Research into the hunting behavior in members of the Cricetidae family offers an opportunity to reveal what changes in the predatory behavioral sequences occur when a rodent species shifts from an omnivorous to a predatory lifestyle. The study tests the following hypotheses: are there phylogenetic differences in the divergence of species’ predatory lifestyles in hamsters or do ecological factors lead to shaping their hunting behavior? We applied the data compression approach for performing comparative analysis of hunting patterns as biological “texts.” The study presents a comparative analysis of hunting behaviors in five Cricetinae species, focusing on the new data obtained for the desert hamster Phodopus roborovskii whose behavior has never been studied before. The hunting behavior of P. roborovskii appeared to be the most variable one. In contrast, behavioral sequences in P. campbelli and Allocricetulus curtatus display more significant order and predictability of behavior during hunting. Optional hunting behavior in the most ancient species P. roborovskii displayed similarities with obligate patterns in “young” Allocricetulus species. It thus turned out to be the most advanced hunter among members of the Phodopus genus. Differences in hunting sequences among Phodopus representatives suggest that the hunting behavior of these species, despite its optional mode, was subject to selection during species splitting within the genus. These results did not reveal the role played by phylogenetic differences in the divergence of species’ predatory lifestyles. They suggested that ecological conditions are the main factors in speciation of the hunting behavior in hamsters.

In laboratory experiments, purposeful predatory inter-relations with moving insects have been revealed and described in three species of herbivorous voles: the East European vole, the narrow-headed vole, and the Tuva silver vole. The appearance of the full hunting stereotype in these species does not require preliminary experience, which indicates its innate nature. The hunting behaviour of the Tuva silver vole differed from that of the East European vole and narrow-headed vole, which probably reflects the phylogenetic relationships between these species.

The development of cognitive ethology and new experimental methods of studying animal intelligence has led to an underestimation of the role of innate stereotypes in the behavioral repertoire. Researchers tend to see cognitive phenomena in animal actions, such as the formation of cultural traditions in communities. On the example of ants and rodents, using an experimental model of interaction with prey, we identified relatively flexible fragments of innate stereotypes prone to recombination or loss. We suggest that the variability of individual fragments of stereotypes underlies the formation of species-specific hunting behavior. The combination of innate fragmentation of behavioral stereotypes and simple forms of social learning may lead to certain behavioral traditions within communities and populations. The review presents the results of the research team's studies and considers the prospects of the proposed direction of investigations, based on a detailed analysis of behavioral stereotypes.

We revealed and analysed patterns of hunting behaviour in three rodent species (the granivorous striped field mouse, the herbivorous narrow-headed vole, and the omnivorous Campbell's dwarf hamster) towards active insects in comparison with the insectivorous common shrew. Unlike shrews, rodents display facultative hunting behaviour, that is, not all specimens can hunt, although the hunting patterns are fully complete in other members of the groups. For instance, the proportion of "hunters" within the group of narrow-headed voles is barely half of that displayed by striped field mice. The rate, effectiveness and features of hunting behaviour are similar in the insectivorous species and the rodent species with different diets. The manner of killing the prey differs between species: mice, voles and shrews apply series of fast bites to kill the insect, whereas hamsters bite its legs off, which can be considered as more specialised hunting pattern. The manner of the attack also varies across species: rodents first grasp the prey with teeth and then move on to grabbing it with the paws, whereas shrews use teeth only, and this can be considered a relatively primitive predatory behaviour. Campbell's dwarf hamster can start the attack both from grasping the prey either with teeth or with paws, and this can be evaluated as the most evolutionary progressive among the species investigated. The main features of hunting behaviour, as well as the ratio of the elements in the patterns, display 'all and immediately' in all three rodent species, and they are not affected by experience. One can consider the hunting behaviour evolutionarily stable strategy of rodents, which allows populations using predation on active insects to expand their feeding resources.

