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The first leopards were released into the wild in the Russian Caucasus in 2016 and 2018 as the first step of the Federal leopard restoration program. Leopards were tagged with GPS-Iridium collars. The obtained GPS-coordinates were used to create and verify a mathematical model of the potential habitats of this species and evaluate the possibility of the way choice made by leopards on the move. The modeling was performed by the maximum entropy method using the MaxEnt program based on the data from six leopards (four males and two females). A variety of basic habitat factors and characteristics are reflected in WorldClim bioclimatic indicators, including the data on surface radar imagery, and indices calculated on the basis of Landsat8 satellite image mosaic. To describe and verify biotopes, the field data collected in the Republics of North Ossetia-Alania, South Ossetia and Kabardino-Balkaria were used. The obtained results confirmed a high) accuracy in determining the predicted points. The largest contribution to the common model of potential leopard habitats is made by 10 main factors from the whole set. That list includes the slope steepness, altitude, several climatic characteristics, bioclimatic indices, and the vegetation index. According to the modeling results, the most preferred habitats for the leopard in the Caucasus are not very steep (up to 30°) slopes with grassy vegetation at altitudes of about 800–1500 m above sea level, independent of exposure, but with the average value of snow indices.

The ability of the polar bear (U. maritimus) to kill and consume conspecifics is accepted, but the reasons behind this behavior and its prevalence remain unclear. Here, we report 14 cases of intraspecific killing, cannibalism, and aggressive behaviors among polar bears observed in seven instances in the Barents Sea and the Kara Sea on Frans-Josef Land, Novaya Zemlya, and Vize Island. All but one of the observations were made on land during the ice-free season. Perpetrators, when observable, were mostly thin. The hunger resulting from a failure to gain fat reserves in spring appears to motivate perpetrators, while bear aggregation on islands could facilitate successful intraspecific killing. Surprisingly, cases of intraspecific killing were observed even in years when sea-ice conditions in the previous spring were relatively good. In one case, the killing of a cub of the year in the spring by a large, fat male could hardly be explained by nutritional demands. This could be a case of sexually selected infanticide, as the killing of cubs during the mating season increases the male’s opportunity to breed.

This is the first study to show the genetic identity of the Altai-Sayan population of the forest reindeer of the Kuznetsk Alatau (Rangifer tarandus valentinae). The population is characterized by the existence of unique mitochondrial lines, the absence of signs of introgression of domestic rein deer mtDNA, as well as a low level of genetic diversity. In the sample studied, only two nucleotide substitutions (both of them transitions) were revealed, the nucleotide diversity (0.0015 ± 0.00136) was almost ten times lower than in most populations of wild reindeer in Russia and was comparable only with that of some wild reindeer populations of Norway and Svalbard. The haplotype diversity (h) was also relatively low (0.615 ± 0.102).

Original data on the ecological relations of Sifonoptera fleas with small and medium-sized predators in southwestern Primorskii krai are presented. The parasitic community of fleas in populations of predatory mammals of the studied territory consists of eight species belonging to three families and five genera. Five flea species—Chaetopsulla appropinquans, Ch. micado, Ch. zibellina, Ch. dogieli, and Paraceras flabellum—are specific for predatory mammals, and another two species (Ctenophthalmus congeneroides and Megabotris calkarifer) have been found on predators, but are rodent parasites.

Data are presented on the variation in the relationships of males and females in felids with different degrees of sexual dimorphism in body size. It was shown that, in the mating season of the Eurasian lynx, a species with the least sexual dimorphism, females determined the relationships with the partner to a large extent. These interactions were characterized by a high frequency of affiliative behavior and courtship elements, while the frequency of aggressive contact was very low. In species with a higher level of sexual dimorphism, the relationships of the partners were determined mainly by males.

The serum prevalence of brown (Ursus arctos) and Asiatic black bears (Ursus thibethanus) to 14 different pathogens is analyzed; seropositive bears to ten different pathogens are found. The serum prevalence is at the maximum for Candida sp., pseudorabies virus and Dirofilaria sp. Species-specific differences in the serum prevalence to different pathogens are observed for Trichinella sp. and Toxoplasma gondii, but seropositive individuals are observed only among brown bears. These variations can be explained by differences in the feeding behavior of the brown and Asiatic black bears and the frequency of contacts with the Amur tiger and its kills.

