Amino acids in the plasma of fasting Japanese monkeys (Macaca fuscata fuscata andM. f. yakui)

The plasma levels of 26 amino acids and related compounds were determined in five male and five female adult members of each of the two subspecies of Japanese monkeys,Macaca fuscata fuscata andM. f. yakui. Activities of L-asparaginase and histaminase in plasma were also measured.Numerous differences in amino acid levels between the sexes in the subspeciesfuscata were noted, with the female consistently exhibiting lower values. Few differences were observed between the sexes of the subspeciesyakui or between the two subspecies of Japanese monkeys. These monkeys were similar to other previously studied nonhuman primates in exhibiting measurable levels of 3-methylhistidine in plasma. There were numerous quantitative differences among Japanese monkeys and stump-tailed macaques, rhesus monkeys, chimpanzees, and man, with the Japanese monkeys usually exhibiting higher plasma levels.L-asparaginase activity was not detectable in these Japanese monkeys. Histaminase activity was similar to that previously measured in pig-tailed macaques and chimpanzees, lower than that in rhesus monkeys and stump-tailed macaques, and higher than that in man.     

Metabolism of daidzein by intestinal bacteria from rhesus monkeys (Macaca mulatta)

PURPOSE: To identify the metabolites produced from an isoflavonoid, daidzein, by colonic bacteria of rhesus monkeys. METHODS: The metabolism of daidzein by the fecal bacteria of nine monkeys was investigated. Daidzein was incubated anaerobically with fecal bacteria, and the metabolites were analyzed by use of liquid chromatography and mass spectrometry. RESULTS: The fecal bacteria of all of the monkeys metabolized daidzein to various extents. Dihydrodaidzein was found in cultures of fecal bacteria from two monkeys; dihydrodaidzein and equol were found in cultures from four monkeys; dihydrodaidzein, equol, and an unknown metabolite (MW = 244) were found in cultures from one monkey; and dihydrodaidzein and the unknown metabolite were found in cultures from two monkeys. CONCLUSIONS: Similar to that in humans, variation was evident in the metabolism of isoflavonoids by fecal bacteria from rhesus monkeys. Some metabolites produced by fecal bacteria from monkeys were the same as those produced by fecal bacteria from humans.     

Monitoring the reproductive status of female gorillas (Gorilla gorilla gorilla) by measuring the steroid hormones in fecal samples

The reproductive status of female gorillas (Gorilla gorilla gorilla) was estimated by measuring the sex steroid hormones in fecal samples instead of in blood samples. Fecal samples from female gorillas were used to examine the reliability of this non-invasive assay system, which included the extraction method for estradiol-17β (E₂) and progesterone (P) from fecal samples. Fecal samples from three female gorillas were collected daily for about 55 days, and fecal E₂ and P were assayed to clarify the fluctuation patterns of these steroids in the feces. Fecal sampling from one female was repeated for another 50-day period (starting 75 days after the end of the first observation period) and assayed to confirm if the menstrual cycle of this subject was ovulatory. Although fecal E₂ concentration measurements were quantitative by using this assay system, fecal P concentration measurements were semi-quantitative. Relative amounts of fecal P in fecal samples were estimated by using the values of B/B₀ (bound/total binding in the radioimmunoassay system). Two of the four fluctuation patterns of fecal hormones observed throughout the menstrual cycle for the three female gorillas were typical for normal ovulatory cycles. In the subject observed for two periods, one pattern was typical and the other atypical. The results show that this non-invasive method is simple and practical for monitoring the reproductive status of great apes as well as Old World monkeys.     

Predation on mammals by chimpanzees in the montane forest of Kahuzi, Zaire

The rate of predation on mammals by chimpanzees was determined from carcasses and from fecal specimens found on fresh trails during a 16-month period in the montane forest of Kahuzi-Biega National Park, Zaire. A unit-group of semi-habituated chimpanzees, composed of 22 – 23 individuals including 8 adult or adolescent males, appeared to kill about 18 – 30 mammalian prey (16 – 28Cercopithecus monkeys) per year, if the multiple kills by chimpanzees were not considered. A juvenile l'Hoest's monkey was recorded for the first time as the prey of chimpanzees in this study. Predation occurred in the late dry and the early rainy seasons, when the diversity of ripe fruits was the highest during the year. The Kahuzi chimpanzees tended to kill mammals less frequently but to killCercopithecus monkeys more frequently than chimpanzees in other habitats. The absence of red colobus monkeys, which are the most frequent prey in Gombe, Mahale, and Tai, might be responsible for the low predation rate. However, the estimated rate of predation onCercopithecus monkeys is the highest record among various chimpanzee habitats. At least 11 – 18% of theCercopithecus population seemed to be lost annually as a result of being killed by chimpanzees. Chimpanzees may be the most important predators on these monkeys in the absence of leopards at Kahuzi. The examination of fecal samples and carcasses suggested that adult (probably male) or adolescent chimpanzees tended to eat juvenile or subadult monkeys most frequently, as is also seen for chimpanzees in Gombe, Mahale, and Tai.     

