Birth-season interactions of adult female Japanese Macaques(Macaca fuscata) without newborn infants

The affiliative interactions of 11 adult female Japanese macaques that did not deliver an infant during the 1981 birth season of the Arashiyama West troop were examined. Consideration was given to the effects of kinship as a structuring element in these birth-season interactions and to the degree of association with various categories of troop members based on age, sex, and (in the case of adult females) whether or not the females were new mothers. Females without infants interacted predominantly with their yearling off-spring, although it was the behavior of the offspring that precipitated the interaction. These females were active in soliciting affiliation with nonkin new mothers, whereas female matrilineal relatives with new infants approached and remained in proximity to them more than did nonrelated new mothers. Females without newborns groomed and approached nonkin infants more than infants within their own matriline, and these infants were predominantly those of females in the highest-ranking matriline of the troop. Adult males were responsible for 40% of all grooming received from nonkin by the females without newborns, and these males approached them significantly more than did other adult females without infants. These patterns demonstrate that the structure of social relationships is influenced by the particular dynamics of troop contexts such as birth seasons, as well as by enduring, broad-based affinities which are less affected by cyclic changes in troop context.     

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.     

Tactics of care for young infants by forest-living ruffed lemurs (Varecia variegata variegata): Ground nests,parking, and biparental guarding

Over a 4 month period, systematic and ad libitum observations were conducted on two adult female black-and-white ruffed lemurs (Varecia variegata variegata) and their infants in a 3.5 ha forest enclosure. The females were mother and daughter, members of a family group that had been semifree-ranging for 2 years and 3 months at the time of the births. One to two weeks before parturition, the females independently constructed nests, in which they kept their infants during the first few weeks following parturition. The older mother, cage-reared herself, prepared at least one nest. Her daughter, who has lived in the forest since late juvenescence, prepared at least four. Two to three weeks after parturition, the mothers moved their infants high into trees. During periods of maternal absence, the infants were often alone, and they rarely or never moved, vocalized, or groomed themselves. The mothers often kept their infants together after nests were no longer used. Each infant nursed freely from both lactating females. The infants were carried orally only by their mothers and were never transported by clinging to the pelage of any group members. Previously, researchers suggested that ruffed lemurs build nests for care of infants high up in trees. The present observations, however, suggest that two major modes of neonate care in Varecia exist: serial use of multiple ground nests and “parking” of infants high in trees. Advance preparation of several nest sites, relative lack of large predators, alternate maternal and paternal guarding of infants, infant immobility during absence of mother, and rapid infant development make this tactic of care for neonates plausible.     

The social grooming of captive female rhesus monkeys: Effects of the births of their infants

We observed the grooming interactions of 13 female rhesus monkeys (Macaca mulatta)before and for 12 weeks after the births of their infants. Mothers groomed for similar amounts of time before and after the birth of their infants, but after the birth, the grooming they directed to their infants may have been at the expense of that directed to other partners. Lactating females did not receive more grooming from other females but were approached more often, suggesting that they were more attractive. Mothers that groomed their infants most groomed others least, as if grooming time was limited for each mother or as if she was trying to compensate for avoiding interactions with other partners. Mothers of male infants groomed others more than mothers with female infants did, which might be due to mothers with daughters receiving more aggression and therefore avoiding interaction. Experienced and high-ranking mothers groomed their newborn infants considerably more than primiparous mothers did in the 24 hr following birth. Grooming was preferentially directed at close kin before the births of the infants. Mothers tended to groom higher-ranked partners more than they were groomed by them, and they tended to receive more grooming from lower-ranked partners than they gave, as suggested in models of rank attractiveness.     

Infant behaviors in mother-reared and harem-reared baboons (Papio cynocephalus)

Seven groups of socially living baboons between the ages of 0 and three months were observed at the Southwest Foundation for Research and Education, San Antonio, Texas. Six groups were harems containing one adult male (the biological father), the nursing mothers and their infants, and adult females without offspring. The other group consisted only of nursing mothers and their infants. All seven groups were housed in identical outdoor enclosures 45 m × 27 m × 23 m. Fourteen behavioral categories were tested. The hypothesis that behavioral sex differences in infant baboons are influenced by the presence of an adult male was not supported by the test results. Sex differences were not detected in either the mother-reared infants or in harem-reared infants. Mother-reared infants (n=13) had significantly greater scores for contact aggression and non-contact aggression categories, whereas harem-reared infants (n=12) scored significantly higher for locomotion, non-aggressive social behaviors, exploration, and rough-and-tumble play.     

