Sorex Caecutiens Research Articles

Abundance, habitat distribution and content of reserve energy substances in shrews (Sorex caecutiens, Sorex isodon) within the Seymchan-Buyundinskaya Depression (Upper Kolyma River region)

This research examined the influence of interspecific interactions among shrew species on their territorial distribution and trophic conditions within larch and poplar-chosenia forests along the upper Kolyma River. The study specifically analyzed the biotopic characteristics associated with the relative abundance and energy reserve content, including fat tissue mass and glycogen levels in the liver, of Sorex caecutiens and S. isodon. Fieldwork was conducted in the Seymchan- Buyunda depression during July and August in 2003 and 2010. A total of 1,588 individuals from both species were captured using pitfall traps. The assessment of energy reserve content in S. caecutiens (n = 736) and S. isodon (n = 113) was carried out between 2006 and 2010. The abundance of S. caecutiens in the examined habitats exhibited consistent trends and a strong correlation (RS = 0.95, p < 0.01). Conversely, S. isodon displayed asynchronous fluctuations in abundance across various habitats, likely attributable to competition with Laxmann’s shrew, which tends to displace S. isodon from its preferred larch forest during periods of elevated population density. The interannual variations in energy reserve content for both shrew species were remarkably similar, with no significant differences observed between habitats. The nature of these variations suggested insufficient feeding conditions for the animals during years of high overall abundance, with the dominant species, S. caecutiens, contributing most significantly to this phenomenon in both habitats of the upper Kolyma. The results indicate that interspecific relationships play a crucial role in shaping both territorial distribution and food availability for these shrew species.

Genetic Variability of the Laxmann’s Shrew (<i>Sorex caecutiens</i> Laxmann, 1788) of the Kolyma River Basin and Chukotka

Nucleotide sequence polymorphism and haplotypic diversity of the cytochrome b gene were studied in samples of the Laxmann’s Shrew Sorex caecutiens koreni from the populations of the Kolyma River basin and Chukotka. 56 cytb-haplotypes differing among themselves by 87 mutations in 84 sites were found. The cytb-haplotypes of individuals of the subspecies S. c. koreni and S. c. macropygmaeus were shown to belong to the same maternal mtDNA lineage, their monophyletic origin from the same ancestral haplotype Scb1, and the presence of identical cytb-haplotypes in both subspecies. The mutual isolation of the shrew populations in the upper basin of the Kolyma River and Chukotka is shown. The proportion of intrapopulation genetic variability is 95.74%, intergroup variability is 5.74%, and intragroup variability is –1.48%, which reflects a very high level of intrapopulation variability of cytb haplotypes in the studied groups of S. c. koreni, their monophyletic origin, and the genetic unity of the Chukchi samples. The values of molecular diversity indices testify to the stability of populations that have a high value of effective abundance for a long time.

Decoding the RNA viromes in shrew lungs along the eastern coast of China

Shrews being insectivores, serve as natural reservoirs for a wide array of zoonotic viruses, including the recently discovered Langya henipavirus (LayV) in China in 2018. It is crucial to understand the shrew-associated virome, viral diversity, and new viruses. In the current study, we conducted high-throughput sequencing on lung samples obtained from 398 shrews captured along the eastern coast of China, and characterized the high-depth virome of 6 common shrew species (Anourosorex squamipes, Crocidura lasiura, Crocidura shantungensis, Crocidura tanakae, Sorex caecutiens, and Suncus murinus). Our analysis revealed numerous shrew-associated viruses comprising 54 known viruses and 72 new viruses that significantly enhance our understanding of mammalian viruses. Notably, 34 identified viruses possess spillover-risk potential and six were human pathogenic viruses: LayV, influenza A virus (H5N6), rotavirus A, rabies virus, avian paramyxovirus 1, and rat hepatitis E virus. Moreover, ten previously unreported viruses in China were discovered, six among them have spillover-risk potential. Additionally, all 54 known viruses and 12 new viruses had the ability to cross species boundaries. Our data underscore the diversity of shrew-associated viruses and provide a foundation for further studies into tracing and predicting emerging infectious diseases originated from shrews.

Genetic Variability of the Laxmann’s Shrew (Sorex caecutiens Laxmann, 1788) of the Kolyma River Basin and Chukotka

Genetic Variability of the Laxmann’s Shrew (Sorex caecutiens Laxmann, 1788) of the Kolyma River Basin and Chukotka

Cestode diversity in shrews from islands in the Sea of Japan and the Sea of Okhotsk.

