Honyurui Kagaku (Mammalian Science)
Online ISSN : 1881-526X
Print ISSN : 0385-437X
ISSN-L : 0385-437X
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Volume 54, Issue 1
Displaying 1-33 of 33 articles from this issue
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Original Articles
  • Development of fetal characteristics and estimation of implantation date in the spotted seal, Phoca largha
    Risa Sasaki, Yuta Sakurai, Mari Kobayashi
    2014 Volume 54 Issue 1 Pages 1-9
    Published: June 30, 2014
    Released on J-STAGE: June 30, 2014
    DOIhttps://doi.org/10.11238/mammalianscience.54.1
    JOURNAL FREE ACCESS
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    This study investigated the development of characteristics during the growth of Phoca largha fetuses. Delayed implantation is known to occur in seals, but there are very few reports investigating the date of implantation. This study estimated the date of implantation and examined the significance of delayed implantation. Dates of deaths of fetuses were converted into sequential day numbers (day 1 = January 1). The whiskers, nails and hairs of fetuses were observed from day 250, 262 and 358, respectively. Early whisker and nails development were followed by the development of hair and was consistent with results reported for other seals. Teething was observed on the same day that hairs were observed. The finding that hair and teeth are developed and eyes open by the time of birth was consistent with precocity. Moreover, analysis of allometric growth based on body length and the measurement of other parts revealed characteristics of tachy-auxesis in many parts of the body. In particular, flippers showed a higher allometric coefficient, possibly because P. largha pups start swimming soon after weaning. The average date of implantation was estimated to be August 7th and the 95% confidence interval was July 23rd to August 15th.
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  • Nest use of Japanese Squirrels in a suburban forest in Morioka city
    Chiaki Nishi, Yoshitaka Deguchi, Toshiki Aoi
    2014 Volume 54 Issue 1 Pages 11-18
    Published: June 30, 2014
    Released on J-STAGE: June 30, 2014
    DOIhttps://doi.org/10.11238/mammalianscience.54.11
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    We investigated the nest use of Japanese squirrels (Sciurus lis) in a suburban forest of Morioka city, Iwate prefecture, north-eastern Japan, from April 1st to December 15th 2010. We searched for squirrel nests used as roosts after sunset via radio tracking and direct observation. Among 60 nests, 32 were on ever-green trees (30 were dreys and two were cavities) and 28 were on deciduous trees (eight were dreys and 20 were cavities). Squirrels selected forest edge as nesting sites. One squirrel used from three to 20 nests, and they changed nests every 2.4 days by male squirrels and 3.4 days by female. Some nests were shared among other individuals, but there was only one case in which a nest was used at same time. The nearest-neighbor distance of nests to walnuts trees was 52.8 ± 49.0 m (mean ± SD), and 73% of nests were located within 60 m from the nearest walnuts trees. Squirrels need several nests near walnut trees, and also need ever-green conifer trees and broadleaf trees with cavities as nests in their home ranges.
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  • Behavior and habitat of Asiatic black bear (Ursus thibetanus) inhabiting near settlements
    Isao Arimoto, Hiroshi Okamura, Shinsuke Koike, Koji Yamazaki, Koichi K ...
    2014 Volume 54 Issue 1 Pages 19-31
    Published: June 30, 2014
    Released on J-STAGE: June 30, 2014
    DOIhttps://doi.org/10.11238/mammalianscience.54.19
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    Recently, conflicts between Asiatic black bears (Ursus thibetanus) and humans are increasing as bears expand their distribution. However, little is known about the biology of bears inhabiting near settlements. We fitted GPS collars on 7 bears during 2010–11, and by fitting the Switching State-Space Model, we smoothed error-prone GPS tracks and categorized bear behavior into transit, active stay, and inactive stay. Additionally, we investigated habitat characteristics by exploring active-stay core areas. On the whole, bears lived near settlements in summer and more distantly from settlements in autumn. However, there were exceptional bears staying more distantly in summer and near settlements in autumn. Near settlements, bears mainly foraged Juglans mandshurica and Castanea crenata in late summer and Diospyros kaki in autumn. In distant areas, bears foraged ants and Prunus spp. in late summer and Quercus mongolica in autumn. Bears’ nocturnal activity became higher near settlements. Our results indicated that bears come close to settlements in particular seasons according to seasonal changes in food availability. Bears were more likely to be near settlements if there were intensively distributed foods derived from humans nearby.
