Noriyuki Ohtaishi

Prehistoric hunting pressure estimated by the age composition of excavated sika deer (Cervus Nippon) using the annual layer of tooth cement

Abstract Age of excavated sika deer was determined not only by the cement-annuli method but also by the observation method to avoid unnecessary destruction of archaeological materials. The observation method is based on tooth replacement, wear index and the appearance of cervical lines on the molar teeth. Stepwise discriminant analysis was used to establish a criterion for the age determination of excavated mandibles. Then the annulation method was carried out for well-preserved specimens older than 3–5 years. The age composition of excavated deer mandibles seems to have changed through the Jomon Period. Age composition at the Torihama sites (the Early Jomon Period) was characterized by an abundance of aged individuals, showing a close similarity with that of the recent deer population under protected conditions. Deer from the Kidosaku and Yahagi sites (the Late Jomon Period) and the SambuUbayama site (the Latest Jomon Period) were composed mainly of deer younger than 5 years, which seems to correspond to that of the recent hunted population living under natural conditions in Hokkaido. These data suggest that the hunting pressure increased during the Late and Latest Jomon Periods and compares with the pressures on recent hunted populations of sika deer.

Molecular Phylogeography of the Red Deer (Cervus elaphus) Populations in Xinjiang of China: Comparison with other Asian, European, and North American Populations

Abstract 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.

Estimation of prehistoric hunting rates based on the age composition of sika deer (Cervus nippon)

Abstract The theoretical background for the simulation of a hunting rate from age-composition data is discussed using excavated sika deer ( Cervus nippon ) remains. To compile life tables for the excavated collections, the number of live deer is calculated from the number of deaths in the age composition. Survival rate was defined as the total number of survivals after 1 year, as compared against the total number of live deer in the life table. Survivorship curves of a non-hunted population are simulated based on the known age composition of recent deer populations. The hunting rate is induced as the difference between the survival rate of a hunted population and that of a non-hunted population. Ages of excavated deer remains from 14 sites were determined both by the annulation of tooth cement and observation of wear conditions. Age compositions were classed into three patterns: adult-abundant, juvenile-dominant and fawn-abundant patterns, suggesting that the former two patterns were probably harvested by hunting, and that the last pattern was possibly a result of trapping. The calculated survival rates were all significantly higher than the simulated rate for the non-hunted population. Hunting rates were estimated at about 5% for the adult-abundant pattern, which was detected mainly during the Earliest and Early Jomon Periods and about 10% for the juvenile-dominant patterns, which were distributed throughout the later periods.

Determination of age in the Japanese monkey from growth layers in the dental cementum

The teeth of 14 Japanese monkeys (Macaca fuscata) were examined to establish an exact method of determining age by histological observation of dental cementum. The cementum showed annual growth layers, which were especially remarkable in the incisor root and in the molar cementum deposited at the junction of the roots. The layer of cementum formed in winter appears as a dark layer in stained sections and as a translucent layer in unstained ground sections. In the incisor the first dark and light layers are formed at the age of three years, whereas in the molar they do not appear at a definite age. The layers are thick and clear in the upper medial incisor. As a result, the age of a Japanese monkey can be determined by adding two to the number of dark layers and an outer light layer.It is interesting that the formation of the cementum of the first molar begins a few years after its eruption. The relation between this fact and the pressure of occlusion is discussed.

Population Genetic Structure of the Spotted Seal Phoca largha along the Coast of Hokkaido, Based on Mitochondrial DNA Sequences

Abstract Population genetic structure of the spotted seal, Phoca largha, along coastal regions of Hokkaido was investigated, using mitochondrial DNA (mtDNA) sequences. A 571-bp fragment of the mtDNA control region and adjacent threonine and proline transfer RNA genes was sequenced from 66 seals. We categorized all individuals into three groups considering sampling area and season: twenty-four seals from the Sea of Okhotsk in winter, 11 seals from the Sea of Okhotsk coast in fall, and 31 seals from the Sea of Japan coast in winter. From the 66 animals, 57 haplotypes were identified. Compared with the harbor seal sequence, all spotted seals examined shared two deletions in the control region, which distinguished between the two species. Forty-nine haplotypes were represented by a single individual, and haplotypes shared by more than two animals were generally restricted to same sampling-groups. Phylogenetic trees did not indicate clear geographic differences among the three groups. An Analysis of molecular variances (AMOVA) did not showed any significant population genetic structure in Hokkaido spotted seals (Φst = −0.003). Our results showed a high level of diversity but no genetic structure, and did not deny the possibility that seals in the Okhotsk breeding concentration mainly stayed in the fall Okhotsk and also inhabited in the winter Sea of Japan.