A comparative analysis of taxonomic diversity on shrew cestodes among four islands in the Sea of Japan and the Sea of Okhotsk (Sakhalin, Kunashir, Hokkaido, and Moneron) was performed. Cestode species shared among the islands were identified and their host specificity was investigated. On Sakhalin Island, 33 species of the families Hymenolepididae, Dilepididae and Mesocestoididae were recorded in four shrew species (Sorex caecutiens, S. gracillimus, S. minutissimus and S. unguiculatus). In S. caecutiens, S. gracillimus, and S. unguiculatus on Kunashir Island, 22 species of the same families were found and, on Hokkaido Island, 23 species of the families Hymenolepididae and Dilepididae were recorded. On Moneron Island, three species of cestodes were registered in S. tundrensis. The Sakhalin-Hokkaido-Kunashir complex of shrew cestodes includes eastern-Palearctic, trans-Palearctic and endemic species. High endemism (~22%) of shrew tapeworms in the Sakhalin-Kunashir-Hokkaido Islands was noted as compared to continental territories. The different numbers of cestode species in S. unguiculatus (31), S. caecutiens (29), S. gracillimus (19) and S. minutissimus (1) were found. It was concluded that the cestodes species diversity of shrews of Sakhalin-Kunashir-Hokkaido depended primarily on the history of island formation, their modern physical and geographical features, the abundance of definitive and intermediate cestodes hosts and, to a lesser extent, on the size and remoteness of the islands from the mainland and the diversity of host species.

Fossil insectivorous mammals (Eulipotyphla) of the southern Pre-Urals (Bashkortostan, Russia)

Seven species of red-toothed shrews (Sorex araneus, Sorex isodon, Sorex tundrensis, Sorex caecutiens, Sorex minutus, Sorex minutissimus, Neomys fodiens), white-toothed shrews (Crocidura sp.), moles (Talpa sp.) and hedgehogs (Erinaceus sp.) were found in Late Pleistocene and Holocene deposits of the southern part of the western slope of the Ural Mountains. In the Late Pleistocene and Early Holocene deposits, the red-toothed shrews were dominated by S. tundrensis. This species disappeared from the area by the Late Holocene, when S. araneus became the predominant species. Smaller mandibular sizes have been registered for S. araneus in the Middle and Late Holocene, as compared to the sizes of older samples. The morphometric criteria have been established for a species differential diagnosis of the Late Pleistocene – Early Holocene mandibular samples of S. araneus and S. tundrensis, found in local deposits of the southern Pre-Urals area studied.

Modifications of Longworth traps to prevent wear and improve catchability of shrews (Sorex spp.)

Abstract Longworth live traps are widely used for trapping mouse-sized rodents and shrews. However, they have a number of disadvantages: some have a manufacturing defect, resulting in reduced sensitivity; smaller species of shrews can pass under the treadle, avoiding capture; captured animals can gnaw specific parts of the sidewalls and decrease the durability of the traps. To increase the efficiency of catching small shrews, we added a movable tin ramp to the treadle of the Longworth live traps and used washers to improve the design. To repair and protect traps damaged by captured animals, we used tin patches. The modified traps were shown to be significantly better than the original traps in catching small shrew species (Sorex caecutiens Laxmann 1788, Sorex minutus Linnaeus, 1766). Tin patches reliably protected live traps from further damages by animals and do not affect their catching efficiency.

Factors that affect long-distance movements of small rodents and shrews in the Ural taiga: disentangling dispersal from excursion movements

Abstract Long-distance movements (LDMs) of small mammals (SMs) are complex phenomena that cover both dispersals and excursions occurring outside the home ranges of individuals. Owing to methodological difficulties, there are a lack of data on LDMs for SMs. In this study, we aimed to determine the factors that influence the LDMs of different mouse-sized rodents and shrews in the Ural taiga (Sverdlovsk region, Russia). We conducted a field experiment in a boreal forest using individual- (capture–marking–recapture [CMR]) and group- (biomarkers: tetracycline and rhodamine B) marking methods, in conjunction with additional feeding. The species, sex, maturity, plot ID, additional food supply, species abundance indices, individuals/100 trap-nights indices in the capture plot, and body weight of each animal were analyzed as predictors of LDMs. We identified 89 individuals from six species that moved at distances of 250, 350, and 500 m. LDMs varied with the particular species and its population abundance. Most of the observed movements were excursions and not dispersal events. Applying mathematical simulations to the obtained empirical data facilitated estimation of the intensity of the excursion activity for different species. We present the 1st excursion data on Sylvaemus uralensis (Pallas, 1811), Microtus arvalis (Pallas, 1778), and Sorex caecutiens (Laxmann, 1788). The detected excursion distance (250 m) for Myodes glareolus (Schreber, 1780) is the maximum excursion distance known for this species. We demonstrate that with comparable labor and time costs, the use of biomarkers makes it possible to detect many more LDMs than CMR allows.

