The sequence variation of the mtDNA control region was analyzed for Myodes rufocanus and M. rex and compared interspecifically and regionally (Hokkaido mainland and Rebun and Rishiri Islands). On the mainland, the observed number of haplotypes (the observed γ-diversity) was 300 (n = 1028) and 46 (n = 136) for M. rufocanus and M. rex, respectively. The estimated γ-diversity, including unobserved haplotypes, was 613.3 and 150.4 for M. rufocanus and M. rex, respectively. The average haplotype richness from 52 sampling plots (α-diversity) of M. rufocanus was 10.1, which was higher than twice that of M. rex (4.6) from 15 plots. The β-diversity showed no interspecific difference. The higher γ-diversity of M. rufocanus on the mainland was explained by having more local populations with higher α-diversity than M. rex. The observed γ-diversity was higher for M. rex than M. rufocanus on Rebun Island, whereas it was similar on Rishiri Island. The α- and β-diversity did not show statistically significant differences between the species on both Rebun and Rishiri Islands, although β-diversity appeared higher for M. rex than M. rufocanus on Rebun Island. These interspecific and regional variations were interpreted based on the historical vegetation changes in the study area.

Published online 27 December, 2023; Print publication 30 April, 2024

To determine the diet selection of a forest-dwelling ungulate, the Japanese serow (Capricornis crispus), we investigated its diet composition in relation to forage availability using direct observation of foraging behavior for individually identified three adult males in three seasons (spring, autumn, and winter) over two years in the cool temperate forests of Mt. Asama, central Japan. We found that they selected deciduous broad-leaved trees (leaves, fruits, twigs, and buds), forbs (leaves and flowers), and ferns (leaves) and avoided leaves of graminoids and coniferous trees throughout the study periods. Our findings clearly indicate that serows are typical browsers, selecting more digestible food plants. Unexpectedly, our analyses indicated a higher selectivity for ferns than deciduous broad-leaved trees, especially in winter. We also showed that diet composition was significantly different among individuals, but there was little difference in diet selectivity among individuals, suggesting that inter-individual differences in diet are affected by forage availability within each individual's home range.

Published online 14 February, 2024; Print publication 30 April, 2024

Phylogeography of terrestrial mammals on islands is complicated because of the geological changes in the island configuration or their past population dynamics on the nearby landmass. To understand the function of Shodoshima Island in the Seto Inland Sea in preserving lineages of Japanese macaques (Macaca fuscata) and sika deer (Cervus nippon), we investigated the molecular phylogeny of these species on the island. We analyzed a partial sequence of the mitochondrial DNA (mtDNA) control region of the two species. We identified four mtDNA haplotypes in macaques, including western and eastern Japan lineages. Two mtDNA haplotypes for deer were discovered, which were categorized into only the northern Japan lineage. Their nucleotide sequences were identical except for a tandem repeat. These results suggest that the phylogeographic trend was remarkably different between the two species, which may be due to the migration of multiple lineages of macaques to the island when it was connected to Honshu Island, and a bottleneck effect on the deer population caused by overhunting. Some haplotypes were probably unique to the Shodoshima population of both species. The presence of region-specific haplotypes suggests the importance of Shodoshima Island to maintain genetic diversity of the species.

Published online 30 January, 2024; Print publication 30 April, 2024

There have been few field studies to date on female reproductive success in the Japanese serow, Capricornis crispus. Data were collected on female reproduction and kid mortality in a high-density population in Akita City, Japan, for seven years from 1979 to 1985. The parturition rate from 1979 to 1984 was at least 81.1%, and the annual variation (73.3–85.7%) was not significant. Each adult female usually gave birth to a single kid in successive years and may have intermittently had 1- or 2-year interruptions of parturition. In the seven females observed from zero or one year of age, four (57.1%) and three females (42.9%) first gave birth at three and four years of age, respectively. The kid mortality rate from 1979 to 1984 was 54.7%, and the annual variation (27.3–88.9%) was significant. Compared with the pregnancy rates of culled serows in low-density local populations, parturition rates were remarkably high in the study area, perhaps because of good nutritional conditions. In low-density populations such as red-listed areas, it is necessary to monitor fertility rates as well as population densities to avoid local extinction.

