Investigation of olfaction of gray and harp seals by the operant training method

The results of studying the possibility of producing a motor conditioned reflex in the gray and harp seals on the smell of an object and the ability of experimental seals to differentiate certain odours have been presented. The study has contained three stages. In the first stage the seals were trained to differentiate a container from the camphor solution from a container with distilled water. In the second - to differentiate the container with a solution of dimethyl sulfide from the container with distilled water. At these stages, the possibility of developing a conditioned motor reflex to the olfactory stimulus in the seals studied has been studied. At the third stage, the ability of experimental animals was examined by paired presentation of a container with the solution of dimethyl sulphide from a container with camphor solution. The experiment has been carried out under the MMBI aquacomplex in the Kola Bay. The experimental animals were two female gray seal ( Halichoerus grypus, Fabricius, 1791) at the age of 7 years and two females of harp seal ( Pagophilus groenlandicus, Erxleben, 1777) at the age of 2 years. For the experiments, the stimulants were diluted in distilled water to such concentration that the odour intensity was minimal, then the solution was placed in a container. The results of the work have demonstrated the ability of experimental seals to develop a motor conditioned reflex to olfactory stimuli and the ability to distinguish one odour from another. When teaching the differentiation of a container with a smell, the rate of training of gray and harp seal is relatively the same, while learning to differentiate two smells, harp seals are trained an order of magnitude slower than gray seals. This difference in the speed of training is probably due to the specific features of the seals studied and indicates a higher plasticity of the nervous activity of gray seals.