Abundance and Condition of Populations of Small Mammals as Carriers of Natural Focal Human Diseases in the Karelia North-East Ladoga

Summing up the results of the long-term studies of population ecology and dynamics of small mammals for more than half a century (1966–2018). Small mammals are involved in the formation and functioning of natural-focil of human vector-borne diseases common in the North-Eastern Ladoga region. Encephalitis and tularemia circulate intensively in the Ladoga region under conditions of intensive anthropogenic transformation of taiga ecosystems. Local landscapes belong to the subzone of the middle taiga forests. Most of the studied species of small mammals are located in the northern periphery of this area. Here representatives of the native taiga fauna of Micromammalia constantly experience powerful anthropogenic pressure, which leads to a decrease in their abundance and correlation of the species. Of the total amount of 22 species of small mammals collected here, Sorex araneus and Myodes glareolus dominate. Next, the species prevalent (according to the degree of predominant species) in the counts are Microtus agrestis, Sorex minutus and Sorex caecutiens. Other species are relatively rare and appear in smaller numbers. Myodes glareolus has main role in the feeding of ticks and, accordingly, in the circulation of infections in nature, the differentiated contribution of individual intrapopulation groups in maintaining the number of vectors and the activity of pathogens. Shrews are important for the development of the larval stages of the tick. In the research area, were recorded total index of trap catch of abundance of small animals with trap lines from 0.34 to 18.5 individuals per 100 snap traps-nights (average of 7.8 ind.) and with pitfall traps recorded from 2.7 to 25.4 individuals per 10 ditch-nights (average of 14 ind.). This indicates that the studied area has smaller amount of mammals compared to other regions in Southern Europe. Nevertheless, the studies determine a rather tense epidemic situation in the studied area. Population of small mammals of boreal ecosystem steadily affect the mass feeding of carriers of natural focal infections.

Cestode Diversity of Shrews on the Kamchatka Peninsula and Paramushir Island

The aim of this study was to assess the taxonomic diversity and prevalence of shrew cestodes on the Kamchatka Peninsula and Paramushir Island on the basis of current understanding of cestode taxonomy. The diversity of shrew cestodes included 22 species from three families: Hymenolepididae, Dilepididae, and Mesocestoididae. In Paramushir, the diversity of shrew cestodes was substantially lower than in Kamchatka (14 and 22, respectively). In Kamchatka, three genera of cestodes (Novobrachylepis, Mathevolepis, Ditestolepis) were not found, but three species from genera Lineolepis, Staphylocystis, and Monocercus are possibly new species. The potential for endemic species and the unique characteristics of the cestode fauna on Kamchatka suggest that the peninsula may have been a refugium for shrews and their parasites in the last glacial maximum. In Kamchatka and Paramushir, two Nearctic species (Lineolepis parva and L. pribilofensis) were found, which indicates potential dispersal from North America. Most cestode species in Kamchatka were associated with the host shrew Sorex caecutiens, while in Paramushir most cestodes were associated with Sorex isodon. In Paramushir, shrews had higher prevalence of infection with cestodes than in Kamchatka. The dominant cestode taxa in shrews on Paramushir Island were species rare in Kamchatka. Conversely, the most abundant cestode species in shrews on Kamchatka were absent from the island fauna.

