Food Habits of Raccoon Dogs at An Agricultural Area in Shikoku, Western Japan.

The diet of raccoon dogs, which live in close proximity to agricultural fields in Matsuyama, western Japan, was studied throughout the year by the fecal analysis method (n = 114). Fruits were most important, accounting for 30-40% of the diet except in winter. Crops were next in importance, accounting for 10-30%. It was characteristic that the proportion of crops was greater and more stable than in other "satoyama" or rural areas in Japan. Crops included rice (Oryza sativa), wheat, sesame (Sesamum indicum), strawberries (Fragaria × ananassa), kiwi fruit (Actinidia chinensis var. deliciosa), ginkgo nuts (Ginkgo biloba), and persimmon (Diospyros kaki). Crops were important as the food for the raccoon dogs, but the use was not regarded as causing serious damage. Although wild boars (Sus scrofa), sika deer (Cervus nippon), and Japanese macaques (Macaca fuscata) were culled for pest control in the area, raccoon dogs were not culled. This may be a reason why the raccoon dog has coexisted with people in Japan.

Food Habits of the Japanese Dormouse in the Yatsugatake Mountains, Japan.

We conducted a quantitative dietary analysis of the Japanese dormouse (Glirulus japonicus) using fecal samples collected in the subalpine zone of the Yatsugatake Mountains, central Japan. Dormouse diets were dominated by insects (69.2%) in summer and both fruit (43.0%) and insects (33.4%) in autumn. Leaves accounted for a small proportion of the diet in all seasons. Dormice may be reliant on insects because fruits are scant in summer, and on fruits to accumulate body fat in autumn before hibernation.

Genetic Variation in Y-Chromosome Genes of Sika Deer (Cervus nippon) in Japan.

Sika deer (Cervus nippon) in Japan are classified into southern and northern groups. However, previous studies primarily relied on maternally inherited mitochondrial DNA (mtDNA). The paternally inherited Y-chromosome is useful for analyzing the contribution of males to the population genetic history of sika deer. In total, approximately 16 kb of partial sequences of four Y-chromosomal genes, Y-linked, sex-determining region Y, DEAD-box helicase 3 Y-linked, and Zinc finger protein Y-linked, were sequenced to investigate intraspecific variation. As a result, we identified nine intronic single nucleotide polymorphisms (SNPs) in 478 sika deer samples collected over the entire Japanese archipelago from Hokkaido to Kyushu. SNP genotyping revealed 10 distinct haplotypes (SYH1-SYH10). The most common haplotype (SYH1) was present in all populations and was the most abundant haplotype, identified in 80.3% of the sampled individuals. The remaining haplotypes were unique to a single locality. SYH1 was also central to all other haplotypes that diverged by a SNP, resulting in this haplotype being the core of a star-like cluster topography. We found that contrary to mtDNA patterns, there was no clear differentiation of Y-chromosome markers between the southern and the northern populations. Due to the female philopatry of sika deer, mtDNA may provide a highly structured differentiation of populations. On the other hand, the male-biased gene flow may provide a reduced differentiation of populations. Our findings revealed that the genetic structure of the Japanese sika deer is more complex than previously thought based on mtDNA-based phylogeographic studies.

A Comparison of Food Habits Between Japanese Marten and Raccoon Dog in Western Tokyo with Reference to Fruit Use.

We studied the food habits of the Japanese marten (Martes melampus) and the raccoon dog (Nyctereutes procionoides) at the Tama Forest Science Garden, western Tokyo, Japan by fecal analysis in 2014/15. Martens were dependent on fruits throughout the year and showed less marked seasonal changes. Raccoon dogs were less dependent on fruits than martens were, and more dependent on mammals in spring, insects in summer and winter, and seeds throughout the year. Martens fed on more fruits containing tiny seeds, such as Actinidia arguta and Stachyurus praecox, whereas raccoon dogs fed on more large-seeded fruits, such as Ginkgo biloba and Diospyros kaki. Martens fed on more fruits that grew at the forest edges, whereas raccoon dogs fed on more fruits growing inside the forest.

Seasonal Variation in the Food Habits of the Eurasian Harvest Mouse (Micromys minutus) from Western Tokyo, Japan.