In laboratory experiments we investigate hunting behavior towards insects in Phodopus sungorus (Pallas 1773), P. сampbelli (Thomas 1905), Allocricetulus eversmanni (Brandt 1859), and A. curtatus (Allen 1925). In these species purposeful inter-relations with insects in the predator–prey manner have been revealed and described in details. In all species investigated, the patterns of hunting behavior are comparable with those of specialized predator hamsters. In a quarter of all cases, hamsters start attacks by seizing the prey with their paws, which is considering more evolutionary progressive than capturing with their teeth. The Djungarian hamster P. sungorus demonstrates the simplest pattern of hunting, whereas in other species some features of specialization have been revealed, such as different forms of manipulation activity. A. curtatus displays the swiftest and most effective attacks towards prey. We speculate that the obligatory innate patterns of hunting in both Allocricetulus species are connected with more specialized predatory behavior of members of this more evolutionary young group as compared to members of the genus Phodopus, with their optional hunting patterns which need experience to be completed.

Ability to shape associations between visual stimuli and a reward under conditions of mass and spaced trainings have been studied for the first time in wild Djungarian hamsters. In a case of a simple task ("spot vs no spot") 7 from 9 animals solved the problem under condition of mass training, whereas under condition of space training only one individual was successful. In a case of more complex task ("a lesser spot vs a greater one") 4 from 9 animals were successful under condition of mass training. Taking into account our previous study of Ph.sungorus's ability to evaluate sets of geometric figures, one can suggest that evaluation of visual stimuli in details is above cognitive competence of this species. Comparative psychological analysis of experimental studies enables us to consider this species a sort of "benchmark", at least when discriminations of visual stimuli are concerned. I n contrast to majority of rodent species as well as genetic lines, the Djungarian hamsters learn to discriminate visual stimuli under conditions of mass training only, that is, they have "short memories".

Mechanisms of interactions between species present one of the central problems of contemporary behavioral and evolutionary ecology. Field observations of possible resource redistribution and mutual behavioral adaptations between representatives of different guilds with substantially overlapping niche parameters are, so far, few. Using the methods of small mammals censuring, with account for their mobility and burrowing activity, at the sites with high and low dynamical density of wood ants Formica aquilonia, as well as in anthills proper, spatial interactions between these animals are revealed for the first time which are based on seasonal transformations of topic competition and synoecism. Species composition and domination structure of small mammals communities appear to be similar in those territories controlled by F. aquilonia and almost free of them. However, judging by animals’ spatial distribution and activity it can be suggested that wood ants, being a disturbing factor, markedly reduce the numbers and burrowing activity of small mammals in their territory and, apparently, hinder mammals dispersion. During seasonal resting of ants, when they move down into the soil, anthills attract a lot of small animals: from October to May up to 84% ant nests are burrowed by murine rodents and insectivore mammals. It seems to be possible that there are trophic relationships between small mammals and wood ants, with mammals consuming nest substrate as well as insects themselves.

Yeast abundance and species diversity in the colonies of Formica aquilonia ants in birch–pine grass forest near Novosibirsk, Russia, were studied. The average yeast number in the anthill material was 103–104 CFU/g, reaching 105 CFU/g in the hatching chambers. Typical litter species (Trichosporon moniliiforme and Cystofilobasidium capitatum) were predominant in soil and litter around the anthills. Apart from these species, ascomycete species of the family Debaryomycetaceae, Debaryomyces hansenii, and Schwanniomyces vanrijiae were predominant in the anthill material. Yeast population of the ant’ bodies consisted exclusively of the members of the last two species. Thus, highly specific yeast communities formed in the colonies of Formica aquilonia ants differ from the communities of surrounding soil. These differences are caused by environment-forming activity of the ants.

Being a great source of nutrition for many rodent species, invertebrates, including insects, have been under–estimated before as an alternative feeding resource. Reactions towards mobile insects (speckled cockroach Nauphoeta cinerea Olivier, 1789) were experimentally investigated in three rodent species with different types of diet, such as omnivorous, granivorous and herbivorous, in comparison with the insectivorous common shrew. In all investigated rodent species highly stereotypical hunting behavior was revealed, comparable with that of a common shrew, which is known as a specialized predator. This enables us to suggest that certain proportion of carriers of hunting stereotypes towards live insects is maintained within populations of rodents, thus enriching their diet.

