Change of nipple preference between successive offspring in Japanese macaques

Selective use of nipples among free-ranging infant Japanese macaques (Macaca fuscata) was studied. Each infant held only one of its mother's two nipples in the mouth during an average of 90.9% ± 1.5% (SEM) of total nipple contact time. The next offspring born to the same mother tended to use the nipple that its previous sibling had not used. Maternal behavior did not cause use of one nipple or the other.     

On operationally defining reconciliation

Post-conflict reconciliatory behavior has been reported to occur with variable frequencies in different primate groups and species. Because different investigators have used different criteria to operationalize reconciliation, however, it is possible that the variation reported merely reflects different methods of study. To compare different groups and species in a meaningful way, an accurate operationalization of reconciliation is necessary. This study explores the correlation between operationally defined reconciliation (what observers recognize, such as friendly reunion) and functional reconciliation (behavior that restores a dyadic social relationship) in a group of captive long-tailed macaques, using results from an experiment originally undertaken to demonstrate the function of friendly reunions in restoring dyadic tolerance after aggression. In dyads of unrelated animals, reunions were equally effective in restoring tolerance whether they involved body contact, overt friendly gestures, or mere proximity. Classification of post-conflict reunions as “reconciliations” depends on comparisons with control observations; these comparisons have been carried out in several ways. Comparisons using the “n-minute rule” missed functional reconciliations, whereas those based on the “post-conflict/matched-control rule” appeared to lead to more accurate classification of functional reconciliations. Post-conflict reunions were equally effective in restoring tolerance whether they were initiated by the original aggressor or by the victim. An accurate operational definition of reconciliation, not a conservative one, is prerequisite to comparisons of the frequency of this behavior, and depends on empirical verification. This study suggests specific guidelines for an operational definition based on such verification. © 1993 Wiley-Liss, Inc.     

Tourism and Infant-Directed Aggression in Tibetan Macaques (Macaca thibetana) at Mt. Huangshan,China

ABSTRACT

Previous studies of habituated Tibetan macaques (Macaca thibetana) at Mt. Huangshan, China demonstrated the negative impact that some tourism management strategies had on monkeys' annual infant mortality, but data on precise causes and perpetrators of infant injuries were not available. We worked at the same site and recorded rates of aggression that older monkeys directed toward group infants as a function of tourist numbers and proximity. We found a negative correlation between the number of people on the viewing platform and the frequency of monkeys' aggression toward the group's infants, but the effect is slight. We noted that infant-directed aggression (IDA) was more likely to occur in the provisioning zone where tourists bounded the monkeys on two sides, despite the fact that infants spent very little time in that location. The alpha and beta males engaged in more IDA than expected, while the other three adult males, adult females, and juveniles exhibited less IDA than expected. Males' IDA included biting, chasing, grabbing, and pushing. Adult females bit and grabbed mostly their own infants in the contexts of punishment and weaning. Juveniles' IDA was uncommon and consisted mostly of open-mouth threats. To minimize the severity and frequency of male-toinfant IDA, we recommend that sections of the tourist viewing platform be closed off so that tourists do not surround the monkeys, particularly when infants are near the viewing platforms and tourist numbers are few. The rule against tourists feeding monkeys should also be strictly enforced, so that altercations between the highest-ranked males and other group members, particularly infants, are less likely to occur.     

Mother–infant relationships and maternal estrogen metabolites changes in macaques (<Emphasis Type="Italic">Macaca fuscata,M. mulatta</Emphasis>)

This research assessed mother–infant relationships in rhesus and Japanese macaques living in analogous captive social groups, and monitored changes in the levels of excreted estrogen metabolites during the peripartum period. Each mother–infant pair was focally observed 3 h per week during the first 12 weeks of life of newborns. Fecal samples were collected twice a week from each mother, starting 4 weeks before delivery and ending 4 weeks after delivery. Infant-directed behaviors appeared to be consistently less protective/controlling and more rejecting in rhesus macaques than in Japanese macaques. Estrogen metabolite levels during the perinatal period were, on average, 3-fold higher in Japanese macaques and showed a sharp increase during the last weeks of pregnancy only in the Japanese macaque group. Considering the ecological and behavioral similarities between Japanese and rhesus macaques, the divergence between the two species in the onset and maintenance of maternal behavior was unexpected. This was possibly linked to the difference in the overall body size and life history, and to the striking divergence in estrogen metabolite variation during the peripartum period. Group size, social relationships, and average age of individuals in the two captive groups were not clearly involved in the recorded differences in maternal behavior. Electronic Publication     

Altitudinal and seasonal variations in the diet of Japanese macaques in Yakushima

Altitudinal and seasonal variations in the diet of Japanese macaques in Yakushima, southwestern Japan, were studied for 2 years by means of fecal analysis. The altitudinal range of fecal samples collected was 30 m to 1,203 m above sea level, and it was divided into three zones: low-zone forest (0–399 m), middle-zone forest (400–799 m), and high-zone forest (800 m–1,230 m). There was a considerable altitudinal and seasonal variation in the macaques' diet. Seed/fruit and animal matter were eaten more in the lower zones, whereas more fiber and fungi were consumed in the higher zones. In all of the zones, they ate seed/fruits the most in autumn (September–November) and the least in spring (March–April). They ate fibrous food the most in spring and the least in autumn. Macaques relied on seed/fruits heavily in the lower zone for a longer period than in the higher zones. Macaques in the high-zone forest ate almost no seed/fruit foods from March to May. Altitudinal variations in availability of seed/fruit foods seem to have influenced the altitudinal variations in diet. Total basal area of seed/fruit-food trees, species richness of seed/fruit-foods, main seed/fruit-food types available, and annual fleshy-fruit production all decreased with increasing altitude. Both interannual variation and annual cyclicity of diet were found in all zones. Electronic Publication     