Assessment of individual differences in the preferred proximity to a human feeder by partitioned raisin test, with two species of macaque monkeys

All animals must acquire food and mates by approaching them despite possibilities of accompanying risks and thus are frequently encountered with approach-avoidance conflicts in daily lives. Behavioral individual differences in such situations may be considered as one of the most biologically fundamental personality trains. “Partitioned raisin test” was devised to assess this trait with macaque monkeys. It involved throwing raisins into groups of monkeys and observing the preferred distance of each from the human feeder, a source of possible harm. The test was administered to 4 groups of Japanese monkeys (30 total) and 3 groups of rhesus monkeys (19 total), all l-yr-old and matched in history. Individual differences in the preferred proximity to the feeder, as expressed by the Proximity Index (PI), were found in both species.PI was not correlated with a measure of dominance over the raisins. Individual differences inPI were also not due to territorial effects unrelated to the location of the feeder.PI was stable in five of the six monkeys re-tested after one year of interval in a newly organized group, where there supposedly had been a change in their social structure. Partitioned raisin test was shown to be capable of depicting individual differences related to differential approach bias in an approach-avoidance conflict situation. Although possible confounding effects by social factors need to be delineated in the following studies, the method may provide a handy and widely applicable way for the assessment of this trait with monkeys.     

Vocal individual discrimination in Japanese monkeys

The present study determines which features of the coo call are used by Japanese monkeys Macaca fuscata for vocal individual discrimination. First, two female Japanese monkeys were trained to discriminate conspecific individuals vocally, using an operant conditioning. Using as stimuli three unknown individuals with 30 calls per individual, the two monkeys succeeded in discriminating new call exemplars from the three stimulus individuals. A discriminant analysis performed on calls used as stimuli indicated that start frequency of the fundamental and call duration were variables that can differentiate individuals efficiently. Then, playbacks of acoustically modified signals were used to indicate which vocal features are used by monkeys for the individual discrimination. Stimuli signals containing modified pitch or duration, or filtered so as to keep only the fundamental component, were tested. Results indicated that Japanese monkeys use multiple acoustical cues to perform vocal individual discrimination, including at least pitch, call duration, and harmonics. However, harmonics seem to be less important for discrimination than pitch and call duration.     

Differences in hair density of Japanese monkeys (Macaca fuscata fuscata) with locality and age

The hair density of free-ranging Japanese monkeys (Macaca fuscata fuscata) living in three different areas was investigated. The Japanese monkeys had thicker hair than other macaques. The hair density in the Japanese monkeys varied with locality: the northern monkeys had thicker hair than the southern ones. The density did not vary markedly with age up to 3 years of age, but then decreased gradually up to adult age (≧7 years old). The remarkable growth of the trunk suggested that the total number of hairs increased with age, especially during the period as a juvenile.     

Hematological analyses of the Japanese monkey (Macaca fuscata)

Various hematological examinations were performed on a total of 208 Japanese monkeys (Macaca fuscata). One hundred and fifty-eight of the monkeys were originally from different habitats in the western part of Japan, where they existed as free-ranging animals. The remaining 50 monkeys were kept in an open-enclosure for about one year. Laboratory examinations on blood specimens included the following; the erythrocyte and leukocyte counts, hemoglobin concentration, hematocrit, the specific gravity of the blood and plasma, protein concentration of the plasma, SGO-T, SGP-T, A/G ratio and the erythrocyte sedimentation rate. Results were similar to those reported for otherMacaca species. When the data reported here was compared with the known values for man, the Japanese monkey showed lower values for the erythrocyte count, hemoglobin concentration, hematocrit, and the specific gravity of the blood. Higher values were shown for the leukocyte count and SGO-T activity, with a wider overall range of variation.     

Lipofuscin in the corpus luteum of macaque ovaries

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.     

