羽山 伸一

コシジロウミツバメ(Oceanodroma leucorhoa)を用いて,翼長,最大尾長,最小尾長,フショ長,嘴高,嘴長の外部計測値と体重から,栄養状態の推定する指標を作成した.6個所の外部計測値から主成分分析によって抽出された第一主成分得点を計算することによって,全体の体サイズを表す指標とした.第一主成分得点を独立変数,体重の3乗根を従属変数とし,単回帰分析を行い,回帰直線から残差を栄養状態の指標とした.本研究では,この指標を余剰栄養指標(residual body condition index)と呼ぶ,コシジロウミツバメを用いて,余剰栄養指標の有効性を実測された脂肪蓄積量と比較することで検討した,コシジロウミツバメを全身麻酔下で殺した後,死体からエチルエーテルによって蓄積脂肪を抽出した.余剰栄養指標は,脂肪量の3乗根の57.4%を説明することが可能であった.したがった,体重と外部形態の測定を行うだけで,野外で繁殖するコシジロウミツバメについて,鳥を犠牲にすることなくまた容易に,栄養状態を推定することが可能となった.

To measure the heart rate of diving seabirds, we tested a new method of attaching electrodes and a miniaturized ECG logger with high memory capacity (2 Mbytes) and high frequent sampling (5ms). A needle type electrode was inserted into subcutaneous tissue of Adelie penguins, and an electrode was implanted under the sternum of hens. Both electrodes were connected to a logger attached to the back of the bird. The mean±SD of heart rate of penguins for 3 h and of hens for 1 h during a resting period were 74.9±15.4 bpm and 245.3±12.1 bpm, respectively. The ECG showed electric noise during exercising periods. However, as R peaks were countable in those periods, it was possible to calculate the heart rate during exercising periods from the interval between R peaks. Though the implantation method needs some recovery time for birds after surgery before the ECG measurement, the method reduces the electric noise caused by the locomotor muscle and electrode movement and is suitable to measure the ECG of free-ranging seabirds during dives.

滋賀県産野生由来のニホンザルを, 室温, 湿度, 光周期が一定の人工環境下において, 1年間にわたり飽食状態で飼育し, 月毎の体重と摂取エネルギー(kcal)を測定して, それらの季節変動を観察した。実験には, 人工環境下で2年以上飼育した成獣のうち, メス6頭, オス4頭を用いた。すべての個体において, 体重および摂取エネルギーは季節的に変化したが, それらのピークの時期には個体によるばらつきがみられた。個体毎の最大体重と最小体重の比は, 1.12〜1.37であった。体重増加期と体重減少期における平均摂取エネルギーは, どちらの性でも体重増加期の方が体重減少期より有意に多かった(p<0.01)。

バンドウイルカ血液性状が, 血液一般検査3項目, 生化学検査18項目において, 摂餌前後でどのように変動するかを検討した。臨床データ:1990〜1997年に, バンドウイルカ成獣雄2頭と雌4頭から定期健康診断の目的で, 合計286回の採血を行った。摂餌前後で分けると, 空腹時の9〜10時に187回, サバ5.0〜10.0kgを摂餌させた13〜14時に99回採血しており, それらを比較した。実験データ:成獣雌2頭で, 空腹時の9時とその後からサバ8.0kgを摂餌された13時に採血し, それを5回行った。さらに, 同じ個体で, 空腹時の9時とそのまま餌を与えなかった13時に採血した。それも同様に, 5回行った。両者のデータで, 摂餌により中性脂肪と尿素窒素は増加し, クロールは減少した。一方, 実験データだけではあるが, 空腹によって遊離脂肪酸と総ビリルビンが増加することが示唆された。

Patterns of body fat deposition and reliability of fat indices in wild Japanese monkeys (Macaca fuscata) were examined using 50 (22 females and 28 males) adult (&ge;5 years of age) specimens. The body fat reserve (%), which was calculated as [amount of whole visible body fat]/[carcass body weight]&times;100, is highly correlated with subcutaneous fat and mesentery (including omentum) fat. Body fat reserve was estimated as 302&times;(mesentery fat/body weight)-0.62. Body fat reserve exhibits a significant seasonality in both sexes.