Growth-related changes in histology and immunolocalization of steroid hormone receptors in gonads of the immature male green turtle (Chelonia mydas)

Studies on the population dynamics of sea turtles require histological evaluation of the ontogenetic development and the activity of the gonads for reproduction. To investigate the growth-related changes of gonads in the immature male green turtle (Chelonia mydas), the histological changes of testes and epididymides and the localization of the androgen receptor, estrogen receptor alpha, estrogen receptor beta, and progesterone receptor were examined. The testes were categorized histologically into six developmental stages, and a scarce relationship between straight carapace length and gonadal development was confirmed based on the histological analysis. Several kinds of steroid hormone receptors were examined to show distributions in both testes and epididymides, for which their immunoreactivities were enhanced according to the developmental stage of the testes. These results suggest that straight carapace length is not an adequate indicator of maturity determination, whereas histological and immunohistochemical evaluations are useful in identifying the growth stages of green turtles, owing to the higher sensitivity to steroid hormones that appear during growth.

Monitoring ovarian cycle and conception by fecal progesterone analysis in sika deer

The ovarian cycle and conception of sika deer were studied to reveal factors responsible for delayed conception. Concentration of progesterone in feces from 12 female Hokkaido sika deer (Cervus nippon yesoensis Heude, 1884) was measured during the mating season in 2000. The cyclic pattern of fecal progesterone synchronized with estrous symptoms, which could hence be interpreted as indicating ovarian cycle. All observed females ovulated by 14 October. However, during the early mating season, females did not permit copulation at ovulation, and the length of luteal phase following ovulation without estrus was 9.8 ± 4.6 days (5–24 days). Most females conceived at the first copulation, which were confirmed by progesterone profiles that was sustained at a high level after the copulation. This indicates the presence of a functional corpus luteum, a state of pregnancy. Thus, some females had repeated ovulation without copulation several times, creating a 3–4 week variation in the timing of conception. But some females conceived very late in the mating season after the repetition of ovulation and copulation.

Significant relationships between the serum leptin concentration and the conventional fat reserve indices in a wildlife species, Hokkaido sika deer (Cervus nippon yesoensis)

We assayed the serum leptin concentration and determined its correlation with the kidney fat mass (KFM), kidney fat index (KFI), and femur marrow fat (FMF) indices in 12 Hokkaido sika deer (Cervus nippon yesoensis Heude, 1884) collected in April, June, and October 2000. The KFM and KFI in April and June were both significantly lower than those in October. The leptin concentrations in April and June and in October were 1.222–1.521 ng mL–1 HE (Human Equivalent) units and 1.676–2.63 ng mL–1 HE, respectively, without overlapping. The relationships between the leptin concentration and the KFM, KFI, and FMF were all significant. Therefore, we conclude that the serum leptin concentration can be used as a new index for fat reserves in Hokkaido sika deer. However, reliable results could not be obtained from four samples collected in April and June when the deer were in a lower nutritional status. This may be due to the limited sensitivity of the antisera in the commercial multi-species leptin RIA kit used. For practical use in wildlife biology, species-specific leptin assays should be developed to eliminate this problem.

Acid-Base Status and Blood Gas Arterial Values in Free-Ranging Sika Deer Hinds Immobilized with Medetomidine and Ketamine

Ten free-ranging female sika deer (Cervus nippon) were captured to obtain the reference values for acid-base status and blood gas when immobilized with the combination of medetomidine and ketamine. The mean ± SE of PaCO2, PaO2, and HCO3− were 58.1 ± 6.1 mmHg, 58.8 ± 6.4 mmHg, and 36.0 ± 4.4 mmol/l, respectively. Although acidosis and alkalosis occurred in three and two animals, respectively, no serious conditions were observed. The blood values, however, suggest that some degree of hypoxemia and respiratory acidosis with metabolic alkalosis are developed. The trapped deer showed a significantly higher than normal rectal temperature reflective of exertion.

Phylogenetic relationships among deer in China derived from mitochondrial DNA cytochromeb sequences

The phylogenetic relationships of Cervidae and Moschidae were examined using partial sequence data of mitochondrial DNA (mtDNA) cytochromeb. Ten new sequences were obtained for six species of Cervidae and Moschidae, and aligned with those previously reported for other deer species. Our results demonstrated that the phylogenetic status of the taxa inferred from molecular data was congruent with taxonomy based on morphological studies. Cervidae formed a monophyletic group that consists of four subfamilies: Cervinae, Muntiacinae, Hydropotinae, and Odocoileinae. Moschidae occurred at the base of the Cervidae clade. On the basis of molecular clocks for genetic distance, the divergence time of mtDNA haplotypes within the subfamily Cervinae, among subfamilies in Cervidae, and between Moschidae and Cervidae was estimated to date 2–7 MYA, 6–10 MYA and 8–13 MYA, respectively.