The development of infant play in a captive group of lowland gorillas (Gorilla gorilla gorilla)

Three infant gorillas born at the Yerkes Regional Primate Research Center of Emory University were studied during their first year and one-half of life for various aspects of behavior, including solitary and social play, using both focal animal and one-zero sampling. The appearance of play in these infants followed a developmental trend, beginning with mother-infant play, and followed by solitary play, and then social play among peers. Mothers were initially very vigilant, repeatedly interrupting infant peer play bouts, this relaxing toward the end of the first year. Evidence for a possible sex difference in active social play is presented.     

Maternal Behavior and Infant Congenital Limb Malformation in a Free-Ranging Group of <Emphasis Type="Italic">Macaca fuscata</Emphasis> on Awaji Island,Japan

We studied the relationship between maternal behavior and infant disability in 12 mother-infant dyads for the first 5 weeks of infant life in the free-ranging Japanese macaque (Macaca fuscata) group on Awaji Island, Japan, from May to September 2001. Congenital limb malformations are prevalent in this population, and as such carry implications for behavior and conservation. We did not detect any differences in maternal activity budgets, mother-infant physical contact, infant holding, and overall nursing and infant transport time between mothers of non-disabled infants, disabled infants that were able to cling to their mothers, and disabled infants whose limb structure prevented clinging. Mothers of infants with limb malformations severe enough to prevent normal clinging behavior manually supported their infants during nursing and locomotion significantly more than other mothers did theirs. Increased support-carrying and support-nursing, and higher frequencies of holding the infant to one's ventrum, suggest that mothers of extensively malformed infants may be investing more to facilitate the survival of their offspring and that infant disability appears to be influencing maternal behaviors in this population.     

Behavioral response of a chimpanzee mother toward her dead infant

The mother-offspring bond is one of the strongest and most essential social bonds. Following is a detailed behavioral report of a female chimpanzee 2 days after her 16-month-old infant died, on the first day that the mother is observed to create distance between her and the corpse. A series of repeated approaches and retreats to and from the body are documented, along with detailed accounts of behaviors directed toward the dead infant by the mother and other group members. The behavior of the mother toward her dead infant not only highlights the maternal contribution to the mother-infant relationship but also elucidates the opportunities chimpanzees have to learn about the sensory cues associated with death, and the implications of death for the social environment.     

Adult male-offspring play interactions within a captive group of Orang-utans (Pongo pygmaeus)

A family of four Sumatran Orang-utans was studied for three months under captive conditions. Thirty discrete playful interactions between a 19-year-old male and his four-year-old male offspring were analyzed from films and notes. Ten behaviors occurred in a typical play-bout, the most frequent of which were hand contact and mouth contact. Developmental studies of the motor patterns involved in orang-utan social behavior are greatly needed, as the orang is the least understood of the great apes. This research is supported by the following sources: National Institute of Health grants to the Emory University experimental psychology program (H0 00208) and to the Yerkes Regional Primate Research Center (HD00165), and a faculty research grant to the third author from Emory University's McCandless Fund for Biological Research.     

Infant response to mother call patterns in Otolemur garnettii

Garnett's greater bushbaby infants vocalize in apparent response to their mother's contact calls. However, it remains unclear whether specific vocal or behavioral patterns by a mother elicit this vocal response. We video-recorded the behaviors and vocalizations of 4 individual mother-infant groups (mother with twins), analyzed vocalizations via spectrography and documented behaviors of mothers and infants. Initial analyses of all groups revealed that short growls and short growl bouts (or chains), but not long growls, emitted by mothers, were followed by infant clicks within 5 s. Further statistical examination of 1 mother-infant group revealed that an infant's vocal response is conditional on the sequencing of the mother's short growls and somewhat conditional on the mother's behavior before or after the short growls.     

Intercorrelations of maternal and infant behaviors inMacaca mulatta

Matrices of correlation coefficients among 38 behaviors of 32 mother-infant pairs are presented as an aid to future investigations involving experimental manipulations of the development of maternal and infant behaviors in the rhesus monkey. Such matrices are particularly useful when employed in the construction of social behavior scoring systems.     

