Facultative hunting in rodents as possible evolutionary stable strategy

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.