Social behavior of infant and mother Japanese Macaques (Macaca fuscata): Effects of kinship,partner sex,and infant sex

The behavioral interactions of 22 infant and mother Japanese macaques with other group members were studied. Focal-animal observations were made from the time of each infant’s birth until 1 year of age. Infants and mothers both displayed exceedingly strong preferences for associating with matrilineal kin and, specifically, for female kin. The degree of genetic relatedness was positively correlated with levels of spatial proximity, contact, grooming, aggression, and play. Overall frequencies of interactions with nonkin were very low, and partner sex was not an important factor in interactions with nonkin. There were no significant differences between male and female infants in interactions with kin versus nonkin. There was only one significant difference between male and female infants in interactions with males versus females: female infants showed stronger preferences for initiating proximity with females over males than did male infants. Because mothers provide the focal point for infant interactions during the first year of life, we compared the behavior of infants and mothers. Mothers were the recipients of more social interactions than were infants, mothers engaged in more grooming than did infants, and infants engaged in more social play than did mothers. These findings are only partially consistent with kin-selection theory, and the inadequacies of studying matrilineal kin discrimination to test kin selection are reviewed. The near-absence of infant sex differences in associations with social partners suggests that although maternal kin other than the mother are important to infant socialization, they probably do not contribute to the development of behavioral sex differences until after the first year of life.     

Proximal Spacing Between Individuals in a Group of Woolly Monkeys (Lagothrix lagotricha) in Tinigua National Park, Colombia

I studied proximal spacing within a group of woolly monkeys (Lagothrix lagotricha) during 7 months at Parque Nacional Tinigua, Colombia. I collected a total of 1188 instantaneous samples on focal individuals, recording the number and age/sex class of individuals that were in contact with, <2 m from, <5 m from the focal animal. The results indicate that proximate spacing reflects social affinities and is related to mother–infant relationship and social grooming. Subadult females and adult males are the sex/age classes with the lowest number of individuals in proximity. There are low proximity between adult females and between adult males and high frequencies of nearness between mother and offspring. Associations between males and females were usually low, but in some cases males showed preferences for a given female. There was a relatively gradual increase in spacing between mothers and their offspring as they became older. Old juvenile males were associated chiefly with other males—mostly subadults—whereas juvenile females maintained some proximity only to their mothers. There are also differences in spacing behavior according to different activity types.     

Sexually dimorphic transitions revealed in the relationships of yearling rhesus monkeys following the birth of siblings

We report here that in a large captive group of monkeys, Macaca mulatta,sudden sex-related changes occur in social interactions in one short phase of an infant’s development. Social interactions of 1-year-old animals (males, N =12; females, N =8) 6 weeks before the birth of siblings were compared with interactions occurring 6 weeks after the birth. On the day of the siblings’ birth, depression-like postures were seen in two yearling males (YMs); 10 YMs showed hyperactivity. In the postbirth period, YMs refocused their attentions away from their mother and toward other, often unrelated members of the group. Although YMs initiated disengagement of interactions with their mothers, there was evidence that mothers attempted to lessen this disengagement. The YMs had close relationships with specific (“preferred”) male individuals. These relationships (particularly those with adult males) became more pronounced following the birth of the sibling. The adult-male group also took an active role in maintaining interactions with YMs. The preferred partners in the YM-other male relationship before the birth of the sibling were, however, not always the same as those in the period after the birth. Dominance relationships and probably genetic factors determined patterns of interaction between YMs and their preferred male partners. Among yearling females (YFs), no dramatic changes in interactions with their mothers or with other group members were detected after their mothers gave birth. Relationships in YF-mother and YF-other-individual pairs (especially when the other individual was kin) seemed to be consolidated during the postbirth interval. There was little evidence of jealousy between the YFs and their younger siblings. Thus, sibling birth acted as a stimulus for the occurrence of sexually dimorphic interactions in yearlings. We suggest that in natural environments, social interactions in YFs promote relationships that will serve to integrate them into the matrilineal social structure, whereas comparable behavior in YMs encourages relationships with males that they may emigrate with into, or meet again in, nonnatal troops.     

