The European hamster (Cricetus cricetus) in captivity: keeping and breeding experience

Hamsters have long been considered agricultural pests and their abundance has been controlled. Now in many countries they are recognized as rare and endangered species that are at a risk of extinction. Among conservation measures to preserve and restore the population of many species is to gain experience in their keeping and reproduction in captivity. The experiments were carried out with hamsters obtained from the Crimea at different times. The keeping experience of hamsters in an ordinary residential apartment and the specifics of domestication of the animals caught in the nature are described. Their captivity, cage arrangement, nutrition, reproduction, specifics of communication, seasonal and circadian rhythms, territorial behaviour, threats and factors influencing their well-being are described in detail. Practice has shown that these are friendly and interacting animals to keep at home, and their breeding as pets is promising. Even adults caught in a trap get used to people in 2–4 weeks, take food from hands, go to the cage door when they are called, remember their nickname, calmly walk on the hands and do not bite at all, even when their babies are taken to the hands. Although hamsters are nocturnal in the nature, they are often active during the day at home. They do not hibernate and are active all-year-round, and even breed in winter. Hamsters are highly sensitive to overheating and draft; both are harmful to them and lead to death. In the evenings, while walking around the room hamsters do not run away and do not hide; the cage is considered their territory, safe, and cosy. Therefore, after walks, they go to the cages themselves or ask to be placed in the cage. Quickly master the treadmill and run in it for hours. Hamsters are very different by their individual behaviour and preferences. The purpose of keeping hamsters in captivity is to introduce the species as pets and to form so-called ‘reserve populations’ to restore populations of the species in the wild. Being among the pets, this species will be preserved in the culture and will be able to be released in places where their existence would be desirable. Based on the experience gained from keeping hamsters in captivity, steps to form "wild" behaviour are recommended. The formation of artificial breeding groups, which together form a reserve population, is an important measure in restoration programmes of natural populations of Cricetus cricetus.

Hamster numbers: biopolitics and animal agency in the dutch fields, circa 1870-present

Numbers of European hamsters (Cricetus cricetus) in the Dutch Province of Limburg have been subject to much scrutiny and controversy. In the late nineteenth century, policymakers who considered them too numerous (and invasive) set up eradication programs. In the second half of the twentieth century, even when its domestic relative (Mesocricetus auratus) increasingly circulated as a pet in urban spaces, the numbers of European hamsters in the rural areas collapsed. Large-scale preservation campaigns and reintroduction programs ensued. According to some media, all this has turned the European hamster into the most expensive undomesticated animal of the Netherlands. A whole network of institutions became involved to save the species – ranging from local activist organizations, over zoos and universities, to federal ministries and international organizations. The interactions between the Dutch and ‘their’ hamsters, this article argues, were inscribed in various forms of biopolitics. The article highlights the changing discursive framings and spatial practices that have shaped the management of Cricetus cricetus over time and calls attention to the diversity of living and non-living agents that produced the multispecies choreographies of the present-day Limburg landscape. Finally, it alerts us to the (sometimes-paradoxical) kinds of agency that reside in the numbers of non-human animals.

European Hamster at the edge: declining in nature and rare in owl pellets

Over the last decades, the European Hamster (Cricetus cricetus) has been declining in many parts of its European range. Due to the lack of recent information on the occurrence and status of the European Hamster in the south-western Carpathian Basin west of the Danube, we used information gathered from prey remains in Common Barn-owl (Tyto alba) pellets. In spite of considerable sampling effort, we retrieved only few hamster remnants. Two skulls were found in Podolje (Croatia) in 2007 and 2016, respectively. Further five hamsters were retrieved from pellets collected in 2017, 11 km to the northwest in Udvar (Hungary). In Sátorhely, 5 km north from Udvar, one roadkill male was found on 27.07.2019. Testimonies from local inhabitants confirmed the current presence of the European Hamster in the area. Our results suggest the presence of a small isolated population in the border area of Croatia (UTM 10 km grid square CR27) and Hungary (CR18, CR19). This small isolated population is on the south-western limit of the range of the species. We presume that the population requires conservation attention because of its isolated position at the edge of the species’ range, its small size and low abundance. We call for a transboundary action by nature conservation authorities in Croatia and Hungary.

