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Vol. 20 (2017 year), No. 2, DOI: 10.21443/1560-9278-2017-20-2
Pakhomov M. V., Ishkulov D. G., Zaytsev A. A.
The influence of the optical characteristics of the environment on colour vision of earless seals
The results of studying the influence of optical characteristics of sea water on the ability of earless seals to differentiate tablets of blue and red colours have been presented. The experiment involved four specimens of gray seals (Halichoerus grypus, Fabricius, 1791), five species of harp seals (Pagophilus groenlandicus, Erxleben, 1777), and two ringed seals (Pusa hispida, Schreber, 1775). The seals have been trained to choose from a pair of plates the plate of blue colour and to mark it by touching. The experiments have been conducted on air (control study) to produce the sensitivity curve in the air without affecting transparency and colour depth and on 2 m underwater. It has been found that at the illumination above 50 lux in all model animals the proportion of correct answers corresponds to the control one and is 89 ± 3.6 % for gray seals, 74.8 ± 6.2 % for harp seals, 71 ± 5.7 % for ringed seals. When light level is reduced the proportion of correct answers decreases and becomes equal to the random selection at 15 lux for gray seals, 20 lux for harp seals and 25 lux for ringed seals. It has been shown that at the depth of 2 m with illumination below 50 lux the average number of errors for the experience slightly increases from 1.2 to gray seals, harp seals at – 0.6, in ringed seals – 1.8. It has been found that the transparency and colour of water have little impact on the ability of model animals to differentiate blue and red tablets at the given depths. Only the light level has the main influence on colour perception of model animals under water.
(in English, стр.7, fig. 6, tables. 0, ref 12, Adobe PDF, Adobe PDF 0 Kb)
Vol. 21 (2018 year), No. 2, DOI: 10.21443/1560-9278-2018-21-2
Litvinov Yu. V., Pakhomov M. V.
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.
(in English, стр.7, fig. 4, tables. 0, ref 27, adobe PDF, adobe PDF 0 Kb)
Vol. 22 (2019 year), No. 2, DOI: 10.21443/1560-9278-2019-22-2
Litvinov Yu. V. , Pakhomov M. V.
Investigation of the ability of gray seals to differentiate composite audio signals
Technogenic noise pollution of the seas and oceans has a significant impact on the physiology and behavior of marine mammals. The ability of gray seals to memorize and differentiate complex acoustic signals with similar amplitude-frequency characteristics has been analyzed while studying this impact. The experiment consisted of three stages. At the first stage, the seals were trained to press the pedal only when a certain sound signal was given. At the second stage, the second sound signal was added, in frequency characteristics significantly different from the reinforced signal. At the third stage, the third sound signal was added close in frequency characteristics to the supported one. At each stage, 12 experiments were conducted, the number of stimulus presentations was not limited, the experiment was considered complete when the seal made 20 correct choices. The sound stimuli used were sound recordings of diesel engines at idle. The experiment was conducted in the MMBI aquacomplex located in the Kola Bay (the town of Polyarny). The experimental animals were 4 species of the gray seal (Halichoerus grypus Fabricius, 1791) of different ages: seals No. 1 and No. 2 – 12-year-old females, seal No. 3 – 2-year-old female, seal No. 4 – 2-year old male. During the experiment, it has been shown that the reproduced sound of a diesel engine at a sound pressure level of 60–70 dB is a perceived sound stimulus for gray seals. At the first demonstration of a sound stimulus in seals, behavior characteristic of the reaction to avoid a new unknown stimulus has been noted, and no further reaction has been observed in the experimental seals. Later on, the seals have managed to develop a stable differentiating conditioned reflex to a given sound stimulus, which all the investigated seals have reliably distinguished from similar stimuli. It has been found that the time of onset of the response to an external stimulus presented is of an individual character in gray seals.
(in Russian, стр.8, fig. 10, tables. 0, ref 24, Adobe PDF, Adobe PDF 0 Kb)
Vol. 26 (2023 year), No. 2, DOI: 10.21443/1560-9278-2023-26-2
Pakhomov M. V., Zaytsev A. A., Litvinov Yu. V., Troshichev A. R.
Application of tonal audiometry methods to assess the hearing of grey seals in air and water environments
Anthropogenic noise load on the traditional habitats of marine mammals continues to increase due to the active development of the Arctic zone. The study of the hearing of Arctic seals is of great importance for the development of measures to reduce the impact of technogenic noise. During the study, a group of ten grey seals of different ages and genders has been trained to press a special key when demonstrating a pure tone sound with a frequency from the standard and extended set of frequencies recommended for pure tone audiometry. The experiments have been carried out by placing the key and the sound source in air and water (at a depth of 2 m) environment. The main indicator is the reaction time of the seal to the demonstrated stimulus. For each seal, individual audiograms for hearing in air and in water have been compiled using 32 frequencies. An analysis of the data obtained has shown that the reaction time can serve as an individual indicator in the study of the hearing of grey seals reflecting their age characteristics. According to the response time to sounds with different tone frequencies it is possible to establish biologically significant and indifferent frequencies for grey seals.
(in Russian, стр.10, fig. 2, tables. 0, ref 29, AdobePDF, AdobePDF 0 Kb)