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  • Habitat selection of sika deer during winter in Kushiro Shitsugen National Park
    Yoshihiro Inatomi, Hiroyuki Uno, Mayumi Ueno
    2014 Volume 54 Issue 1 Pages 33-41
    Published: June 30, 2014
    Released on J-STAGE: June 30, 2014
    DOIhttps://doi.org/10.11238/mammalianscience.54.33
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    Habitat selection of sika deer (Cervus nippon yesoensis) during the winter in Kushiro Shitsugen National Park was investigated via road counts and aerial survey to implement effective management of deer in the national park. We conducted road counts along the fix route running through the marshland between November 2010 and May 2011, and aerial surveys in the north of the national park early in February, 2011. Confidence intervals of Manly’s selection index for broad-leaved forests calculated via road counts and aerial survey ranged above 1. This suggests that deer selected broad-leaved forests during the long period of winter in the national park. We observed few deer in November, December, April and May, whereas deer density index exceeded 60 deer/km2 between January and March along the route from Kottaro Marsh Observatory to Lake Toro. Thus, we suggest the study area is wintering area for deer. We conclude that broad-leaved forests during the winter will be an effective place and season to cull deer with guns or traps in the national park.
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  • Numerical vertebral variations and characteristics of deformed first lumbar vertebrae and lumbosacral regions in the Japanese black bear (Ursus thibetanus japonicus)
    Sachiko Nakamura, Mayumi Yokoyama, Erina Saita, Yoshiki Morimitsu
    2014 Volume 54 Issue 1 Pages 43-51
    Published: June 30, 2014
    Released on J-STAGE: June 30, 2014
    DOIhttps://doi.org/10.11238/mammalianscience.54.43
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    Japanese black bears (Ursus thibetanus japonicus) in Hyogo Prefecture exhibit abnormal bone morphology with high frequency. Basic knowledge about the bones of the Japanese black bear is necessary for diagnosis, for cause identification, and for evaluation of the influences of these abnormally formed bones on populations. This study analyzed the regular number and morphology of Japanese black bears vertebrae by comparison with those from three areas: Higashi-chugoku, Kita-kinki, and Iwate. The normal number of vertebrae in Japanese black bears is 7 cervical vertebrae, 14 thoracic vertebrae, 6 lumbar vertebrae, and 5 sacral vertebrae. When vertebrae of three kinds other than the sacral vertebrae were analyzed, three irregular patterns of vertebral combinations were observed. Each was found to be regionally idiosyncratic. Vertebral deformation of two types was identified. One type included extension of the transverse process of the first lumbar vertebrae. It was found more frequently in Kita-kinki. Another type included lumbosacral transitional vertebrae. It was found in Higashi-chugoku and Kita-kinki. Numerical variation of the vertebrae and vertebral deformation might be the result of different genetic characteristics of the three populations.
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  • Bayesian estimation of Reeves’ muntjac (Muntiacus reevesi) populations using state-space models
    Masahiko Asada, Yutaka Osada, Keita Fukasawa, Keiji Ochiai
    2014 Volume 54 Issue 1 Pages 53-72
    Published: June 30, 2014
    Released on J-STAGE: June 30, 2014
    DOIhttps://doi.org/10.11238/mammalianscience.54.53
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    The total population size of Reeves’ muntjac (Muntiacus reevesi) in 59 management units in Boso peninsula, Chiba Prefecture from fiscal year 2006 to 2011 was estimated via hierarchical Bayesian state-space models based on fecal pellets counts, direct abundance counts by the block-count method, and pest control capture data. The total abundance of muntjac deer was estimated as 19,826 in median (95% C. I.: 14,542 to 26,422) in the end of the fiscal year 2011. The mean population growth rate was estimated as 1.294. It is suggested that there has been considerable mortality affecting population dynamics, because fecundity estimates based on pregnancy rates and sex-age structure have been 1.356 or 1.407 assuming yearly breeding.
