N., 1988: Effects of resource limitation on the physical and reproductive condition of sika deer on Nakanoshima Island, Hokkaido. Acta theriol., 33, 13 :187-208 2 ) were studied during a 5-year-period. The population density increased from 31.5 deer/km 2 in 1980 to 57.5 deer/km 2 in the autumn of 1983, and declined the following winter to 26.3 deer/km 2 due to both natural mortality (22%) and removal (32%). As the population increased, availability of summer and winter forages rapidly decreased. Deer had eliminated dwarf bamboo by 1983, which was the most important forage in winter, and were forced to consume more bark and unpalatable plant species. In the winter of 1983-84, in conjunction with a longer snow cover than usual, a mass mortality (22%) from starvation was recorded. Although the body weights and skeletal size of island deer initially were almost the same as those of mainland deer, the 1984 animals of both sexes were smaller in body weight and chest girth than the 1982 animals. Sexual dimorphism in body weight and measurements (chest girth and hind foot length) became apparent only after 1.5-years-old in 1982, and after 2.5-years-old in 1984. Skeletal growth (jaw length and skull length) gradually declined in immature age classes with a higher population density. Antler growth, associated with the decrease in body weight, also decreased. The ratio of fawn to one-year-old or older females in autumn declined drastically from 65% in 1980 to 7% in 1984. Resource limitation caused by high population density, and fluctuating climatic conditions are the main factors that determined both the size of the individual deer and the population.
Twenty‐one species of deer occur in China: one species of Tragulidae, three species of Moschidae and 17 species of Cervidae. The foundation of this review is the research conducted in the early 1940s by Allen, combined with the research and investigation by the authors and other Chinese specialists since that time. This paper focuses on the tentative distribution of these species of deer for future research efforts.
To illustrate phylogeography of red deer (Cervus elaphus) populations of Xinjiang, we determined their mitochondrial DNA (mtDNA) control region sequences, and then investigated geographic variations and phylogenetic relationships between Xinjiang populations and other populations from Asia, Europe, and North America. The C. elaphus mtDNA control region shared different copy numbers of tandem repeats of 38 to 43-bp motifs which clearly distinguished the Western lineage from the Eastern lineage of this species in Eurasia. The western lineage comprised the Tarim populations from southern Xinjiang and the European populations, all of which had four copies of the motifs. By contrast, the Eastern lineage consisted of populations from northern Xinjiang (Tianshan and Altai Mountains), other Asian areas (Alashan, Gansu, Tibet, Mongolia, and northeastern China), and North America, all of which shared six copies of the motifs. MtDNA phylogenetic trees showed that there are two major clusters of haplotypes which referred to the Western and Eastern lineages, and that subgroupings of haplotypes in each cluster were congruent with their geographic distributions. The present study revealed that a boundary separating the Western lineage from the Eastern lineage occurs between Tarim Basin and Tianshan Mountains in Xinjiang. Meanwhile, North American populations were genetically closer to those of northern Xinjiang, northeastern China, and Mongolia, supporting that C. elaphus immigrated from northeastern Eurasia to North America through the glacier-induced land-bridge (Beringia) which had formed between the two continents after Late Pleistocene.
ABSTRACT. Periodic growth incremental lines are found universally in dental hard tissues. This periodicity theoretically allows for estimation of age, even in days, which would be useful in studies of wild animals. In the present study, enamel and dentin increments of the sika deer (Cervus nippon) were observed in ground sections with a polarized light microscope, and their periodicity was examined by the use of a chronological labeling method with fluorochromes. Enamel increments occurred at a mean interval of 10.6 (SD=1.5) µm, and mean spacing of dentin increments was 17.3 (SD=1.8) µm. Fluorochromic marking revealed that incremental lines form each day in enamel and almost every second day in dentin. The fluorescence-labeled lines suggest that enamel formation of the first m olar is complete by the age of 5 months. Due to its longer interval of incremental lines and longer term of formation, we conclude that dentin is more suitable than enamel for day-age estimation in sika deer. Experimental confirmation of incremental growth periodicity in various species can improve the reliability of use of tooth increments for age estimation and life history reconstruction.
ABSTRACT. Reproduction of feral raccoons (Procyon lotor) in Hokkaido, Japan, was examined during a 2-year period by analysis of placental scars or fetuses in the uterus. Of 242 collected females, 69 (29%) were juveniles, 71 (29%) yearlings, and 102 (42%) adu lts. The pregnancy rate averaged 66% in yearlings and was significantly lower than the 96% average observed in adults (p<0.01). Litter size ranged from 1 to 7 offspring per female, and averaged 3.6 in yearlings and 3.9 in adults. There was no significant difference in mean litter size between yearlings and adults. In Hokkaido, the raccoon mating season peaked in February and the majority of litters were born between March and May, similar to patterns described in North America, but some females mated in summer. The reproductive potential of feral raccoons in Hokkaido was similar to that reported in North America. The recent increase in raccoon numbers can be explained by their high productivity. Harvest data suggest that hunting pressure on juveniles is lower than that for older age classes when using box traps in summer. In order to reduce the feral raccoon population, alternative hunting methods that increase juvenile mortality rates are needed.
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