Social grooming is one of the most common forms of affiliative behaviour among socially living animals and has been in the centre of interest from the early beginnings of primatology. Social grooming is a behaviour in which social animals, clean or maintain one another's body and many studies focused on investigating the function of grooming behaviour. This thesis consists of general introduction and three studies that investigate social grooming in a population of semi-free ranging Barbary macaques from Gibraltar. The studies are based on original data and the results provide an interesting and new insight into the grooming behaviour in Barbary macaques. The first study focused on grooming patterns among females and we found that grooming was directed up the hierarchy, was affected by friendship and kinship. In the second study we tested the effect of maternal status on grooming among females and results showed that mothers gave less grooming but did not receive more grooming from other females. On the basis of these results we proposed that the observed patterns would be better explained by time constraints posed on mothers, rather than by grooming for infant handling exchange. In the last study we investigated the relationship between grooming and sexual activity between males and females. Our data showed that males as well as females preferred for mating activities those individuals that groom them most.

I have investigated the social grooming in kinship, rank, age and seasonal change among adult female Formosan macaques (Macaca cyclopis) that inhabit Mt. Longevity, Kaohsiung. The major study groups were C and Cd groups. Field observations were conducted from August 2000 to February 2003 covering three mating seasons and two non-mating seasons. The observations covered a total of 188 work days including 1248.8 hours. I actually had recorded C group for 660.6 hours, and Cd group for 244.5 hours. During my study, C group consisted of 8-13 adult males and 14-15 adult females, while group Cd had 1-3 adult males and 2-4 adult females. In order to analyze grooming data, I divided 15 adult females into sub-groups such as dominant/ submissive groups, old (>13) /young age (5-12), relative higher/lower ranking and related/unrelated. I have also divided adult males into troop-males and periphery males. Adult female allo-grooming activities accounted for 37.62% ¡Ó 13.59 (n = 15) of the behaviors in the daytime. I also found that adult females grooming infants and juveniles were greater than received from them (p < 0.001). The social grooming among adult females occurred mainly during non-mating seasons and its frequency was 2.12 times of mating seasons. Regardless of mating or non-mating seasons, the frequency of grooming among related females was significantly higher than among unrelated females (both p < 0.001). In addition, kinship affected the grooming frequency among female macaques with relative lower or higher ranking females during mating seasons (p < 0.05), while the dominant rank did not have the effect. However, the highest grooming frequency occurred in the high-ranking females who groomed relative lower ranking females within relatives (0.38 ¡Ó 0.40 bouts / 100 scans, n = 7). During non-mating seasons, kinship affected the grooming frequency among female macaques with relative lower ranking females (p < 0.05); the highest grooming frequency occurred in the old females who groomed relative lower ranking females within relatives (1.57 ¡Ó 1.74 bouts / 100 scans, n = 8). Moreover, seasons (mating or non-mating) and kinship relationship had significant effects on grooming frequencies among female macaques (both giving and receiving p < 0.01), as well as on the grooming frequency of females groomed with relative lower ranking females (p < 0.01). The highest grooming frequency occurred on females groomed with relative lower ranking females within relatives during non-mating seasons (1.25 ¡Ó 1.48 bouts / 100 scans, n = 11). Without kinship relationship, low-ranking females groomed relative higher ranking females more frequent than high-ranking females did (p < 0.05). Within adult females, 65% of social grooming was among relatives. However, 40% of adult females groomed equally with related and unrelated females, while 20% disproportionately groomed more with unrelated females than with related females. The grooming was kin-biased for 40%. About 8.68% of social grooming among unrelated females was being reciprocated. On the other hand, the ratio of related grooming female partners to the total number of available related females was higher than that with unrelated females (p < 0.05). It also indicated that the ratio of each female received grooming from high-ranking grooming partners was higher than that from low-ranking females (p < 0.01).On the other hand, the ratio of the number of old or young grooming partners of adult females had similar values. The grooming frequency of adult females gave or received from adult males during mating seasons was higher than non-mating seasons (both p < 0.05) while high-rank females groomed adult males more than low-rank females did. The socionomic sex ratios of these two social groups were similar during mating seasons (AM:AF = 1:1.8). Both troop and periphery males had significantly higher frequency of social grooming with adult females in mating seasons than in non-mating seasons. The types of males and social groups had significant effects on the allogrooming frequency among adult males in mating seasons (p < 0.05) but not in non-mating seasons (p > 0.1). Moreover, troop males had higher grooming partners than periphery males. Major grooming partners of troop males were adult females regardless of the seasons. Subordinate males were mostly the receivers in the grooming dyads with dominant males in the mating seasons, but the relationships changed during non-mating seasons. Agonistic interactions occurred mainly during mating seasons and its frequency among periphery males was 1.8 times of troop males (p < 0.05). The preference grooming sites between allo-grooming and auto-grooming of C and Cd groups had varied significantly (p < 0.001). The back region was the preferred grooming site in allo-grooming of C and Cd group and the ano-genital region was the least groomed site. In auto-grooming, monkeys paid much attention to the legs ignoring the back and face. The result indicated that when the adult individuals groomed the head, back and face which showed significant difference in the frequency among AM and AF (p < 0.05). The related female adults groomed head more frequently than unrelated female adults (p < 0.05), but dominance rank and age-class did not apparently affect the corresponding values for the frequency of grooming sites among adult females (both p > 0.1). The results indicated that social grooming among adult females took place more often during non-mating seasons, and more often in kin-related females than unrelated females. Moreover, the dominant females were likely to groom related females. Therefore social grooming among kin-related females may reinforce relationships while reciprocal grooming of unrelated females may serve to form alliance or ranking promotion in the social group. On the other hand, social grooming between adult male and female macaques more frequent in mating seasons than in non-mating seasons. This showed that adult male Formosan macaques employed complex strategies to achieve reproductive success. Nonetheless, the periphery males had more male grooming partners than troop males did which seemingly to enhance male coalitions.

付記する学位プログラム名: 霊長類学・ワイルドライフサイエンス・リーディング大学院 / 京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第22635号 / 理博第4624号 / 新制||理||1664(附属図書館) / 京都大学大学院理学研究科生物科学専攻 / (主査)准教授 足立 幾磨, 准教授 後藤 幸織, 教授 濱田 穣 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM

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