Wild boar (Sus scrofa) prefer to feed on hard masts, but some hard mast species contain tannins which are astringent substances used as defensive chemicals. Tannins have negative effects on consumers, such as decreased protein digestibility owing to their astringent properties. As a defense mechanism against tannins, pigs (S. s. domesticus) secrete proline-rich proteins (PRPs) in their saliva which bind to tannins. However, it remains unclear how well PRPs bind to hydrolyzable tannins in hard masts. We analyzed PRPs extracted from wild boar parotid glands and tannins extracted from Quercus serrata acorns and found that the relative binding affinity of PRPs to the hydrolyzable tannins was 1.61, which was 2.5 times higher than that of bovine serum albumin. The amount of chestnut (Castanea crenata) and Q. serrata hard mast consumed positively affected PRP production per total parotid gland, whereas the amount of Castanopsis cuspidata acorns and bamboo shoots consumed negatively affected PRP production. Wild boar may adjust their PRP production in response to the opportunity to consume tannin-containing hard masts.
In the temperate zones, mammalian body weight increases via fat deposition prior to the onset of winter. However, seasonal variations in the body weight of wild raccoon dogs (Nyctereutes procyonoides) have never been assessed. We assessed seasonal changes in raccoon dog body weight using 118 males and 77 females aged at least 1 year in Wakayama, western Japan. Mean body weight was lowest in May (3.4 kg) and peaked in November (4.1 kg), representing an increase of 21.2% from summer to autumn. This pattern of body weight change is likely to reflect caloric consumption and use throughout the year, given that raccoon dogs consume fruit to increase body fat in autumn, and then utilize their fat resources during winter.
To reduce the population size of sika deer, efficient operation of snare traps is necessary. However, there have been few studies on the sika deer’s response to snare trap capture. We aimed to compare sika deer’s vigilance behavior and stay time at the trap sites before and after snare trap captures. We also monitored the frequency of appearance at trap sites and in the surrounding area. This study was conducted from August 2019 to February 2020 to collect data on the vigilant behaviors, stay time, and frequency of appearance in photographs. We found that vigilance behavior during the capture phase was higher than before the capture phase and remained high afterwards. Although the frequency of appearance in photographs at the capture sites was highest before the capture phase, no significant differences were detected in the frequencies at the surrounding sites throughout the study period. This result indicates that it would be desirable to relocate snare traps and bait from trap sites to the surrounding areas after capturing sika deer in the target area. Consequently, it is possible that snare traps can continue to be used to capture sika deer and effectively reduce their population.
Wildlife habitats in urban areas are generally highly fragmented and this has negative impacts on mammalian species. However, some mammals have adapted to urban environments sufficiently well to maintain and expand their population. The Japanese squirrel (Sciurus lis), an arboreal animal, is thought to be sensitive to habitat fragmentation. In some urban areas, they do move between habitats. To clarify the inter-habitat movement of squirrels within the urban landscape based on seasonal changes and sex differences, we radio-tracked 18 squirrels in Morioka City, Iwate Prefecture, Japan. We observed 204 movements between habitats in eight males and three females. The number and frequency of inter-habitat movement of individuals were significantly higher in males than in females. Males showed a high frequency of inter-habitat movement during the leaf expansion period and significantly less movement during the deciduous period. The different movement patterns between the sexes were attributed to differences in habitat use and mode of establishing home ranges. Seasonal changes in inter-habitat movement are thought to be driven by changes in food resources and endeavor to avoid predation risks. Little movement was observed during the mating season, suggesting that genetic exchange was not promoted by the inter-habitat movement of adults within the study site.
A literature survey on the use of lutai (fetal Sika deer, Cervus nippon) yielded 128 references in the literature (108 from Japan and 20 from mainland China and Taiwan). Lutai was first used as a medicine among some highly-ranked samurai in the early 17th century. In the early 19th century (late Edo period), lutai was believed to be an efficacious remedy for women with sickness following childbirth. In the late 19th century and the early 20th century (from the end of the Edo period to the Meiji-Taisho period), medical practices were widely published and the use of lutai became popular among ordinary Japanese people. In the mid-19th century (the early Meiji period), at least 27,000–40,000 pieces of lutai were produced in Hokkaido, mostly for domestic and international trade. Some lutai was also produced in Honshu, Shikoku, and Kyushu. The commercial value of lutai varied considerably among regions and over time. It is probable that targeted hunting of pregnant female deer prevailed in regions where lutai had a high commercial value, which could be a cause of the severe population decline of Sika deer in Japan during the Meiji-Taisho period.
