In April 1910, Professor Shozaburou Watase, Tokyo Imperial University, introduced the mongoose, Hesperates auropunctatus, an alien mammal, into the Okinawa and Tonaki Islands, in the Nansei Islands, Japan. This paper reviews the introduction process and reveals the following seven points. First, Hisatomo Nakagawa partially translated an article on alien mammals and birds, including the mongoose in Jamaica, from English into Japanese, without indicating the article’s source (Nakagawa 1900). Second, S. Watase was advised to maintain a friendship with H. Nakagawa throughout their careers. Third, it has been proved that an article by Palmer (1899) was the source for Nakagawa’s translation (1900), and a comparison of Nakagawa (1900) with Palmer (1899) showed that Nakagawa (1900) did not translate some alien species and the need for legislation, as illustrated by Palmer (1899). Fourth, S. Watase’s logic for introducing the mongoose into the Okinawa Islands was explained in his publications and newspapers reporting his lecture held in Naha (Okinawa), April 14, 1910. Fifth, although S. Watase did not list the literature cited in his publications, it was suggested that he had read Espeut (1882), Duerden (1896), and Palmer (1899) about the mongoose introduction to Jamaica, and the words “S. WATASE,” “3 SEP. 1907,” and “IMPERIAL UNIVERSITY, TOKIO” had been stamped on the cover of the offprint of Palmer (1899), housed in the Watase Library, the Library of National Taiwan University, Taiwan. Sixth, the events of the mongoose introduction into Okinawa carried out by S. Watase were recorded chronologically from 1907 to 1910. Seventh, due to poor accessibility, three publications from 1910 had been overlooked until an edition was reprinted in 2015. By comparing them carefully, it was apparent that Kishida (1924, 1927, 1931) lacked references in his descriptions and incorrectly reported locality names and the number of mongooses introduced, although his publication had been the only literature in Japanese describing the history of the mongoose introduction into Jamaica, Okinawa, and other foreign areas at that time.

We aimed to clarify the effects of deer-proof fences and the differences in grassland utilization on the frequency of occurrence of sika deer and the intensity of grass consumption in artificial grasslands and adjacent forests. We evaluated the frequency of occurrence of sika deer by camera-trap surveys, and the intensity of grass consumption was evaluated by an exclosure experiment in six artificial grasslands in the Yatsugatake region, Japan. The occurrence frequency of sika deer in the artificial grasslands was higher than that in the adjacent forests, regardless of the protection offered by using deer-proof fences. In contrast, in the artificial grasslands within settlements surrounded by deer-proof fences, the occurrence frequency was much lower than in the grasslands protected individually by deer-proof fences. Sika deer intensively used grasslands unprotected by deer-proof fences, and the differences in grassland utilization did not affect their frequency of occurrence. In the artificial grasslands unprotected by the deer-proof fences, grass biomass outside the exclosures decreased significantly, up to 43%, compared to that within the exclosures. These results indicate that sika deer grazing has an intensive impact on artificial grasslands and that deer-proof fences should be established around artificial grasslands and grasslands within settlements to prevent grazing damage.

It is challenging to study the social relationships of wild narrow-ridged finless porpoises because they do not have the dorsal fin or clear body coloration patterns usually used by researchers for individual identification to record interactions among individuals. Here, we investigated the affiliative and aggressive behaviors of individually identified captive narrow-ridged finless porpoises (five males and six females) in Toba Aquarium and Minamichita Beachland Aquarium, Japan, using 437 hours (54 days) of visual observations and video recordings to reveal their social relationships and the robustness of the relationships between individuals. We found a bout structure in the back-rubbing behavior and defined the bout as successive behaviors occurring within 2 min. Various social relationships were found, including three long-term stable affiliative pairs that were independent of sex and age. Within the three long-term stable affiliative pairs, one pair maintained the affiliative relationship after a social disturbance, defined as an event, in which the individuals in the same tank were changed, and another pair restored their affiliative relationship following one day of aggressive behavior after the social disturbance. These results suggest that several captive narrow-ridged finless porpoises have robust and stable affiliative social relationships that are not affected by social disturbance.