Macroscopic and histological changes were examined on the female reproductive organs of Japanese monkeys (Macaca fuscata) with varying reproductive status in enclosed and provisioned troops. The weight and size of reproductive organs are described. The size of uterus declined in 2-3 months after parturition. The number of parturition was roughly estimated by degrees of sclerosis in myometrial vessels. The nipple length of parous animals was longer than that of nulliparous ones. The bilateral differnce in the length (more than 3 mm) between nipples indicated the experience of nursing. Interpreting ovaries on the basis of macroscopic examination alone was less precise. The present results suggested that the female sexual maturity and the experience of nursing can be estimated by the measurement of reproductive organs in the Japanese monkey.

神奈川県丹沢山地に生息するニホンジカ野生個体と同じ地域由来の飼育個体の体重増加, 出産の有無ならびに越冬期間の体重変化について比較・分析し, 食物条件の影響について考察した。この結果, (1)野生個体と飼育個体とも初冬における成獣(4歳以上)の平均体重は雄で約75kg, 雌で約50kgに達し, 顕著な性的二型が認められた。, (2)野生個体は飼育個体に比べて発育段階の体重増加と初産年齢に1年の遅滞が認められた, (3)飼育個体と野生個体の間の出生時の体重に有意差はなかったが, 両者に出生時期と出生時から0歳初冬までの期間の体重増加速度に違いがみられた, (4)越冬期間の体重変化は, 野生個体と飼育個体で異なり, 幼獣, 亜成獣雄および妊娠雌で違いが明瞭であった。以上の結果は生息地の食物条件の違いが, ニホンジカの発育段階の体重増加過程の影響し, 性成熟に到達する期間に影響することを示すものと考えられた。

Continuous body weight dynamics in supplementally fed free-ranging sika deer (Cervus nippon) during the three consecutive over-winters (from January to April), 1992-1994 were surveyed. Almost all individuals lost weight continuously throughout each winter (adult deer 5-13%; young deer 3-19%) and several deer lost weight even in April. Weight gain after loss began in the mid-April when ambient temperature increased and when plant growth began. Weight dynamics varied according to sex, age and reproductive status. Adult deer showed significant large weight loss than the young. Young deer lost weight (calves 18 ± 11 g/day, yearling and two-year-olds 27 ± 29 g/day) more slowly than the adults (65 ± 23 g/day). Following this study of over-winter body weight dynamics, it seems that early springs are the most critical periods for the survival of free-ranging sika deer because of their poor nutritional condition.

飼育下における年齢や性の異なる17頭のニホンジカを用い, 各個体の体重および集団の月毎の採食量の変化について, 1993年の8月から1年間にわたって調査した。9月から11月の発情期には, 成獣雄, 成獣雌および亜成獣雄の体重は減少傾向にあったが, 亜成獣雌や幼獣はこの間も成長し続けた。12月から3月までの越冬期には, 十分な餌が与えられているにもかかわらず, 総ての個体の体重にあまり大きな変化は見られなかった。4月から7月の出産育子期には, 全体的に体重は増加傾向となり, 特に前年生まれの幼獣および1994年生まれの幼獣の体重増加が顕著であった。ただし, 成獣雌および亜成獣雌の体重は出産によって約6kg減少し, その後も回復は見られなかった。この集団における月平均の代謝体重当たりの乾物(DM)摂取量は, 9月に一時減少し, 10月に再び高くなった。11月から3月までの間には大きな変化はなかったが, 4月から急激に増加する傾向が見られた。また, 代謝体重当たりの可消化エネルギー(DE)摂取量の変化も, DM摂取量の変化とほぼ同様であった。これらの結果から代謝体重当たりのDM摂取量がおよそ65gになると代謝体重の増加量が0となることが推定でき, 体重維持に必要なDE要求量は約196kcalであることが推定できた。