In 1872, Alphonse Milne-Edwards, a mammologist of National Museum of Natural History (NMNH) in Paris, described a new species of Arvicola montebelli, the Japanese field vole, “hatenezumi” in Japanese. Without referring to the original description by Milne-Edwards (1872), Professor Chujirou Sasaki, an entomologist at Tokyo Imperial University, named the vole Arvicola hatanedzumi in 1904 (currently a junior synonym of Microtus (=Alexandromys) montebelli). A detailed examination of the literature from around 1900 is as follows: First, because Sasaki (1904) did not provide a precise locality, the collection locality of Arvicola hatanedzumi was presumed to be Tamamura, Yuuki-gun, Ibaraki Prefecture, based on the occurrence of the vole’s plague in Tamamura (Onuki 1900). Second, Onuki (1900) and Sasaki (1904) would have consulted Ludwig (1883) and Bos (1891) for Arvicolidae; Onuki (1901) allocated the vole to the genus Arvicola without references, and Sasaki (1904) cited the literature incorrectly and insufficiently. Third, because the vole in Sasaki (1901) was affirmed as a new species with the description of the body, the name “Arvicola hatanedzumi” given by Sasaki (1901) was assigned as a valid species name by articles 11 and 12 (ICZN 2000). Fourth, Miyajima (1908) first introduced M. montebelli (Milne-Edwards, 1872) in Japan through Thomas (1906), and Aoki (1913, 1915) stabilized A. hatanedzumi as a junior synonym of M. montebelli.
Owing to crop damage by wild boars (Sus scrofa) and sika deer (Cervus nippon), the motivation to engage in agriculture is decreasing, resulting in an increasing amount of abandoned farmland. Proactive measures by villagers, such as installing protective fencing and capturing nuisance animals, are important to ameliorate this situation, as they can effectively reduce damage and improve the attitude and motivation to engage in agriculture and damage prevention. However, no previous studies have addressed this issue quantitatively or qualitatively. Therefore, this study aimed to demonstrate the effectiveness of these measures through a social experiment. To capture nuisance animals, villagers received instructions regarding the tasks and resolution methods based on the concept of action research. Thereafter, the number of captured nuisance animals increased from zero to 40. Consequently, crop damage decreased significantly from approximately JPY 4.5 million to JPY 70,000. Furthermore, text mining of the results of the interviews with village officials showed marked improvement in their attitude toward damage control, capture of animals, and agriculture. Therefore, it can be concluded that appropriate educational outreach can improve damage prevention and increase the capture of nuisance animals, thus reducing the damage by wild boars and deer, leading to corresponding improvements in residents’ attitudes.
We examined morphological variations of the Herpestes auropunctatus population introduced to Okinawa Island from India approximately 100 years ago, and from there to Amami-Oshima Island and Kagoshima City approximately 30 years ago. The sexual dimorphism of H. auropunctatus was pronounced in the three populations. The average total length and head-body length in both sexes were smaller in Kagoshima than in Okinawa or Amami-Oshima. It was found that those from higher latitudes exhibited larger body mass. The plump body shape in Kagoshima may be an adaptation to the temperate climate. Larger skull size and bizygomatic width were observed in Kagoshima. These traits may reflect more frequent predation on flesh items, particularly in winter. Foot length was also larger in Kagoshima. This may help the animals dig more effectively and find insect larvae in the soil. Tail and hind foot lengths were lower in Amami-Oshima. These traits appeared to be adaptions to rugged mountains.
To determine factors associated with the selection of rooting sites by wild boar (Sus scrofa) during winter snowfall, we conducted a snow-track census from January 2020 to February 2021 in Shizukuishi Town, Iwate Prefecture, Japan. We also collected and analyzed fresh boar feces during the study period. A generalized linear model was applied using the presence and absence of rooting tracks as the response variable; and forest type, snow depth on the survey date, and year as the explanatory variables. The best model, which used Akaike’s information criterion, included the forest type and snow depth on the survey date. The positive effect of broad-leaved mixed forest dominated by Quercus serrata and Q. crispula was statistically significant. In addition, acorns were frequently found and occupied 78.5% (mean proportion in total contents) of the sampled feces in 2020, when the snow depth range was 30–40 cm. Our findings indicate that wild boars prefer broad-leaved forests with less than 40 cm of snow depth, where acorns might be available. The positive effect of Cryptomeria japonica plantations and the negative effect of snow depth also showed statistical significance. These results indicate that wild boars selectively used evergreen coniferous forests to avoid deep snow and for easy rooting.