The social behavior of adult male-infant pairs of Rhesus macaques in a laboratory environment

Adult males in nonhuman primate societies exhibit a wide range of behaviors toward immature members of their social group, ranging from virtually continuous nurturance to systematic infanticide. Among macaques, rhesus monkey males in the wild display perhaps the least degree of paternalistic behavior toward conspecific infants. But adult male-infant rhesus attachments have not as yet been explored in a controlled longitudinal study, even though the mother-infant bond has received careful attention for several decades. In the present study two pairs of adult male and infant rhesus macaques were housed together without the mother for a period of at least seven months. To minimize the probability of physical harm to the infants, one adult male was present at the birth of the infant with whom it was paired and the other was visually familiarized with the infant for several weeks before being paired with it. Both pairs have shown much less ventral-ventral contact than mother-infant pairs and the infants have rarely attempted to gain nipple contact. The female infant now initiates and maintains ventral-ventral contact much more frequently than the male infant in spite of the higher degree of aggression directed toward her by the male. The adults frequently groom their infants and exhibit varying degrees of both tolerance and aggression. Rough-and-tumble play appeared quite early in both pairs and is much more vigorous than mother-infant play. Recently the male-male pair has exhibited reciprocal mounting and thrusting. Comparisons are made with data obtained in an earlier study of mother-infant pairs conducted under nearly identical experimental circumstances. The effects of separating the adult males and infants at seven months are also described.     

神农架川金丝猴投食群0-6月龄的母亲照顾行为

与其它哺乳动物相比,灵长类动物的一个最典型的特征就是婴儿在出生之后完全没有独立生活能力,处于这个时期的动物非常软弱(Nicolson,1987)。在这段发育期内,必须依靠社群内成年或亚成年个体的照顾才能顺利存活,尤其是来自母亲的照顾,母亲通过哺乳提供给它们成长所需要的营养,并通过限制行为实施保护,同时教会婴儿基本的生存技能,为今后能更好地融入社群做好充足准     

神农架川金丝猴投食群的母婴关系

灵长类动物母亲的育婴行为不仅对后代的存活起着关键作用,而且对婴猴的发育和成年后的社会交往有着重大影响,因此母-婴关系一直是灵长类学研究的热点之一。为了解川金丝猴的母-婴关系,探讨川金丝猴母-婴关系个体差异的影响因素,我们于2013年3月至2014年10月,以母-婴间相对距离表示照料强度,对神农架川金丝猴的母-婴照料关系以及母亲照料强度个体差异的影响因素进行了定量研究。结果表明：母亲照料行为强度、母亲对阿姨行为的容忍与婴猴年龄相关,限制行为与婴猴年龄不相关。身体接触与婴猴年龄不相关;腹部接触以及母-婴相对距离小于1 m与婴猴年龄呈负相关;相对距离1 m至5 m、相对距离5 m至10 m和相对距离大于10 m与婴猴年龄呈正相关;母亲对阿姨行为的拒绝与婴猴年龄呈负相关;母亲对婴猴的限制行为与年龄不相关。总的来说,即随着婴猴成长,母婴间距离越来越远,母亲也逐渐减少对婴猴的保护。母亲的生育经验、婴猴性别、婴猴出生先后和社会单元大小对神农架川金丝猴母婴关系没有显著影响,补食群丰富的食物资源和群内雌性友好的关系可能是导致本结果的原因。     

