雄性短尾猴个体特征与临时配偶关系研究

多雄多雌的灵长类社会群体中,性成熟的雄性和雌性形成临时性的配偶关系（Consortship）是极其显著特征,但这种关系对个体的交配和繁殖成功作用缺少深入研究。本研究以栖息于安徽黄山的短尾猴YA1群为研究对象,采用全事件取样法（All occurrences recording）、目标动物取样法（Focal animal sampling）以及行为取样法（Behavioral sampling method）记录个体间的社会行为、雄性的配偶数量和临时配偶关系的持续时间,对雄性短尾猴临时配偶关系的基本特征与适应策略进行了初步探讨。研究期间,雄性个体的顺位发生替换,在替换前后,处于高顺位的雄性个体始终拥有最多的配偶数量以及形成的临时配偶关系的持续时间最长,并且雄性个体的顺位与临时配偶关系呈正相关关系（顺位变化前：配偶数量：P = 0.010;持续时间：P = 0.014;顺位变化后：配偶数量：P = 0.032;持续时间：P = 0.035）;雄性个体的年龄与临时配偶关系无显著相关性（配偶关系：P = 0.150;持续时间：P = 0.511）;雄性个体在群体中生活的时间与临时配偶关系呈显著正相关（配偶数量：P = 0.034;持续时间：P = 0.023）;雄性个体的社会关系与临时配偶关系呈显著正相关（顺位变化前：配偶数量,P = 0.013;持续时间,P = 0.001;顺位变化后：配偶数量,P < 0.001;持续时间,P = 0.003）。研究结果表明：雄性个体的顺位、在群体中生活时间以及社会关系对临时配偶的形成起主要作用,这为进一步阐明雄性行为策略与临时配偶关系提供新的科学依据。     

雄性黄山短尾猴(Macaca thibetana)攻击支持雌性以换取交配回报

生物市场理论认为动物个体之间通过某种协定交换有价值的商品,使双方均受益。该研究采用目标动物法、行为取样法和连续记录法,对浮溪黄山野生猴谷鱼鳞坑短尾猴(Macaca thibetana)A1群(YA1群)和A2群(YA2群)成年个体在非繁殖季节(2011年8月—12月)和繁殖季节(2012年2月—5月)的雄性攻击支持雌性行为和交配行为进行研究,探讨雄性攻击支持雌性与交配之间的关系。两猴群在繁殖季节和非繁殖季节雄性攻击支持雌性与交配行为均呈显著正相关;YA2群繁殖季节与非繁殖季节攻击支持后交配频次均显著高于随机交配;YA1群在繁殖季节攻击支持后交配频次与随机交配频次差异不显著,但在非繁殖季节攻击支持后交配频次显著高于随机交配,说明短尾猴成年雄性攻击支持雌性可以换取与该雌性个体的交配回报。本研究验证了生物市场理论中社会行为存在交换,首次证明了雄性攻击支持可以换取雌性的交配回报,为进一步研究雄性性竞争与雌性选择提供了实例。     

雄性黄山短尾猴攻击行为和粪便睾酮水平季节性变化

睾酮对启动和维持雄性动物的性行为及保持雄性第二性征有重要作用,高浓度的睾酮还可促进雄性的攻击性。但是长时期维持高的睾酮水平还会使雄性付出很高的能量代价,所以雄性不会长时期地维持高的睾酮水平。本研究对黄山短尾猴鱼鳞坑YA2群雄性个体交配期（2006年9月-12月）与产仔期（2007年1月-4月）攻击行为进行研究,同时收集研究个体的新鲜粪便,并用放射免疫分析法测定粪便睾酮水平,以探讨雄性黄山短尾猴不同时期睾酮水平差异及睾酮水平与攻击行为的关系。结果表明,成年雄性黄山短尾猴攻击行为发生频次在交配期显著高于非交配期;成年雄性粪便睾酮水平在交配期显著高于非交配期;交配期成年雄性的粪便睾酮水平与攻击行为发生频次有较显著的正相关关系,而在非交配期无显著相关;低顺位个体在交配期和非交配期都没有观察到攻击行为。本研究的结果支持了“繁殖竞争假说”。     