Raccoon dog roadkills were recorded on a 35-km research route between Ami Town, Ibaraki Prefecture, and Narita City, Chiba Prefecture, on weekdays for 32 months. A total of 124 roadkills were recorded, most of which occurred in autumn. Approximately half of the roadkills occurred in the paddy-field dominated zone, which accounted for only 1/3 of the total route. We performed PLS regression to analyze the relationship between roadkill incidents and land use using GIS, and the results showed that the rates of paddy fields and residential areas with ≥30% vegetation had significant positive effects on the number of raccoon dog roadkills. In addition, in the paddy-field dominated zone, the roadkills occurred differently between the homogeneous region of the large-scale paddy fields and the complex region of the small-scale paddy fields with houses and woodlots, showing that landscape complexity affected when and where the raccoon dog roadkills occurred. In conclusion, seasonal behaviors such as dispersion, habitat selection, and landscape structure can affect raccoon dog roadkills.

We report a new problem for snare traps, in addition to the various other problems associated with snare traps. Specifically, we observed an increase in cases in Karuizawa, Nagano Prefecture, at the southern foot of Mt. Asama, where Japanese black bears (Ursus thibetanus) fed on sika deer (Cervus nippon) captured by snare traps. A total of 66 wild boars (Sus scrofa) and 178 deer (40 males and 138 females and fawns) were caught in snare traps between April 2017 and June 2019. From these, at least one boarlet and 64 female deer and fawns were eaten by black bears. However, adult boars and male deer were not attacked or consumed. In addition, the bears buried their prey (one boarlet and 39 deer) to hide them from other predators. Overall, the bears had become considerably more aggressive when searching for deer leftovers, which became dangerous for cullers controlling deer populations in the area and for hikers. In 2019, bears did not seem to be threatened by the presence of humans because they continued to feed on deer. Therefore, for safety reasons, the feeding behavior of bears should be considered when setting traps in bear-inhabited areas.

We observed and analyzed the social behavior of one mature male and two mature female Commerson’s dolphins in the Toba Aquarium in Mie, Japan. Both females delivered calves the following year, enabling us to roughly estimate the date of conception based on the gestation period of the species. Aquarium staff observed the male displaying approaching and following behaviors toward the female four times a day for 119 days. When these behaviors were most frequent, we determined that the female was in estrus. The estrous cycle was estimated at 28 days from the behavioral record. We observed and quantitatively analyzed the following social behaviors performed by the male in relation to the female: parallel swimming, following, stopping in parallel positions, contact, flipper rubbing, male contact to the female genital area, and approaching a female with an erection. We compared these behaviors among estrus, anestrus and pregnancy periods, and concluded that these social behaviors were more frequent during the estrus period. Social behaviors toward an estrus female occurred more frequently than toward an anestrus female. Furthermore, the duration of the following behavior and parallel swimming were significantly longer during the estrus period. These behavioral characteristics might help us to understand estrus in females in a non-invasive manner.

An ecological survey of the Japanese northern bat, Eptesicus japonensis, roosting in artificial structures was conducted at Norikura Kogen, Nagano Prefecture, central Honshu, from May to October 1990 to 2018. The Japanese northern bat forms nursing colonies to give birth and nurse infants. Roost switching occurs due to predatory activities and the improvement or abandonment of roosts. The start date of the formation of nursing colonies, the stability of the number of colonies, the maximum number of colonies, and the dissolution date of the nursing colonies changed each year. Populations in nursery colonies fluctuated from 77 individuals to 347 individuals.