Mammals in the warm temperate and boreal zones typically deposit body fat prior to the onset of winter. A recent study from Wakayama, Japan, located in warm temperate zone, showed that raccoon dog (Nyctereutes procyonoides) body weight increased by 21% in October. To determine how this increase may change in different climate zones, we assessed body weight increase in raccoon dogs (n = 192) in and near Tokyo, Japan, which is located in a cool temperate zone. The body weight increased by 37% in October, and the kidney fat index (n = 152) peaked during this month. This was likely caused by the diet, as raccoon dogs in this region feed mainly on insects during the summer, but switch to feeding exclusively on fleshy fruits during autumn. We conclude that the autumn weight increase in raccoon dogs is greater in the cool temperate zone than in the warm temperate zone in Japan.
To date, Endo’s pipistrelle (Pipistrellus endoi) had not been recorded, in Kyushu District. To confirm the bat fauna, particularly whether P. endoi occurred, we performed a capture survey using mist nets in Yamaemura, Kumamoto Prefecture, in August 2021. Two bats were captured, one of which was identified as Myotis macrodactylus. The other bat which could not be identified was used as a specimen, which was considered to be either P. abramus or P. endoi. Measurements showed that the tragus of the specimen was wider than that of P. abramus. The upper first incisor was significantly longer than the upper second incisor. The upper second premolar of the specimen was larger than that of P. abramus, and the lower canine was smaller than that of P. abramus. The skull measurements of the specimen were the same as those of P. endoi in Honshu. The shape of the baculum of the specimen was similar to that of P. endoi in Honshu, and the length of the baculum was 9 mm, which was shorter than that of P. abramus. On the basis of these results, the specimen was identified as P. endoi. The results of principal component analysis for the 15 skull measurements of both species, including the present specimen, also indicated that the specimen was within the range of P. endoi, and skull shapes differed between the two species. Furthermore, phylogenetic analyses based on mitochondrial CO1 sequences showed that the specimen belonged to a different genetic lineage than P. abramus.
The racoon (Procyon lotor) is an invasive alien species with an expanding distribution throughout Japan. Given that racoons have a negative impact on ecosystems and agricultural crops, management and control of their population is required. In Toyama Prefecture, where the distribution has not been clearly defined, we investigated the current distribution based on claw marks of the racoon and camera traps. We found claw marks of them at 94 (48.7%) of 193 survey sites in the lowlands of Toyama Prefecture. The 94 sites were located in the eastern and western areas of the prefecture. We also recorded one incidence using a camera trap survey, suggesting a low population density of racoon in Toyama Prefecture. Our results showed that within different areas of Toyama Prefecture, the population density of racoons varied. Thus, it is necessary to devise management strategies that are specific to each area.
The Asian parti-colored bat Vespertilio sinensis, both juvenile and adult, was the prey of the carrion crow Corvus corone in Amakusa City, Kumamoto Prefecture, Japan. Carrion crows flew into the roost and breeding sites of the Asian parti-colored bat, possibly by listening to their audible sound calls, and caught them by sight. From the bat carcasses collected at the site, at least nine Asian parti-colored bats were thought to have been eaten by crows between June and August. Crow behaviors such as swallowing the bats and flying away from the sites holding the bats in their beaks showed that not all bat carcasses were left at the building site. This indicates that more bats are likely to have been consumed by carrion crows. The predation pressure of carrion crows on Asian parti-colored bats appears to be high at the survey site.
From February, 1984, to June, 1986, twenty-one Japanese squirrels (Sciurus lis; 11 males, 10 females) were reintroduced into Shinjuku Gyoen (58 ha) in central Tokyo. However, squirrels were not observed since December 1987. This report summarizes the issues related to the reintroduction of squirrels based on the results of this project and the ecological knowledge on squirrels produced by subsequent research. Approximately 36 ha of the forest were used by squirrels. The main foods were walnut and Lithocarpus edulis acorn from feeding stands, seeds of Pinus thunbergii, P. densiflora, exotic conifer trees, and Castnopsis cuspidata var. sieboldii acorn. Three carcasses of squirrels predated by Felis catus were confirmed, and Corvus spp. chased the squirrels. The squirrels did not settle because the forest area of the site was not sufficient considering the home range of squirrels; there was no habitat to move to close by, and dependence on acorns as forage was overestimated. Issues: 1) forest area of the site corresponding to the home range size of squirrels, 2) conservation of forests with diverse tree species, and 3) management of feral cats and crows as predators.