Origin and fate of a one-male savanna babbon group formed by fissioning

An adult male chacma baboon,Papio hamadryas ursinus, emigrated from his habituated natal group at age 100 months and joined a neighboring multimale-multifemale group. Subsequently this male, together with eight adult females, all with infants <1 year old, formed a one-male group (OMU). The male was the only adult male in this group for over 200 days. Circumstantial evidence shows that shared parentage of the infants with this male determined which females joined the new group. In addition, 10 juveniles younger than 4.5 years joined the new group. Based upon persistent close physical association, especially at sleeping sites, these juveniles were presumed to be the older independent progeny of the eight adult females. Thus, the founding elements of the new group were the adult male and partial matrilines—mothers, their infants, and their independent juvenile offspring. The OMU status of the group ended with the sequential intrusion of three males known to be low ranking in other groups. The first of these intruders was successful in joining the OMU in spite of the OMU male's earlier successes in rebuffing this and other potentially high-ranking males. Six additional males later entered the fission group during a 6-month interval. Two of them outranked the original male. All additional males present in the last 100 days of observations came from the same group, which was not the group of origin of the females.     

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.     

Development in Japanese macaques (Macaca fuscata): Sexually dimorphic behavior during the first year of life

We have documented several sexually dimorphic patterns of behavior that develop during the first year of life in infant Japanese macaques and their mothers. Mothers treated their infants differently by sex—mothers of males broke contact with them and retrieved them more frequently than did mothers of females. And mothers of male infants moved more frequently than did mothers of female infants. Male infants played more, played in larger groups, and mounted more frequently; female infants groomed and spent more time close to other monkeys in larger social groups than did males. Female infants were also punished by other group members more frequently than were male infants. We conclude that male and female Japanese macaque infants receive differential treatment early in life by both their own mothers and other animals, and males and females in turn treat their mothers and other animals differently. There appears to be a reciprocal relationship between the behavior of infants, mothers and other social partners that contributes to the development of sexually dimorphic patterns of behavior.     

Contributions to infant care in captive cotton-top tamarins (Saguinus oedipus): The influence of age,sex, and reproductive status

Marmosets and tamarins are characterized by a reproductive strategy that includes twinning, and a communal rearing system in which infant care is shared among all group members, both breeders and nonbreeding helpers (often older offspring). In order to test some predictions about the extent to which different age-sex classes should invest in infants, contributions to infant carrying and food-sharing by all family members were measured in captive groups of cotton-top tamarins (Saquinus oedipus) ranging in size from 2 to 12 independent individuals. Fourteen litters were observed from birth to 12 weeks. Carrying by mothers decreased steadily over the study period, while carrying by fathers and other offspring increased for 3–5 weeks, then declined. Infants spent more time carried by siblings than by either parent, but parents did more carrying than individual siblings and, also, shared more food with infants. Older siblings contributed more care than younger siblings did. Adult sons carried infants more than adult daughters did, but immature daughters carried more than immature sons did. However, adult daughters actively offered food to infants more than any other class of helper did. These results were interpreted in the light of hypotheses concerning the reproductive and dispersal strategies of callitrichid species.     

Maternal Infant Monitoring in a Free-ranging Group of Japanese Macaques (<Emphasis Type="Italic">Macaca fuscata</Emphasis>)

In nonhuman primates, females with infants visually monitor their infants from a distance to detect and consequently avoid potential threats to their infants. We recorded maternal visual monitoring of infants (infant monitoring) ages 7–18 wk in a free-ranging, provisioned group of Japanese macaques (Macaca fuscata). The infant monitoring rate declined as a function of infants’ ages in weeks and increased when the infants were beyond their mother’s reach, indicating that infant monitoring reflects the vulnerability of infants. Females with infants increased infant monitoring when their infants were handled by other group members but not when their infants moved alone. This suggests that intragroup threats (harassment/mishandling or kidnapping) have a relatively stronger influence on infant monitoring than external threats (predation or infanticide) under the condition of this study. Infant monitoring of middle-/low-ranking females was more frequent than that of high-ranking females when their infants were handled by other individuals. This may reflect greater intragroup threats to infants of middle-/low-ranking females; however, further study is needed to confirm this. During important activities (feeding or grooming), the infant monitoring rate was lower than that during other activities (resting or self-directed behavior). However, even during important activities, females with infants increased infant monitoring when infants were handled. This indicates that females with infants face a trade-off between infant monitoring and other important activities, and even if females have to reduce the time spent on important activities, they increase infant monitoring when their infants face greater potential intragroup threats.     