Fecal testosterone immunoreactivity as a non-invasive index of functional testosterone dynamics in male Japanese macaques (Macaca fuscata)

Validation of a simple method for the extraction and quantification of testosterone (T) from the excreta of male Japanese macaques (Macaca fuscata) is presented. Radioimmunoassay of paired fecal and serum samples collected from four intact sexually mature males during the breeding season provided profiles that were significantly correlated when samples were offset by approximately 48 hr. Additionally, no significant differences were observed in the pattern of temporal variation of T levels in serum and feces. Two castrated males were injected with radioinert T, and the patterns of excretion were observed by analysis of serial fecal and urine samples. Approximately 48 hr after the steroid was administered, a significant peak in the average fecal T levels was apparent. The injection event was also registered in the urine of both males, although qualitative differences were observed. These data suggest that measures of fecal T provide a reliable and non-invasive means of assessing gonadal function in this species. As the analysis of hormone levels in feces allows for frequent, stress-free sampling with minimal disruption, this method should be preferred in long-term orin situ applications requiring endocrine monitoring.     

Prevalence of gastrointestinal parasites in captive non‐human primates of twenty‐four zoological gardens in China

Captive primates are susceptible to gastrointestinal (GIT) parasitic infections, which are often zoonotic and can contribute to morbidity and mortality. Fecal samples were examined by the means of direct smear, fecal flotation, fecal sedimentation, and fecal cultures. Of 26.51% (317/1196) of the captive primates were diagnosed gastrointestinal parasitic infections. Trichuris spp. were the most predominant in the primates, while Entamoeba spp. were the most prevalent in Old World monkeys (P < 0.05). These preliminary data will improve the management of captive primates and the safety of animal keepers and visitors.     

How laboratory-raised Japanese monkeys (Macaca fuscata) perceive rotated photographs of monkeys: Evidence for an inversion effect in face perception

Five laboratory-raised Japanese monkeys (Macaca fuscata) were presented various types of photographs of Japanese and rhesus monkeys (Macaca mulatta) in upright, horizontal, and inverted orientations in a sensory-reinforcement experiment. The ratio of the duration of potential viewing time for the photographs which the subjects controlled to the interval between subject-controlled presentations of them (the D/I score) was used as a measure of preference for the photographs. When inverted photographs were presented, the D/I scores were lower than for upright photographs. The difference in D/I scores between photographs of the two species, which indicated discriminability between them, also diminished when the photographs were inverted. The results obtained suggest an inversion effect in face perception in macaque monkeys.     

A cytogenetic study on congenital limb malformations in the Japanese monkey (Macaca fuscata)

A cytogenetic investigation was performed on 88 Japanese monkeys (Macaca fuscata) with abnormal limbs from 11 free-ranging provisioned troops including nine individuals with abnormalities indistinguishable as to whether they were congenital or injurious. All of the monkeys with abnormal limbs including the nine questionable individuals had the same karyotypes as those of normal individuals. The chromosome number was 42, consisting of 20 bi-arm autosome pairs and a submetacentric X-chromosome and Y-chromosome. The ninth chromosome pair, which was the only chromosome pair with remarkable secondary constriction, displayed length polymorphism of the centromeric C-band and secondary constriction in both deformed and normal monkeys. These kinds of variants have also been commonly found in other monkey species, which have almost the same karyotype as the Japanese monkey and have not been reported to show frequent occurrence of limb malformation. We concluded therefore that chromosomal abnormalities could be excluded from the main causal factors for limb malformations of the Japanese monkey.     

Histological and microbiological aspects of the vagina in captive howler monkeys (Alouatta caraya)

The histology and the glycogen content of the vaginal epithelium was studied in 15 adultAlouatta caraya monkeys. The histological sections revealed a thin epithelium without cornification. The application of the PAS-amylase method showed absence of glycogen. The microbial flora of the vagina was examined in eight adultAlouatta caraya. The vaginal smears showed a mixed flora with a predominance of Gram+cocci. Haemolytic streptococci were found in 100% of the tested monkeys. Other cocci, such asStaphylococcus albus, Streptococcus faecalis andMicrococcus sp. were less frequent. Of the fecal organisms,Proteus sp. was the most frequently isolated. Neither ureaplasms nor any species ofLactobacillus could be isolated. Positive cultures for nonpathogenic yeasts was a common feature. The relation between the absence of glycogen in the vaginal epithelium and the impossibility to isolate lactobacilli is discussed.     

Prevalence of IgE antibody to crude and purified allergens of Japanese cedar pollen among different troops of Japanese monkeys (Macaca fuscata)

We measured specific IgE antibodies to the crude allergen as well as two purified allergens (Cry j I and Cry j II) of Japanese cedar (Cryptomeria japonica—CJ) pollen in the serum of 276 Japanese monkeys in nine troops. Of 45 monkeys with CJ specific IgE in eight of nine troops, 23 (51%) were found to have IgE to both Cry j I and Cry j II, 21 (47%) only to Cry j I, and one (2.2%) only to Cry j II. The positive rate of specific IgE antibody to each allergen varied among the troops.     