This paper describes the mammalian fauna present during the first half of the 20th century (1900–1945) in the drainage area of Kurobe Gorge, eastern Toyama Prefecture, central Japan, originally recorded by mountaineers of that time. The mammalian fauna described in the mountaineering reports are as follows: wild boar (Sus scrofa), Japanese serow (Capricornis crispus), Asian black bear (Ursus thibetanus), Japanese monkey (Macaca fuscata), Japanese marten (Martes melampus), Japanese raccoon dog (Nyctereutes procyonoides) or badger (Meles anakuma) (both referred as “Mujina”), Japanese hare (Lepus brachyurus), Japanese squirrel (Sciurus lis), Japanese giant flying squirrel (Petaurista leucogenys), and Chiroptera (bats). In the early 1900s, the wild boar had been reliably recorded only at Yanagawara, the most downstream area of Kurobe Gorge, which is currently submerged in Unazuki-Dam Lake. These reports indicate that the major game animals in Kurobe Gorge at the time were Asian black bears, Japanese serows, and Japanese macaques; Japanese giant flying squirrel, Japanese squirrel, and “Mujina” were also hunted on occasion. Many mammal sightings recorded in the mountaineering reports include the date and locality. In addition, the mountaineers hired mountain guides who made a living as hunters and anglers. While trekking, information on hunting and mammals was communicated between guides and mountaineers and often recorded in the mountaineers’ reports. The mammalian species recorded were restricted to medium- or large-sized mammals, likely because they are easily sighted, and some were important game animals. In contrast, there are limited scientific reports documenting the mammals in Kurobe Gorge during the first half of the 1900s. Thus, mountaineering reports provide valuable resources for early 20th-century mammalian information

It is well known that acorns, the seeds of Fagaceae family plants, are important food sources for many wildlife species during autumn and winter. However, they contain tannins as defensive chemicals. We conducted cafeteria tests on wild mammals using acorns of four plant species: Quercus serrata, Quercus acutissima, Quercus glauca, and Castanopsis cuspidata, all of which have different tannin astringencies. In the cafeteria tests, although the data were insufficient and fragmentary, raccoon dogs (Nyctereutes procyonoides) significantly selected the less astringent Castanopsis cuspidata over the relatively strong astringent Quercus spp. Since some rodents and browsers have been reported to have physiological responses to tannins, it is desirable to develop physiological studies in raccoon dogs and other middle- and large-sized omnivores.

This report describes the occurrence of Japanese serow fecal pellets in Touki-hodou Tunnel (an artificial pedestrian tunnel adjacent to the Kurobe Gorge Railway; 1 m wide and 1.8–2.1 m high) in eastern Toyama prefecture, central Japan. The occurrences of fecal pellets at five locations within the tunnel were described. DNA examination was conducted for five fecal pellets to confirm the identification of species. Serow feces were dotted along both sides in the tunnel at each location at approximately 1 km intervals. Serow fecal matter extended 10–30 cm and comprised >100–200 fusiform-shaped pellets, which adhered to each other. During the late spring to late fall period of 2019, Japanese serow reached 50–370 m deep into the tunnel from the gateways and traveled at least 100–740 m within the tunnel. The Touki-hodou Tunnel could be classified as an artificial cave. As there are no completely dark areas within the tunnel, Japanese serows were able to travel long distances of several hundred meters. At present, it remains unclear what induced Japanese serow to enter the tunnel.

The Asian black bear in Kyushu is believed to be extinct, and very few specimens remain. In addition, their morphological characteristics remain unclear. In 1976, an Asian black bear was found in the Wanabano Daiichi Cave, located on Mt. Kyojo Kyushu. 14C dating and genetic traits were reported for this specimen. In 2013, the author rediscovered the cave and unearthed 50 postcranial bones of a bear. The femur of the bear was dated to 2,080 ± 20 yr. BP by the 14C method. These data correspond to the early Yayoi period. These postcranial bones and the cranium found in 1976 are thought to be the same individual because the cranium articulated to the first cervical vertebrae accurately, and the results of 14C dating are consistent. To clarify the morphological characteristics of the specimens from Mt. Kyojo, the measurements of the cranium and mandible of this specimen were compared with specimens from the Asian continent, Taiwan, and the other population from Japan. The measurement of the specimen from Mt. Kyojo fitted within the range of the specimens from Japan. The specimen from Mt. Kyojo is characterized by relatively large LMOL (Greatest anterior-posterior length of left second upper molar) and LLM2 (Greatest anterior-posterior length of left lower second molar) compared with GLC (Greatest length of cranium). Using discriminant functions, the scores of the specimen from Mt. Kyojo were included in the range of the scores of the specimens from the Western Chugoku population. These results are consistent with the previous report of the genetic traits’ study.