非优势顺位雄性黄山短尾猴的交配策略

在多雄多雌、顺位决定交配机会、雄性偏斜繁殖的非人灵长类社会中,低顺位雄性为提高自己的繁殖成功率,通常采取多样的交配策略以获得较多的交配机会。对非优势顺位雄性交配策略的研究可以增加对灵长类社会性行为复杂性的理解,对于深入探讨动物的婚配制度及繁殖策略具有十分重要的科学意义。本研究采用目 标动物取样法和全事件记录法,在２０１２ 年９ －１２ 月（交配期）记录了安徽黄山短尾猴鱼鳞坑ＹＡ１ 群中４ 只成年雄性个体的交配及有关的行为。研究发现：（１）非优势顺位雄性个体在远离优势顺位雄性视野范围的交配频次和交配时间显著高于优势顺位视野范围内;（２）与优势顺位雄性个体相比,非优势顺位雄性的强行交配（forced copulation）和隐秘交配（clandestine copulation）比例较高;（３） 就交配对象而言,对成功生育的雌性个体,优势顺位雄性在选择交配对象时具有明显的倾向性,非优势顺位雄性在选择时倾向性不显著;对未生育的雌性,优势顺位雄性更倾向于选择没有生殖经历的亚成年雌性个体,非优势顺位雄性则倾向于选择处于哺乳后期的成年雌性个体;（４）在具体交配策略上,优势顺位雄性选择跟随（follow） 雌性,非优势顺位雄性则通过做鬼脸 （grimacing）和性追求（sexual chasing）直接获取交配机会。本研究结果表明黄山短尾猴中非优势雄性个体形成了多变的交配策略,更多采取强制性方式,以获得更多的交配机会,多数的交配都是机会性的。     

青藏铁路对雄性藏羚行为时间分配的影响

行为时间分配是动物对资源获取和风险防御的权衡,受到诸多因素影响。本研究采用目标动物观察法记录了可可西里冬季（交配季）雄性藏羚的行为表现,并将行为分为觅食、警戒、卧息、移动和“其他”5种类型。首先,本文通过对比青藏铁路运营前后两个交配季（2003-2004年建设期和2017-2018年运行期）之间雄性藏羚的行为时间分配差异,探讨青藏铁路的出现对雄性藏羚行为的影响。随后,基于2017-2018年交配季雄性藏羚的行为数据,分析了年龄对其行为时间分配的影响。结果表明：与建设期相比,雄性藏羚的觅食和“其他”行为时间比例明显增加,而警戒和卧息的行为时间比例显著降低,这说明铁路稳定运营后对雄性藏羚的影响降低。交配群中成年雄性藏羚的警戒、移动,以及“其他”行为中的繁殖行为的时间比例显著高于亚成体,而觅食和卧息行为时间比例显著低于亚成体, 这与交配群中不同年龄雄性个体所处的地位等级有关。成年雄性藏羚在交配群中占据主导地位,拥有更多配偶资源,增加警戒和移动,减少觅食和卧息有助于其维持交配群的稳定。     

黄山短尾猴繁殖的季节性和雌性性活动方式

1987年开始,我们对中国黄山的短尾猴(Macaca thibetana)的性和繁殖行为进行了研究。本文根据1992年全年野外观察,对黄山短尾猴的繁殖季节性和雌性性活动方式进行深入研究,以揭示短尾猴繁殖方式和雌性性行为如何影响雄性性行为。研究采用全事件取样和目标动物取样法。结果表明,短尾猴黄山种群的交配和产仔是季节性的：交配季节发生在7月至12月,其特征是交配频率高并伴有射精;产仔季节为1月至4月。交配季节之外的交配虽有少量发生．但交配频率很低且几乎不射精。成年雌性的会阴部有轻微肿胀的性皮,但性皮的大小和颜色既不随猴群繁殖季节变化,也不随雌性个体生理周期变化。同时,雌性缺乏典型的性要求的行为——发情。因此,我们认为雌性短尾猴倾向于隐蔽自己的排卵。对46个连续观察日中成年雄性对雌性的性行为分析还表明：雄性能够区别潜在繁殖和不繁殖的雌性但不能对同一雌性的生理状况做出准确判断。隐蔽排卵是雌性在性接受期间接受大量交配的主要原因。本研究否定了短尾猴的交配是非季节性的假设(Wadaand Xicmg,1996)[动物学报51(3)：365—375,2005]。     