Data on the reproductive success and reproductive behavior of the domestic cat, the most widespread representative of the family Felidae, are presented. The effects of the number of partners, mating order, and sperm quality on male and female reproductive success were assessed. The experiments showed that the fertility of female cats that mated with two partners was higher. Here, male reproductive success was less dependent on the attitude of females to the males, whereas the sperm quality (percentage of morphologically intact spermatozoa) and order of mating with the female had considerable effects on reproductive success. However, male sperm quality did not have a significant effect on the number of offspring if the mating pattern was monogamous.

The data on the content of carbon and nitrogen isotopes in the blood samples of polar bears obtained in the present study confirm that polar bears in the Taimyr region (and the Kara-Barents sea population in general) are partly dependent on the resources of terrestrial origin. However the "terrestrial carbon" evidently reaches bears' tissues indirectly, via marine food webs utilizing organic carbon brought into the polar basin by Siberian rivers.

The polar bear movement trajectory in relation to onset date of the sea-ice break-up was studied in the coastal zone of the Taimyr Peninsula, eastern part of the Kara Sea, using as an example a female polar bear tagged by a radio collar with an Argos satellite transmitter. Analysis of the long-term pattern of ice melting and tracking, by means of satellite telemetry, of the female polar bear who followed the ice-edge outgoing in the north-eastern direction (in summer 2012) suggests that direction of the polar bear movement depends precisely on the direction of the sea-ice cover break-up.

The possibility of the occurrence of seropositive reactions against four pathogens in two feline species (Pallas cat (Otocolobus manul) and domestic cat (Felis catus)) and six species of their potential prey was studied. Blood serum was analyzed for the presence of antibodies to the pathogens by enzyme immunoassay. The occurrence pattern of influenza A virus in manuls was the largest among tested pathogens (22%, n = 18). In this case, positive animals were not discovered among domestic cats. Antibodies against Coxiella burnetii were registered only in domestic cats (3.6%, n = 55). Antibodies against Toxoplasma gondii were found in wild and domestic animals: domestic cats (14.7%, n = 61), Pallas’ cats (9.1%, n = 18), and their prey (3.7%, n = 273). The occurrence of Trichinella sp. was comparatively low in domestic cats (1.6%, n = 61); among prey, antibodies to the parasite were found only in one species, the transbaikal hamster (Cricetulus pseudogriseus) (10.9%, n = 119).

It was shown previously that the Mongolian hamster (Allocricetulus curtatus) is a mammalian species with irregular short hibernation. The purpose of the present study was to determine how this status affects seasonal changes in the biochemical and hematological parameters in A. curtatus males under a natural temperature and light regime. It was found that a reduction in circulating white blood cells, specifically lymphocytes, neutrophils, eosinophils, basophils, and monocytes, occurred in-winter. and bilirubin levels increased in spring. These characteristics make Mongolian hamsters closer to the true hibernating species. At the same time, the character of seasonal changes in the number of red blood cells, glucose, total protein, creatinine, and albumin is closer to species with torpor.

Based on the locations reported over 15 months from the satellite GPS-collar of Amur leopard female, we estimated the size of its home range, the time of parturition, the location of dens, and hunting sites for large prey. The successive changes in the size and location of the home range and the core area during 30-day periods were traced. The home range remains stable, when the female moves without cubs outside the estrus period. During estrus and pregnancy, the size of the home range and the core area increases, and the core area is displaced. After the birth, the sizes of the home range and core area are sharply reduced. After the weaning of the Amur leopard female leaves the den and begins to move across the home range, the sizes of the range and the core area start to increase.

The behavior of female polar bears with cubs in an isolated terrestrial area of Alexandra Land Island (Franz Josef Land Archipelago) was analyzed in the fall of 2011 in an ice-free period using Argos satellite telemetry and the data of ground observations. The size and structure of their home ranges and selection of their habitats have been estimated; the differences in behavior of tagged animals have been analyzed.