Published online 13 March, 2024; Print publication 30 April, 2024

The head contains the visual and the vestibular receptor organs, both of which are important for the control of locomotion. When animals make a turn, they inevitably lean into the circle, or rotate in roll. The aim of this study was to quantify roll rotation of the head and trunk in agility dogs to test the hypothesis that dogs maintain stability of the head in roll independently from the trunk during high-speed turning. Five agility dogs were required to run on a figure-of-eight course. Inertial measurement units (IMUs) comprising gyroscopes and accelerometers were attached to three locations along the body midline: the head, withers (upper trunk), and tuber sacrale (lower trunk). Roll rotation of body segments was estimated using a Madgwick filter. All the body segments leant more to the right during clockwise turning and more to the left during counterclockwise turning. The roll amplitude of the head was approximately half those of the withers and tuber sacrale. These findings support our hypothesis and suggest that head stabilization in roll leads to better vision and vestibular perception during high-speed turning than if roll orientation of the head is fixed to the trunk.

Published online 13 March, 2024; Print publication 30 April, 2024

The present study focused on the above-ground activity of shrews by observing their climbing frequency and duration on aerial parts of plants in a laboratory setting for four sympatric shrew species (Sorex unguiculatus, S. caecutiens, S. gracillimus, and S. minutissimus) in Hokkaido, Japan. All shrew species utilized aerial parts of plant. The lighter S. gracillimus tended to exhibit a higher frequency and longer duration of climbing on aerial parts compared to the heaviest S. unguiculatus, which tended to avoid using such parts. While the sample size is small, the smallest S. minutissimus and medium-sized S. caecutiens seemed to use more aerial parts than S. unguiculatus. All shrew species tended to prefer using the fuki butterbur and the sasa bamboo compared to the other plant types. Additionally, S. unguiculatus and S. caecutiens tended to avoid the use of herbs with the thinnest diameters. These findings are probably related with the diameter and morphology of plant. The result of the present study provides novel insights into the potential niche separation among the four sympatric shrew species in Hokkaido.

Published online 13 March, 2024; Print publication 30 April, 2024

Historically, the excavation in the 1970s and publication in the 80s of Rhinoceros sinensis hayasakai (now known as Nesorhinus hayasakai) represents a milestone in vertebrate paleontology in Taiwan. However, the type materials (including 22 syntypes) are missing after the 1984 publication due to the lack of proper curation and management and reflect the undervalued vertebrate paleontology in Taiwan. Here we found five original specimens out of 22 in two collections (National Taiwan University and Tainan City Zuojhen Fossil Park). The original 22 specimens were recovered from two geographical localities and geological horizons: northern (Taoyuan, Tunghsiao Formation: Early Pleistocene) and southern (Tainan, Chiting Formation: Middle Pleistocene) Taiwan. Our rediscovery of long-forgotten type materials emphasizes the importance of proper specimen curation. Similarly, by clarifying the historical issues and collecting more fossils, vertebrate paleontology from Taiwan promises to offer novel perspectives to understand the origin of modern biodiversity and large-scale extinctions along the eastern margin of Eurasia.

Published online 18 December, 2023; Print publication 30 April, 2024

Cold, hyperarid mountain ecosystems in Central Asia are largely unstudied, and standard studies of well-known phenomena often give surprising results. Here, we tried to look at long-tailed marmots (Marmota caudata) inhabiting a glacier valley in Eastern Pamir as keystone species, providing important resources for other groups of animals. We made several observations suggesting that marmot burrows are a unique habitat used in different ways by several groups of animals: arthropods, birds, and small mammals. Direct measurements showed that burrows maintain a stable temperature despite daily fluctuations outside, and have a much higher humidity. Using camera traps and a self-made endoscope camera, we found that burrows are inhabited by several arthropod species, and are used as shelter by birds and small mammals. Scat analysis showed that marmots were the main food source of predatory mammals inhabiting the valley. Similar observations have been previously made in other habitats. Using a camera trap, we recorded the use of burrows of unknown origin by Turkestan red pika (Ochotona rutila) or the large-eared pika (O. macrostis)—neither of which inhabit burrows. Despite their preliminary character, the results are a valuable insight into the ecological role of marmots in this type of environment.

Published online 4 March, 2024; Print publication 30 April, 2024