A previous quantitative analysis of the food composition of the Eurasian harvest mouse (Micromys minutus) in Japan showed that it is insectivorous and granivorous. This supports the expectation that such a small mammal requires highly nutritious foods. Other studies have analyzed the feces of harvest mice, but these were only collected during winter in order to minimize disturbance of the animals. In the present study, we collected samples from all four seasons in order to understand changes in diet throughout the year. Results showed apparent seasonal differences in the diet of harvest mice. Insects accounted for ca. 30% of the diet in summer and autumn and seeds increased from 27% in winter to 50% in spring, suggesting the insectivorous nature of the harvest mouse in summer and autumn and graminivorous nature in winter and spring. These results strongly suggest that the harvest mouse is an opportunistic feeder. It has previously been thought that the harvest mice capture insects in the stalk zone of tall grassland community, but here, DNA analysis shows that harvest mice feed on ground-dwelling invertebrates, such as pill bugs (Armadillidium sp.) and carrion beetles (Calosilpha sp. or Ptomascopus sp.). This suggests that the harvest mouse goes down to the ground to feed on them.

Seeds Recovered from the Droppings at Latrines of the Raccoon Dog (Nyctereutes procyonoides viverrinus): The Possibility of Seed Dispersal.

Medium-sized carnivorous mammals are important seed dispersers of fleshy fruits. The raccoon dog (Nyctereutes procyonoides viverrinus) often feeds on fleshy fruits and forms latrines. This behavior may potentially lead to seed dispersal. To determine if this is the case, we studied 1) seed recovery in the droppings of raccoon dogs, and 2) the transportation of seeds between habitats using plastic markers in a western suburb of Tokyo, Japan. In total, 32,473 seeds of 50 plant taxa were recovered from 120 raccoon dog droppings during a year, and 95.7% of the seeds were found to be those of fleshy fruits. The species most frequently recovered were the eurya (Eurya japonica, 52.6%), the brambles (Rubus spp., 17.4%), and the black night shade (Solanum nigrum, 16.0%). A total of 7,412 plastic markers were embedded in baits at 14 bait plots and were recovered in the feces of the raccoon dogs at 22 latrines. The "transportation rates" were calculated in 50-m distance classes and found that most seeds (43.5%) were deposited within 50 m from the bait point, suggesting very short seed dispersal distances. Inter-habitat transportation was observed: 64.9% of the retrieved markers deposited in the forest were transported to other places within the forest. In contrast, almost all of the markers (99.4%) deposited in the open site were transported within the same habitat. These findings suggest that the seeds of forest plants bearing berries can be dispersed out of the forest to open areas by raccoon dogs.

The Japanese Marten Favors Actinidia arguta, a Forest Edge Liane as a Directed Seed Disperser.

This study demonstrates the potential of the Japanese marten (Martes melampus) to serve as a directed seed disperser of Actinidia arguta, a representative forest edge liane. Fecal compositions of the Japanese marten in a western part of Tokyo, Japan were analyzed by the point-frame method. It fed on fruits in autumn (73.1%) and winter (63.0%), and the seeds of A. arguta were most frequently eaten (47.4%). Although the vegetation in the study area was dominated by forest (95.5%), seeds found in the marten feces were dominated by those of forest edge plants (92.1%), suggesting a strong selective bias, both habitat and food, toward these species. The density of marten feces was also higher at forest edges than forest interiors. A. arguta plants were more abundant at forest edges than within the forest at Afan Wood, Nagano Prefecture. These results suggest that the Japanese marten selectively uses forest edges as a location for feeding and defecation and thus functions as a directed seed disperser of A. arguta.

Costs of parturition and rearing in female sika deer (Cervus nippon).