To better understand the spatial structure of Amur tigers (Panthera tigris altaica) at the southern edge of their range we fitted 14 tigers (6♀♀ and 8♂♂) with 15 GPS-Argos collars between 2008 and 2011 in 2 study sites: the Ussuriskii Reserve of southern Sikhote-Alin and the Land of the Leopard National Park in southwest Primorye, Russian Far East. Fixed kernel estimates of male home ranges were larger than those of female home ranges (P < 0.05 [mean 95% fixed kernel(♀) = 401 ± 205 km(2) ; mean 95% fixed kernel(♂) = 778 ± 267 km(2)]). The home range size of females varied greatly, but on average was similar to estimates derived from earlier work further north. Low overlap of adjacent home ranges suggested that females retained exclusive territories. Real core areas of females overlapped only slightly, and remained stable over multiple years. The home ranges of adult males were smaller than those of males to the north, and in contrast to previous studies, high overlap among males indicated the absence of territoriality. Nonetheless, real core areas of males did not overlap, suggesting some spatial separation. In comparison to other tiger populations and other areas of the Russian Far East, the sex ratio in our 2 study areas was highly skewed towards males. We believe this skewed sex ratio resulted in the dissolution of territoriality of males due to an inability to defend individual females, with males resorting to scramble competition for mates. Continued monitoring of these sites to determine whether shifts in the sex ratio might result in a return to male territoriality would provide confirmation of our tentative hypothesis.

Based on data from camera traps installed throughout the model territory in southwest Primorye, information was received during an annual cycle on the presence of individually identified Amur leopards in the area of study. Analysis of the data using a combination of different techniques has determined the mutual spatial arrangement and sizes of approximated home ranges for both male and female leopards. The dataset of individually identified animals proves sufficient in describing the social organization of the studied group of Amur leopard using the spatial overlapping of individual home ranges as a characteristic of social relationships. Each individual home range overlaps with several home ranges belonging to both individuals of the opposite and same sex, with the overlapped portion larger in males than in females.

Analysis of serum prevalence of antibodies to six pathogens was performed in 26 polar bears from the Barents Sea population. Animals seropositive for the viruses of pseudorabies, canine distemper, and influenza A, Dirofilaria sp., Trichinella spiralis, and Toxoplasma gondii were revealed, with prevalence of antibodies to T. spiralis being the highest. Most of them were adult bears, while cubs (under 1 year of age) proved to be seronegative for all pathogens.

For the first time, the genetic structure of a population of Amur leopards (Panthera pardus orientalis) in southwest Primorie was analyzed in detail. In 2010–2012, 23 individuals were identified individually. It was shown that the studied microsatellite markers are suitable for individual identification of leopards, monitoring the population numbers, and creating a unified database of genetic profiles of this species to solve research and nature-conservation tasks.

Analysis of the seasonal dynamics of body weight and steroid hormones (cortisol, progesterone, and testosterone), the pattern of hypothermia, and basic reproductive parameters has been performed in the Mongolian hamster (Allocricetulus curtatus), a poorly studied rodent species inhabiting areas with a sharply continental climate. The results show that torpor bouts take place in wintering animals. Changes in body weight during the autumn-winter season are insignificant. The pattern of fluctuations in the levels of sex steroids and cortisol is similar to that in dwarf hamsters of the genus Phodopus. Seasonal features in the dynamics of basal cortisol level differentiate A. curtatus from the closely related Eversmann’s hamster (A. eversmanni), which may be due to differences in the social structure of these species.

Changes in diestrous female blood plasma progesterone, estradiol, and cortisol in response to odors of urine and midventral gland secretion (MVGS) of conspecific males during different seasons have been studied in the desert hamster (Phodopus roborowskii and Djungarian hamster (P. sungorus). In desert hamster females, a statistically significant (p ≤ 0.05) increase in the plasma hormonal level was observed: for progesterone in response to conspecific male MGVS in all seasons except winter, and to conspecific male urine in spring and summer; for cortisol in response to male MVGS and urine in all seasons except spring; and for estradiol in response to male MGVS in autumn. Djungarian hamster females demonstrated a statistically significant increase in the plasma progesterone level in response to conspecific male MVGS and urine in winter and summer, and no response to the estradiol and cortisol level for both odors in all seasons. The results showed important differences in the physiological response to odors of conspecific males between females of two species of dwarf hamsters.