MOTHER-INFANT SPATIAL RELATIONS IN CAPTIVE BOTTLENOSE DOLPHINS,TURSIOPS TRUNCATUS

The prolonged nursing period and strong, extended mother-infant bond observed among bottlenose dolphins may reflect social and physical ontogeny critical for infant survival. This study was conducted to quantify ontogentic changes in mother-infant contact time and the amount of time infants spent in specific spatial states with their mothers from birth to age 12 mo. These behaviors were studied through a systematic, longitudinal study of six mother-infant pairs of captive bottlenose dolphins from three different social groups. There was a significant decrease in the time infants spent with their mothers (logistic regression, P < 0.001), following the general mammalian pattern of increasing independence with age. When with their mothers, the probability that infants would be found in “echelon” position, flanking the mother, decreased as the calf aged (logistic regression, P <0.001), possibly due to anatomical and hydrodynamic factors. The probability that infants would be found in “infant” position, underneath the mother, increased with calf age (logistic regression, P < 0.001). Results obtained in this study are consistent with similar studies of wild bottlenose dolphin mother-infant pairs, indicating a suite of ontogenetically comparable behaviors between wild and captive bottlenose dolphins.     

Development of behaviors in a male spectacled langur (Presbytis obscurus)

An infant langur,Presbytis obscurus, was observed in a group setting, from birth until 1 year of age. Frequency or duration of 30 behaviors was recorded during 2 hour periods and plotted chronologically. Based on fluctuations and interrelations of these behaviors, age classes were designated. The Maternal Care Period (0–20 days) is characterized by close mother-infant contact, including a great deal of nipple contact and a high frequency of maternal behaviors. The Individuation Period (21–70 days) is typified by maternal restraint and retrieval, and independence and self-oriented behaviors like scratching, mouthing, and locomotory skills. The Socialization Period (71–240 days) is manifested by behavioral fluctuations, involving nipple contact, play, and care by other troop members and coincides with the molt from infant to juvenile pelage. Finally, during the Juvenile Period, the motherinfant distance increases and the mother interacts more with other troop members. Behavioral fluctuations observed in this infant langur are discussed with reference to other primates studied.     

Dyadic interactions of infant lowland gorillas in an outdoor exhibit compared to an indoor holding area

The behavior of two lowland gorilla mother-infant pairs living in a social group at Zoo Atlanta was compared in an indoor holding area vs. an outdoor exhibit. Focal animal data were collected for each pair during 30-min observation sessions over 24 days, alternating between indoors and outdoors. A variety of individual and social behaviors differed in the two conditions, particularly infant behaviors and infant-controlled behaviors. Mothers and infants spent more time closer together inside than outside, and infants left mothers more and mothers approached infants more outside than inside. Additional differences included more object examination and solitary play by the infants, and more feeding by the mothers, outside. Mothers autogroomed more and infants engaged in more self-manipulation inside. Additionally, there were significantly more aggressive display behaviors directed toward the mother-infant pairs inside than outside, and the adults engaged in coprophagy inside but not outside. A variety of other behaviors measured did not change between the two environments. There was a clear effect on behavior of the different housing conditions in which the gorillas were kept. © 1994 Wiley-Liss, Inc.     

Comparing maternal styles in bonobos (Pan paniscus) and chimpanzees (Pan troglodytes)

Studies on Cercopithecine primate maternal styles, using factor analysis on a set of maternal behaviors, commonly render two factors that describe separate dimensions of maternal behavior: protectiveness and rejection. The aims of this study were to 1) investigate whether this method for determining maternal styles in Cercopithecine species can be applied to bonobos (Pan paniscus) and chimpanzees (Pan troglodytes), 2) determine whether they follow the same pattern, and 3) assess whether species differences in maternal style are apparent. We performed a factor analysis on nine maternal behaviors using data on eight mother-infant pairs of each species. This resulted in three factors: protectiveness, distance, and refusal. Protectiveness is positively correlated with time spent in ventral contact, making contact, approaching, and restraining. Distance is positively related with breaking contact and leaving. Refusal is positively correlated with rejecting and nipple-rejecting. The pattern of protectiveness corresponds with the pattern found in Cercopithecine species, suggesting a high consistency of this dimension across species and higher taxa. The retention of the other two factors indicates that in the Pan species, breaking contact and leaving represent another dimension, apart from rejecting and nipple-rejecting, which usually fall under one dimension in Cercopithecine species. An interspecific comparison of the factor scores for each dimension of maternal behavior reveals that, on average, bonobos and chimpanzees score equally on protectiveness. Scores on distance increase positively with infant age in chimpanzees, and negatively in bonobos, and on average bonobos have higher scores on refusal. These interspecies differences in maternal style are discussed in the light of interspecies differences in infant development, infant vulnerability to aggression, interbirth intervals, and female sociality.     

