Look who behave like true insect hunters: voles and mice (#129)
There are some specialized insect hunters among rodents such as killer mouse of the genus Onychomys, and there are also generalists frequently attacking and eating live prey such as Norway rats, deer mouse Peromyscus maniculatus andgolden humster Mesocricetus auratus. Our experiments with striped field mice showed that they can interact with ants as predators and mass prey (Panteleeva et. al., 2013). Mice displayed high hunting activity towards aggressive and dangerous red wood ants, and their hunting efficiency was comparable with specialized predators: mice killed and ate 0,36±0,19 ants per minute. Surprisingly, A. agrarius displayed efficient and laconic hunting behavioural pattern. This makes a suggestion that granivorous and possibly herbivorous rodents share hunting stereotypes with “predatory” rodents, possibly inheriting these behaviours from common ancestors. We examined hunting behaviour in three species of rodents in comparison with insectivorous common shrew. Animals were placed one by one into the arena together with the cockroach Nauphoeta cinerea. We used 81 Rattus norvegicus (generalists) from which 67,9% displayed hunting, 26 striped field mice A. agrarius (granivorous; 65,38%), 27 narrow-headed voles Lasiopodomys gregalis (herbivorous; 51,85%) and 11 common shrew Sorex araneus (naturally 100%). Voles differ significantly (p<0,01 in all cases) from all other species by their minimal numbers of successful attacks (23 from 99). Video records of animals' interaction with prey were analyzed by Noldus Observer and 19 behavioural acts were revealed common to all species, including encountering, pursuit, capturing by forepaws, bites and handling of different forms and levels, amputating legs of the victim, and eating. Schemes of the hunting stereotypes revealed by Markov chain analysis turned out to be similar in three rodent species, and they differ from that in the shrew by a manner of prey capturing (by forepaws in rodents and by teeth in the shrew) as well as by some details of pursuit. In general, we revealed unexpected hunters among granivorous and herbivorous rodents which can clarify evolution of their behaviour.