In all felid species, females are able to mate with several males during the estrus period. The pro� miscuity mating system is the most common for solitary species with large home ranges, because females are widely distributed over the territory and males move actively in search of receptive females, defending them over the whole or some stages of the estrus period. In this situation, it is difficult for a male to be the only one mating with a female. Thus, the latter is able to mate with several males. Mating with several males is usually considered an opportunity to improve the quality of offspring. Nevertheless, the influence of the mating sys� tem upon reproductive success in felids is still not fully understood. It is well known that mating with several individuals in rodents with induced ovulation favors reproductive success in females, increases the reproduc� tive efforts of males, and reduces embryo loss. These things have been studied little in carnivores. The goal of this article is to analyze the spatial organization and behavior associated with the mating strategies of felids, and to consider differences in the reproductive success of felids under various mating strategies.

The possibility of application of satellite collars to the study of home range and activity of Amur tigers has been analyzed. The possibility of obtaining information about the size and structure of a home range, discerning the home range core areas, seasonal changes in the use of space by tigers, and collecting detailed data on animals’ activity and characteristics of the use of different elements of landscape and terrain has been demonstrated. In contrast to VHF transmitters, satellite collars allow tigers to be tracked even in the cases of very long travels.

A noninvasive evaluation method of hypothalamo-pituitary-adrenals axis (HPA) activity in the Siberian tiger was verified. Comparison of the activity level of HPA in Siberian tigers in the wild and in captivity, and their alterations over the year was carried out. Significant seasonal differences between activity levels of HPA in tigers in captivity were not found. In the wild, this level was significantly higher, reaching the maximum from November to January, which can be related with an unfavorable influence on tigers in low temperatures and deep snow cover.

ELISA with antibodies to corticosterone was used to evaluate the possibility of estimating the level of adrenocortical activity in male bank voles, Myodes glareolus (Rodentia, Cricetidae), by determining the concentration of immunoreactive steroids (IRS) in their feces. The binding curves of dilutions of the corticosterone standard and the extracts from dried feces were shown to be parallel. The corticosteroid response was evoked by ACTH injection, blood sampling, or immobilization. The response to ACTH injection was highly significant both in the blood in and fecal samples (a delayed response after 4 h), with daily variation in the IRS level being insignificant. In the case of blood sampling, the increased level of fecal IRS was recorded after 4 h and remained high after 8 h. Immobilization did not result in any significant increase in blood corticosterone or fecal IRS level. Individual baseline concentrations of fecal IRS levels were found to be highly repeatable between days. Thus, the antibodies to corticosterone used in this study (IZW, Berlin, Germany) proved effective for the assessment of stress by measuring fecal IRS in bank voles.

To develop a reliable approach to pregnancy diagnosis in sables based on noninvasive methods of hormonal status assessment, the concentrations of immunoreactive compounds (IRC) binding with antibodies to progesterone have been measured in the feces of females at different stages of the reproductive cycle. The results show that this concentration is higher in truly pregnant than in mated but nonreproducing females. An increase in the IRC concentration relative to its individual baseline level may be regarded as a reliable indication of true pregnancy.

This study was based on data on the feeding of the chum salmon Oncorhynchus keta sampled at daily stations in areas of the Navarin Shelf and Aleutian Basin in the Bering Sea in August and September 2004. The food composition and daily dynamics of chum feeding were investigated. The rate of food evacuation from the stomach and the amount of the daily diet were estimated. The distinctions in the feeding patterns of chum sampled from different areas were considered. In the Navarin Shelf area the chumis prey were primarily nekton species (mostly Alaskan pollack underyearlings) and the amount of the daily diet for chum of various size groups was 1.8–3.8% of their body weight. In the deep-water Aleutian Basin, the daily dynamics of chum feeding depended on migration of euphausiids, amphipods and mesopelagic fishes to the surface water layers of epipelagics during the night. The daily ration for chum that fed mainly on plankton did not exceed 2.6–2.8% of their body weight in August and 1.2–2.5% in September.

