Cricetus Research Articles

Common hamster (Cricetus cricetus, Cricetidae, Rodentia) in the Simferopol city: Population dynamics and survival outlook

In the Simferopol city, the numbers of Common hamsters began to grow since the early 1970s and reached a peak in the mid-1990s. The abundance was kept at a high level until 2014–2015 and then began to decline. In multi-storey residential development areas, steady settlements of hamsters have now virtually disappeared, and even in large green areas (the City Park and Botanical Garden), the numbers dropped almost tenfold. One of the possible causes for this decline was cutting down shrubs and hedges, which began since 2016–2017. However, the population has also severe declined in areas with no such activities. Thus, the fate of the Simferopol hamster population is worrisome. Obviously, we are dealing with a multi-factor process which requires special studying, without which no estimating of population viability or developing of conservation measures are possible.

From Seasonality to Species Conservation: Chronobiological Research on European Hamsters in Strasbourg, France.

The first monograph on the European hamster from the Strasbourg region dates back to 1765. By the 1930s, a long and continuous chronobiological research tradition was established for this species, starting with the works of Charles Kayser, who published between 1938 and 1971. Another early key researcher in this area was Bernhard Canguilhem with publications from 1966 to 1999. From the 1980s onwards, "the Pévets," Paul Pévet and his wife, Mireille Masson-Pévet, gave new energy to European hamster research. They broadened the research scope from basic hibernation research to mechanistic studies of circannual rhythms and from physiological aspects to molecular details. One main underlying question in their research was the role of melatonin. Thanks to their enthusiasm and vision, the European hamster is today one of the best - if not the best - studied circannual species. At least 73 parameters are described to cycle. Thirty-two of them have been shown to be driven by a circannual clock. Moreover, ground-breaking advances in our understanding of the mechanistic of hibernation, circannual clock functioning, and its entrainment were made. With most of this research being conducted in Strasbourg, Paul Pévet was instrumental in providing the necessary resources that made these innovative and unconventional long-term animal studies possible, contributing to fundamental research and, ultimately, to species conservation.

Different types of marking behavior observed in the wild during the breeding period of the common hamster (Cricetus cricetus, cricetidae, rodentia)

Different types of marking behavior observed in the wild during the breeding period of the common hamster (Cricetus cricetus, cricetidae, rodentia)

Friend or foe? Engaging public can save the critically endangered common hamster (Cricetus cricetus)

AbstractThe common hamster (Cricetus cricetus) occupies a controversial position among mammals inhabiting agricultural areas, as it is possibly the only critically endangered species that is legally targeted by lethal control methods, making it a conflict‐generating pest. We surveyed various stakeholders, agrarian consultants, wildlife rangers, and residents for the first time in Hungary, with two interrelated questionnaires to obtain accurate information about hamster populations, and to learn about the participants knowledge of, and attitude toward hamsters in order to provide fundamental information for planning and strengthening social embeddedness. Additionally, we prepared the current distribution map of the hamster. Based on the relatively wide distribution and locally high abundance of the species, Hungary has a key role in hamster conservation. We identified several factors, which can contribute to successful species protection. The results indicated that more than 60% of the respondent's liked hamsters. In contrast, only a few residents considered hamsters in their settlement to be beneficial. Our results suggest that the hamster's reputation is disproportionately negative due to vaguely known perceptions of harm as compared with actual reported damage. This imbalance could be rectified through enhanced communication efforts. Improving the species' reputation is integral to effective species conservation initiatives. Current pest control practices (poisons and snap traps) kill the hamsters, even though 82% of the residents would prefer to keep the hamsters alive, conforming to conservation efforts. The results also indicated that the hamster could be a flagship species in Hungary. Knowledge of the protected status of the hamster predicted a positive attitude toward the species and related to nature conservation consciousness. We conclude that requirements of residents should be included in the species action plan along with the experts' knowledge, as this could contribute to successful, long‐term conservation of the hamster.