Биофаунистические заметки по млекопитающим южных отрогов хребта Черского (Магаданская область)

Data on the species composition of theriofauna in the mountain-lake district of the Cherskiу Range southern spurs are given. New data on habitats, relative abundance, and some population characteristics of mass species of small mammals are also reported. The basins of Lake Momontay and Lake Urultun, located at 1048 and 944 m above the sea level and belonging to the basin of the Omulyovka River upper reaches, were inspected in August 2021. Small mammals were caught using the standard trap-line and cone methods. A total of 650 trap-days and 80 cone-days were worked out; 260 animals were caught. The species composition of large and medium-size mammals was identified by traces of their life activity and by visual contacts during route surveys of the total area about 350 km2. The routes made 50 km of length. 18 species of mammals referring to 16 genera, 9 families, and 5 orders were found to inhabit the area; they prevalently belong to the most numerous and elements of the theriofauna, widespread in the North-East of Siberia boreal Holarctic (Clethrionomys rutilus, Alexandromys oeconomus, Ursus arctos, Rangifer tarandus, Alces alces) and ancient taiga Palearctic (Sorex caecutiens, S. isodon, Myopus schisticolor, Craseomys rufocanus, Martes zibellina). A new habitat (the northwestern coast of Lake Momontai) was identified for the North Siberian vole (Alexandromys hyperboreus). Besides, the findings of the equal-toothed shrew (Sorex isodon) in the study area expand its distribution borders 160-180 km to the north of the Upper Kolyma basin.

Repellent effect of synanthropic house mouse urine odor on small forest mammals.

In this study, we examined the effect of synanthropic house mouse (Mus musculus) urine odor on catching probability of small mammals to live traps. We conducted a series of field experiments in August 2016 and 2017 in a natural forests of the northwestern Moscow Region (Russia). Small mammals were trapped at two 4-ha fields using capture-mark-recapture technique by setting 200 live traps (100 points, 2 traps per point) within each field. One trap in each pair was odorless (control) with bait only, whereas the other one was odor-baited with 20 μL of the urine of a synanthropic house mouse. Further analysis was based on the data collected from 2 rodent species (bank vole Myodes glareolus, herb field mouse Apodemus uralensis) and 3 shrew species (common shrew Sorex araneus, Laxmann's shrew Sorex caecutiens, and Eurasian pygmy shrew Sorex minutus). As a result, only bank voles significantly avoided odor-baited live traps. Using generalized linear mixed models, we showed that the choice of a trap by bank voles depended on their age, whereas the probability of repeated capture to a certain live trap was related to their prior experience. We discuss the possible role of components of synanthropic house mouse urine in the population management of exoanthropic small mammals.

Long-distance dispersal of two species of shrews (Sorex caecutiens Laxmann, 1788 and Sorex minutus Linnaeus, 1766)

Abstract Data on the dispersal of shrews are still rare, and for some species of Soricidae these are not available at all. Group marking with bait containing rhodamine B was used to study the dispersal of two species of shrews – Laxmann’s shrew (Sorex caecutiens) and pygmy shrew (Sorex minutus) in the Middle Urals (Russia). Twelve Laxmann’s shrews moved straight-line distances ranging from 80 to 4500 m. Five pygmy shrews dispersed from 475 to 2570 m. The are first field data obtained on dispersal distances of the pygmy shrew. The reported dispersal distances of the Laxmann`s shrew are the maximum known for this species.

Interannual Variability in the Energy Reserves of Laxmann’s Shrew (Sorex caecutiens) on the Northern Coast of the Sea of Okhotsk

Interannual Variability in the Energy Reserves of Laxmann’s Shrew (Sorex caecutiens) on the Northern Coast of the Sea of Okhotsk

