In laboratory experiments, purposeful inter-relations with moving insects in the “predator–prey” manner have been revealed and described in two species of herbivorous mountain voles: the Tuva vole and the flat-headed vole. The patterns of the hunting behavior are similar in these species. The appearance of the full hunting stereotype in mountain voles does not require preliminary experience and does not improve, which indicates its innate nature. Unlike the rodent species studied earlier, mountain voles demonstrate “storing” behavioral patterns when operating with live prey. According to the characteristics of the interactions with prey, mountain voles are among the most successful and effective hunters for moving insects. Regarding the hunting tactics and the manners of their manipulations with prey, mountain voles are similar to the most “predatory” of omnivorous hamsters, Eversmann’s hamsters, but differ from them in an optional manifestation of the hunting stereotype. The frequency of occurrence of the stereotype and the success of hunting in mountain voles are twice as high as in the previously studied herbivorous narrow-head vole. Characteristics of a hunting behavior so unexpected in herbivorous rodents were revealed in mountain voles for the first time. The expansion of the diet due to the hunt for insects can be attributed to dwelling in arid places with a deficit of plant food resources.