The costs of parturition and lactation of female sika deer on Kinkazan Island (9.6 km(2) in size), northern Japan, which live at a high density (about 50 deer/km(2)), were evaluated by comparison of body weights of 481 females measured during a 15 year study (1993-2008). Weight data were chosen from only females that did not give birth in the preceding year. The mean body weight of females that did not give birth ("yelds") was significantly lower (P < 0.001) than that of females who gave birth ("milks"); yelds' body weight was 93.1% and 83.5% that of milks in the preceding and parturition years, respectively. The yelds increased in body weight by the following March by 8.2% (P < 0.001), whereas milks did not. Among the milks, those whose fawns survived until the following May ("rearing milks") lost body weight by 14.9% (P < 0.001). Milks who lost fawns within a week after birth ("early fawn-less milks") did not lose body weight (P = 0.583), while those whose fawns died after the first autumn but died before May ("late fawn-less milks") lost body weight by 19.9% (P < 0.001). These results indicate that sika deer females do not enter estrus unless they are heavy enough, and that both parturition and rearing are costly for sika deer mothers living in high-density conditions.

Genetic variation and population structure of the Japanese sika deer (Cervus nippon) in the Tohoku District based on mitochondrial D-loop sequences.

The sika deer (Cervus nippon) once inhabited the entire Tohoku District, the northeastern part of the main island of Japan. Currently, they are isolated as three discontinuous populations on Mt. Goyo, the Oshika Peninsula, and Kinkazan Island. To assess the genetic diversity and relationships among the sika deer populations in the Tohoku District, we analyzed the mitochondrial DNA D-loop sequences from 177 individuals. We detected a total of five haplotypes. Three haplotypes were present in the population from Mt. Goyo at a haplotype diversity of 0.235 ± 0.061, two haplotypes in the population from the Oshika Peninsula at 0.171 ± 0.064, and only one haplotype was detected in the population from the Kinkazan Island. A significant genetic differentiation was observed among all population pairs. Collectively, our data supports the observed population bottlenecks in the past. Four of the five haplotypes were specific to one of the three populations, whereas only one haplotype was shared between the Mt. Goyo and the Oshika Peninsula populations. This common haplotype may indicate a common ancestral population in the Tohoku District. Conversely, the D-loop haplotypes were completely different among the Kinkazan Island and Oshika Peninsula populations. The lack of a shared haplotype indicates that female gene flow between the two populations is very limited and that the 0.6 km strait acts as a strong barrier.

Effects of 137Cs contamination after the TEPCO Fukushima Dai-ichi Nuclear Power Station accident on food and habitat of wild boar in Fukushima Prefecture.

After the Tokyo Electric Power Company Fukushima Dai-ichi Nuclear Power Station accident, wild boar was found to have greater radiocesium (137Cs) activity concentrations in their bodies than other wild animals in Japan; however, the reason for this remains unknown. To understand the mechanism of 137Cs transfer from the environment to wild boar, and the factors that affect variation in 137Cs contamination in wild boar, we sampled muscle and stomach contents from wild boar captured in Fukushima Prefecture and analyzed the relationships among 137Cs concentrations in muscle tissue and in the stomach contents, 137Cs ground deposition at capture sites, and wild boar food habits. Significant positive relationships were observed among 137Cs activity concentrations in muscle and stomach contents, as well as 137Cs deposition density at capture sites. These results suggest that 137Cs is transferred from the environment to plant and animal materials consumed by wild boar, and then from these foods to the bodies of wild boar through digestion. However, no correlation was observed between 137Cs concentrations in stomach contents and the presence of any particular food item in stomachs of wild boar, including mushrooms. These findings suggest mushrooms and underground food items, which were found to affect 137Cs concentrations in wild animals in Europe, were not important contributors to high levels of 137Cs contamination in Japanese wild animals.

Seasonal and sexual variation in the diet and gastrointestinal features of the sika deer in western Japan: implications for the feeding strategy.