Some traits of ecology and demography in settlements of the common hamster (<i>cricetus cricetus</i>, cricetidae, rodentia) under different levels of environmental comfort in a Simferopol city park

The spatial and demographic structure of two common hamster settlements was studied in two adjacent areas in a park of Simferopol City, Crimea, one differing in a lower vegetation storey (protective factor) while the other in the frequency of human visits (disturbance factor). We counted environmental comfort as the sum of scores (on a ten-point scale) of safe conditions (positive value) and disturbance factors (negative value). A strong positive relation was found between environmental comfort and the following characteristics of the settlements: (a) the number of burrows per area unit; (b) a nonrandom number of aggregative burrows; and (c) the percentage of juveniles in the population. The seldom visited places with a dense cover of grass and bushes appear to be the most favorable habitats, yet these are not typical of an urban landscape. However, it is those places that seem to serve as the sources that support the existence of hamster populations in less favorable city territories. Preservation of such places is one of the essential factors determining the survival of urban populations of the hamster.

Under pressure: the Critically Endangered common hamster in Hungary reached an all-time demographic low in 2024

Under pressure: the Critically Endangered common hamster in Hungary reached an all-time demographic low in 2024

Threatened chronotopes: can chronobiology help endangered species?

Pittendrigh and Daan's 1976 article "Pacemaker structure: A clock for all seasons" marks the foundation of modern seasonal chronobiology. It proposed the internal coincidence model comprised of a Morning (M) and Evening (E) oscillator, which are coupled but synchronized separately by dawn and dusk. It has become an attractive model to explain the seasonal adaptation of circadian rhythms. Using the example of the European hamster, this article connects the classical entrainment concept to species decline and, ultimately, conservation concepts. Seasonality of this species is well studied and circannual rhythms have been described in at least 32 parameters. The European hamster is listed as critically endangered on the International Union for Conservation of Nature (IUCN) red list. Changes in the temporal structure of the environment (the chronotope) caused by climate change and light pollution might be responsible for the global decline. The article shows that classical chronobiological concepts such as the internal coincidence model (Pittendrigh and Daan Pittendrigh and Daan, J Comp Physiol [a] 106:333-355, 1976) are helpful to understand the (chronobiological) causes of the decline and can potentially support species conservation. Knowing the species' physiological limitations as well as its adaptation capacities can potentially prevent its extinction at a time when classical conservation concepts have reached their limits.

A validated LC–MS/MS method for simultaneous determination of key glucocorticoids in animal hair for applications in conservation biology

A new method for the determination of main glucocorticoids (cortisol, cortisone, and corticosterone) in hair by liquid chromatography-tandem mass spectrometry was developed. Glucocorticoids were extracted from hair shafts using methanol followed by solid-phase extraction. A validation test was performed using hair from three species of wild mammals with different body size (0.2–800 kg), lifestyle (terrestrial, burrowing and arboreal species), social organization (living in herds or solitary), and different predicted type of hair glucocorticoids: European bison (Bison bonasus), European hamster (Cricetus cricetus), and Eurasian red squirrel (Sciurus vulgaris). Regardless of the species evaluated, the method shows good linearity for all analytes accompanied by satisfactory accuracy (91–114%) and precision (RSD < 13%). Depending on the analyte and hair origin, the calculated limits of quantification were between 0.05 and 1.19 ng/mL, which corresponds to 1.28–31.51 pg/mg. Using cortisol and cortisone as examples, we have demonstrated that measuring multiple glucocorticoids simultaneously provides more comprehensive information than solely concentrating on one, thereby contributing to a more balanced and reliable interpretation of the acquired results. However, the utility of cortisol metabolites as markers of stress response in keratinized tissues should be substantiated by additional experimental studies on targeted animals. We posit that this paper could serve as a crucial catalyst to prompt such experiments.