The effect of long-term exposure to natural excretions of the European polecat on the morphological parameters and hormonal status of adult male Campbell hamsters (Phodopus campbelli) and dwarf hamsters (Ph. sungorus) was studied. Exposure to volatile components of natural excreta of a potential predator did not have any significant effect on hamsters. The combined influence of volatile and nonvolatile components of the polecat’s excretions caused physiological stress in Ph. campbelli, while in Ph. sungorus, on the contrary, an increase in thymus weight and the plasma testosterone level was recorded.

Changes in male blood plasma testosterone and cortisol in response to exposure to scent marks (urine and midventral gland secretion, MVGS) of conspecific males and diestrous females in different seasons have been studied in the desert hamster (Phodopus roborovskii), a species whose ecological features are poorly known. The results show that a significant increase in the plasma testosterone level is observed in winter (only to female MVGS), spring (to female MVGS and urine), and summer (to female urine), but not in autumn. The level of plasma cortisol significantly increases only in response to female urine in spring and male MVGS in summer.

The quantities of consumed food and water, quantity and moisture contents of faeces as well as quantity and concentration of excreted urine were determined in representatives of Martes—European pine marten (M. martes) and sable (M. zibellina)—as well as in polecat (Mustela putorius). Under the same cage conditions and free access to food, all three species have similar energy value of their daily diet. However, the level of drinking water consumption and the ratio between the daily total water and energy intake was reliably higher in both Martes species than in polecat. In addition, both marten and sable featured much higher rate of evaporation loss in the overall water balance and, consequently, a higher quantity of heat dissipated with evaporation as compared to polecat. Comparison of the obtained and previous data (Sokolov et al., 1995; Rozhnov, 1991) allowed us to propose that the mentioned differences are specific for representatives of Martes and Mustela genera irrespective of ecological specialization of particular species.

The critically endangered population of Far Eastern leopards ( Panthera pardus orientalis) may number as few as 60 individuals and is at risk from stochastic processes such as infectious disease. During May 2015, a case of canine distemper virus (CDV) was diagnosed in a wild leopard exhibiting severe neurologic disease in the Russian territory of Primorskii Krai. Amplified sequences of the CDV hemagglutinin gene and phosphoprotein gene aligned within the Arctic-like clade of CDV, which includes viruses from elsewhere in Russia, China, Europe, and North America. Histologic examination of cerebral tissue revealed perivascular lymphoid cuffing and demyelination of the white matter consistent with CDV infection. Neutralizing antibodies against CDV were detected in archived serum from two wild Far Eastern leopards sampled during 1993-94, confirming previous exposure in the population. This leopard population is likely too small to maintain circulation of CDV, suggesting that infections arise from spillover from more-abundant domestic or wild carnivore reservoirs. Increasing the population size and establishment of additional populations of leopards would be important steps toward securing the future of this subspecies and reducing the risk posed by future outbreaks of CDV or other infectious diseases.

Based on the data on feeding ecology of common species of zooplankton, the main trophic groups of plankton of the southern Kuril region are identified. These are phytophages, zoophages, and omnivores. The interannual dynamics of trophic characteristics of the plankton community are examined. Predatory plankton significantly dominated in 1992–1994; however, in 1995–1996 its biomass decreased markedly. The biomass dynamics of predatory and nonpredatory zooplankton, as well as changes in the structure of nonpredatory zoolankton, suggest structural changes in the planktonic community.