Население мелких млекопитающих подтайги Южного Зауралья

On the basis of materials obtained using two generally accepted counting methods, data on the species composition of small mammals, the ratio of background and dominant species, the total abundance in the main groups of biotopes of the South Trans-Ural region are presented. The differences in the community structure of small mammals in the subtaiga and forest-steppe sub-zone of the South Trans-Ural region have been analysed. The paper discusses materials on the community of small mammals in the sub-taiga of the South Trans-Ural region. A brief history of the study of this group of animals is reviewed. The use of two counting methods (the ditch with pitfalls and trap-lines) allowed the most complete identification of the species composition of insectivores and rodents in the sub-taiga of the South Trans-Ural region in 2021. In terms of species, the ditch with pitfalls were more effective, with 17 species identified; trap-lines counted 13 species. The abundance of animals in 2021 was very low. In our opinion, was determined by the abnormally hot spring and summer period. On average, only rare and very rare species have been recorded in the snap-trap counts in the study area. Numerous species were absent in the average meaning regardless of the method of capture. The core of small mammals of the sub-taiga of the South Trans-Ural region consisted of species typical of humid habitats and small-leaved forests, such as the Laxmann's shrew Sorex caecutiens, common shrew S. araneus and Eurasian pygmy shrew S. minutus rodents, as well as the common vole Microtus arvalis and harvest mouse Micromys minutus (surveys using the ditch with pitfalls). The common shrew was predominant in the snap-trap counts, accounting for about 45% of the total abundance of all animals recorded. In pine forests with poor productivity and in open spaces, the total abundance of insectivores and rodents is lowest. The species composition of small mammals of the sub-taiga and forest-steppe subzone of the South Trans-Ural region are largely similar (83% of the total species). Specific features of the taiga subzone were determined by the taiga shrew Sorex isodon and Siberian chipmunk Eutamias sibiricus, unusual for the forest-steppe and herb-bunchgrass steppe subzone of the South Trans-Ural region. A characteristic feature of the sub-taiga of the South Trans-Ural region is a specific proportion of the northern red-backed vole Myodes rutilus and European bank vole M. glareolus, their abundance is comparable, or the M. glareolus predominates, which is not observed in the forest-steppe. In the sub-taiga, in the surveys using ditch with pitfalls among insectivores and rodents, the Laxmann's shrew prevailed, its share was approximately one fourth of all recorded animals, although in general the community of small mammals is polydominant, in contrast to the surveys using the trap-line method, where one species dominated – the common shrew. In 2021 (sub-taiga) as well as in 2020 (forest-steppe) the territory of the South TransUral region was characterized by a deep depression of water vole Arvicola amphibius numbers, which was completely absent in the counts.

Geographic Distribution and Phylogeny of Soricine Shrew-Borne Seewis Virus and Altai Virus in Russia.

The discovery of genetically distinct hantaviruses (family Hantaviridae) in multiple species of shrews, moles and bats has revealed a complex evolutionary history involving cross-species transmission. Seewis virus (SWSV) is widely distributed throughout the geographic ranges of its soricid hosts, including the Eurasian common shrew (Sorex araneus), tundra shrew (Sorex tundrensis) and Siberian large-toothed shrew (Sorex daphaenodon), suggesting host sharing. In addition, genetic variants of SWSV, previously named Artybash virus (ARTV) and Amga virus, have been detected in the Laxmann’s shrew (Sorex caecutiens). Here, we describe the geographic distribution and phylogeny of SWSV and Altai virus (ALTV) in Asian Russia. The complete genomic sequence analysis showed that ALTV, also harbored by the Eurasian common shrew, is a new hantavirus species, distantly related to SWSV. Moreover, Lena River virus (LENV) appears to be a distinct hantavirus species, harbored by Laxmann’s shrews and flat-skulled shrews (Sorex roboratus) in Eastern Siberia and far-eastern Russia. Another ALTV-related virus, which is more closely related to Camp Ripley virus from the United States, has been identified in the Eurasian least shrew (Sorex minutissimus) from far-eastern Russia. Two highly divergent viruses, ALTV and SWSV co-circulate among common shrews in Western Siberia, while LENV and the ARTV variant of SWSV co-circulate among Laxmann’s shrews in Eastern Siberia and far-eastern Russia. ALTV and ALTV-related viruses appear to belong to the Mobatvirus genus, while SWSV is a member of the Orthohantavirus genus. These findings suggest that ALTV and ALTV-related hantaviruses might have emerged from ancient cross-species transmission with subsequent diversification within Sorex shrews in Eurasia.

Revisiting «Malaya Sosva» state reserve characteristics of fauna and population structure of small mammals

The paper deals with the study of species composition and small mammals population structure of Malaya Sosva (Little Sosva) state nature reserve, Khanty-Mansi Autonomous Okrug Yugra, Russia. The research was conducted within the last ten days of June, 2019 on the Malaya Sosva River flood plain (Shukhtungort ranger station neighborhood, northern taiga). The animals were registered in typical biotopes of the research area: a herb-oxalis pinery, a lingonberry-lidum pinery, a lingonberry-pleurocarpous moss pinery, a herb-oxalis spruce forest, a herb-woodreed pinery, on the skirts of a mixed forest around the ranger station on the border of a mowed secondary meadow. In the course of investigation, the following five species of small rodents and insectivores were registered: Myodes rutilus, Myodes rufocanus, Sorex caecutiens, Talpa europaea, Pteromys volans. M. rutilus was an absolute dominant species in terms of numbers in the majority of the studied biotopes. S. caecutiens is co-dominating in the herb-oxalis pinery and herb-oxalis spruce forest, and M. rufocanus is co-dominating in the lingonberry-lidum pinery. In the herb-woodreed pinery, only individuals of S. caecutiens species were caught in a pitfall trap. Communities of small mammals in different types of habitats show low values of species diversity and sustainability due to harsh natural-climatic conditions of the region. A small mammals community of mature herb-oxalis pinery on the bank of Svyatoy Sor Lake, where the protected species, Pteromys volans, was registered, shows the highest values of abundance of small mammals and a maximum level of overall welfare index. It suggests that the habitat under study should be studied further and protected.