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.     

Social development of stumptail macaques (Macaca arctoides): Synchrony of changes in mother-infant interactions and individual behaviors during the first 60 days of life

Several categories of social and individual behaviors were recorded during the first 60 days of life for seven stumptail macaques. Mother-infant interactions tended to decelerate in synchrony with increases in infant nonsocial behaviors, such as object manipulation. Several aspects of stumptail social growth during the first two months were similar to those of rhesus and other macaques. Approaching-leaving, which has been used previously as an index of waning of the mother-infant bond, was due more to infants than to mothers during the second month of life     

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.     

Attacks on neonates by a male mangabey (Cercocebus atys)

Aggressive behavior by an adult male toward selected infants and their mothers was observed during a long-term study of reproduction in a captive social group of sooty mangabeys (Cercocebus atys). The highest-ranking adult male in this group was observed to attack and bite three neonates out of a total of 13 infants born in 1982. All three attacks were directed attacks in which infants were grabbed from their mothers and bitten in the head. The first infant was fatally injured; the other two probably would have sustained fatal wounds had the male's canines not been blunted beforehand and had observers not intervened. The attacks were preceded by a pattern in which the male persistently stalked or chased the mother-infant pairs, a behavior first observed in the hours immediately following parturition. Unlike attacks in wild baboon groups following male immigration, these attacks on infants occurred in a stable social group in which the male attacker had been a lifelong resident. This male, however, had gained alpha rank only 3 months before attacking the first infant. These attacks, in the context of other evidence of aggression and wounding, are discussed relative to current models of infanticide in primates.     

Investigation of the role of postnatal testosterone in the expression of sex differences in behavior in infant rhesus macaques (Macaca mulatta)

In several primate species, males have been shown to exhibit a surge in circulating testosterone during the early postnatal period. This surge has been postulated to play a role in the development of sex differences in behavior. In this study, the role of postnatal testosterone in infant behavioral development was investigated in socially living rhesus macaques. Seven male infants were treated with a GnRH agonist, avorelin, from the first week of life onwards. Ten female infants were exposed to testosterone by implantation of capsules containing testosterone. The behavioral development of these and control infants was recorded from birth to 6 months of age. The sexually dimorphic patterns of play and mounting were not affected by manipulation of postnatal testosterone in either male or female infants. Similarly, most mother-infant interactions were not affected by the hormonal manipulation of infants. Mothers of testosterone-treated females were found to take more responsibility for moving into and out of arm's reach of their infants than mothers of some other groups of infants; however, this measure did not normally differ between mothers of male and female infants. Manipulation of the postnatal testosterone surge does significantly affect penile growth and development, but does not affect the expression of infant sex differences in behavior nor greatly affect the development of the mother-infant relationship in rhesus macaques.     

Variability in the development of mother-infant relationships among free-ranging Japanese macaques

Mother-infant relationships were studied during the infant's first year in free-ranging Japanese macaques (Macaca fuscata). Three possible factors controlling the mother-infant relationships were examined using multivariate analysis. Parity was determined to exert the strongest influence on mother-infant relationships. Specifically, during month 1, multiparous mothers showed greater maternal suckling rejection than primiparous mothers, and primparae and multiparae differed in their responses to suckling behavior. During month 6, multiparous mothers prompted independence of their offspring more than primiparous mothers. By month 8, however, parity differences in maternal behavior were substantially reduced. Maternal rank was a less important factor, although during month 1, high-ranking mothers showed greater maternal restriction than low-ranking ones. In the present study, infant gender appeared to have no effect on mother-infant relationships. That most differences were due to parity indicates that mother-infant relations were largely determined by the mothers. This observation conflicts with the “learning-to-mother” hypothesis. Allo-mothering of neonates by nulliparae is rare among Japanese macaques. Primiparous mothers learned appropriate suckling care from handling their own infants.