Genetic differentiation within two large phylogroups of the common hamster (&lt;i&gt;Cricetus cricetus&lt;/i&gt;) (Cricetidae, Rodentia), the boundary between them, and the population abundance

clarification. In the course of our specially organized expedition, tissue samples of the common hamster were collected in 12 regions of Russia and Kazakhstan, including areas at the potential border of the ranges of phylogroups “A” and “E” (“Europe”). Analysis of the nucleotide sequences of the cytb gene of the captured animals has shown that the boundary between these phylogroups runs between Turinsk and Yekaterinburg, further between Chelyabinsk and Kurgan, between Omsk and Tatarsk, and turns to the south, leaving the village of Turgai and the town of Temirtau in the west and the village of Bayanaul in the east. The structure of territorial genetic clades belonging to phylogroups “A” and “E” and the history of their formation were also analyzed. Most of the detected territorial clades were formed during the Late Pleistocene and Holocene. The population dynamics of phylogroups “A” and “E” was analyzed and its decline was shown in 8 of the 12 surveyed regions.

From an Agrophile to a Synurbist: Settlement of the Common Hamster (Cricetus cricetus) into an Urban Environment

From an Agrophile to a Synurbist: Settlement of the Common Hamster (Cricetus cricetus) into an Urban Environment

Influence of Landscape Transformation and the Anxiety Factor on the Distribution of Burrows of the Common Hamster (Cricetus cricetus L., 1758) (Rodentia: Cricetidae) in the Conditions of the Park Zone of the City of Simferopol

Influence of Landscape Transformation and the Anxiety Factor on the Distribution of Burrows of the Common Hamster (Cricetus cricetus L., 1758) (Rodentia: Cricetidae) in the Conditions of the Park Zone of the City of Simferopol

Coordinating farms in collective agri-environmental schemes: the role of conditional incentives

Abstract This paper analyses data from a novel collective agri-environmental scheme (cAES) in Alsace, France, designed to protect the local European hamster population by motivating farmers to engage in habitat conservation measures. In contrast to typical conservation contracts that pay individual farmers based on their own performance, the cAES studied here pays farmers only when the percentage of land conserved by all farmers within a collective zone reaches a critical threshold. We find that the likelihood of participation is higher for farmers with a relatively large agricultural surface within the collective zone, increases with the number of farmers in a collective zone, and increases over time. Those with more land in the collective zone allocate more acreage to conservation. We define different contributor types and provide insight into the possible motives underlying contributions to collective conservation schemes.

Improving the success of reinforcement programs: effects of a two-week confinement in a field enclosure on the anti-predator behaviour of captive-bred European hamsters.

Captive breeding programs are an important pillar in biodiversity conservation, aiming to prevent the extinction of threatened species. However, the establishment of self-sustaining populations in the wild through the release of captive-bred animals is often hampered by a high mortality upon release. In this study, we investigated how a 2-week confinement period within a large field enclosure affected the anti-predator behaviour of 'naive' captive-bred hamsters and how potential modifications persisted over time. During three consecutive tests, hamsters were confronted with a moving predator model (a red fox mount, Vulpes vulpes) and their behaviour was filmed. After the initial round of confrontation with the predator model, one group of hamsters (field group) was released into a field enclosure protected from predators, while the other group (control) remained in their individual laboratory cages. After 2 weeks, hamsters from the field group were recaptured and individuals of both groups underwent a second confrontation test. A total of 1 month after their return from the field enclosure, field hamsters were subjected to a last confrontation test. Video analysis, investigating four behavioural variables, revealed that field hamsters significantly modified their behavioural response following the 2 weeks confinement in the enclosure, while this was not the case for control hamsters. In addition, most behavioural modifications in field hamsters persisted over 1 month, while others started to revert. We suggest that an appropriate pre-release period inside a field enclosure will enable naive (captive-bred) hamsters to develop an adequate anti-predator behaviour that will increase their immediate survival probability upon release into the wild. We believe that such measure will be of great importance for hamster conservation programs.