笼养雌性短尾猴月经周期及性行为

在多雄多雌的灵长类社会中,成年雌雄个体的性行为并不局限于雌性受孕期,但仍认为性行为在受孕期最为活跃。对于雌性隐藏发情的灵长类物种,雌雄个体的性行为与雌性月经周期的相关性尚不清楚。本研究以短尾猴(Macaca thibetana)为研究对象,研究雌性隐藏发情灵长类的性行为与月经周期阶段的关系。在短尾猴繁殖季节,从2019年10月2日至2020年1月14日连续采集了安徽省铜陵市动物园6只成年雌性短尾猴的490份粪便样本,采用放射免疫分析法检测粪便中雌二醇激素的浓度,并用焦点动物取样法和行为取样法采集目标个体(4只雌性、4只雄性)的性行为数据。本研究利用Spearman相关系数检验雌激素与性行为的相关性;独立样本T检验分析雌性短尾猴发情的邀配性指标(雌性呈臀行为)、吸引性指标(雄性性检查行为)和交配行为在月经周期三个阶段(受孕期前:受孕期前的5 d;受孕期:最有可能排卵的2 d加上精子能在雌性生殖道中存活的3 d;受孕期后:受孕期后的5 d)的分布差异性。结果表明,雌性短尾猴的雌二醇浓度在繁殖季节呈现周期性波动,周期长度为(31.1±1.8)d(n=7,范围23～37 d);同时在月经周期内,雌二醇浓度与雌性呈臀行为呈显著负相关(r=﹣0.616,n=15,P=0.015),而与交配行为和雄性性检查行为均无显著相关性;雌性呈臀行为的平均频次主要集中在受孕期前(T=﹣1.215,df=12,P=0.044);交配行为和雄性性检查行为在月经周期的三个阶段无显著性差异。短尾猴的性行为并没有集中在雌性的受孕期,说明雌激素对短尾猴的性行为无严格控制作用,且雄性短尾猴无法准确识别雌性的受孕期。     

黄山短尾猴交配叫声及其影响因素

哺乳动物在交配过程中经常会发出独特且有节奏的交配叫声（Copulation call）,这通常被认为是雌雄双方交配策略的一种体现。交配叫声的发生及其影响因素在不同物种间差异较大,对其深入研究有助于比较和揭示不同动物交配策略的差异及其适应性功能。为了阐明交配叫声的生物学和社会学因素,我们在安徽黄山记录了野生黄山短尾猴（Macaca thibetana）交配行为中雄性和雌性发出叫声的过程,分析了影响交配叫声的相关因素,探讨了伴随叫声的交配行为对后续友好行为的影响。结果表明,在交配过程中,高顺位成年雄性短尾猴比其他性别—顺位组个体更易发出叫声,而优势个体雌性和从属个体雌性在交配过程中的发声频次无显著差异。此外,交配叫声能促进参与者之间在交配后表现出更多的友好行为和更近的空间距离。本研究为理解多雄多雌婚配制度的短尾猴群体交配策略提供了声音通讯方面的理论支持。     

散养塞加羚羊两个主要繁殖时段的昼间时间分配

对散养在30hm^2场地内的塞加羚羊（Saiga tatarica）一个敏殖群体在2000年12月（酱期及其前、后）和2001年5-7月（哺乳期）的昼间时间分配做了观察研究。数据用个体扫描-瞬时取样法收集。结果表明：①雌性塞加羚羊在交配期结束后,躺卧时间减少,进食时间增加;从前期到后期,站立时间连续递减;母羊分娩后2周内离群单独活动,往返于觅食地和幼仔隐藏地之间;第3周起,母仔合群。②雄性在交配期的移动多于交配前,交配后躺卧时间增加。③塞加羚羊时间分配的性别差异始于交配期;这时,雄性个体忙于追逐圈赶雌性,导致移动时间增加,躺卧减少;交配期后,雌性觅食时间突增,而雄性不变;雌性进入哺乳期后,各月觅食时间均多于雄性。以上时间分配的性别差异反映了它们的繁殖投资差异。上述结果暗示,对此类散养动物,应在其能量需求高峰期增加投食量,以提高繁殖成功率。     

成年雌性短尾猴的社会联系强度及影响因素

灵长类动物社会中,个体间的社会关系是维系群体稳定的重要基础,也影响个体的寿命和繁殖成功。本研究以栖息于安徽黄山的短尾猴YA1群为对象,采用焦点动物取样法和行为取样法采集成年雌性个体在交配期（2015.9 - 2015.12）和非交配期（2016.3 - 2016.5）的社会行为,通过理毛和近距行为计算社会联系强度,探讨群体成员之间的社会关系及影响因素。结果表明：在交配期和非交配期,雌性短尾猴的社会联系强度无显著差异（t = 0.181,P = 0.857）;亲缘关系和社会联系强度呈显著正相关（交配期：r = 0.534, P = 0.001; 非交配期：r = 0.469, P= 0.001）;个体间的等级距离和社会联系强度呈显著负相关（交配期：r = -0.288, P= 0.014; 非交配期：r = -0.238, P= 0.048）;年龄差异和社会联系强度无显著相关性（交配期：r = -0.176, P = 0.181; 非交配期：r = -0.192, P = 0.151）。本研究提示成年雌性短尾猴个体间会形成稳定的社会关系,亲缘关系和等级顺位是影响个体之间社会关系的重要因素。     