Natal Attraction in Adult Female Baboons (Papio cynocephalus ursinus) in the Moremi Reserve, Botswana

Mammalian females are strongly attracted to infants and interact regularly with them. Female baboons make persistent attempts to touch, nuzzle, smell and inspect other females’ infants, but do not hold them for long periods, carry them, or provide other kinds of care for them. Mothers generally tolerate these interactions, but never initiate them. The function of these brief alloparental interactions is not well understood. Infant handling might be a form of reproductive competition if females’ interest in infants causes distress to mothers or harm to their infants. Alternatively, infant handling might be the product of selection for appropriate maternal care if females who are highly responsive to infants are the most successful mothers. We test several predictions derived from these hypotheses with data collected in a free‐ranging group of baboons (Papio cynocephalus ursinus) in the Moremi Reserve of Botswana. Infants were most attractive when they were very young. Mothers of young infants were approached by other adult females on average once every 6 min, and other females attempted to handle their infants approximately once every 9 min. By the time infants were a year old, their mothers were being approached only once every 30 min and infants were being handled only once every 5 h. Females were more strongly attracted to other females’ infants when they had young infants of their own, and their interest in other females’ infants declined as their own infants matured. Females seemed to be equally attracted to all infants, but had greater access to offspring of their relatives and subordinate females. Females nearly always grunted as they handled infants. As in other contexts grunts are a reliable predictive signal that non‐aggressive behavior will follow, the use of grunts before handling suggests that these interactions were not a form of deliberate harassment.     

Factors Affecting Proximity Among Members of a Wild Group of Moor Macaques During Feeding,Moving, and Resting

We studied the effects of kinship, age, sex, and other factors on patterns of spatial proximity among group members in a wild group of moor macaques (Macaca maurus) in Sulawesi, Indonesia. We assessed the importance of each factor via multiple linear regression analyses. Moor macaques stay close to their matrilineal relatives more frequently when the group moves or rests than when they feed. Subjects of similar age, sex, or rank tended to stay close to each other. Females were in the proximity of females with newborn infants regardless of the phase of activity of the group. Kinship may have less effect on proximity during feeding in moor macaques than in Japanese macaques. Weak effects of kinship during feeding may result from weak contest competition for food within the group.     

The process of weaning in hanuman langursPresbytis entellus entellus

Twelve langur infants (seven males and five females) of three focal bisexual unimale troops of Hanuman langurs,Presbytis entellus entellus living near Kailana, Jodhpur, Rajasthan (India) were observed for their weaning behaviour. Weaning starts between 7.0 to 10.0 months of age, average 8.6 months. The process of weaning lasts between 3.2 to 5.6 months, average 4.2 months. A 13-month-old infant is fully weaned. Infants are independent at this age. Male infants are weaned earlier compared to females. Males react to their mothers' rejections more fearlessly and are more vocal compared to females. By and large, infants were found in stress during this period as their mothers are often very harsh, hostile, punitive, and indifferent to their infants. By severing ties with their infants, mothers serve dual purpose of allowing their infants to become independent and may be to become ready to bear offspring.     

Lactation and care for unrelated infants in forest-living ringtailed Lemurs

An adult female ringtailed lemur (Lemur catta) known not to have been pregnant showed spontaneous lactation in response to twin infants born to an unrelated female. The females had met only 7 months earlier, when they and two other unrelated adult females were released from separate locations in a forest enclosure to form a new social group. Three months after release, an adult male from an adjacent enclosure gained access to the new group for 1 day, the day of one female's estrus. No males had access to the females throughout the remainder of the breeding season. Within 2 weeks of the birth of the twins, one of the other adult females began carrying the infants frequently, typically one at a time. All three females were checked for lactation when the infants were two months old. Both their mother and the unrelated adult who had been carrying the infants were producing milk. The third adult female, who never carried either infant, had no milk. The third adult female, who never carried either infant, had no milk. This female, however, like the two maternal females, frequently attacked unfamiliar immigrating adult males when the males approached the infants. Potential implications of these observations concerning the social organization of ringtailed lemurs are discussed.     