Predation and survival in reintroduced populations of the Common hamster Cricetus cricetus in the Netherlands

European populations of Common hamster (Cricetus cricetus) have dramatically declined in the last decades, and in many EU countries, the species is on the brink of extinction. In the Netherlands, a research and reintroduction program was started in three areas with hamster-friendly management to reverse the decline of the species. Since 2002, more than 800 captive-bred and wild-born hamsters were monitored using implant radiotransmitters to quantify survival rates and discover the main causes of death after release compared to those of wild individuals. Individuals with a transmitter were regularly checked at their burrow. Predation by foxes, birds of prey, and small mustelids was the most important cause of mortality of this medium-sized rodent, while crop type and harvest regime were also likely to be important drivers as they influenced survival rates through the presence or absence of protective cover. The fitted weekly survival model showed that male hamsters had much lower survival rates during the active season than females, which corresponds with the ‘risky male hypothesis’. Survival rates of females appeared too low to keep populations at a stable level. To establish a viable population, more optimal environmental conditions for both survival and reproduction of the hamsters are necessary. Using electric fences around fields with hamsters significantly increased the survival of females. However, hamster conservationists need to consider not just subadult and adult survival rates, but also habitat connectivity, weather effects on reproduction, and alternative agricultural practices on a landscape scale.

New records of rare and non-abundant mammal species in Medobory Nature Reserve and its vicinities

The report presents data on 9 rare mammal species that have been recorded in Medobory Nature Reserve and its vicinities for the last seven years. Seven species are listed in the Red Book of Ukraine: the common hamster (Cricetus cricetus L.), the northern birch mouse (Siсista betulina Pall.), white-toothed (Crocidura leucodon Hermann), the wild cat (Felis silvestris Schr.), the Eurasian otter (Lutra lutra L.), the grey long-eared bat (Plecotus austriacus Fischer), and the brown long-eared bat (Plecotus auritus L.). The Eurasian beaver (Castor fiber L.) and the grey wolf (Canis lupus L.) are not included into the Red Book of Ukraine, although they are rare species in the reserve. The northern birch mouse was last recorded in 1994, whereas the wild cat had not been sighted until 2019.

Monitoring of the Cricetus cricetus L. population in the Upper Pobuzhzhia region

The research was carried out in Letychiv Raion of Khmelnytsky Oblast during 2003–2017. In 2016–2020, the population of the common hamster was monitored near the village of Holoskiv. During the research, we recorded 15 hamster encounters and finds of 220 burrows: 15 burrows near the village of Rusanivtsi and 205 burrows around the village of Holoskiv. 163 burrows were found directly at the monitoring site. The density of burrows in gardens ranges from 1.03 burrows / ha to 2.39 burrows / ha, and in large fields — 0.025–0.02 burrows / ha. Most burrows are located on fields of alfalfa (32.3 %) and winter wheat (25.9 %).

Findings of the common hamster (Cricetus cricetus) in Kharkiv Oblast, Ukraine

The article considers the change in the state of the common hamster from a widespread to a rare species in Ukraine. In 1994, it was listed in the Red Book of Ukraine. The most significant changes in the status of hamsters in the last 100 years in Kharkiv Oblast had occurred in 1982 to 2006. Isolated finds of this species in 2020 show its presence. Two actual finds from one location near Kharkiv are described. The species was found in areas not involved in intensive agricultural production. The population decline and range contraction can be explained by excessive ploughing of agricultural lands. This reduces the prospects of the species' survival.

The European hamster (Cricetus cricetus) in Podillia: description of a new settlement and the finding of a melanistic form

The material for the writing of this article is based on the observation of animals hunted by domestic cats. The hamsters were immobilized and killed by the predators mostly by biting through the spine at the back of the neck. Regarding the dispersal of melanistic forms, it has been established that today the boundary of the Podillia segment of the species’ range is much further to the west of the point determined by V. Samosh (1978), which suggests the idea about the expansion of the distribution range of melanistic variants. The results of the study of quantitative parameters of the hamster population show that the density of inhabited burrows and the activity of their use decrease from perennial grasses, crops, and motley grass crops to gardens and areas overgrown by weeds. A colony of this rodent was found on the banks of the Strypa River as well.