Japanese macaques Macaca fuscata inhabit the Japanese archipelago where they experience markedly seasonal warm and cool temperate climates. Their reproduction and their nutritional status follow clearly seasonal patterns. Their status can be effectively evaluated based on their total body fat, but making such measurements has been difficult. In this study, the body fat of Japanese macaques was studied using Double Energy X-ray Absorptiometry (DXA). Adult males were found to have a median fat mass of 7% and adult females 9%. Using the 90th percentile as the criterion, we determined the levels of obesity in Japanese macaques as 17% in males and 27% in females. Fatness indicators (physique index and skinfold thickness) were found to correlate well with total body fat and fat mass percentage. Fat mass is estimated fairly well from these indicators. Fatness indicators change seasonally in artificially reared Japanese macaques.
Putative nucleotide sequences for DQB exon 2 alleles of the major histocompatibility complex (MHC) were amplified and determined in the 16 cetacean species using the PCR technique. The 172 bp sequences amplified showed no multiple alleles more than two in each of the examined individuals. The sequences of the 31 cetacean DQB alleles detected were monophyletic with the HLA-DQB1, and were separated from the lineages of HLA- DQB2 and DQB3. These results suggest that the locus is the homolog to the human DQB1 gene. The observed frequency of nonsynonymous substitutions in the cetacean DQB sequences was significantly higher than that of synonymous substitutions. The amino acid variation at the putative peptide binding region (PBR) was considerably high. These results imply that positive selection has promoted its variability at the cetacean DQB gene as other mammalian MHC. The DQB gene tree showed that four Mysticetialleles branched off from the clade consisted of Mysticetialleles only and were included in the clade consisted of Odontoceti alleles. This suggests trans-species polymorphism in the cetacean MHC gene.
Distributions of fish otoliths and squid beaks in the stomach, small intestine, and large intestine of northern fur seal (Callorhinus ursinus) were examined to assess their relevance to biases in diet estimation by scat analysis. The contents of the digestive tracts of 51 seals collected in the western North Pacific off northern Japan were inspected. The large intestines contained more fish otoliths and squid beaks than either the stomachs or the small intestines. The prey composition estimated from hard parts in the small intestines was similar to the large intestines, but there was a greater dominance of squid in the stomachs. Squid beaks found in the digestive tracts ranged from 2.26-22.20 mm in wing length, although large beaks (≥10 mm) were found only in the stomachs. In addition, there were significant differences in the sizes of fish otoliths found in the stomachs and the large intestines. The difference of the prey composition and the size may have resulted from the limited passage of large particles at the pyloric end of the stomach. In order to improve the accuracy of scat analysis, we must investigate to restrict passing the large particles.
We carried out an aerial survey to estimate the abundance of finless porpoises Neophocaena phocaenoides off the Pacific coast of eastern Japan between Sendai Bay (38°23'N) and the mouth of Tokyo Bay (35°13'N) in May and July 2000. In this region, almost nothing is known about the status of this species. Thirty-seven east-west transects (707.0 km in total) were flown at intervals of 11.1 km. A total of 59 animals (37 primary sightings) was observed along the transects. Although the finless porpoises in this area have been assumed to constitute a single population, two distributional gaps at around 35°N and 37°N suggest the possibility of population subdivision. Finless porpoise sightings were not restricted by distance from the coast, but by water depth (<40 m). The density and abundance of finless porpoises in the area from Sendai Bay to the east coast of Boso Peninsula were tentatively estimated at 0.502 animals/km2 and 3,387 animals (CV = 32.7%), respectively. This density was lower than in other areas around Japan.
From March 2000 to July 2001, an intensive biological survey was carried out of the bat fauna of Lore Lindu National Park, Central Sulawesi, Indonesia. The study covered all 11 major vegetation types and an altitudinal range of 300 to 2400 m a.s.l. All habitat types were surveyed applying the same standardized mist-net efforts. Among other things, the survey resulted in the collection of four specimens of Rousettus (Megachiroptera) in the swamp forest of Kenawu village, Lindu Lake, Lore Lindu National Park, which represent a new species, described in the present paper. The new species is compared with the other species of Rousettus in Indonesia, most notably with the common Sulawesian rouset bat (Rousettus celebensis); nearly all skull, dentary and dental dimensions of this new species are smaller than in R. celebensis. Moreover, breast fur colour and glans penis morphology are different from these characters in the common Sulawesian rouset bat. The breast fur in the new species is of a cream colour, the abdomen is negro to chocolate, and the sides are brown leather. The glans penis of Rousettus celebensis is flattened and triangular, whereas it has an irregular shape in the new species.
We tracked six female raccoons (Procyon lotor) from June 1997 to October 1999 on the in Hokkaido, Japan and examined the distribution of home range characteristics, habitat selection, and interaction among individuals to identify the factors that affect seasonal spacing patterns. Female raccoons maintained home ranges throughout the year. Habitat use changed seasonally, with frequent use of wetlands and riparian areas between March and August, and higher use of forests from September to December. Home ranges overlapped broadly, but the core areas were generally exclusive of each other. Female raccoons are likely to have stable home ranges through a year to secure the various resources (food, water, and resting site) that are required and select the habitat associated with food resource available within each home range. This spacing pattern among female raccoons was similar to that in their native habitat and was consistent with the general mammalian pattern where female distribution was affected by resources. The control of this non-native species should focus on the aquatic areas during spring to summer.
To analyze the seasonal variation in the diet of the Japanese sable Martes zibellina brachyura, 193 feces and 20 stomachs, collected in eastern Hokkaido from 1998 to 2002, were examined. The Japanese sable proved to be omnivorous, taking various food items including mammals, insects, plants, birds, reptiles, amphibians, fish and crustaceans. Mammals were the commonest food items throughout the year, with voles Clethrionomys spp. (frequency of occurrence 56.5%), Siberian chipmunks Tamias sibiricus (19.3%) and wood mice Apodemus spp. (14.6%), most often found in feces. Insects appeared mainly in summer (48.8%) and less often in other seasons (9.3% on average). Plant materials, chiefly fruits, were found mainly in autumn (45.7%) and winter (68.4%) but were rare in spring (5.1%) and summer (1.3%). These results suggest that the Japanese sable depends mainly on mammalian prey, but also takes other food items, probably to compensate for fluctuations in mammal abundance. Maintaining natural habitats, which provide various food resources, is thus important for conservation of the Japanese sable.
The relationship between deer-train collisions and daily activity of sika deer Cervus nippon was investigated between Mashu and Biruwa railway stations on the Senmou Line in eastern Hokkaido from April 1995 to March 1997. Deer-train collisions were concentrated near Mt. Biruwa, in the period from January to March (72% of the total), and in the evening (69%). Few collisions occurred in April when the first train passed through after sunrise. Deer crossing concentrated around sunset or sunrise during January to April. Monthly deer-train collisions were positively correlated with the number of deer crossing the railway tracks. Furthermore a constant directionality in railway crossing was detected in most months. This directionality resulted from deer moving between a feeding site in the evening and a resting site in the morning. Deer-train collisions occurred in relation to the daily activity pattern of deer in the vicinity of the railway tracks.