Mariya N. Erofeeva

Research on endocrine patterns associated with reproduction and lactation in felids has focused mainly on rare or endangered species and remains limited in the domestic cat (Felis catus). Using a non-invasive longitudinal approach, we measured faecal glucocorticoid, progesterone, and testosterone metabolites (fGCm, fPm, and fTm) in nine females before mating and during three months of lactation, examining associations with litter characteristics and kitten survival. Lactational concentrations were expressed relative to each female’s median baseline, while baseline concentrations were analysed separately. Relative fGCm concentrations were negatively associated with the number of surviving kittens but not with litter losses. Relative fPm concentrations were positively associated with both fGCm and fTm, whereas the fGCm–fTm relationship did not reach statistical significance. Relative fPm concentrations were lower in the third than in the first month of lactation, while fTm showed a similar decreasing tendency. Baseline fGCm and fPm were not associated with reproductive parameters. Median baseline fTm showed a negative, non-significant relationship with first-month kitten survival. These findings indicate distinct temporal patterns and associations among steroid metabolites, while the relationship between baseline fTm and kitten survival requires validation in larger datasets.

For felids of the genus Prionailurus, data on call types and the spectral structure of the calls are scarce. We investigated, for the first time, call types of the Amur subspecies of the leopard cat Prionailurus bengalensis euptilurus. We analysed acoustic parameters and nonlinear vocal phenomena in the chirr contact calls of a captive female and report the ontogenetic changes in three call types (meow, chirp, and meow-chirr) of her five cubs between two weeks and three months of age. In addition, we describe the overall anatomy of the larynx of an adult female Amur leopard cat for comparison with the vocal anatomy of the family Felidae. We discuss the similarity of the acoustic structure of the chirr of the female Amur leopard cat with murmur call type of adult female rusty-spotted cats P. rubiginosus and the chirr call type of female cheetahs Acinonyx jubatus, functioning for mother-offspring communication. We discuss the anatomical features distinctive of those of “roaring cats” in the genus Panthera and similar to those in small felids. We also discuss that chirr and meow-chirr may serve for discriminating vocalizations of wild-living Amur leopard cats from calls of sympatric felids during passive acoustic monitoring in the wild. Published online 2 June, 2026; Print publication 31 October, 2026

We investigated the ontogenetic development of vocal repertoire in cubs of the Eurasian lynx Lynx lynx from birth until 3 months of age. Calls of four litters of captive lynxes kept in large outdoor enclosures were recorded within natal dens and during activities near the dens automatically and manually. We confirmed early findings that Eurasian lynx cubs are capable of producing biphonic calls with two independent fundamental frequencies in call spectra, the low (f0) and the high (g0), potentially created with two different sound sources. In the vocal repertoire of cub Eurasian lynxes, we subdivided 3 structural classes, which included in total 10 call types. The structural classes were classified based on presence/absence of one or two fundamental frequencies: two low-frequency call types with f0-singly, four high-frequency call types with g0-singly, and four biphonic call types with both f0 and g0. The f0 ranged from 0.17 kHz to 1.19 kHz, the g0 ranged from 0.21 kHz to 7.19 kHz among different call types. All the 10 calls types were present in Eurasian lynx cubs starting from the first week of age; no one of these call types disappeared to 3 months of age and no additional call types appeared to this age. Assignment the calls to the predicted call type with discriminant analysis was 94.5% for the low-frequency calls, 89.3% for the high-frequency calls, and 67.8% for the biphonic calls, thus suggesting robust classification. Acoustic parameters of both f0 and g0 frequencies decreased with age. We discuss the ontogeny of g0 in biphonic calls of mammals and the high acoustic complexity of vocal repertoire of Eurasian lynx cubs in relation to evolution of vocal traits across the studied Felidae species.