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  • Osteological characteristics of gray whales Eschrichtius robustus collected from the coast of Japan (1990–2005) and possible population mixing with eastern gray whales in the western North Pacific
    Gen Nakamura, Hidehiro Kato
    2014 Volume 54 Issue 1 Pages 73-88
    Published: June 30, 2014
    Released on J-STAGE: June 30, 2014
    DOIhttps://doi.org/10.11238/mammalianscience.54.73
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    The gray whale Eschrichtius robustus is distributed in the North Pacific dividing into two distinctive stocks: eastern stock and western. In recent years the structure and possible population mixing of gray whale stocks have been under debate. To investigate this issue, we examined the skeletal features of 5 gray whales collected through relatively current stranding or entanglement off the Pacific coast of Japan between 1990 and 2005, and compared measurements and images of specimens from Ulsan, Korea (n = 1), Zhejiang and Guangzhou, China (n = 2) and California, USA (n = 1) reported in published studies. Clear morphological differences were identified in the anterior part of the nasal bones, the posterior ends of the maxilla and premaxilla, and in the sternum and the vestigial pelvis. In all cases, morphological features of the 5 specimens from the coast of Japan were very similar to those reported for the specimen from California (eastern stock), not for the specimen from Ulsan, Korea (western stock). This finding suggests that the range of the eastern stock may have expanded to the coastal area of Japan. This should be further morphologically examined using more samples as well as genetic analyses in future studies.
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Short Communication
  • Morphological variation in populations of the harvest mouse, Micromys minutus, on the Oki Islands, and from Honshu to Kyushu, Japan
    Yasushi Takada, Yasushi Uematsu, Eiichi Sakai, Takashi Tateishi
    2014 Volume 54 Issue 1 Pages 89-94
    Published: June 30, 2014
    Released on J-STAGE: June 30, 2014
    DOIhttps://doi.org/10.11238/mammalianscience.54.89
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    We examined morphological variation in twelve populations of the harvest mouse (Micromys minutus) on the Oki Islands, and from Honshu to Kyushu. Multivariate analyses (PCA, CDA) were conducted on the mandible dimensions. Significant differences among the populations were found for the second and the third principal component scores (PC2, PC3; shape factors), but not for the first principal component score (PC1; a size factor). PC2 sample means were significantly correlated with island area, and some environmental effects might therefore affect shape variation. A canonical discriminant analysis revealed morphological differences among islets from the Oki Islands. Genetic drift coupled with the geographical isolation seemed to lead to these differences. On the other hand, the populations did not show inter-regional morphological variation in mandible size, and did not differ morphologically among populations from far away localities. This may be accounted for by a low level of genetic diversity in the harvest mouse from the Japanese Archipelago, as was found by Yasuda et al. (2005).
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Report
  • Identification of plant residual substances in the feces of Apodemus speciosus and A. argenteus by chloroplast rbcL gene sequences
    Tomoyasu Shirako, Makiko Aichi, Kaoru Ueno, Motoyasu Minami
    2014 Volume 54 Issue 1 Pages 95-101
    Published: June 30, 2014
    Released on J-STAGE: June 30, 2014
    DOIhttps://doi.org/10.11238/mammalianscience.54.95
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    A molecular identification method for residual food substances in the feces of Apodemus speciosus and A. argenteus was evaluated. We collected the feces in Mt. Miroku, Aichi Pref., Japan, using Sherman traps during 2009–2010. To understand plant food utilization of both mice species in the research area, total DNA was extracted from fecal samples and the chloroplast rbcL gene region (262 bp) was amplified by PCR. We successfully amplified and obtained 262 bp DNA sequences by subcloning. Homology searches of the sequences via BLAST were then performed to identify food resources from the feces of both species. Lactuca serriola (Asteraceae), Wisteria floribunda (Fabaceae), and Cerasus jamasakura var. jamasakura (Rosaceae) were confirmed from the feces of A. speciosus. In addition, four plant species, L. serriola, Chamaecyparis obtuse var. obtusa (Cupressaceae), Pieris japonica var. japonica (Ericaceae), and C. jamasakura var. jamasakura were also found in the feces of A. argenteus. The present method using fecal DNA and molecular techniques was well suited for the identification of plant materials considering the diet of small rodents.
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Reports on the Mini-Symposia at the Joint Congress of the 29th Annual Meeting of PSJ and the Annual Meeting of MSJ 2013
Reports on the Workshops at the Joint Congress of the 29th Annual Meeting of PSJ and the Annual Meeting of MSJ 2013
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