Shin-ichi Hayama

An index of body condition was calculated as the residual from the regression of the cubed root of body mass against the first principle component score of a principle component analysis of six external measurements, which was represented as total body size. This index was called the residual body condition index, or RBCI. To evaluate the utility of the RBCI in studies of Leach's Storm-petrels (Oceanodroma leucorhoa), the RBCI was compared to measurements of total lipid mass. Total lipid content was extracted using ethyl-ether after birds had been killed under anesthesia. The RBCI explained 57.4 % of the variation of the cubed root of total lipid mass. We could thus reasonably estimate the body condition of the parents breeding under natural conditions by measuring their body mass and external measurements.

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.

Japanese monkeys of the wild origin in Shiga Prefecture were housed under the artificial environment where a room temperature, humidity, photoperiod were fixed through the year. Their body weight and voluntary intake energy(kcal)of every month were measured, and those seasonal changes were observed. Adult six females and four males maintained under this environment for more than two years were used for the experiment. Body weight and intake energy changed in all the individuals seasonally. But, the time of that maximum value and the minimum value was not unified by individuals. The ratio of maximum and minimum body weight in every individual was 1.12〜1.37. Average intake energy in the body weight in crease term was higher than that in decrease term(p<0.01).

We studied in bottlenose dolphins, Tursiops truncatus, how blood values changed before and after feeding with 3 hematological and 18 serum chemistry tests. Clinical data:A total of 286 blood samples were clinically examined from two male and four female adult dolphins from 1990-1997;187 samples were taken between 09:00-10:00 before feeding, and 99 samples were taken between 13:00-14:00 after they had been fed 5.0-10.0 kg of mackerel. Experimental data:Blood samples from two female dolphins were taken at 09:00 before feeding and at 13:00 after they had been fed on 8.0 kg mackerel on five separate times. On five other times, blood samples from the same dolphins were also taken at 09:00 and 13:00 before they had been fed any fish. In both data, it is concluded that TG and BUN will increase, and Cl decrease due to dietary factors. Experimental data, however, suggests that FFA and T-Bil will increase when an animal has not eaten.

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.

Age-related body weight changes, winter body weight changes and breeding condition of free-ranging sika deer and captive sika deer, which had the same genetic origin and different nutritional conditions, were surveyed. The adult male reached around 75 kg in body weight and the adult female reached around 50 kg, and they showed an apparent difference of sexual demography. The captive deer under yearlong good food condition showed large body weight increase until winter of yearling and the free-ranging deer under yearlong poor food condition kept large body weight increase until winter of two-years old. The body weights at birth were not different significantly each other, but the body weight gains from the birth to the beginning of first winter and the mean birth date were different between free-ranging deer and captive deer. The body weight increase and sexual maturation of free-ranging deer delayed about a year compared with those of the captive deer. The winter weight changes also showed different patterns each other, especially in the case of young deer and pregnant deer. Above results suggest that poor food condition may delay body growth during the period of development and sexual maturation on sika deer.

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.

Seasonal trends in voluntarily food intake and body weights of groupfed sika deer(Cervus nippon)were monitored from July 1993 to July 1994 in Nogeyama Zoological Gardens, Yokohama, Japan. In this study, 2 adult(over 2 years old)males, 3 adult females, 1 young(1〜2 years old)males, 2 young females, 4 fawns(0〜1 years old)and 5 new born(May to June 1994)fawns were used. During the mating season from September through November, body weights of adult specimens and young males decreased, but these of young females and fawns continuously increased. During winter season from December through March, there was very little change in body weights of all specimens. From April through July, body weight of specimens increased, but these of adult and young females decreased about 6 kg after giving birth. The monthly average dry matter(DM) intake per metabolic body weight of the group decreased for a time in September. Great change in DM intake was not observed during winter, however, DM intake increased markedly from April. Digestive energy(DE) intake per metabolic body weight was much the same as the changes in DM intake. From this, DE intake for maintenance was estimated in approximately 196 kcal per metabolic body weight of the group.

The authors examined the stomach contents of 636 dead birds (38 species) that were recovered at Tokyo International Airport and the adjacent areas. Of these, 228 birds (35.8%) ingested plastic particles in their stomachs. Anseriformes and Columbiformes, which have developed and musculative gizzards, ingested more plastic particles than other orders. Furthermore the Anseriform had a tendency to ingest more greenish and stringy plastics like marine plants or other kinds of botanical fibers. Whereas the Columbiform took more yellowish plastics similar to botanical seeds and grain of Indian corn. Those facts suggested that the plastic particles were ingested selectively as food just as grid.

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.