Long-term studies (1963-2000) of a local population of the largha seal Phoca largha in the waters of Primorye Region were reviewed. In winter, largha seals were observed mainly in the southern coast of Primorye (the Peter the Great Bay: PGB). In contrast, abundance was low along the eastern coast of Primorye, where waters were mostly open throughout the winter. In summer and fall, numbers decreased in PGB, whereas those along the eastern coast of Primorye increased. This might reflect seal movements between PGB and the eastern coast. The majority of the coastal haul-out sites were confined to the protected zone of the Far Eastern Marine Reserve in PGB, and seals used PGB haul-out sites year round. The results of seal tagging studies on the Rimskii-Korsakov Islands in PGB, suggest that largha seals are able to move far to the north from PGB, reaching the Sea of Okhotsk waters and the Pacific coast of Hokkaido, Japan. Population size was estimated recently to be about one thousand individuals. Further growth of the population may be limited by incidental take by the trap net fishery in PGB waters in winter, which accounts for up to 10% of annual mortality.

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To understand social organization among Japanese badgers (Meles meles anakuma), we investigated their spatial distribution and sett use in Yamaguchi City, Western Honshu, Japan. Field observations were made from 1995 to 2000, and 19 badgers were monitored by radio-tracking between 1997 and 2000. A badger family consisted of a mother and her offspring. Mature adult males seldom visited the family except in early spring, and they were found to have large home ranges that encompassed the home ranges of two to three adult females. Individual home ranges of mature adult male and adult females did not overlap with those of other mature adult male and other adult females of the same sex, suggesting intra-sexual territoriality. Badgers used an average of 13.5 setts in a year, and mature adult males and females seldom stayed in the same sett together. Male offspring shared a sett with their mother for up to 26 months, whereas female offspring remained with the mother for only 14 months. The average time male offspring spent with their mothers decreased when young were between 15 and 19 months old.

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Morphological variation was examined in the house mouse, Mus musculus, from the islands of Chichijima and Hahajima in the Ogasawara archipelago, Japan, and compared with that of mice from five islands in the more northerly Izu Island chain. Mice from the two Ogasawara islands were similar in body-, mandible-, and molar-sizes, and incidence of molar tubercles, indicating that they are genetically closely related, while substantial divergences were seen between populations on the different islands, and between samples collected from Chichijima in 1977/1980 and in 1999. The Ogasawara mice showed affinities with the European house mouse M. musculus domesticus in their body sizes and were distinct from those from the Izu Islands (Hachijojima, Kozushima, Miyakejima, Nijima, and Oshima) and Honshu, which were identified as being Japanese wild mice, M. m. molossinus, based on their body and mandibular dimensions. The mice from Ogasawara and Nijima (Izu Islands), however, shared a unique variant of molar tubercles, implying that there may have been genetic exchange between the islands. These findings are concordant with historical records of human immigration to these islands during the 19th century.

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I classified about 600 museum specimens of Père David’s vole and examined its distribution. In a restricted area of Burma (25.70-26.13°N, 98.13-98.70°E; Myanmar, Area V), 150 individual specimens sampled during the same period could be classified into two groups on the basis of the relationship between the hind foot length (HFL) and tail length (TL): the large (L) and small (S) types. Group L was distributed at altitudes above 2460 m, whereas Group S was found below 2460 m. The distance between the incisor and third upper molar (I-M3) exceeded 14.3 mm in Group L, and was less than 15.2 mm in Group S. Except for young individuals, specimens from Groups L and S from Area V differed in two external and 14 cranial measurements. The molar pattern of the third upper molar ranged from simple to complex types, and varied both within and between Groups L (Types B, C, and D) and S (Types B and C), indicating that it is inadequate as a primary diagnostic character. The relationship between TL and HFL differentiated the groups in Areas III, IV (Yunnan Province, China), VI (India, Thailand, Vietnam, and northern Burma), and VII (the provinces of Zhejiang and Fujian in China, and Taiwan), but did not differentiate them in Areas I (the provinces of Hubei and Guizhou) or II (the provinces of Gansu and Sichuan), where histograms of I-M3 distinguished Groups L and S. Proportional likeness was represented using a ratio diagram; the lines for 11 cranial dimensions distinguished Group L from Group S, indicating that they are two distinct species. Group L was identified as Eothenomys mucronatus (Allen, 1912); it was distributed in Areas II, III, V, and VI. Group S was identified as E. melanogaster (Milne-Edwards, 1872); it was distributed in Areas I, II, IV, V, and VII. The elevations at which E. melanogaster occurred decreased from southwest to northeast, whereas no clear altitudinal tendency was seen in E. mucronatus.

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I describe the seasonal food habits of the Asiatic black bear, Ursus thibetanus, based on 193 fecal droppings collected in 1993 and 1994 in the Chichibu Mountains of Japan. The percent importance value of each food item was estimated based on the frequency of its occurrence and the volumes of all food items. The bears’ diet changed seasonally and annually. In spring of 1993, the importance value of new leaves was 100%, whereas in 1994 it was only 57%, while the importance value of various nuts was 44%. In contrast, berries (46%) and animal materials (34%), e.g., colonial insects (particularly Hymenopterans), were dominant in the summer of both years, while green vegetation was less important (17%). In the fall of both years, nuts were eaten almost exclusively (74% and 82%). These data suggest that these bears forage for high-quality food in the summer and fall, but not in spring, probably because they find less high-quality food in spring.

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Bisphenol A (BPA), which has previously been shown to have estrogenic activity, was examined for its effect on spermatogenesis in offspring of mice that had been exposed to BPA during gestation. BPA (0, 1, 10, or 100 mg/kg body weight) was orally administered to pregnant mice from the 10th to the 17th day of gestation, and testes of 60- and 120-day-old male offspring were removed and processed for histological analysis. The results demonstrate that prenatal exposure to BPA brings about histopathological changes in the seminiferous epithelium of testes in mouse offspring, such as loss of the luminal space of the seminiferous tubules, accumulation of amorphous material in the tubes, reduction in the number of maturating elongate spermatids, and an aberrant distribution of spermatogenic cells within the epithelium. Electron microscopy suggested that disturbed spermiogenesis is one of the reasons for the reduction in the number of elongate spermatids, and that degeneration of somatic Sertoli cells might be responsible for the aberrant distribution of spermatogenic cells within the epithelium. These data suggest that exposure to BPA during fetal life has profound effects on spermatogenesis in the testes when the offspring become adult.

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