Comparative analysis of stereotypical behavioral patterns including elements of flexible behavior is presented, with hunting behavior of small mammals as an example. Reactions towards live prey (cockroaches) were investigated in rodents possessing different feeding specialization, in comparison with the insectivorous common shrew. Quantitative analysis was used, and Markov chains were constructed to generate schemes of stereotypes of hunting behavior in different species. The characteristic feature of hunting stereotypes in rodents is that after seizing an insect with teeth, they seize and hold it with their forepaws. This is the more evolutionary progressive feature than seizing the prey with teeth only, like shrews do. As schemes of stereotypes and tactics of hunting appeared to be similar in herbivorous narrow-headed voles and granivorous striped field mice, one can assume that these rodents possess specific adaptations to carnivorous life style. Norway rats display the less specialized hunting stereotypes. The studied rodent species demonstrate more primitive hunting stereotypes than specialized hunting rodents; however, their hunting stereotype is rather specific, and this can be considered behavioral adaptation allowing rodents to broaden feeding resources by the use of active hunting towards insects. A suggested scheme of comparative analysis of stereotypical behavior can be used in ethological and psychological studies. The study was supported by the Russian Science Foundation (grant No. 14-14-00603).

A hypothesis of ambivalent foraging is proposed based on ideas about dual treating of the prey by a consumer: the food value attracts while the danger repulses. The foraging strategy of the great tit was investigated experimentally with the use of artificial “food patches” with variable amounts of dangerous prey (live red wood ants) and non-dangerous prey (fly larvae). With non-dangerous prey, the behavior of the birds corresponded to the known marginal value theorem: they proceeded with foraging until the resources were exhausted. We found the threshold amount of dangerous prey that prevents tits from hunting.

Проявлению и становлению поведенческих традиций у разных видов животных посвящено огромное количество работ, но до сих пор остается неясным, какие факторы способствуют, а какие препятствуют распространению новых для популяции форм поведения. В статье представлен аналитический обзор исследований на эту тему, рассмотрены результаты исследований “культуры” у животных и проанализированы противоречия, возникающие при попытках выяснения этологических механизмов культурной преемственности. Сформулирована гипотеза “распределенного социального обучения”: для распространения в популяции сложных поведенческих стереотипов достаточно присутствия в ней немногочисленных носителей целостных стереотипов, если остальные животные являются носителями неполных генетических программ, запускающих эти стереотипы. Наличие “спящих” фрагментов программ создает у их носителей врожденную предрасположенность к совершению определенной последовательности действий. Для достройки целостного стереотипа достаточно самых простых форм социального обучения (“социальное облегчение”). Гипотеза рассмотрена на поведенческом уровне и подкреплена экспериментальными данными, полученными при исследовании сценариев развития охотничьего поведения у муравьев Myrmica rubra L. Она позволяет объяснить распространение поведенческих моделей в сообществах животных более простым путем, чем с помощью культурной преемственности.

There is a plethora of works on the origin and genesis of behavioral traditions in different animal species. Nevertheless, it still remains unclear as for which factors facilitate and which factors hinder the spreading those forms of behavior that are new for a population. Here, we present an analytical review on the topic, considering also the results of studies on 'culture' in animals and analyzing contradictions that arise when attempting to clarify the ethological mechanisms of cultural succession. The hypothesis of 'distributed social learning' is formulated, meaning that for spreading of complex behavioral stereotypes in a population the presence of few carriers of consistent stereotypes is enough under the condition that the rest of animals carry incomplete genetic programmes that start up these stereotypes. Existence of 'dormant' fragments of such programmes determines an inborn predisposition of their bearer to perform a certain sequence of acts. To complete the consistent stereotype, the simplest forms of social learning ('social alleviation') turn to be enough. The hypothesis is examined at the behavioral level and supported by experimental data obtained when studying the scenarios of hunting behavior development in ants Myrmica rubra L. It makes possible to explain the spreading of behavioral models in animal communities in a simpler way than cultural succession.