東京湾で回収された鳥類38種636羽の胃内容物を調査した結果,18種228羽(35.8%)が,さまざまな色彩および形状のプラスチック小片を保有していた.その中でも,他の目の鳥類と比較して,よく発達し,貯留性にすぐれた筋胃を持つガンカモ目およびハト目の鳥類は,他の目の鳥類と比較して多くのプラスチック小片を保有していた.ガンカモ目は海藻および他の植物繊維に類似した緑色および紐状のプラスチック小片を,ハト目は植物の種子やトウモロコシに似た色彩および形状のプラスチック小片をそれぞれ多く保有していた.これらの事実は,プラスチック小片は小石の代用品としてだけでなく,餌と誤認され摂取されている可能性を示唆している.

Milking under anesthesia in pregnant free‐ranging Japanese macaques (Macaca fuscata) directly revealed lactation in gestation at Jigokudani Monkey Park, the Shiga Heights, Nagano Prefecture, Japan, from 12 to 14 February 1992. Multiparae secreted milk at 76–97 days of estimated fertilization age when the birth intervals to the next offspring were 2 years. The observation of sucking behavior from February 1991 to March 1992 indicated that concurrent suckling by these multiparae terminated approximately 70 days before the next parturition after the growth of fetuses had accelerated and the embryos survived the crisis of abortion. Thus, Japanese macaque mothers appear to hedge maternal investment with concurrent lactation against possible miscarriage. Two nulliparous pregnant females secreted milk 3 months before the first parturition although they had no suckers. The first preparation of lactation appears to require the duration of longer than 3 months in nulliparae although worked mammary glands appear to be able to resume within 1 month in multiparae. © 1993 Wiley‐Liss, Inc. Copyright © 1993 Wiley‐Liss, Inc., A Wiley Company

The present study examined the histochemistry of pigments in the corpus luteum of the ovaries of cynomolgus monkeys (Macaca fascicularis), Japanese monkeys (Macaca fuscata), and rhesus monkeys (Macaca mulatta). Yellowish brown pigments were found in the regressing corpus luteum cells. Histochemical studies revealed that these pigments consisted of lipofuscin, the so-called age pigment. The findings obtained suggest that accumulation of lipofuscin might be related to cellular aging of the corpus luteum. © 1992 Japan Monkey Centre.

Sex and age compositions of wild Japanese monkeys captured as agricultural pests in Shiga prefecture for 11 years from 1981 to 1991 were studied. The composition of sex and age of 7 wild troops on Kyoto and Hyogo prefectures was also examined for comparison. The rate of males over 4 years old were higher in captured monkeys as agricultural pests than in wild troops. Most of captures as agricultural pests were performed in restricted seasons and areas. Over harvesting will exterminate some local populations of wild Japanese monkeys. We propose a moratorium on the capture as agricultural pests until the monitoring systems on influences to wild populations by captures are established.

An annual average of 163 Kuril seals was found dead in two years in salmon trap nets along the coastal waters of the Nemuro Peninsula and adjacent areas. The seal‐caused damage to the total salmon catch at the salmon trap nets was concentrated in some of them, particularly No. 27, where seals killed or injured 5.1% of the catch in 1982, and 1.8% in 1983. Based on the proportion of Kuril seals among the dead seals in the trap nets, it was estimated that Kuril seals damaged 4.7% of the total salmon catch at No. 27 in 1982, and 1.7% in 1983. Not all seals that entered the trap net drowned; some killed or damaged salmon, and then escaped. Copyright © 1991, Wiley Blackwell. All rights reserved

Sclerotic changes were found histologically in the myometrial vessels of 27 out of 33 cynomolgus monkeys (Macaca fascicularis). The sclerosis was composed of fibrous proliferations and intimal thickening. These changes were not observed in nulliparous cases, but were found only in multiparous ones. The findings suggest that the sclerotic changes in the myometrial vessels of cynomolgus monkeys are a pregnancy-induced phenomenon. © 1990 Japan Monkey Centre.

