Tetsuhiro Minami

Mother-infant interactions of wild-born, individually-caged cynomolgus monkeys (Macaca fascicularis) during the first 14 weeks of infant life

This study documents age-related changes in the interactions of wild-born cynomolgus macaque mothers and their infants living in individual cages during the first 14 weeks of infant life. Body contact between mother and infant, maternal holding, and infant sucking were found to decrease, and the mothers showed an increased frequency of aggression toward their infants with age. These results were broadly similar to those reported for mother-infant interactions in other macaques living in social groups. Nevertheless, a clear difference between the present cynomolgus macaques and other macaques in social groups was apparent. The cynomolgus macaque mothers tended to permit their infants to move about freely without displaying maternal protectiveness such as restraint or retrieval, unlike other macaque mothers in social groups. Such maternal behaviors might derive from the experience of living in individual cages for many years and the relative safety of living in individual cages. The lack of maternal restraint and retrieval could be responsible for the observed sex differences in behavior: male infants moved more actively, and broke, and made contact with their mothers more frequently than did female infants. Moreover, mothers of female infants held and groomed them more frequently and were less aggressive toward them.

Playback experiment to test maternal responses of Japanese macaques (Macaca fuscata) to their own infant's call when the infants were four to six months old

Calls emitted by infants when the infant loses sight of its parents are useful to estimate the infants requirement for parental care. When an Old World monkey infant loses sight of its mother it emits whistles. Therefore, it would be interesting to determine whether mothers could distinguish their own infants whistles from the whistles of other infants. The response of each of seven Japanese macaque (Macaca fuscata) mothers to her own infants whistle was compared with their responses to another infants whistle. Matched control playback experiments were performed when the infants were four to six months old. The results showed that each mother could distinguish her own infants whistle from that of another infant when the infants were four to six months old. Although a stricter experimental plan is required to further examine the issue, we found that the dominance rank of the infants mother was another important factor in the female response to the infants call. The finding suggests that females can associate a call emitted by an infant with its mothers rank, even before the infant begins to wander far from its mother.

Comparison Between Wild-born Mother-female Infant Interactions and Laboratory-born Mother-female Infant Interactions During the First 14 Weeks After Birth in Individually Caged Cynomolgus Macaques

In this study we compared mother-female infant interactions between primiparous and multiparous laboratory-born (F1) cynomolgus macaques (Macaca fascicularis) in individual cages at Tsukuba Primate Center (TPC), Japan, during the first 14 weeks of infant life. We also compared interactions between multiparousF1 mothers and their female infants with those between wild-born mothers and their female infants when mothers and their infants were housed in the same individual cages. PrimiparousF1 mothers showed significantly higher values for contact with and holding of their infants than multiparousF1 mothers. The primiparousF1 mothers also tended to behave aggressively toward their infants when the latter did not show any obviously irritating behaviors. Thus, the primiparousF1 mothers seemed to be inconsistent in terms of maternal behavior. Compared with multiparous wild-born mothers, multiparousF1 mothers moved more frequently, held their infants less frequently and acted aggressively toward their infants less frequently. However, infants ofF1 mothers, as well as infants of wild-born mothers, interacted with their mothers through approaching and playful contact with them. These findings indicate that the attitude of multiparousF1 mothers toward their infants was relatively passive. Possible reasons for the passive maternal style of multiparousF1 mothers are discussed.

Correspondence between children's indoor and outdoor play in Japanese preschool daily life

This study examined the correspondence between childrens indoor and outdoor play in a preschool environment to investigate whether the children maintained a tendency to engage in a particular type of play irrespective of the environment, or whether they changed the type of play according to the environment. Play behaviours of 18 three-year-old and 20 five-year-old children were observed in both settings in an urban preschool in Japan. Various characteristics of play were examined based on cognitive play categories, social play categories, and types of objects used. The results indicate that children do not maintain fixed play behaviour without taking into consideration the play settings: their play differed greatly in accordance with the play setting. Not every child showed the same differences in play corresponding to differences in the setting. However, for each age group there was a qualitative difference based on the setting. For the three-year-olds, the ‘subject of interest’ changed between settings, whereas for the five-year-olds, the ‘participation in society’ changed related to the setting (indoor or outdoor). The ‘relation with the environment’ was greater for both age groups in the outdoor setting. There were no significant sex differences.

Development of eating behavior by Japanese toddlers in a nursery school: relation to independent walking.

The eating behavior of 32 toddlers in a nursery school at 10, 12, and 14 months old was observed in relation to the age at onset of independent walking. With increasing age, the frequency at which the toddlers ate food given by a teacher decreased, and the frequency at which the toddlers ate by themselves increased. The toddlers who started walking earlier also advanced faster in the development of eating behavior. The time when the frequency of eating by oneself surpassed the frequency of passive eating coincided with the time when the toddlers started walking.

Locomotive stereotyped behavior in cynomolgus macaques, Macaca fascicularis.

Primate infants separated from their mothers and kept alone for a long period may exhibit behavioral disorders and develop stereotyped behavior according to genetic predispositions of the infants and environmental factors such as characteristics of the cage. However, it is not clear whether the locomotive and repetitive stereotyped behaviors are related to maternal separation or isolation rearing early in life. The locomotive and repetitive stereotyped behaviors and their relationship were examined with 65 juveniles of cynomolgus macaques kept under artificial conditions. All infants were separated from their mothers and kept with peers. Observations were conducted when they were about three to five years old. The monkeys exhibited locomotive and repetitive stereotyped behavior such as turning, backward somersaulting, and bouncing. Most showed both turning and backward somersaulting. Observations indicated that social interactions with peers following maternal separation at the age of 3 to 5 mo. produce the locomotive and repetitive stereotyped behavior and that turning may change to backward somersaulting for older infants. Further work with controls for several factors is needed.

Walking and Eating Behavior of Toddlers at 12 Months Old.

Locomotive and eating behavior of 52 toddlers was observed at 12 months old in a nursery school and investigated in relation to the acquisition of independent walking. The toddlers who acquired walking ate more by themselves using the hands than the toddlers who did not start walking. This suggested that acquisition of walking was associated with eating behavior. However, onset of walking did not immediately influence the toddlers’ interest in other persons or skilful ability to use tools. Sex differences in the toddlers’ behavior were minor, but the teachers showed sex bias to the toddlers’ behavior.

Cardiac and Behavioral Responses to Humans in an Adult Female Japanese Monkey (Macaca Fuscata)

ABSTRACTThe effects of the appearance of a human on the mean arterial blood pressure (BP) and behavior of an adult female Japanese monkey were examined to clarify whether or not the monkey discriminated between men and women, and between caretakers and strangers. Each human (5 male and 6 female caretakers; 5 male and 6 female strangers) sat facing the monkey whose BP was recorded with an unrestrained telemetry system. Behavior of the monkey was recorded on videotape and BP was measured for 10 minutes prior to the appearance of the human (pre-appearance stage) and for 10 minutes during which the human appeared and faced the monkey (appearance stage). The BP and the frequency of alert behavior increased immediately after the appearance of a human. The increase in the BP and the duration during which the BP was high were significantly greater with men than with women. The duration of alert behavior in the beginning of the appearance stage was longer with men than with women and its duration at the beginning ...