Interactions Between Males and Unweaned Barbary Macaques: Testing the Agonistic Buffering Hypothesis

Abstract

Abstract1. Observations of wild Barbary macaques in the Moroccan Middle Atlas revealed more male interaction with unweaned monkeys than has been described for other Cercopithecoidea. 2. Adult, subadult and juveniles males were all involved. On the birth of a new season's babies the males interacted with them and virtually ignored the infants (still unweaned) from the previous birth season. They continued to interact with the new babies when these were infants. 3. Adult and subadult males approached mothers with babies, sat with them, removed their babies and cared for them. Babies were rarely threatened, or attacked, but in agonistic interactions infants were treated more like juveniles. 4. Close non-agonistic interaction between males occurred in the presence of babies (type b interactions). This was initiated by males taking babies to other males, or by males without babies approaching those with them. A framework (based on the most consistently repeated behavioural elements) is presented for describing the seven phases of these complex interactions. 5. Elements of male-care and type b interactions often punctuated play bouts between infant and juvenile males and babies. The interactions involving males, babies and non-maternal females are also briefly described. They were far less frequent than type b interactions and female-care interactions. 6. Individual males and babies did not interact with each other equally often. Particular male-baby partnerships occurred regularly in the context of both male care and type b interactions. The males' rank did not determine these relationships. 7. Examination of nearest neighbour records revealed that the presence of a baby near a male was associated with a clumping of other individuals (particularly other males) near the male. Infants did not have this effect. 8. Most friendly approaches given to and received from males (particularly those to and from other males) were in the presence of babies. 9. There was a relationship between agonistic rank and approaches between males in the presence of babies. Between unlike age classes and between adults, an approacher carrying a baby was usually subordinate. Most approaches to males in possession of babies were by subordinates but there were exceptions. 10. Males carried babies away from and left babies with males both dominant and subordinate to themselves. This showed how limited competition for babies was between males. 11. There was a higher probability of a male being threatened if he made a friendly approach in the presence of a baby. However, it seemed that males found the risk of receiving an aggressive response acceptable because it was coupled with a higher probability of non-agonistic interaction with males who could rarely be approached without a baby present. 12. Low ranking males approaching high ranking males positioned themselves so as to judge the response of the approached male and they also drew the baby to his attention. Several behaviour patterns were used to maintain proximity with other males. Most male-male grooming occurred in the presence of babies. 13. The results confirmed the importance of a baby's presence in the dynamics of male-male interaction and justify the use of the term 'agonistic buffering'. The behaviour between males of considerably different rank (e.g. between subadults and adults; juveniles and adults) most clearly fitted the agonistic buffering hypothesis. The behaviour between males of more similar rank (e.g. adults and adults) was less consistent and did not fit the hypothesis so closely.

Triadic awareness predicts partner choice in male–infant–male interactions in Barbary macaques

“…During the interaction the adult male and infant were in body contact that included cradling, dorsal carrying, ventral carrying, grooming, resting in body contact and "contact crawling" defined as an infant crawling in body contact with a male or playfully climbing over a male's body (see Thierry et al 2000;Deag 1980) for more detailed description of the behaviors). We also included polyadic interactions if they involved only one adult male and one or more females or non-adult males (e.g.…”

“…We defined bridging as an interaction involving (at least) two adult males, who simultaneously manipulated one infant exhibiting a series of ritualized behavior including teeth-chattering or lip smacking, inspection of the infant's genitalia, lifting infant above heads (Deag 1980). We scored the start of the interaction once both males (being already in body contact with the infant and to each other) displayed teeth chattering in a way typical for bridging behavior.…”

“…In several species of Old World monkeys, males engage in a specific type of polyadic infant handling so called bridging interactions (Ogawa 1995a), triadic male-infant interactions (Taub 1980), male-infant-male interactions (Zhao 1996), or agonistic buffering (Deag and Crook 1971). During these interactions typically two males simultaneously manipulate one infant exhibiting a typical series of ritualized behaviour including teeth chattering, lifting the infant above their heads and inspection of the infant's genitals (see Deag 1980). Bridging has been reported in several papionin primates: Barbary Macaca sylvanus (Deag and Crook 1971), Tibetan M. thibetana (Ogawa 1995a), stumptail M. acrtoides (Estrada and Sandoval 1977), longtail M. fascicularis (de Waal et al 1976), Assamese M. assamensis (Bernstein and Cooper 1998) and bonnet macaques M. radiata (Silk and Samuels 1984) as well as yellow Papio cynocephalus (Collins 1986), olive P. anubis (Smuts 1985) and chacma baboons P. ursinus (Busse and Hamilton 1981), sooty mangabeys Cercocebus atys (Busse and Gordon 1984), gray-cheeked mangabeys Cercocebus albigena (Chalmers 1968) and geladas Theropithecus gelada (Dunbar 1984).…”

“…Estrada and Sandoval 1977;Dunbar 1984;Taub 1984;Ogawa 1995a). Males initiate bridging interactions more often with relatively higher ranking males than with lower ranking Silk and Samuels 1984;Collins 1986;Deag 1980) and/or with males, who are relatively close to their own rank (Stein 1984;Paul et al 1996). It has been suggested also that the male initiating the bridging interaction preferentially uses the infant that is preferred by the receiver to increase the chances of a successful interaction, indicating that males recognize affiliative relationships between other males and infants (Ogawa 1995b).…”

“…Despite of the promiscuity selecting against male care for offspring (see van Schaik and Paul 1996), infants may spend exceedingly large proportions of the time being carried, cradled and groomed by males, whereas aggression or abuse by males are rare (e.g. Deag 1980;Whitten 1987;Paul 1999). Most interactions are initiated and maintained by males, but the contact seems voluntary and infants can be responsible for its start or termination (BK personal observation).…”