Mother-infant cannibalism in thick-tailed bushbabies (Galago crassicaudatus umbrosus)

Mother-infant cannibalism in species of galagos as in several other species of non-human primates is a common phenomenon. In non-human primates kept in laboratory conditions many of the observed cases of cannibalism were not associated with starvation and with infanticide. Cannibalism in galagos was observed in at least five different species. In several laboratories, like the Duke University Primate Center, the frequencies of cannibalism in galagos species in captivity have been reduced by the isolation of pregnant female before the parturition from her companions, especially adult males. At the Primate Behaviour Research Group (University of Witwatersrand, Johannesburg, South Africa) three cases of cannibalism were observed in twoGalago crassicaudatus umbrosus' mothers before the end of the third day after birth. To understand the reasons why the mothers cannibalize their own infants, it was decided to analyze the mother-infant interaction which preceded the death of the infants. InGalago crassicaudatus twin and triplet births are very common. In one of our two observed mothers who cannibalized their infants, there was one triplet birth. In this study the two pregnant females were isolated in two separated cages ten days before giving birth. One of the two observed mothers gave birth to triplets, the other had a single birth. At the end all four infants were cannibalized. In all cases the cannibalization started after the infant's death. The infants' deaths were caused by lack of maternal care which caused them to starve. The results show that the triplet's mother differed in some of her behaviour towards her infants. In one of the cannibalized infants behaviours such asNipple andMother Passive Prevent were never seen before death. In our cases it seems that cannibalism was probably due to the laboratory condition that for generation to generation caused stress to the mothers and changed their maternal behaviours, which lead to the death of the offspring which after death became a consumable resource.     

Grouping-patterns and inter-group relationships of Japanese wild boars (Sus scrofa leucomystax) in the Rokko mountain area

Grouping-patterns and inter-group relationships of Japanese wild boars (Sus scrofa leucomystax) were studied at a provisioning site in the Rokko mountain area, Hyogo Prefecture, Japan, from 1982 to 1983. The observations were divided into four study periods. Almost all wild boars were individually identified and their kin-relationships were followed from the beginning of the study. To examine grouping-patterns of Japanese wild boars, the degree of association between any two individuals, based on coexisting time at the provisioning site, was analyzed for each study period. Mother and her litter group (MLG), female littermate group (FLG) and solitary individual were recognized grouping-patterns. Groups did not associate with each other. Male offspring separated from their mother before 1 year of age and become solitary. Separation of female offspring occurred before the subsequent parturition of their mother. The proximate cause of separation was increased aggression by the mother. After separation, female offspring formed a FLG. However, the FLG seemed to be generally a temporary one, maintaining its stability only until parturition of it's members. Thereafter adult females had no close association with any other individuals, except for their own infants. Male offspring disappeared from their natal area, while female offspring could remain there.     

Costs and benefits of maternal aggression in lactating female rhesus macaques

Data from over 400 hr of observation of mother-infant rhesus macaques indicate that during the first 12 weeks of lactation infants are at risk from other group members and that mothers use aggression as well as restraining to protect them. Maternal aggression was negatively correlated with infant restraining. High-ranking mothers reacted aggressively to individuals handling their infants more than did middle- and low-ranking mothers. Conversely, middle- and low-ranking mothers restrained their infants more than did high-ranking mothers. Maternal aggression did not vary with infant age. Maternal aggression was directed toward a higher proportion of higher-ranking adult females and their immature offspring and was more likely to be followed by counter-aggression than nonmaternal aggression, i.e. aggression not related to interactions involving the infant. Middle-and low-ranking mothers suffered higher costs in terms of retaliation than high-ranking mothers. It is argued that the occurrence and distribution of maternal aggression among species and individuals should depend on the risk posed to infants by conspecifics as well as on the characteristics of the social structure (e.g. degree of asymmetry of agonistic contests) and of the mother (e.g. her dominance rank) which may affect the probability of retaliation.