Hormonal Correlates of Maternal Style in Captive Macaques (Macaca fuscata and M. mulatta)

Previous studies on nonhuman primate maternal styles showed that variation in infant-directed behavior falls along two dimensions, traditionally labeled as protectiveness and rejection. We investigated maternal styles in rhesus (Macaca mulatta) and Japanese (M. fuscata) macaques living in analogous captive social groups, and correlated them with the levels of estrogen metabolites excreted in female feces during the perinatal period. We focally observed mother-infant pairs 3 hours per week during the first 12 weeks of infant life. We collected fecal samples twice a week from each mother, starting 4 weeks before delivery and ending 4 weeks after delivery. Three significant components were extracted by principal component analysis from 15 different infant directed behaviors, each reflecting a different aspect of mothering style: rejection is correlated with behavioral measures of maternal opposition to contact; protectiveness is correlated with maternal solicitude; and independence is correlated with time in contact, grooming and cradling. Levels of estrogen metabolites are significantly correlated to rejection but not to protectiveness or independence, indicating that, in nonhuman primates, individual endocrine changes related to maternal behavior might specifically affect the timing of contact interruption.     

CSF 5-HIAA concentration as an early screening tool for predicting significant life history outcomes in female specific-pathogen-free (SPF) rhesus macaques (Macaca mulatta) maintained in captive breeding groups

We examined relationships among cerebrospinal fluid (CSF) concentrations of the major serotonin metabolite (5-HIAA, 5-hydroxyindoleacetic acid) and significant medical and behavioral outcomes for female rhesus macaques. Based on earlier findings with males we predicted that low CSF 5-HIAA concentrations would be associated with a range of negative life history outcomes in our captive specific-pathogen-free (SPF) breeding colony. We found that the mean CSF 5-HIAA concentration among animals that died over the course of the study period was significantly lower than among animals that survived. Further examination indicated an inverse relationship between CSF 5-HIAA concentration and number of treatments for illness, further suggesting a link between serotonergic functioning and overall animal health. Examination of behavioral data indicated that individuals with low CSF 5-HIAA concentrations were more often the targets of aggressive bouts than were individuals with high CSF 5-HIAA concentrations. Finally, we found a positive relationship between CSF 5-HIAA concentration and infant survivorship. These results suggest negative life history consequences of impaired serotonergic functioning in captive female rhesus macaques, and indicate that CSF 5-HIAA concentration sampled early in life may provide a useful tool in facilitating colony management decisions concerning utilization of scarce and increasingly valuable non-human primate resources.     

Monkeys with disabilities: prevalence and severity of congenital limb malformations in <Emphasis Type="Italic">Macaca fuscata</Emphasis> on Awaji Island

The Awajishima Monkey Center (AMC) free-ranging, provisioned population of Japanese macaques has included individuals with congenital limb malformations (CLMs) for at least 40 years. Including new data from this study, 16.1% of AMC infants from 1969 to 2007 (185 of 1,150) were born with CLMs. However, relatively little is known about the demographics of CLMs in the population, particularly the relationships among occurrence and severity of CLMs and age-sex demographics after infancy. In 2004, we conducted a census at AMC. Of the 199 monkeys censused, 34 individuals (17.1%) had CLMs. To estimate the severity of CLMs, we created an index that ranks individuals on a scale of 0 to 1 based on affected and absent limbs and digits. The severity of CLMs varied greatly (index range = 0.01-0.79, mean = 0.29), with similar variation in severity in each age-sex class (Student t-test, P > 0.05).     

Developmental changes of plasma alkaline phosphatase,calcium, and inorganic phosphorus in relation to the growth of bones in the Japanese macaque (Macaca fuscata)

The plasma levels of alkaline phosphatase (ALP), calcium, and inorganic phosphorus in the Japanese macaque were measured during its growing period. The plasma ALP level within two days after birth was 818±186 IU/1, and the level showed a temporary peak at about 2 months of age (2747±763 IU/1). The ALP level formed a plateau from 1 to 3 years of age, then decreased again and reached finally an adult level (211±71 IU/1). Sex differences were observed twice during the animal's lifetime, from 6 to 9 months of age and from 3 to 7 years of age. On integration of this complicated curve, a correlation was observed with the development of the length of the bones. The plasma levels of calcium and inorganic phosphorus which were high within two days after birth, reached adult levels at 3 months and 5 years of age, respectively.     

Diet of a Japanese Macaque Troop in the Coniferous Forest of Yakushima

I studied the diet of a troop of Japanese macaques in the coniferous forest of Yakushima over one year via focal animal sampling. Fiber-rich foods constituted 45% of annual feeding time, and mature leaves constituted 38% of total feeding time. Feeding time on fruits and seeds was only 13% and 4%, respectively. Flowers and fungi contributed a considerable amount of annual feeding time: 15% and 14%, respectively. Their diet changed seasonally. They fed on more fruits and seeds in response to increased availability, and when these foods were not available, they ate mature leaves. When the temperature was low, they ate more herbs, possibly to save energy by not climbing trees and staying in sunny places. The results imply two dietary characteristics of the species that might relate to adaptations in temperate regions, where fruit is available during a limited season and fiber-rich foods are the only candidate of fallback food. They are capable of digesting a large amount of fiber-rich food, but at the same time they preferentially select high-quality fruits or seeds when they are available.