As human-dominated lands expand, wide-ranging large carnivores increasingly occupy the same lands as people, which has become a worldwide issue. It is increasingly challenging to conserve wildlife populations and mitigate human-wildlife conflict simultaneously. To foster coexistence with bear species, the reduction of human-bear encounters and the frequent bear occurrence in human-dominated lands should be addressed first. Understanding how bears use anthropogenic landscape components and identifying factors that influence the frequency of bear occurrence are critical for developing long-term solutions. By reviewing previous studies, I focused on woodland patches, an open matrix of agricultural lands and settlements, riparian forests, and roads to explore how bears used and selected such anthropogenic lands as a part of their habitat. I also provide a case study of habitat selection by Asiatic black bears around villages and farmlands on foothills in the central Japan Alps to help understand the situation in detail. By synthesizing biological and ecological hypotheses to explain the factors behind increased bear use of human-dominated lands, I identify the most plausible explanation in the case of Asiatic black bears and suggest future directions for research and management implications to solve this issue and enable long-term coexistence with large, elusive carnivores.

The distribution range of wild animals in Japan has expanded rapidly in recent years, and conflicts with human activities have become a problem. This paper presents the results of the field sign and camera trap surveys that were conducted in two areas in southwestern Tochigi Prefecture and outlines the habitat use patterns of wild boar in Japan’s “satoyama” landscapes – culturally iconic rural areas characterized by mixed forests and fields.

Assessing wildlife habitat is important for elucidating the ecology of target animals and the conservation of habitats. At this time, it is necessary to evaluate what animals are selected and how they are distributed. Animal habitat selection and distribution patterns result from the decision-making process of how animals react to the landscape structures. It is important to evaluate the spatial scale on which processes are captured (individual to individual population, local population, etc.). This paper deals with the importance of spatial scales in wildlife habitat assessment; it summarizes the cases in which spatial scales (extent and grain size) were taken into consideration in previous studies and introduces the scale dependence of resource selection that the authors examined for Japanese macaques (Macaca fuscata). Crop damage is the result of the decision-making process on which Japanese macaques are selected. Here, the paper clarifies the scale dependence of how this process responds to spatial spread. It was found that environmental factors related to crop damage change depending on the spatial scale setting. However, it was also found that the linear relationship between crop damage and each environmental factor was constant, independent of the spatial scale. In other words, it was shown that the same measures may have different effects depending on the extent to which the measures are implemented when damage is being managed. Furthermore, the paper estimates the importance of scale setting in wildlife management by finding the optimal spatial scale for each herd. A meaningful discussion of spatial scales in habitat assessments is necessary to develop concrete policies for wildlife management.

Landscape genetics was proposed in 2003 as a discipline to examine the effect of spatial patterns of habitat on the genetic diversity of wildlife populations. It aims to clarify the effects of landscape characteristics on genetic structure and to clarify ecological processes using genetic data. In conventional population genetics, one of the major objectives is to verify the effect of isolation-by-distance (IBD), but in landscape genetics, the effect of landscape factors on isolation-by-resistance (IBR) and isolation-by-barrier (IBB) is examined. For the black bear, farmland and residential area functioned 25-times as much as resistance. In addition, the influence of topography was also detected. In the Asian black bear, the difference in elevation and the degree of undulation between individuals affected the gene flow rather than the elevation. IBB did not have any effects. Our genetic data suggested sexually dimorphic patterns of behavior exist in the Asian Black Bear, corroborating findings previously reported using landscape ecological methods. Landscape genetics is expected to shift from population-based analysis to individual-based analysis. In addition to genetic analysis technology, knowledge of spatial analysis, and statistics is required; therefore, cooperation between different fields will be necessary.