the number of Cladocera species, on the contrary, decreases in mountainous areas. For the meiobenthos, the type of feeding of the reservoir turned out to be critical, but the height of its location had almost no effect. For planktonic animals, the size of the reservoir and, to a lesser extent, the species composition of macrophytes - aquatic plants in which they can hide and hunt - held higher importance. “The fauna of microcrustaceans in the northern part of Central Siberia in general and the Putorana Plateau in particular is characterized by high species richness and differs significantly from that of both the western and eastern regions of the continental Arctic. The specificity is due to the climatic features of Central Siberia, as well as the preservation of the relict Pleistocene fauna in refugia, that is, a kind of refuge that did not undergo the last glaciation, ”explains Anna Novichkova, PhD in Biology, researcher at the IEE RAS and the Faculty of Biology of Moscow State University. Studies of aquatic communities in the north of Central Siberia, which is one of the most remote regions of Russia, are important both for revising the species richness of the Arctic fauna and for assessing the variability of polar ecosystems against the backdrop of growing anthropogenic pressure and global climate change. This, in turn, is of key importance for understanding the processes of transformation of natural ecosystems, as well as for developing scientifically based methods and schemes for monitoring the state of the aquatic environment.

An international team of scientists has found that the Malayan tupaya uses the same motor patterns as primates when moving through trees. This shows that some of the characteristics of primates appeared in evolution before themselves. The work was attended by scientists of the A.N. Severtsov Institute of Ecology and Evolution (IEE) RAS. One of the most interesting mysteries in human evolution is the transition to the arboreal lifestyle of its ancestors, the primates. Most of them, including the most primitive representatives, are arboreal animals. According to one theory, it is assumed that human upright posture arose as a result of the adaptation of his closest ancestors to one of the most specialized ways of arboreal movement - brachiation. During brachiation, the animal moves by hanging under the branches of trees and throwing itself from branch to branch with its forelimbs (arms). This method is well suited for the movement of relatively large animals in crowns with horizontal branches. Gibbons, orangutans, and some South American monkeys are capable of brachiation. Today, the brachiation hypothesis has become one of the main reconstructions of the formation of human upright posture, since the body is located vertically, and the musculoskeletal system adapts to this position. However, the question of how exactly the primates mastered the arboreal way of life, and how their early locomotor adaptations were formed, remains open. Their next of kin can help answer it. Tupai are small semi-arboreal animals, genetically the closest relatives of primates. They live mainly on the ground, but some of their species deftly move in the crowns of trees. For scientists, the tupai is the best "live" model of a primate ancestor. In order to study their ability to move on branches, an international team of researchers surveyed the Malayan tupaya (Tupaia belangeri) at the Moscow Zoo. It was originally assumed that the tupai used a "squirrel-like" way of moving along the branches. Squirrels are rodents that have perfectly mastered the three-dimensional locomotor environment of tree crowns. However, their arboreal specializations arose and developed quite independently of primates, and the initial stage was terrestrial rodents, reminiscent of modern marmots or ground squirrels. The gaits (order of rearrangement of legs) used by arboreal rodents differ from those of primitive primates on branches. Thus, it was expected that a detailed study would be able to find more similarities in the movement along the branches in the tupai and primates than between rodents and tupai. The study of the Malay tupaya made it possible to significantly supplement the ideas about the technique of their movement (gaits and the way of grabbing branches with their paws), as well as to analyze the similarities and differences in the locomotion of these animals with primitive primates (using the example of the fat-tailed lemur). In the experiment, the tupai willingly climbed the branches, using predominantly quadrupedal climbing and jumping. The quadrupedal climbing sequence of the tupaya was similar to that of the fat-tailed lemur (Cheirogaleus medius), a primitive primate of the same size. In addition, the animals developed a grasping mechanism similar to primates, in which the big toe of the hind leg is opposed to the rest of the fingers, and as a result, the paw covers the branch from two sides. An analysis of the surveys showed that the tupai have primitive locomotor characteristics of mammals and more specific features that are characteristic of lower primates. “The study suggests that a number of locomotion patterns that were thought to be unique to primates actually characterize a broader group of mammals called Euarchonta, which, in addition to primates, also includes tupai and colugos,” said Alexandra Panyutina, senior researcher at IEE RAS. The fact that tupai and primates share specialized locomotion traits that are not found in other placental mammals suggests that they had a common ancestor. This means that thumb opposition in walking is not unique to primates, as previously thought. Moreover, everything indicates that this trait arose earlier, even at the evolutionary stage of the common ancestor of the tupai and primates. Researchers believe that the most primitive primates already possessed both this specialization and its characteristic morphology (the science of the shape and structure of the body), which can be confirmed in the future by paleontological data. Further study of these animals will help to understand what morphological appearance the distant ancestors of humans had. The study is published in the Journal of Experimental Zoology Part A.Related materials: TASS Nauka: "The opposition of the thumb in primates was not unique" MK.ru: "Russian scientists have found the predecessor of monkeys"