We examined morphological growth variations in skull features between the Kuril harbor seal and the spotted seal in Hokkaido, Japan. Skulls from 80 Kuril harbor seals and 41 spotted seals were collected, and we measured 29 metric and 6 non-metric cranial characteristics. Three growth classes were defined according to the postnatal developmental stage: pups (0 year), subadults (1-4 years old) and adults (more than 5 years old). We detected sexual dimorphism in Kuril harbor seal pups, subadults, and adults. Although interspecies differences were detected in each growth class, Kuril harbor seals were larger and more massive than spotted seals; this feature was already detectable in pups. We did not detect certain cranial characteristics with which to identify the two species, but it was possible to identify any unknown specimens to their species, sex, and growth class using the cranial data generated in this study. Using 6 non-metric cranial characteristics, we identified significant interspecies differences with regard to the shape of the temporozygomatic suture and the extent of the nasal-incisive suture; the shape of the temporozygomatic suture and the shape of the nares were indicators of growth class in Kuril harbor seals. Although non-metric cranial characteristics have a lower discriminating power than metric characteristics, they are easy to use in the field even by inexperienced researchers.

In the conditions of the Republic of Belarus there was presented a characteristic of breeding stock of mares of Trakensky breed in accordance with body conformation and exterior. In course of the study there were taken measurements of height at the shoulder, heart-girth, metacarpus circumference at 1 year old and two year old age stages. There was calculated an index of massiveness which characterize the development of chest, index of bone which provided insight into skeleton development. Research results showed that in accordance with an exterior the breeding stock mares had a deep and massive barrel, good skeleton and developed muscle. The index of massivness was 118,4-120,5, bone index – 20,8-21,6, that corresponded to a type of riding horses. In accordance with the exterior, measurements and quality of posterity the mares of the bred lines obtained high grades and 93,5% were graded as elite class.

Determination of regular variations of macromorphological and topographical characteristics of thymus gland, spleen, thyroid gland, and atrabiliary capsules of swamp beavers (Myocastor coypus) at the postnatal ontogenesis was realized in the conditions of the Republic of Belarus. Taking into consideration active participation of immune and endocrine system organs in metabolic processes and vicarious and adaptive reactions there were revealed species and age-specific anatomical peculiar features of thymus gland, spleen, thyroid gland, and atrabiliary capsules of swamp beavers that made it possible to broader knowledge in the sphere of species, age-specific, breed and topographic anatomy