FROM AN AGROPHILE TO A SYNURBIST: HOW THE COMMON HAMSTER (&lt;i&gt;CRICETUS CRICETUS&lt;/i&gt;) IS SETTLING INTO THE URBAN ENVIRONMENT

In this review, using our own and published data, we discuss the processes that occur in populations of small mammals when they adapt to and master the urban environment, using the common hamster as an example. Originally, the common hamster was apparently associated with the forest-steppe zone, but with the development of agriculture, it became an agrophile, populating the outskirts of fields, which provided it with a good food base throughout the year. Changes in farming culture (fragmentary fields replaced with vast areas of arable land occupied by monocultures, the use of poisons and fertilizers) led to a shift in the ecological optimum of the species to areas occupied by gardens, kitchen gardens and urban ecosystems. This led to changes in the genetic structure of populations, a greater (compared to suburbs) diversity of alleles of the major histocompatibility complex responsible for resistance to pathogens, a reduced hibernation period up to its complete abandonment, and a reduced aggressiveness to conspecifics which allows for more burrows to be arranged in a limited space and for general food storages to be shared and consumed. The use of food wastes as an additional food resource by this species may have led to changes in its digestive and other systems. All of this has allowed the common hamster to successfully exist in an urbanized environment, despite the reduction in life expectancy due to many stressors (parasitic load, pollution etc.). It is assumed that not all of the above traits have been formed in the process of synurbization. Many adaptations acquired earlier, before urbanization, proved to be effective in its development of the urban environment. Obviously, the path taken by the common hamster from a non-commensal species to an agrophile, and finally a synurbist is not unique; many other species of mammals and birds have passed or are on this evolutionary path at the present time.

SEASONAL DYNAMICS OF THE DIET OF IMPERIAL EAGLES (&lt;i&gt;AQUILA HELIACA&lt;/i&gt;, ACCIPITRIDAE, ACCIPITRIFORMES) IN THE LEFT-BANK MIDDLE VOLGA REGION

The seasonal and between-year dynamics in the diet of a pair of Imperial eagles (Aquila heliaca) were observed at a nesting site on the left bank of Volga River in the Ulyanovsk Region, European Russia. The research covered three seasons (2019–2021) using an autonomous video surveillance system. During the research period, 555 prey objects brought by eagles to the nest were identified, these representing 30 taxa of wild vertebrates and four species of domestic animals, all from four vertebrate classes. The predominant prey objects were the Russet ground squirrel (Spermophilus major) (35%), the Rock pigeon (Columba livia) (22%), and the Common hamster (Cricetus cricetus) (14%). Rodents prevailed in nutrition during nest construction (April), hatching (May), and at the initial stages of feeding the chick(s) (June–July). The proportion of pigeons and corvines increased significantly in nutrition during the feeding period of grown-up chicks and fledglings (August–September). Raising two chicks compared to one chick led to an average of 1.5 times increase in food intake, mainly due to rodents.

Сезонные аспекты питания Поволжской популяции солнечных орлов в гнездовой период

Сезонные аспекты питания Поволжской популяции солнечных орлов в гнездовой период

Monitoring of the mammal fauna by studying owl pellets: a case of small mammals in protected areas of Podillia

Using owl pellets analysis to monitor mammals in protected areas makes it possible to accumulate a unique material to study the distribution and relative abundance of both common and rare species. Due to the ease of collecting and accumulating of pellets, this method helps to quickly obtain a large amount of material to monitor the changes in natural areas and objects during certain time intervals without interfering with the course of natural processes. The proportions of small-mammal species in the diet of most owls are representative of the proportions of species in their groups. Therefore, the pellet method can be used to organise monitoring of mammal species of natural regions. We analysed nearly 2000 pellets of several species of owls collected in Podillia in the course of the study. Pellets are mostly collected within protected areas. Small mammals form the basis of the diet of the studied species of owls. The diet of the short-eared owl is the most diverse, and it includes 18 species of small mammals. The common vole occurs the most often. The diet of other owl species is also diverse, in particular of the little owl, tawny owl, and eagle owl. As in the case of the short-eared owl, the main prey of the barn owl and grey owl is a common species—the common vole. The diet of the eagle owl, unlike others, is dominated by larger small-mammal species—brown rat, white-breasted hedgehog, and European hamster. In addition to common species, the analysis of owl pellets allows us to identify not only the most common, but also rare species, such as the European hamster, bicoloured shrew, lesser white-toothed shrew, and various bats. Therefore, the pellet method of research is highly effective in analysing the composition of the fauna and the structure of communities, of both prey and predator species. Owl pellet analysis is a valuable asset during small-mammal monitoring studies, and is especially useful for sampling of indicator small-mammal species during environmental impact assessments in protected areas. The method has considerable advantages compared to standard survey methods of small mammals— it does not require the removal of animals from the natural environment, which makes it relevant for use in protected areas.

