The genera Meles and Martes both belong to the family Mustelidae, both exhibit similar life history traits, ecology and foraging behaviour, and yet while Meles species are facultatively social, all Martes species are solitary. We compare and contrast the socio-biology of these two genera, establishing that as generalist omnivores both experience similar conditions of resource dispersion, but have intrinsic differences in their morphological and physiological capacity to exploit resources. The rotund body-type of badgers predisposes them to be able to tolerate conditions of restricted food security, by buffering periods of scarcity with increased body-mass. Badgers also use torpor to cope with seasonal food scarcity, and conserve energy by remaining within complex subterranean dens. Martens, in contrast, must maintain a lean, elongate body-type for effective hunting and thus do not store energy as increased body-mass to a comparable extent. Martens do not exhibit torpor and their dens are simple. We conclude that these differences prevent martens from being able to tolerate restricted food security; the type of precursive aggregation fundamental to the formation of social groups observed in badgers. We argue that the Japanese badger is transitionary in the development of integrated social organisation, forming spatial groups with extended juvenile philopatry.

To determine the influence of the forest type on bats in terms of roosting sites and foraging habitats, we compared species richness and abundance (total and by species) of forest-dwelling bats in old-growth forests and conifer (larch) plantations in central Japan. We also compared species richness and abundance of the bats in riparian and non-riparian habitats, and compared the old-growth forest stands with the larch plantation stands to examine differences in the forest stand structures. Species richness, total bat abundance, and the abundances of two tree-roosting specialists, the Ikonnikovi's Myotis (Myotis ikonnikovi) and the Ussurian tube-nosed bat (Murina ussuriensis), were significantly higher in the old-growth forests than in the conifer plantations. The old-growth forests contained larger trees and more snag trees, which provided roosting sites for tree-roosting species. Species richness, total bat abundance, and abundances of the two tree-roosting specialists and the Japanese large-footed bat (My. macrodactylus) were also significantly higher in the riparian habitats than in the non-riparian habitats. The riparian old-growth forest appears to be an important habitat for forest-dwelling bats. Our results suggest that a shift from old-growth forests to conifer plantations has negative effects on forest-dwelling bats, particularly tree-roosting specialists.

We examined food habits and home-range elevations of Japanese black bears (Ursus thibetanus japonicus) in relation to Fagaceae mast production in Toyama Prefecture. Nine bears (four males and five females) fitted with GPS collars were tracked for various periods from July to December in 2005–2007. We investigated the food habits of each bear using traces found at GPS-fix locations. Bears selectively fed on Fagus crenata mast when F. crenata and Quercus crispula mast was abundant and consumed Q. crispula and Q. serrata mast when F. crenata mast was scarce. When both F. crenata and Q. crispula mast was scarce, bears fed on multiple alternatives, such as Diospyros kaki. Home-range elevations of bears also differed among years in response to vertical distributions of available foods. Individual bears captured in the Q. serrata zone (lower elevation) and F. crenata zone (higher elevation) tended to eat Q. serrata and Q. crispula acorns, respectively, when F. crenata mast was not available. Therefore, food habits and home-range elevations of bears were influenced greatly by fluctuations in Fagaceae mast production and the species' vertical distribution, as well as by factors such as food preference for F. crenata mast and food resource distribution around the home ranges.

Intra-species genetic variations of the sable Martes zibellina (Carnivora, Mustelidae), originating from Russian Far East and Hokkadio, were assessed by using nucleotide sequences of the mitochondrial NADH dehydrogenase subunit 2 gene (976 base pairs). Evaluation of the genetic diversity of the sables demonstrated that populations in the southern Primorsky territory in Russian Far East harbors high genetic diversity. We assumed that the high genetic variations might have been due to effects of refugia, secondary admixture of allopatrically differentiated lineages, or massive anthropogenic introductions. Molecular phylogenetic (maximum likelihood and Bayesian inference approaches) and network (median joining method) analyses clarified that sables in Hokkaido was monophyletic. Bayesian-relaxed molecular dating approach estimated the date for migration of sables into Hokkaido to lie between 0.10–0.27 Myr BP. Considering the geological evidence, the Late Pleistocene was presumed to be the plausible epoch for the establishment of the sables in Hokkaido. Lower genetic diversity of the sables in Hokkaido observed in this study was probably caused by the foundation effects or anthropogenic hunting pressures. Mammalian faunal construction in Hokkaido was also discussed.