The Far East leopard (Panthera pardus orientalis) is the rarest subspecies of cats (Felidae) on Earth. Its his� toric range embraces the northeast of China, the Korean Peninsula, and the southern part of Primorskii krai of Russia [1]. At the present time, only a small population of Far East leopard has retained in the southwest of Primorye and in adjacent regions of China. Although the population of this subspecies has remained relatively stable throughout several decades [2], very small numbers (20–40 individuals) and a low genetic diversity [3] make this species extremely vul� nerable. In addition, Far East leopard dwells in the most densely inhabited regions of Primorye and undergoes a strong impact related not only to illegal hunt for the predator and its prey, but also to the rec� reation load and disturbance because of a dense net� work of motor roads. For successful preservation of Far East leopard, detailed data on the state of its population and data on the impact of environmental factors on the physiolog� ical state of animals in nature are needed. One of approaches to the characteristic of the physiological state of animals is assessment of their hormonal status, mainly the level of glucocorticoids. Glucocorticoid hormones (cortisol and corticoster� one) play the leading role in the maintenance of homeostasis and in the energy exchange in mammals. An increase in the level of glucocorticoids leads to an increase in the concentration of glucose and triggers processes of gluconeogenesis and catabolism of pro� teins. This enables the animal to mobilize body resources in situations related to seasonal changes in the behavior of animals (for instance, at the onset of the reproductive season) and food accessibility, and to

Over the last decades the phylogeography and genetic structure of a multitude of species inhabiting Europe and North America have been described. The flora and fauna of the vast landmasses of north-eastern Eurasia are still largely unexplored in this respect. The Eurasian lynx is a large felid that is relatively abundant over much of the Russian sub-continent and the adjoining countries. Analyzing 148 museum specimens collected throughout its range over the last 150 years we have described the large-scale genetic structuring in this highly mobile species. We have investigated the spatial genetic patterns using mitochondrial DNA sequences (D-loop and cytochrome b) and 11 microsatellite loci, and describe three phylogenetic clades and a clear structuring along an east-west gradient. The most likely scenario is that the contemporary Eurasian lynx populations originated in central Asia and that parts of Europe were inhabited by lynx during the Pleistocene. After the Last Glacial Maximum (LGM) range expansions lead to colonization of north-western Siberia and Scandinavia from the Caucasus and north-eastern Siberia from a refugium further east. No evidence of a Berinigan refugium could be detected in our data. We observed restricted gene flow and suggest that future studies of the Eurasian lynx explore to what extent the contemporary population structure may be explained by ecological variables.

A noninvasive evaluation method of hypothalamo-pituitary-adrenals axis (HPA) activity in the Siberian tiger was verified. Comparison of the activity level of HPA in Siberian tigers in the wild and in captivity, and their alterations over the year was carried out. Significant seasonal deviations between activity levels of HPA in tigers in captivity were not found. In the wild, this level was significantly higher, reaching the maximum from November to January, which can be related with an unfavorable influence on tigers in low temperatures and deep snow cover.

The prevalence of infectious diseases in wild and feral carnivores is poorly known in Primorsky Krai, where rare species such as the Amur tiger and the Far East leopard roam. In this study we evaluated the prevalence of seropositivity in feral (cats, dogs) and wild (raccoon dog, badger, American mink, Far Eastern wild cat) carnivores to various pathogens: distemper virus, parvovirus, feline immunodeficiency and feline leukemia virus, feline coronavirus, Toxoplasma gondii, Mycoplasma sp., and Chlamydia sp. It was shown that seropositivity occurred significantly more frequent in feral animals than in wild ones. The highest percentage of seropositive animals was observed in feral dogs. It is these diseases that can be dangerous for the Amur tiger and the Far East leopard, thus affecting their populations.

The importance of chemical signals as precopulatory isolating mechanisms in different taxa of the Mus musculus species group was investigated. In laboratory conditions two experiments were conducted: preference of urine odors in a two-choice situation and sexual activation of males in response to homo- and heterospecific estrous females. Individuals of sympatric species distinguished between the urine odors of con- and heterospecifics. Both males and females investigated conspecific urine odors more than heterospecific odors in tests with a variety of heterospecific urines. During development the time of appearance of species-specific characteristic of urine odors is about 17 days of age. The physiological isolating mechanism in Mus musculus musculus and M. spicilegus may be the species-specific hormonal response of males to exposure to estrous females.