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The development of industry and agriculture and the continuous growth of human population on Earth have dramatically increased anthropogenic pressure on natural ecosystems and wildlife. As a result, fragmentation of the natural habitats and the decrease in genetic diversity in these populations increase the probability of reproduction with genetically closely related individuals (inbreeding). However, the effect of inbreeding in felids has been studied insufficiently and data are scarce. We decided to study the effect of inbreeding on kittens’ body mass in captivity in the Eurasian lynx (Lynx lynx) colony which we keep near Moscow to study behavior and reproductive physiology of this species. This study analyzed the data on lynx kittens’ body mass in inbred and non-inbred litters. Newborn kittens’ body mass correlated negatively with the parents’ inbreeding coefficient. Inbred parents had smaller kittens at birth in comparison with non-inbred ones. These differences disappeared when kittens reached 2 months of age. It is probable that this correlates with the maternal effect (higher investment in smaller kittens) and changes in the diet of kittens. more...

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. more...

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. more...

Since blood cells count is the most important indicator of animals' physiological status, we investigated the effects of age, litter size, and multiple paternity on the total number of white blood cells, the number of their individual types (lymphocytes, neutrophils, eosinophils, monocytes), and the ratio of neutrophils to lymphocytes in domestic cat during early postnatal ontogenesis. The study was conducted on kittens living in outdoor conditions, aged from birth to 6 months. The number of white blood cells was evaluated using a hemoanalyzer, the leukocyte formula and the proportion of cell types were determined manually from blood smears. Age significantly affected the number of leukocytes in the first 3 months of kittens' age. The number and proportion of neutrophils were the highest after birth and gradually decreased during the first month. Lymphocytes number, on the contrary, increased during this period. Monocytes and eosinophils increased in number in the first 2 months. The litter size affected the number of leukocytes and neutrophils in the first 2 months of life, their number being significantly higher in kittens from the small litters than from the large ones. In kittens from the litters with multiple paternity, the number of leukocytes and the proportion of neutrophils was higher than in litters from a single male. Thus, age, litter size and type of paternity may affect the hematological indices in domestic cats, which must be taken into account during the estimation of the health status of kittens in domestic and wild cats. more...

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. more...

Seroprevalence to nine different virus pathogens was estimated for Russian big cats (Amur tiger (Panthera tigris altaica Temminck, 1844) and far-eastern leopard (Panthera pardus orientalis (Schiegel, 1857))) in Southern Primorie, Russia (n = 25), in 2008–2016. Serum samples from smaller cats (Eurasian lynx (Lynx lynx (Linnaeus, 1758)) and far-eastern wildcat (leopard cat) (Prionailurus bengalensis euptilurus (Elliot, 1871))) were also tested for these pathogens (n = 19) during the same period. Felids of Russian Southern Primorie showed seroprevalence to eight out of nine tested pathogens, including highly dangerous feline immunodeficiency virus, feline leukemia virus, and canine distemper virus. Antibodies to feline panleukopenia virus were found to be much more widespread in cats (45%) than antibodies to any other virus. They were detected in samples taken from tigers, leopards, and far-eastern wildcats but not lynxes. Antibodies to pseudorabies virus were detected only in Amur tiger (29%), whose main prey is the most common carrier of the virus (wild boar), unlike for the other studied cats’ species. more...

The Russian Far East is a unique location that may be considered a hot spot of biodiversity in Russia. In 2010, a new illuminated highway for high-speed traffic was built on its territory. The aim of this study was to evaluate the impact of this highway on the distribution and activity of various mammalian species. We set up camera traps in five lines near the road and obtained photos of 1372 passes of various animals. In total, 15 species of wild mammals were captured by camera traps. Animals preferred to stay far away from the road. This highway became a serious barrier separating the local populations of ungulates and carnivores. Only domestic animals and Amur wild cat used the underpasses more often than other areas. The distance from the road did not affect the daily activity of the mammals. more...

Lactation is the most energetically expensive component of maternal care in mammals. Increased reproductive investment can lead to physiological stress for the mothers, based on the exhaustion of energy resources and increase in glucocorticoids level. This study aimed to estimate the changes in cortisol concentrations during lactation in domestic cats and compared the differences among litter sizes. Eleven females gave birth to 27 litters, which were divided in two groups&mdash, small (1&ndash, 3 kittens) and large (4&ndash, 7 kittens) litters. Blood samples were collected from each female before mating, after parturition, at 4 and 8 weeks of lactation. We showed that the cortisol level in females changed significantly during lactation&mdash, the highest concentrations were observed at the peak of lactation at 4 weeks. Cortisol levels varied significantly among females but did not depend on their maternal experience. We also revealed that there were no differences in cortisol levels between females with small and large litters, but at 4 weeks of lactation, the hormone concentrations were higher in females with small litters. It is likely that these females initially invested less in reproduction, giving birth to fewer offspring. more...

Serum prevalence to six different non-viral pathogens was estimated for big Russian cats (Amur tiger (Panthera tigris altaica) and the Far Eastern leopard (Panthera pardus orientalis)) in Southern Primorye, Russia (n = 26) in 2008–2016. Serum samples from smaller cats (Eurasian lynx (Lynx lynx) and Far Eastern wildcat (Prionailurus bengalensis euptilurus)) were also tested for these pathogens (n = 28) during the same period. Felids of Russian Southern Primorye showed serum prevalence to five out of six tested pathogens. Antibodies to Candida sp. and Trichinella sp. were found to be much more widespread in cats (47% and 42%) than antibodies to other tested pathogens (20% and less). Large cats demonstrated a higher serum prevalence to these pathogens than smaller ones. We did not detect animals seropositive to Coxiella burnetii. more...

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. more...

Social play fulfills an important function in creating and maintaining relations between siblings. However, its relationship with the intralitter social processes is poorly understood. It was noticed that, in Eurasian lynx (Lynx lynx) litters, sex differences in social play are absent in the first 2-3 months of life. Itwas found that the most intense periods of play behavior (at an age of 9 and 1-2 weeks) coincide with periods of aggression. Gradual change in play interactions, which require close physical contact by play elements with increased motor activity, are described. This reflects the changes in the relevance of certain skills of lynx cubs as they grow older. more...

In all Felidae species, females are able to mate with several males during the estrus. Promiscuity mating system is the most typical of the solitary living species that have large home ranges. Females are usually widely distributed over the area and males move actively searching for the receptive females and defending them during the estrus period. Mating with few males is usually considered as a possibility to improve the quality of the offspring. In this article, some characteristics of home range use, marking and acoustic activity, traits of physiology which may result in promiscuity mating in felids are considered. An adaptive significance of mating few males is also discussed. more...

Social play fulfills an important function in creating and maintaining relations between siblings. However, its relationship with the intralitter social processes is poorly understood. It was noticed that, in Eurasian lynx (Lynx lynx) litters, sex differences in social play are absent in the first 2-3 months of life. Itwas found that the most intense periods of play behavior (at an age of 9 and 1-2 weeks) coincide with periods of aggression. Gradual change in play interactions, which require close physical contact by play elements with increased motor activity, are described. This reflects the changes in the relevance of certain skills of lynx cubs as they grow older. more...