This is the first report of the morphology of innominate bones (pelvic bones) and femurs with cartilage of Bryde’s whales Balaenoptera edeni in all waters around the world. We examined morphometric features of the bones via measurement and direct observation of 34 Bryde’s whales. The innominate bones were located at approximately 71% of the body length from tip of the rostrum, and we confirmed a pair of femurs from one individual. The innominate bones had a process in the mid-lateral part, and in the anterior they were elongated toward the cranial while lacking any elongation (n = 8). Also, the bones were statistically thicker and narrower in males than females (mean values of the width/length of 0.22 (female) to 0.17 (male)), and the mid-lateral process was located more caudally in females (length anterior to mid-lateral process/length, 0.62) than males (0.51). The anterior tips of the bones were horizontally flat in females, while the males were dorso-ventrally flat. In comparison with past studies, although some common characteristics were found among other balaenopterids, the lack of elongation, and the occurrence of sexual dimorphism in the anterior tip of the bone, were found only in Bryde’s whale.

View full abstract

Gralloching of sika deer (Cervus nippon) in slaughterhouses is urged in case the carcasses are supplied for human consumption in Japan. Gralloching in the field is permitted in the European Union for the purpose of reducing contamination risk and cooling the carcass as soon as possible. We studied the hygiene status of dressed carcasses that were gralloched in the field by comparing with those in the slaughterhouse to assess the possibility of introducing this method in Japan. We examined 10 animals gralloched in the field, which were culled in Nishi-Okoppe village located in the northern part of Hokkaido, and 4 animals from a slaughterhouse located in the western part of Hokkaido. The enteropathogenic bacteria Campylobacter, Salmonella, Yersinia nor Escherichia coli were not detected in both cases. Counts of viable bacteria were also low in both cases, and that trend was noticeable during the snowy season. It was possible to gralloch hygienically in the field in an appropriate way, but the method requires adequate knowledge and skills in meat hygiene. When introducing this method to Japan, a certificate, a kind of Deer stalking certificate in England, should be introduced at the same instant to assure an adequate ability to handle carcasses.

View full abstract

Using nest-boxes and camera traps, we carried out a study on the winter activity of the Japanese dormouse Glirulus japonicus from December 2013 to February 2014 in a lowland evergreen broad-leaved temperate forest in southern Kyushu, Japan. The Japanese dormice were occasionally photographed in the mid-winter with short intermissions of less than 20 days. The daily mean air temperature at the study site from late December 2013 to late February 2014 was 9.0°C (range: 3.5–16.8°C), which was the same as the hibernation threshold level of the Japanese dormouse (mean air temperature: 8.8°C). Our results suggest that the wild Japanese dormouse in southern Kyushu has a short hibernation period, or that a part of the population is active during warm periods in mid-winter. We also expect that some individuals of this area do not hibernate when the winter temperature is higher than normal.

View full abstract

We investigated differences in displacement of the diaphragmatic vertebra between Otariidae, the forelimb swimmers, and Phocidae, the hind limb swimmers. The diaphragmatic vertebra was displaced in the caudal direction on vertebrae in Otariidae, whereas it was displaced in the cranial direction in Phocidae. The displacement occurred in samples that had abnormal vertebral counts as well as those with normal counts. This vertebra occurs at the boundary between the thoracic type vertebra (or prediaphragmatic) and lumber type vertebra (or postdiaphragmatic). When the diaphragmatic vertebra is displaced in the cranial direction, the lumber type area increases whereas the thoracic type area decreases. On the other hand, when it displaces in the caudal direction, the thoracic type area increases whereas the lumber type area decreases. Because a long thoracic region might be more advantageous for otariids and a long lumber region might be more advantageous for phocids when they swim, caudal displacement of diaphragmatic vertebra might tend to occur in otariids and cranial displacement might tend to occur in phocids.

View full abstract

Using nest-box and camera trap, we carried out a 30-month census (from October 2011 to March 2014) of seasonal and daily activities of the Japanese dormouse Glirulus japonicus inhabiting an evergreen broad-leaved temperate forest in the northern part of Kyushu Island, Japan. The study site was on the foot of Mt. Tara (elevation 400 m), Nagasaki Prefecture. The Japanese dormouse was frequently photographed throughout the year except in mid-winter (middle of December or early January to late February; 2–3 months). Using regression equation of the daily mean air temperature between the study site and the nearest meteorological station (Shimabara) recorded in winter 2014, we estimated the air temperature of dormouse hibernation period. This nest-box and camera trap method is a useful tool to study the seasonal and daily activities of the species.

View full abstract

Although Japanese macaques, Macaca fuscata, are not game animals, they are culled as pest mammals without sufficient evidence to verify effectiveness. Using a nationwide questionnaire survey, we conducted a review of the present macaque management policy. Questionnaires were administered to 542 municipalities where population control has been exerted for the past 5 years, and 366 (67.5%) municipalities responded. The major findings of the survey are as follows: (1) most municipalities culled macaques as a stopgap damage control (and not via systematic population control); (2) most population control projects are executed by clubs hunting for sport, with administrative supervision; (3) evidence that determines the number of macaques to be captured is often negligible; (4) the most common population control method in every municipality is shooting, and some regions also use large-sized box traps to cull macaque troops; (5) the effectiveness of population control has not been determined in most municipalities because of a lack of continuous assessment of population dynamics; (6) although some municipalities indulging in troop culling have succeeded in achieving effective damage control, such a situation is not widely prevalent.

View full abstract

It is difficult to study the Siberian flying squirrel (Pteromys volans) throughout the year using nest boxes, because this species does not use nest box in midwinter. To establish an effective capture method to collect data throughout the year, a new cavity trap was created and installed on tree cavities used by Siberian flying squirrels. A plastic plate that blocks return to cavities was attached inside the trap. In Obihiro, Hokkaido, Japan, 38 flying squirrels were found in cavities from January 2006 to April 2008. Thirty-three individuals were captured with the traps; however, the remaining five individuals were not captured during midwinter due to not leaving their nests. Since activity and active time of Siberian flying squirrels decreases and becomes irregular in midwinter, it could be difficult to capture all individuals nesting in cavities via this trap. However, 70% of flying squirrels during midwinter and all flying squirrels during other seasons were successfully captured. This suggests that the new trap method could be more effective than the nest box method to collect regular data for this species.

View full abstract

We evaluated the use of automatic infrared sensor cameras for ecological research on terrestrial small mammals with correct species identification. First, we constructed the best system by: (1) photographing vertically using a tripod and a mesh mat (10-mm squares) as a scale, (2) using a bait basket set on the mesh mat to induce them to come and stay for a long time (over 24 hours at least), and (3) photographing in 1-min intervals to preserve camera batteries for sustained periods of time. Second, we set up this system on forest floors and obtained pictures of four mammals. Of them, Urotrichus talpoides and Rattus norvegicus were easily identified based on external characteristics. However, identification of Apodemus speciosus and A. argenteus were difficult because of their external similarity. Their heads were clearly photographed and eye diameter and the maximum and minimum widths between both eyes were measured. The width difference between the innermost and the outermost edges of both eyes, and eye diameter, were useful in identifying both species. Third, the daily activity of A. speciosus was researched monthly at a locality. We ascertained that A. speciosus was nocturnal throughout the year.

View full abstract