Sexual and seasonal variation in diet quality and the gastrointestine have important implications for forage acquisition and the feeding strategy. We assessed the botanical and chemical compositions of the diet and the gastrointestinal macrostructure of the sika deer (Cervus nippon) in western Japan. The sexual dimorphism-body size hypothesis predicts that smaller females will have a better diet than larger males to meet a higher nutritional demand due to a higher metabolic rate. According to the optimal digestion theory, the gut of larger males will retain a greater quantity of digesta of poor forage to compensate for the reduction in net energy obtained per unit of digesta. The relatively greater omasum content in winter than in summer was the only feature consistent with this prediction. This may suggest that the omasum is the organ that most sensitively reflects diet quality, because the summer diet quality is little better than that in winter. Contrary to predictions, the botanical composition of the diet did not show a sexual difference, but females had greater relative weights of stomach contents, tissues, and hindgut segments (small and large Intestines, and cecum-colon), and a relatively greater small Intestine length than males in summer. Further, females had greater relative weights of abomasum contents, ruminoreticulum tissue, and small Intestine in summer than in winter, but no seasonal variation in gastrointestinal features was detected in males. The sexual variation in diet and in the gastrointestine in summer suggest that lactating females Intake more forage and maintain more digesta in the gut, due to not body size but to higher energy requirements for lactation. The greater gut fill and tissue weight of females in summer than in winter likely resulted from a nutrient demand from lactation greater than that from gestation.

Behavior rather than diet mediates seasonal differences in seed dispersal by Asian elephants.

Digestive physiology and movement patterns of animal dispersers determine deposition patterns for endozoochorously dispersed seeds. We combined data from feeding trials, germination tests, and GPS telemetry of Asian elephants (Elephas maximus) to (1) describe the spatial scale at which Asian elephants disperse seeds; (2) assess whether seasonal differences in diet composition and ranging behavior translate into differences in seed shadows; and (3) evaluate whether scale and seasonal patterns vary between two ecologically distinct areas: Sri Lanka's dry monsoon forests and Myanmar's (Burma) mixed-deciduous forests. The combination of seed retention times (mean 39.5 h, maximum 114 h) and elephant displacement rates (average 1988 m in 116 hours) resulted in 50% of seeds dispersed over 1.2 km (mean 1222-2105 m, maximum 5772 m). Shifts in diet composition did not affect gut retention time and germination of ingested seeds. Elephant displacements were slightly longer, with stronger seasonal variation in Myanmar. As a consequence, seed dispersal curves varied seasonally with longer distances during the dry season in Myanmar but not in Sri Lanka. Seasonal and geographic variation in seed dispersal curves was the result of variation in elephant movement patterns, rather than the effect of diet changes on the fate of ingested seeds.

Local variation in diet composition of the Japanese serow during winter.

We investigated local geographical variation in the plant composition and quality (crude protein) of the diet of the Japanese serow (Capricornis crispus) by analyzing rumen contents. We collected the rumen contents from 111 Japanese serows culled for pest control between January and March 1997 in Shizuoka Prefecture, central Japan. The composition of the diet, characterized by a high proportion of browse (65.2%), including green plant leaves (55.3%), confirmed that the Japanese serow is a typical browser, at least in winter. Although the composition of the diet varied geographically even within Shizuoka Prefecture (i.e. the northern populations included less green broad leaves, and more grasses and Sasa spp.), altitude did not affect the composition. Latitudinal variation in plant composition of the diet was explained by a shift in plant availability within vegetation zones from evergreen broad-leaf to deciduous broad-leaf forests. Lack of variation in the diet plant composition with changes in altitude may be explained by probably greater altitudinal than latitudinal variation in the territories of the Japanese serow, and by greater individual variation in food habits. Diet quality remained at a constant high level regardless of altitudinal and latitudinal variation in diet plant composition. This suggests that the Japanese serow maintains a high-quality diet by selective feeding, which is possible only when the serow is at low population density and in possession of a territory.

A more detailed seasonal division of the energy balance and the protein balance of Japanese macaques (Macaca fuscata) on Kinkazan Island, northern Japan.

Nakagawa (Am J Primatol 41:267-288, 1997) reported that both the gross energy and gross protein intakes of an adult female Japanese macaque (Macaca fuscata) on Kinkazan Island, northern Japan, were high in spring (March-May) and fall (September-November) and low in summer (June-August) and winter (December-February), and that these values reflected the seasonal differences in nutritional conditions (defined as whether the intakes of energy and protein satisfy the requirements). We estimated the energy balance (energy intake minus its expenditure) and the protein balance (protein intake minus its requirement) of the monkeys on Kinkazan Island every month over the course of 1 year (2004--2005) in order to verify Nakagawa's conclusions. Like Nakagawa, we found that the energy balance of the monkeys in the fall was higher than in the summer and winter, whereas the protein balance in the fall was higher than in the winter. However, we did not find that spring energy and protein values were greater than summer and winter values. We also did not find that summer protein values were low. Both the energy balance and the protein balance changed rapidly within the same season. The energy intakes and the energy balances were higher in mid-spring and mid- and late fall and lower in late spring and early summer, whereas the protein intakes and the protein balances were higher in mid-spring and mid-summer and lower in early and mid-winter. Since Japanese macaques respond to seasonal changes in food supply by changing their foods, continuous data collection with short intervals is recommended in order to accurately document the energy and protein balances of the monkeys.