Clinical blood analysis is considered not only a method of assessing the health status of individuals, but also their fitness and welfare, although the interpretation of the obtained data is complicated by the combined influence of various factors. For most wild carnivore species, there is insufficient information about the effect of environmental factors on hematological parameters. Mammals in the Far East are exposed to hard seasonal climate changes, and therefore have physiological adaptations that enable them to survive the cold season. The aim of this study was to estimate the hematological parameters of three widespread species of medium carnivorous mammals in this region, namely Meles leucurus amurensis, Prionailurus bengalensis euptilura, and Nyctereutes procyonoides ussuriensis, taking into account such factors as sex, age and season in the Ussuriisky State Nature Reserve (Russia), as well as to identify the most informative blood indicators of the animal physiological status. In spring and autumn of 2014–2023, blood samples were collected from 103 individuals of the studied carnivores. The animals were captured, immobilised, blood-sampled and released in the wild at the capture site. The number of leucocytes was counted in the field, and their ratio was detected on the blood smears in the lab. The absence of sex differences and the presence of age differences in the studied species were revealed, which corresponds to the already known data on the parameters of mammalian blood. In spring, Nyctereutes procyonoides ussuriensis had higher leucocyte count (14.77 ± 1.76 mln/ml and 12.33 ± 1.08 mln/ml (hereinafter, in spring vs. autumn, respectively)), the ratio of neutrophils to lymphocytes (4.87 ± 0.47 and 3.02 ± 0.28), and the percentage of segmented neutrophils (73.12 ± 1.77% and 62.95 ± 2.29%), and the lower percentage of lymphocytes (20.35 ± 1.45% and 25.64 ± 1.49%) compared to autumn. Similar blood patterns were observed in two other species. This may be the result of a decrease in body mass and poor condition of animals, i.e. physiological stress after a long winter period and a lack of food resources. In addition, Nyctereutes procyonoides ussuriensis had higher percentages of eosinophils, basophils, and band neutrophils (7.85 ± 1.61%, 3.69 ± 1.26%, 2.15 ± 0.34%, respectively) than Meles leucurus amurensis (2.55 ± 1.09%, 0.45 ± 0.17%, 0.55 ± 0.18%, respectively) and Prionailurus bengalensis euptilura (1.48 ± 0.59%, 0.30 ± 0.16%, 1.74 ± 0.47%, respectively). These differences are probably determined by the biological characteristics of Nyctereutes procyonoides ussuriensis, since this species is an ideal host and carrier of various diseases, and it also has specific morphological features of blood cells. Thus, our results demonstrate the importance of systematic blood tests and the necessity of considering both species-specific characteristics and environmental factors for assessing animal health.

This study investigates the frequency, temporal and power parameters in 11 (5 males, 6 females) captive feral domestic cats Felis silvestris catus, vocalising in their individual outdoor enclosures during the mating season. Discriminant function analysis (DFA) classified the meows to correct callers with 79.2% accuracy, which exceeded the chance level of 22.9 ± 2.8%, calculated with permutation test. Male meows were lower-frequency, with the maximum fundamental frequency of 0.37 ± 0.05 kHz vs 0.61 ± 0.16 kHz in females. Sex differences in the maximum, beginning and end fundamental frequencies varied from 32 to 39%, depending on acoustic parameter. The DFA classified the meows to correct sex with accuracy of 88.0%, which exceeded the chance level of 58.2 ± 3.1%. We discuss that the meows encode information about individual identity and sex and that acoustic differences in frequency parameters of the meows exceed sexual dimorphism of body size in domestic cat.

Hair can be a useful matrix to examine the hormonal status of an animal, although it is difficult to correlate the results to a specific time point. The aim of this study was to evaluate seasonal changes in cortisol and testosterone levels in the hair of four feline species (lynx, Lynx lynx, n = 8; Amur wildcat, Prionailurus bengalensis euptilurus, n = 8; caracal, Caracal caracal, n = 6 and domestic cat, Felis catus, n = 17) with different breeding strategies. Animals of both sexes were sampled over the year, once per season (every three months), and the concentrations of hair testosterone and cortisol were measured by EIA. Both hormones showed annual dynamic changes, which coincided with the reproductive seasonality of the studied species. Sexual differences in testosterone level were found only during the mating season (spring for lynx and Amur wildcats, spring–summer for domestic cats), when testosterone levels were higher in males than in females. Cortisol levels were higher in males than in females in domestic cats and Amur wildcat, but also only during the mating season. Seasonal increases in testosterone were observed in three seasonal breeders (lynx, Amur wildcat and domestic cat) but not in caracal, which had high testosterone levels over the whole year. In lynx and Amur wildcat, it decreased sharply in the summer. Cortisol levels increased during the mating period in domestic cat males and lynx of both sexes; in caracal, an increase in cortisol was related to the transfer of animals to smaller winter cages. Measurements of steroids in hair can provide a reliable method for evaluating the reproductive status and the activity of the hypothalamus–pituitary–adrenal axis in several felid species.