A proposal of the method of deer density estimate without fecal decomposition rate: a case study of fecal accumulation rate technique in Japan

The accuracy of estimating deer density using the fecal pellet count method is greatly limited by variability of the fecal decomposition rate. The fecal accumulation rate technique can avoid the issue of decomposition rate. However, the precision of this technique is not clear when the decomposition rate is relatively high, such as in Japanese forests. We estimated deer population densities on Yakushima Island by the fecal accumulation rate technique and compared them between seasons. The estimated densities were similar to reported estimates, and did not differ seasonally, in accord with reports that deer on Yakushima do not migrate seasonally. Thus, we conclude that the fecal accumulation rate technique is applicable in Japanese forests.     

Age-Related Changes of Elements in the Coronary Arteries of Monkeys in Comparison with Those of Humans

To elucidate compositional changes of the coronary artery with aging, the authors investigated age-related changes of elements in the coronary arteries of rhesus and Japanese monkeys by direct chemical analysis in comparison with the coronary arteries of Japanese and Thai. Used monkeys consisted of 38 rhesus monkeys and 23 Japanese monkeys, ranging in age from newborn to 33 years. After perfusion with a fixative, the hearts were resected from the monkeys, and the anterior interventricular branches of the left coronary artery and the right coronary arteries were resected from the hearts. After ashing of the arteries, element contents were determined by inductively coupled plasma-atomic emission spectrometry. It was found that the Ca and P contents did not increase in both the left and right coronary arteries of rhesus and Japanese monkeys at old age. The average contents of Ca and P decreased by 13% and 25% in the left coronary arteries more than 20 years of age in comparison with those below 20 years of age, whereas they decreased by 4% and 15% in the right coronary arteries more than 20 years of age in comparison with those below 20 years of age. This finding indicated that atherosclerosis scarcely occurred in both the left and right coronary arteries of rhesus and Japanese monkeys at old age. In contrast with monkeys, atherosclerosis occurred frequently in the coronary arteries of Japanese and Thai at old age.     

Sequential pattern of limb anomalies in Japanese monkeys on Awajishima Island

X-ray examinations of Japanese monkeys (Macaca fuscata) in two groups on Awajishima Island revealed that 11 of 46 monkeys from the Kaminada group and 5 of 37 monkeys from the Shirasaki group had limb anomalies. All the cleft hands, which comprised most of the anomalies in these Awajishima monkeys, involved reduction of one, two, or three fingers. The digital reductions showed a definite pattern: cleft hands with four, three, or two fingers lacking the digital rays III, III & IV, or II, III & IV, respectively. A similar teratological pattern has been recognized in the anomalies of other troops of Japanese monkeys. The presence of such a common teratological pattern among Japanese monkeys may be related to the high incidence of the anomalies and suggests that they may have a common etiological factor.     

Circulating blood volume of the Japanese monkey (Macaca fuscata) by means of the dye T-1824

The circulating blood volume has been measured in 65 healthy Japanese monkeys (Macaca fuscata) with the dye T-1824 (Evans blue). The values obtained were 83 ± 13 ml/kg in females, and 85 ± 12 ml/kg in females, almost the same as the figures reported in man.Sex difference of blood volume has been reported to be present in man, but from the data obtained here no significant difference was found in the Japanese monkey.In young monkeys aged from 1 to 5.5 years, the blood volume was 77 ± 5 ml/kg in males, and 78 ± 4 ml/kg in females. The blood volume of the monkey was found to increase with age; a significant difference was demonstrated between adult males and young males.     

Species preference by infant macaques with controlled social experience

In Experiment 1, infant Japanese monkeys and rhesus monkeys were artificially reared in pairs with conspecific or heterospecific monkeys. Preferences of these monkeys for a variety of pictures of Japanese monkeys and rhesus monkeys were repeatedly tested during the first 1 or 2 years of life. The duration of lever-pressing responses to see those pictures was a measure of the preference. All monkeys, Japanese or rhesus, preferred pictures of rhesus monkeys to pictures of Japanese monkeys, without regard to their social experiences. Experiment 2, with an adult Japanese monkey as the subject, and Experiment 3, with different pictures as stimuli, suggested that this preference was not a consequence of any bias in the pictures used. In Experiment 4, a Japanese monkey reared by a rhesus foster mother and rhesus monkeys reared by Japanese monkey mothers received the same preference test. The Japanese monkey infant preferred to see pictures of rhesus monkeys. However, rhesus infants did not show clear species preferences. These results suggest that infants of both Japanese and rhesus monkeys have a native tendency to prefer to see physical characteristics of rhesus monkeys over Japanese monkeys.