Популяційна динаміка та розподіл за біотопами хом’яка (Cricetus cricetus) в Медоборах (Поділля)

The results of the surveys and data on biotopic distribution of common hamster burrows in the vicinity of the Medobory Nature Reserve were collected and summarised. In order to study the abundance and density of hamsters, two monitoring sites were established. The first is in the fields between the village of Butsyky and the town of Hrymailiv, and the second is on a farming field in the town of Hrymailiv, where since 2013 the number of common hamster burrows have been recorded in the autumn period of the year. Homestead plots and small-scale plantations of agricultural crops were surveyed using the transect method by one or two investigators. During nine years of research, 170 living burrows were found on the first site, which covers an area of about 10 hectares, and only 7 on the second site, which is located on a farm field. The majority of living burrows were recorded on crops of 3 to 4-year-old alfalfa. An increase in the number of burrows was observed in 2015 and 2019. Additional research was carried out in separate gardens with alfalfa in the vicinity of the town of Hrymailiv, the villages of Lezhanivka, Lychkivtsi, Zelene, and Paivka, and in farm fields, where 52 living burrows were recorded. Separate data were obtained from observation cards of reserve workers and by surveying the local population. The largest colony was found in the village of Lychkivtsi in 2021 in a garden with a four-year-old alfalfa plantation of 0.3 ha, and there were 16 settlements there (3 to 5 burrows per settlements). During nine years of observation, live animals were found only twice: in the village of Butsyky in 2013 (two individuals in a field in fodder beet crops) and near Lezhanivka in 2019 (one individual in a disced rapeseed field, during stork foraging). Usually, they are recorded dead: killed by predators or killed by motor vehicle collisions. Taking into account the distribution of burrows by biotopes, it is worth noting that the decline in the number of hamsters is the result of a decrease in agricultural land area suitable for their existence. The exception is the years 2019–2020, when their number began to increase rapidly, the cause of which could be the mass death of foxes that occurred as a result of poisoning by mouse-like rodents in farm fields in 2018, which served as their food base. As for the animals of the dark morph, their share in the population is no more than 10%, and they often become victims too, since their colouration is clearly visible in their living environs.

Influence of landscape transformation and anxiety factor on the distribution of burrows of the Common hamster (Cricetus cricetus L., 1758) (Rodentia: Cricetidae) in the conditions of the park zone of the city of Simferopol

Based on our analysis of long-term (2015–2021) observations carried out at a registration spot in the park named after Yu. A. Gagarin (Simferopol, Crimea), patterns were revealed in the spatial distribution of burrows of the Common hamster (Cricetus cricetus L., 1758) depending on the state of the tree and shrub layer, as well as disturbance factors. It is shown that the leading factor influencing the spatial distribution of burrows is the location of trees, and the total number of burrows is mainly affected by the projective covering by shrubs; these factors were revealed as a result of cluster analysis for the spatial-geographical formulation of the problem and crosscorrelation analysis. It is assumed that the use of spatial modeling makes it possible to identify environmental factors, including plant communities, influencing the choice and exploitation of microhabitats by animals, as well as to find approaches to the analysis of the implementation of behavioral patterns during the development and exploitation of a habitat.

Use of Internet Resources to Estimate the Abundance of Species in Contact with Humans (Using the Common Hamster (Cricetus cricetus L., 1758, Cricetidae, Rodentia) as an Example)

Use of Internet Resources to Estimate the Abundance of Species in Contact with Humans (Using the Common Hamster (Cricetus cricetus L., 1758, Cricetidae, Rodentia) as an Example)