Fecal compositions of the Japanese marten (Martes melampus melampus) in the suburbs of Uenohara City, eastern Yamanashi, central Japan showed clear seasonal changes. In spring, animal materials such as mammals (33.3%) and insects (29.1%) were dominant. In summer, fruits such as Morus australis, Broussonetia kazinoki, and Cerasus (Prunus) spp. increased to 35.0%, and insects (29.7%) were also important. The occupancy of fruits such as Cornus controversa, Cornus macrophylla, Aphananthe aspera, and Celtis sinensis further increased up to 46.4% in autumn. The proportion of fruits and seeds further increased in winter (67.5%). This seasonal pattern is typical of the Japanese marten, as shown in the previous studies, although contrary to expectation, the marten fed on a considerable proportion of fresh leaves and insects in spring, small amounts of crustaceans in autumn, and rarely fed on Actinidia aruguta. Occupancy-rank curves showed three patterns: 1) Many samples contained great occupancy values, showing concave shaped curves. Fruits in summer, autumn, and winter showed this pattern. 2) Occupancy values gradually declined along the rank order. This pattern included mammals in spring and insects in spring and summer. 3) Small portions of samples took great values and then abruptly declined, yielding an L-shape. This pattern included stems and fruits in spring, crustaceans and insects in autumn, insects and leaves in winter. Factors affecting these patterns include food availability and the marten’s selectivity.
To analyze the radiocesium contamination of wild boars (Sus scrofa) caused by the Fukushima Nuclear Power Plant accident, we measured the radiocesium concentration in the masseter muscle of 288 wild boars collected in the Yamizo region between March 2011 and January 2013. To compare contamination before and after the accident, we conducted the same measurements on 18 individuals collected between December 2010 and February 2011 before the accident. We also collected stomach and rectal contents, as well as urine, to examine the concentration of radiocesium. The contamination level of muscle significantly increased immediately after the accident; however, it fell to the previous level after 10 months, and increased again 19 months later. The contamination level of stomach contents changed seasonally, but the relationship of the level between stomach and muscle was unclear. Rectal contents showed a constant contamination level that was higher than that of muscle. In contrast, the contamination level of urine was lower than that of muscle.
Based on our results, it is possible that radiocesium in the stomach contents was partly absorbed by the muscle of wild boars. Furthermore, it is possible that wild boars accumulate radiocesium and scatter it as excretion.
Acoustic monitoring of the echolocation calls of bats has recently attracted attention as a means of evaluating environmental conditions. However the ultrasound calls of bats have a large variety depending on the species’ characteristics, activities and surrounding environments. Therefore it is necessary to develop classifiers that can identify bat species by various echolocation calls precisely. In this study, we developed a bat species classifier and applied it to acoustic monitoring. A dataset of 6,348 echolocation calls consisting of 3 families, 7 genera and 11 species of Japanese bats was developed by extracting 75 dimensional feature vectors from each echolocation call with a bat acoustic analyzing tool. A classifier was developed combining the Random Forest and Support Vector Machine algorithms. The overall accuracy of classification at the genus level was 96.3%, and the species level was 94.0%. We applied the classifier to a site in Osaka, Japan and we estimated the existence of Pipistrellus abramus and Miniopterus fuliginosus successfully and Rhinolophus ferrumequinum, Myotis ikonnikovi and Myotis macrodactylus incorrectly in the field. Based on this result, we discuss the improvement of classifiers and applicability to real world situations.
Recently, the number of harbor seals on Daikoku island in the Akkeshi region have tended to increase. Consequently, fishery damage caused by the seals has also increased in the bay, which is located near Daikoku island. However, because the seals leave no trace after they feed, it is unclear how much seals actually feed on the fish and what is the real impact on the fisheries. In this study, we aimed to clarify when and how often seals use the Akkeshi Bay as a feeding ground, and what kind of individuals are utilizing the area. The behavioral patterns of harbor seals that use the Akkeshi Bay were studied based on information from transmitters and land-based observation on Daikoku island. As a result, two individuals—an adult female and a female pup—were captured in Akkeshi Bay. The location used by both individuals in the bay overlapped with small fixed nets, and they generally conducted short, shallow dives. The seals moved to another location from the inside of the Akkeshi Bay after early spring, and the timing of the move overlapped with the end of fishing season. These results showed that fishing and the seals are closely related.