Periodic Changes in the Abundance of Laxmann’s Shrew (Sorex caecutiens, Eulipotyphla) and Factors of Its Population Dynamics in the Foothill Taiga of the Northern Urals

Long-term data on fluctuations in the abundance of Laxmann’s shrew (Sorex caecutiens Laxmann) in the foothill taiga of the Northern Urals (Pechora-Ilych State Biosphere Reserve) have been evaluated using spectral analysis of time series. Periodic components in the population dynamics of the species have been revealed, including a statistically significant component that had a period of 3 years but was not highly regular. Analysis of factors accounting for variation in abundance parameters has shown that the population dynamics of S. caecutiens are influenced by both weather conditions and mechanisms of density-dependent regulation.

Late Pleistocene and Holocene small mammal (Lipotyphla, Rodentia, Lagomorpha) remains from Medvezhyi Klyk Cave in the Southern Russian Far East

Late Pleistocene-Holocene faunal complexes of small mammals (Lipotyphla, Rodentia, and Lagomorpha) from the Russian Far East are described for the first time. We used material from the Medvezhyi Klyk Cave, located in Southern Sikhote-Alin. The numerous fossil findings from the cave display a remarkable taxonomic diversity and high degree of preservation. AMS 14C dating used for determination of deposits age. The Holocene sediments were divided into three periods: Early, Middle, and Late. The Pleistocene deposits age was not exactly determined, but under approximately estimation it can reach 50–60 ka. Thirty-nine species were found, including one member of the extinct genus of arvicolins. There are six faunal complexes identified from the studied Late Pleistocene and Holocene deposits. In general, the faunal complexes characterized by the dominance of Craseomys rufocanus within rodents, Sorex caecutiens within lipotyphlans; and relatively stability composition of most number of the dominant, codominant and subdominant species. Accordingly, the faunal complexes were described by means of two determining criteria only: relative number of species; and presence or absence of certain species. The dominant species are eurytopic and so they cannot use for reconstruction of the paleoenvironment.

Первые сведения о фауне и населении грызунов (Rodentia) и насекомоядных (Eulipotyphla) Хингано-Архаринского заказника

This is the first data on the fauna and biotopical distribution of rodents and insectivores of the Khingano-Arkharinskyi zakaznik. The preliminary results are based on field research led in 2011, 2012, 2015 and 2017. Five species of shrews (Sorex caecutiens, S. daphaenodon, S. tundrensis, S. isodon, S. roboratus) and nine species of rodents (Sciurus vulgaris, Tamias sibiricus, Craseomys rufocanus, Myodes rutilus, Alexandromys maximowiczii, Micromys minutus, Apodemus peninsulae, A. agrarius, Sicista caudata) were reliably detected, including the first find of S. caudata in Amurskaya Oblast (this is the most northwestern point of the range, 190 km to west-northwest from the previously known place). A track on snow has been found that was possibly left by Neomys fodiens. The possibility of residence of other species is discussed according to their ranges analysis and presence in Khinganskyi Nature Reserve situated 40 km to the south. The whole Middle Amur region is a territory with a complex landscape structure with intermixture of boreal, nemoral and steppe biotic components and the corresponding «transitional» character of the fauna. Many species have range borders here. Two steppe species (Cricetulus barabensis, Urocitellus undulatus) living in Khinganskyi Reserve or on adjacent territories cannot be found in the zakaznik. Two nemoral species (Erinaceus amurensis and Сrocidura lasiura, rare in Khinganskyi Reserve) have their northern range borders near the southern border of the zakaznik, they are likely to be absent here due to lack of needed habitats. The zakaznik is situated on the northern periphery of Alexandromys fortis range and the western periphery of Sorex gracillimus range, further field research is needed to clarify their status here. Two more species (Sorex minutissimus, Pteromys volans) have not been found yet but they obviously live on this territory.