We analyzed the diets of sika deer from Kyushu University’s Kasuya Research Forest based on point-frame fecal surveys conducted between February 2023 and January 2024. Leaves, mainly from evergreen species, accounted for 42.1% of the fecal contents in February, with the remainder comprising fiber and culms. In April, the leaf component decreased, whereas the fiber component increased to 45.8%. In August, grass leaves comprised only 11.2%, and culms increased to 56.5%, suggesting that deer ventured out of the forest to feed on grasses. In October, the leaf component decreased further, while culms decreased to 12.0% and the fiber content again increased to 39.0%. Acorns of Castanopsis cuspidata and seeds of pokeweed (Phytolacca decandra) seeds were recovered from fecal samples in October. In January, the leaf component decreased to 16.8% and the proportion of unidentifiable materials increased to 35.1%. The deer population in our study area increased rapidly over several years around 2010, profoundly affecting the local vegetation. The small occupation of green leaves in the deer diets (23–33%), even during the plant growth season, reflected the vegetation deterioration caused by the increase in deer.

To overcome severe environmental conditions such as cold or food shortage, many small mammals utilize hibernation or daily torpor. Hamsters (subfamily Cricetinae) are a well-known group using hibernation and daily torpor. Interestingly, among hamsters, hibernators tend to have relatively larger body sizes. In contrast, species that use daily torpor have a small body size, although some hamsters still remain unknown in torpor characteristics. In this study, we attempted to induce torpor in the greater long-tailed hamster (Tscherskia triton), which has a large body size among hamsters, by exposing them to condition that mimic winter (short photoperiod 8L:16D and low temperature 5°C). We successfully observed a spontaneous decrease in body temperature, and the duration of the torpor bout did not exceed 24 hours. Therefore, it was revealed for the first time that the greater long-tailed hamster is a heterothermic mammal that utilizes spontaneous daily torpor.

The Ryukyu flying fox, Pteropus dasymallus dasymallus, which is distributed in the Tokara Archipelago, was investigated in 2023. We reconfirmed that the flying fox P. d. dasymallus inhabits the Nakano-Shima, Akuseki-Jima, and Taira-Jima since over 30 years before the survey. The population of flying foxes on each island were 35, 26, and 2. Flying foxes were not observed at Takara-Jima, Kodakara-Jima, Kuchino-Shima, or Suwanose-Jima; however, in the past, they were temporarily confirmed to have inhabited these regions. Once flying foxes disappear, their population cannot be recovered and resettled on these islands. Because tree species that provided stable food and roosting sites for flying foxes were concentrated in the villages, the living spaces of the flying foxes and local citizens might have overlapped. In other words, the habitats of flying foxes depend on citizens’ awareness of the natural environment. In the future, it will be necessary to promote the rehabilitation of flying foxes by improving their environments; this would require collaboration of islanders, governments, and scientists.

The dietary habits of raccoon dogs (Nyctereutes procyonoides) in the Hokkaido and Kyusyu regions of Japan differ depending on their habitats. Information on the dietary habits of raccoon dogs in Hokkaido is limited to populations distributed in the forested areas of the central region and Okushiri Island. We aimed to understand the dietary habits of raccoon dogs in Tokachi, Eastern Hokkaido, by analyzing their stomach contents. Raccoon dog carcasses were collected between December 2021 and November, 2022. Eleven food groups (17 food items) were identified from the stomach contents of 38 raccoon dogs. The frequencies of occurrence and percentage volumes were calculated using the point-frame method. The frequency of occurrence and percentage volume of grasses (94.7 and 18.1%, respectively) and insects (71.1 and 13.5%, respectively) were high. These items are thought to be important foods for raccoon dogs in Hokkaido because they are frequently foraged on, as per the results of a previous study on their dietary habits. Our findings suggest that raccoon dogs forage on grasses, concentrated feed, and maggots within and around livestock sheds in winter, when food is scarce. The presence of multiple food items affected the dietary selection of the raccoon dogs.

In the management of alien raccoon (Procyon lotor), confirming the presence of the species is crucial. Raccoon bait traps, which can be easily and inexpensively constructed, serve as a method for confirming raccoon visits. However, their effectiveness as a detection method, including their detection power, remains unclear. In this study, we investigated the detection power of bait traps in confirming presence by assessing false-positive and false- negative rates per visit. Additionally, we compared the effectiveness of bait traps with that of camera trapping. The results showed that the false-positive rate per other carnivore visit for bait traps was 0.00, indicating a low rate, while the false-negative rate was 0.66 (95% CI: 0.55–0.76), suggesting a high rate. Furthermore, there was a significant correlation between the measurements made using bait traps and the frequency of captures using camera traps, with higher capture frequencies correlating with more positive determinations. These findings suggest that bait traps have a certain level of effectiveness for confirming presence. Although the false-negative rate per visit was high, no false-positives were observed in this study. Therefore, by implementing strategies, such as long-term and large-scale deployment, bait traps could potentially become an effective method for detecting presence of raccoons.

We examined microscopic features of dorsal guard hairs in 20 species of bats (Pteropus dasymallus, Rhinolophus nippon, Rhinolophus cornutus, Hipposideros turpis, Pipistrellus abramus, Pipistrellus endoi, Hypsugo pulveratus, Myotis macrodactylus, Myotis bombinus, Myotis pruinosus, Myotis yanbarensis, Vespertilio sinensis, Plecotus sacrimontis, Murina hilgendorfi, Murina ussuriensis, Murina ryukyuana, Miniopterus fuliginosus, Miniopterus fuscus, Tadarida insignis, Tadarida latouchei) from the Kyushu District and the Ryukyu Islands. The medulla was observed only in Pteropus dasymallus. The tips of the hair were of the bamboo-shoot and insect-antennae type. The connection types of the scales were broadly divided into imbricate and coronal. The shapes of the upper edges of the scales were classified into four types: crenate, denticulate, equal, and unequal hastate. In addition, mingling (irregular scale length) and zigzagging (connecting the scales in a zigzag shape) were observed. We constructed a hair identification key based on morphological characteristics and measured hair length, scale length, and width for each species. This study suggests that hair identification keys can be useful in fields such as foraging ecology.

We conducted an acoustic survey of bats from late May to early September 2023 on Miyake-jima Island, the Izu islands. Miyake-jima Island is located approximately 75 km from the Izu Peninsula in mainland Japan. Here, bat calls in 20 kHz range of the FM/QCF shape were recorded in June 2023. These bat calls were made by bat species not previously recorded on the Izu Islands. Based on the shape and peak frequency of the pulse, the calls seem to be those of Nyctalus aviator or Vespertilio sinensis. Further surveys are needed to determine whether the appearance of these bats on Miyake-jima Island was accidental or seasonal.