Sexual variations in food quality and gastrointestinal features of sika deer (Cervus nippon) in Japan during winter: implications for feeding strategy.

We assessed sexual variation in food quality and gut macrostructure in adult male and pregnant female sika deer, Cervus nippon (Temminck, 1838), in Japan during winter. These variations might have important implications relative to sexual differences in habitat use, forage acquisition, and digestive strategy. According to the sexual dimorphism-body size hypothesis the larger males would feed on poorer forage and have heavier stomach contents and heavier intestine contents and longer intestines than smaller females. However, the food quality in rumen contents of males was higher than, or at least similar with, that of pregnant females. In correspondence to food quality, the relative weights of stomach contents and intestines with contents, the relative lengths of intestines to the lengths of body and total intestines in pregnant females were similar to adult males. The relative weights of omasum and abomasum tissues in pregnant females were greater than in males. Our findings suggest sexual differences in feeding strategy in sika deer in Japan during winter. To meet greater nutritional demands of high metabolic rate and gestation, pregnant females seemed to maintain a greater volume of digesta in guts and had more stomach tissues than expected by the sexual dimorphism-body size hypothesis to compensate for poorer forage quality.

Fragmentation of the habitat of wild ungulates by anthropogenic barriers in Mongolia.

Habitat loss and habitat fragmentation caused by anthropogenic activities are the main factors that constrain long-distance movement of ungulates. Mongolian gazelles (Procapra gutturosa) and Asiatic wild asses (Equus hemionus) in Mongolia are facing habitat fragmentation and loss. To better understand how their movements respond to potential anthropogenic and natural barriers, we tracked 24 Mongolian gazelles and 12 wild asses near the Ulaanbaatar-Beijing Railroad and the fenced international border between Mongolia and China between 2002 and 2012. None of the tracked gazelles crossed the railroad, even though gazelles were captured on both sides of the tracks at the start of the study. Similarly, we did not observe cross-border movements between Mongolia and China for either species, even though some animals used areas adjacent to the border. The both species used close areas to the anthropogenic barriers more frequently during winter than summer. These results suggest strong impacts by the artificial barriers. The construction of new railroads and roads to permit mining and other resource development therefore creates the threat of further habitat fragmentation, because the planned routes will divide the remaining non-fragmented habitats of the ungulates into smaller pieces. To conserve long-distance movement of the ungulates in this area, it will be necessary to remove or mitigate the barrier effects of the existing and planned roads and railroads and to adopt a landscape-level approach to allow access by ungulates to wide ranges throughout their distribution.

Long-term variation in fruiting and the food habits of wild Japanese macaques on Kinkazan Island, northern Japan.

We studied the relationship between the food habits of Japanese macaques (Macaca fuscata) and the availability of nuts (Fagus crenata, Zelkova serrata, Carpinus spp., and Torreya nucifera) on Kinkazan Island, northern Japan, from 1997 to 2005 to examine the long-term variations in both food habits and availability. The food habits of the monkeys showed clear seasonal changes: the staple foods were woody leaves and flowers in spring (May and June), woody leaves and seeds or fruits other than nuts in summer (July and August), nuts and seeds or fruits other than nuts in fall (September-November), and herbaceous plants in winter (December-April). The availability of nuts, combinations of masting species, and energy production varied among years. Food habits varied among years, but the magnitude of variability of food habits differed among seasons, with large variability during summer and winter, and small variability in spring. Food availability was poor in summer and winter, but in several years the monkeys were able to consume nuts during those seasons. We emphasize the importance of conducting long-term studies on both food availability and the food habits of animals in the temperate zone.