The efficient use of various culling methods is necessary for sika deer population management. We investigated the appearance of sika deer before and during culling operations on Nakanoshima Island, Hokkaido, Japan, on 11th February and 19th March in 2016, respectively. Setting infrared-triggered cameras at 7 bait sites, we first classified the situation, and second provided the number of deer photographed per hour at morning, afternoon, and night. We classified the situation at 4 sites and all sites into nocturnal activity before and during culling operation, respectively. Before the culling operation, the number of deer photographed in the morning and afternoon were significantly lower at 5 and 2 sites than that in night, respectively. Additionally, sightings in the morning and afternoon were significantly lower at 6 and 5 sites than sightings at night during the culling operation, respectively. Although the total number of deer photographed during the culling operation decreased, we found no significant results of the number in the morning, in the afternoon, and at night. Therefore, we suggest that the situation at bait sites was influenced by past continuous culling operations before the start of our culling operation. Wildlife managers should understand and monitor the daily activity patterns of sika deer, and select safe and efficient culling methods.
We captured 11 Japanese white-toothed shrews (Crocidura dsinezumi) on Tobishima Island, Yamagata Prefecture in 2015 and 2016. We determined haplotypes of mitochondrial cytochrome b gene for the shrews on Tobisima Island. We constructed a maximum likelihood tree and a statistical parsimony network, and determined the phylogenetic position of the shrews on Tobishima Island among the shrews in Japan and Cheju Island (South Korea). We found that the population on Tobishima Island belonged to the haplogroup consisting of those from the eastern part of Japan, but had unique haplotypes which have not been reported. In addition, we describe the body weight, head and body length, tail length, ear length, hind foot length, total length and tail ratio of the shrew on Tobishima Island.
We measured the density and length of underfur and straight guard hair of the Japanese dormouse Glirulus japonicus (n = 30) using museum specimens and compared these two characters with those of the large Japanese field mouse Apodemus speciosus (n = 5) caught in wild. We also investigated geographical variation in dormouse body hair. We found that density of body hair and the relative ratio of underfur of the dormouse is greater than those of the field mouse. We also found that the dormice investigated in the study were divided into two groups based on the cluster analysis, which did not seem to correspond to known genetically different populations. This indicates that local variation can be found in body hair irrespective of genetic variation.
To reveal the roosting behavior of Hilgendorf’s tube-nosed bat Murina hilgendorfi, we studied their usage of a range of potential roost habitats, including abandoned mines, tunnels, dead broadleaf traps, dead summer cypress (Bassia scoparia) thickets, and outer building walls, in Hayakawa, Yamanashi Prefecture, Central Japan, between September 2013 and August 2016. Abandoned mines and tunnels were used from May to November, and most frequently in May, June and July. Dead broadleaf traps were used in only September. Dead summer cypress thickets were used in June, August, September and October. The outer walls of buildings were used in June and October. Bats appeared to select exposed roost habitats, such as dead summer cypress thickets and outer building walls, in preference to hidden roost habitats, such as dead broadleaf traps. Hilgendorf’s tube-nosed bats used a variety of roosts in June, August, September and October, but when the same roost habitat was checked on successive days, bats appeared and disappeared at intervals of a few days, implying that they frequently switched roost sites.
We applied infrared thermography to detect sika deer for culling. Deer were distinguished from ground surface or surrounding vegetation by high temperature in early morning. Using infrared thermography, we could find more deer than those without use of that device. The number of deer in a herd tend to be larger with the device than without it. The device was able to detect deer no matter where they stood behind vegetation in so far as a part of deer could be visible. Thus, we could find deer in a herd with less omission, and herd size could be estimated more correctly with infrared thermography. Using such a device could also lead to improved efficiency of culling methods by detecting carcasses easily.
Between 12th July and 3rd September 2014, a camera trap survey (n = 10) was conducted at three small green areas (0.13–1.65 ha) in the Fuchu campus of Tokyo University of Agriculture and Technology, Fuchu-city, urban area of Tokyo. Raccoon dogs (Nyctereutes procyonoides), Japanese badgers (Meles anakuma), and masked palm civets (Paguma larvata) were photographed. Raccoon dog cubs were also photographed. Japanese badgers were newly discovered in this area.