Copulatory behavior unrelated to conception is sometimes observed in some non-human primates including the Japanese monkey. In the present study, the authors examined whether a mature follicle or a newly formed fresh corpus luteum was observed in the ovaries of female Japanese monkeys which displayed the copulatory behavior unrelated to conception. Post-conception copulatory behaviors were observed in three out of four females usually kept in individual cages in an air-conditioned room, and in two out of three females without infants kept in an outdoor group cage. However, neither a mature Graafian follicle nor a fresh corpus luteum formed newly after conception was observed in any of these females by laparoscopic examinations conducted immediately after termination of the copulatory behavior. In females with infants born in the preceding birth season, copulatory behaviors were observed in three out of four females kept in the outdoor group cage, and in two out of four females in a free-ranging troop. Ovulation was confirmed in one case out of the three kept in the outdoor group cage, but neither a mature follicle nor a newly formed corpus luteum was observed in the remaining four females. These findings suggest that copulatory behavior in the Japanese monkey is not always controlled by the development of a follicle or ovulation in the ovary. © 1990 Japan Monkey Centre.

A few reports have suggested the possibility that feeding conditions might affect the sexual maturation of free-ranging Japanese monkeys in provisionized troops. In the present study, the sexual maturation of male monkeys at Takasakiyama in 1984, nine years after the start of restriction of artificial feeding, was examined externally and histologically and the results were compared with data obtained in 1971, when artificial foods were abundantly given. Spermatogenesis was not observed in any of the males under 4.5 years old in the present study, whereas it was noted in some premature 3.5-year-old males and in all males over 4.5 years old in the 1971 study. The age of sexual maturation thus rose by one or more years over the 13-year period from 1971 to 1984. The lag in sexual maturation of the males at Takasakiyama in 1984 could have been induced by the restriction of artificial feeding. © 1989 Japan Monkey Centre.

Forty-nine free-ranging Japanese monkeys (Macaca fuscata) were immobilized with 4.3-15.6 mg/kg (mean±S.D.=10.0±2.5 mg/kg) of ketamine hydrochloride (HCl), and 27 Japanese monkeys kept in enclosures were immobilized with a combination of 0.8-1.4 mg/kg (1.0±0.2 mg/kg) of xylazine HCl and 4.0-7.1 mg/kg (5.0±0.6 mg/kg) of ketamine HCl. In the xylazine HCl-ketamine HCl combination, good myorelaxation was induced. The mean induction times for the single dosage of ketamine HCl and the xylazine HCl-ketamine HCl combination were 2.8±1.5 min and 6.9±4.4 min, respectively. The mean immobilization times with the single dosage of ketamine HCl and the xylazine HCl-ketamine HCl combination were 39.3±16.5 min and 58.8±34.2 min, respectively. A half dose of ketamine HCl in combination with xylazine HCl could also immobilize Japanese monkeys successfully. Administrations of 0.5 mg/kg i.v. and 1.0 mg/kg i.m. of yohimbine HCl as an antagonist to xylazine HCl at 30 min after the induction reduced the immobilization time to 31.4±0.5 min and 49.0±22.1 min, respectively. Yohimbine HCl appears to be an effective antagonist to combination anesthesia by xylazine HCl-ketamine HCl in the Japanese monkey. © 1989 Japan Monkey Centre.

Diverticular disease of the colon was detected in a female Japanese monkey by X-ray examination. The monkey was 15 years old and had been kept under captive conditions for nine years. Lack of appetite and activity, and constipation were observed. The monkey was given fiber-rich vegetables and wild plants, and its appetite and activity then improved. Based on a consideration of various factors, it is suggested that one possible cause of the diverticulosis in this case was a low dietary fiber intake. © 1988 Japan Monkey Centre.