Hereditary determined diving behaviour in rats as a factor of fitness

Abstract

Background. Rats natural ability to swim and dive provides adaptation in the wildlife and is widely applied as an instrument in experimental physiology. Nevertheless theres little scientific evidence on diving behaviour in rats itself. Meanwhile this behavioural pattern might be a notable trait to shed light on functional features of the nervous system, the higher nervous activity structure and evolutional adaptability in animals, including inherited ones. Materials and methods. In the present work we compared the performance of the spontaneous diving behaviour in the Morris water maze and forced diving behaviour in the Extrapolation escape task in two selected rat strains genetically differing in the nervous system excitability threshold. Results. We found a greater extent and adaptive pattern of both types of the diving behaviour in the high-excitable LT strain. This may be due to such basic features of this strain as high exploratory activity and an increased level of fear reactions. It was also shown that the second, low-excitable HT rat strain, demonstrates maladaptive jumping behaviour in the Extrapolation escape task due to higher anxiety level in the stress conditions. Conclusion. Observed differences between two strains allow us to consider the diving behaviour performed by high-excitable rats an inherited strain characteristic resembling adaptive rat behaviours in the wild and look forward to investigate its genetic mechanisms.