A phylogeographic study of the large Japanese wood mouse, Apodemus speciosus, on Sado Island, Japan, was performed based on sequences of the mitochondrial cytochrome b gene (1,140 bp). Our previous study covered the entire species range and suggested that the mice on Sado Island are monophyletic, exhibiting two well diverged lineages throughout the island. The present data also supported two lineages (the average number of nucleotide difference was 11.4), showing a weak phylogeographic structure. Given the high sequence divergence observed, we assumed historically subdivided populations within the island. Bayesian coalescent analysis supported a dual-population model rather than that of one large population. The times to most recent common ancestor of all sequences were 293,000 years ago [ka; 95% highest probability density (HPD) 85–634 ka] and 292 ka (HPD 102–605 ka) for the one- and dual-population models, respectively. These results suggest that the populations have undergone repeated separations and reconnections, rather than being subdivided completely through time. Our results are in accordance with other paleogeographic and phylogeographic evidence from the island. The present study highlighted a unique system of producing and maintaining genetic diversity and suggested prehistoric colonization of the A. speciosus population on Sado Island, thus supporting the ancient origin of the mammalian fauna of Sado Island.

Roosting of Asian parti-coloured bats (Vespertilio sinensis) in man-made structures is frequently results in conflict with humans. Therefore, to determine optimal alternative roosts, we studied roost preference of this species by testing the effects of roost temperature, surrounding environment and the distance from the nearest nursery colony on roost selection by V. sinensis in manipulative field experiments. We installed white (cooler) and black (warmer) bat boxes at shaded and sun-exposed sites. Although no nursery colonies were formed in the bat boxes, a few individuals (1–5) roosted during the lactation period, while many individuals (≥20) roosted during the post-lactation period. During lactation, bats used both white and black boxes, but preferred using the boxes placed at the shaded sites over those placed at the sun-exposed sites. On the other hand, during the post-lactation period, almost all individuals used the white boxes rather than the black boxes. However, adult females preferred the shaded sites while young females preferred the sun-exposed sites. In conclusion, V. sinensis exhibited seasonal changes in roost selection, implying that several types of bat boxes in different environments need to be installed as alternative roosts. In the future, other types of bat boxes should be tested as alternative nursery roosts.

We evaluated the performance of global positioning system (GPS) collars deployed on free-ranging sika deer (Cervus nippon) to study their seasonal migration. We placed 21 GPS collars on 20 individual deer in the Shiranuka Hills, eastern Hokkaido, between March 2002 and March 2004. We could recover 17 (81.0%) collars and retrieved 20,278 location data from 13 collars on 12 individuals during 2002 and 2005. Tracking duration averaged 267 ± 17 (SE) days, fix success rate averaged 62.9% and ranged 34.4–81.8%. The proportion of 3-dimensional location averaged 46.4% and ranged 12.8–99.0%). We evaluated the fix success rates of three seasons (winter, migration period, and summer). In most cases, we found that the fix success rate in winter was significantly higher than that in summer. We consider the canopy cover of habitat affects the fix success rate of GPS collar. Although the GPS-based telemetry has some risks related to collar recovery and data retrieval, this method provides us a large volume of location data and is a suitable method for studying migratory behavior of sika deer.

Wildlife managers perform several preventative measures against crop damage caused by sika deer (e.g., fencing and population control); however, these measures have not completely eliminated crop damage, indicating that additional methods should be explored. Therefore, to propose useful agronomical techniques for further decreasing crop damage, we investigated sika deer behavior in apple orchards. The feeding behavior of sika deer was observed using sensor cameras set within apple orchards adjacent to forest. These photographs showed that sika deer mainly used apple orchards in the summer, feeding on both crops (i.e., apple leaves and fruits) and weeds. The estimated 95% confidence interval of the crop-feeding ratio [crop feeding/(crop feeding - weed feeding)] ranged from 0.20 to 0.41, indicating that sika deer more frequently fed on weeds rather than crops. Chemical analyses of the vegetation indicated that only protein content differed among weeds, crops, and forest understory vegetation, with weeds exhibiting the highest protein content. Protein content was probably higher in the apple orchard than in the forest because farmers use nitrogen fertilizer in the apple orchards. We concluded that sika deer are attracted to apple orchards because of the high protein content of the weeds; therefore, weeding might be an effective agronomical technique for reducing crop damage.

The author measured 111 specimens (61 male, 50 female) of the Japanese red fox (Vulpes vulpes japonica) collected by the Tochigi Prefectural Museum during 1981–1991 and by the author during 1986–1994. Analyses of 16 parameters of external morphology of the specimens revealed sexual dimorphisms in linear parameters: total length, head and body length (HBL), and hind foot length (HFL) were significantly greater in males (5–6%: P < 0.001). Furthermore, analyses of these parameters using an allometric formula showed that the relative growth of HFL to HBL and shoulder height to HBL stops earlier in males than in females. The male/female ratios were large for body weight, body length, and parameters related to circumference, but they were mostly not significant because they are influenced by seasonal changes and body conditions that are influenced mainly by fat deposition. Greater thickness gives the visual impression of largeness, providing advantages for males to be selected by females. Consequently, greater thickness might have caused, at least partially, male-bias size dimorphism. Moreover, sexual difference in relative growth might be some adaptive advantage of locomotive behavior in males. Early investment in locomotive capability in males might engender acquirement of females and consequently, mating success.

Little is known about the biology of harbour porpoises (Phocoena phocoena) around Japanese waters. This study estimates the seasonal distribution of harbour porpoises in Japan using 240 stranding and bycatch records from 1966 to August 2009 deposited at the Institute of Cetacean Research, Tokyo, the Stranding Network Hokkaido, Hokkaido, and records summarized in a previous study. Over 70% of all the records were bycatch from use of three types fishing gear: large set-nets, other type set-nets, and gill nets. Most of the bycatch records were derived from Usujiri, Hokkaido, where a regular monitoring survey on harbour porpoises caught incidentally by large set-nets has been conducted since the 1980s. These records showed that harbour porpoises migrate to the coast of Honshu (mainland of Japan) in the winter, and move north in the summer. Their latitudinal range coincided with the sea surface temperature (SST) range between 6 and 17°C. Additionally, the stranding and bycatch records which were found only from April to June in Funka Bay, Hokkaido suggested that Funka Bay is used only for a few months in spring. Overall, the present study clarifies the finer seasonal distribution of harbour porpoise around Japan, and its strong dependence on SST.

Biological factors influencing exploratory behavior were investigated in 80 litters of CD-1 control mice in two-generation toxicity studies. Litter size and sex ratio were measured at birth [postnatal day (PND) 0], while offspring body weight were measured on PND 0 and 21 during the lactation period. Offspring were examined for exploratory behavior at three weeks of age. After weaning, mice were weighed and examined for exploratory behavior at eight weeks of age. The relationships between biological factors and exploratory behavior were assessed with canonical correlation analysis at three and eight weeks of age in the F₁ generation. Litter size at birth, secondary sex ratio (male%), body weight (g) at birth, and body weight (g) at the time of examination were used as explanatory data, and exploratory behavior variables were used as response variables. After canonical correlation analysis, variables having a significant axis in coefficient of structure were assessed with multiple regression analysis. In female offspring, body weight at the time of examination showed a positive effect (coefficient of determination R² = 0.559) on vertical time (sec) at three weeks of age. Therefore, it is necessary to observe the changes in vertical time in relation to body weight in immature females.