A workshop targeted for young researchers and students was held during the 2016 Annual Meeting of the Mammal Society of Japan. The purpose of this workshop was to provide opportunities for young researchers and students to interact with each other. Various lectures and talks were given by the authors and seven lightning talkers. The number of participants reached about 50. A questionnaire given to attendees indicated 75% of the participants were students. Also, 88% of the people were satisfied with the contents of this workshop, and all of them wanted more events in the conference based on their generation. From these results, it was suggested that academic events targeted for young researchers and students may contribute to develop their research and interactions. However, the students who attended the workshop were only 18% of the total number of students who joined the Annual Meeting. In order to cover the opinion of the young researchers and students as a whole, it may be necessary to distribute the questionnaire all participants in the Annual Meeting for the future. To improve the management of MSJ for next generation, we should try to understand the wishes and demands of young researchers and students as much as possible.
In early April of 2016, in an apple orchard of Aomori Prefecture, Japan, a male albino individual of the Japanese field vole, Microtus montebelli was captured. This individual weighed 23.0 g as a young age and carried five plantar pads. In contrast to the wild type of the Japanese field vole which has a grayish-brown colored coat, the present individual had an entirely white-colored coat and red eyes, as is consistent with the typical appearance of albino. This albino vole was one of twelve voles captured during the trapping survey for small mammals (90 trap nights). After the capture of this albino vole, we continued to survey at the same orchard but no other albino voles have been trapped. To date, the current report is the third record of an albino individual of M. montebelli.
Night shooting of sika deer (Cervus nippon), which became legal with restricted conditions in 2015, without proper strategy and tactics may increase the number of deer habituated to hunters, and may not be an efficient method to reduce overabundant deer populations. We took the White Buffalo Inc. Professional Shooting Training course between August 5 and 7, 2016. The training included 10 hours of shooting practice and test on the shooting range, 4.5 hours of shooting practice on a mobile shooting training range in a forested environment, 4.5 hours of live deer shooting in an enclosed deer research facility, 2.5 hours of lecture about equipment and so on, and 1.5 hours of discussion. We practiced shooting targets and live deer by 5.56 mm caliber rifles with optical scopes, heavy barrels and sound suppressors at various distances with bench rest and mobile shooting. It is necessary to practice shooting proper firearms intensively in order to shoot the centers of brains of all deer in a herd consecutively. Marksmen should kill all deer of a herd in order not to increase the number of deer habituated to hunters, since night shooting is a last resort to reduce deer populations. We conclude that a training program for safe and efficient night shooting should be developed in Japan.
Specimens of the Korean giant flying squirrel, Petaurista leucogenys hintoni, and the Korean marten, Martes melampus coreensis, registered as type specimens in the Natural History Museum, London were considered based on the combined examinations of specimens’ characters and attached specimens’ tags. The type specimens of these two Korean mammals had not found in previous research; however, a specimen of Petaurista leucogenys hintoni (specimen’s code: BM184.108.40.206) is considered to be the holotype of this species. A specimen of Martes melampus coreensis (specimen’s code: BM220.127.116.11) was not corresponded to the type described in the original description, but the measurements and specimen’s appearance were fit to the referred specimen used in the species description. These specimens were previously deposited in Keijo First High School, where one of the authors of these original descriptions, Tamezo Mori, was appointed to be a professor, then donated to the Natural History Museum, London. The histories of these specimens are discussed with the biographies of related researchers Tamezo Mori and Nagamichi Kuroda.
In early Meiji, when Japanese zoology met modern scientific color under lectures by foreign teachers, we did not have any researchers specialized on mammals. Some scholars started to introduce foreign literature about mammals in several journals. After the Tokyo Society of Zoology were settled with publishing the “Doubutsu Gaku Zassi”, Isao Iijima of the Imperial University and Motoyoshi Namie of Tokyo Education Museum firstly endeavored to disperse the faunal information or knowledges for the mammalian study. In the early 20th century, Bun-ichiro Aoki, Yoshio Abe or some representative researchers educated at the Imperial University contributed to Japanese mammalogy in early Showa. Several foreign people who visited or stayed in this period also facilitated to study Japanese mammals on the abroad by collecting and sending the specimens here. In this review paper, our account of Japanese mammalogy from the Meiji to 1923, the year first mammalogical society settled in Japan, focuses on representative individuals with their achievements and historical contexts.