Female behavioral strategies during consortship in Tibetan macaques (Macaca thibetana)

Consortship has been defined as a temporary association between an adult male and an estrous/receptive female. It has been considered as male mating strategies to improve male mating success and potential reproductive success. However, the female roles have been more or less neglected, and thus, less is known about female behavioral strategies during the consortship periods. In this study, during the two consecutive mating seasons, we collected behavioral data of free‐ranging Tibetan macaques (Macaca thibetana) habituated in Mt. Huangshan, China, to investigate female behaviors when she was consorted by an adult male. The results showed that (a) females were more likely to approach and exhibit sexual solicitation to their consorting males during the consorted period, and females also exhibited less approach to their nonconsorting males; (b) females exhibited strong responses (either departed distantly or formed affiliative relationships with their consorting male partner) when their consorting males mated with rival females or showed sexual motivation toward rival females; (c) female preferences were positively correlated to the duration of consortships and the frequencies of ejaculation copulations, independent of the social ranks of their consorting male partners. Our results suggested that female strategies played much more important roles in forming and maintaining consortship than previously assumed. It provides new insight into understanding female adaptive strategies to male strategies by forming consortships in multimale–multifemale primate species when males could not identify female''s fertile phase accurately.     

Consortships and conceptions in captive rhesus macaques (Macaca mulatta)

A captive group of rhesus macaques (Macaca mulatta) was observed during the breeding season to determine if consortship behavior, rather than promiscuous matings, resulted in higher reproductive success for either partner. The 38 adult females in this group were observed “in consort” with the 5 adult or 4 subadult males on 179 occasions. Most of these consortships were short-term, lasting less than one day. Six females engaged in consortships with one male that spanned more than three days, but the majority of these long-term associations did not result in a pregnancy with that male. The term “consortship” has been traditionally accepted as a specific nonhuman primate mating pattern, but the exact nature of this behavioral pattern and its evolutionary importance have been less clearly understood. Consort behavior could be considered a precursor to a monogamous mating system if long-term exclusive sexual associations resulted in higher reproductive success for the participants. But this study demonstrates that for rhesus macaques, who exhibit both consort behavior and more promiscuous matings, there is no clear reproductive advantage to long-term consortships. In light of the inconsistent use of the term consortship, the possible adaptive significance of an exclusive male-female sexual association for the evolution of human mating patterns needs to be reevaluated.     

Social relationships between adult male and female rhesus macaques: 1. Sexual consortships

The sexual relationships of 15 adult male rhesus macaques (Macaca mulatta), of one social group in the Cayo Santiago colony, Puerto Rico, were studied during the 1981 mating season. Two criteria were used to determine whether or not a focal male was in consort in a given 20-min observational sample. One hundred and thirty-two consortships were recorded. The distribution and duration of all consortships, and the distribution of those consortships that coincided with the estimated time of conception, were positively correlated with male dominance rank and length of tenure. Correlations with dominance were stronger than those with tenure. Older females had more consortships with focal males than younger females. There was no relationship between female rank and the distribution of consortships. Consortships did not give exclusive access to receptive females although they may do in feral situations. Males were primarily responsible for maintaining proximity in about two thirds of consortships. The four top-ranking males were primarily responsible in all but one of their consortships. Almost all of those in which the female was primarily responsible involved younger, slightly lower-ranking males. This pattern may have resulted from the females being attracted to the latter males although other interpretations are possible. The partner who was primarily responsible for maintaining proximity also tended to be the predominant groomer, supporting the view that grooming plays a role in the maintenance of sexual consortships. Almost a third of consortships were with females who had conceived, suggesting that males could not accurately assess female reproductive state. Consortships maintained by the male were longer than those maintained by the female. Males may try to increase their chances of fertilising a female by prolonging the consortship. High-ranking males may have been more successful at this, resulting in the positive correlation between male dominance rank and consortship duration.     

Correlates of Male Consortship Rate in Free-Ranging Rhesus Macaques (Macaca mulatta)

Male–male competition for access to receptive females can take the form of nonrecurring fights and/or a sustained contest over mating opportunities. Male physical condition has been linked to dominance rank and reproductive success in species characterized by intrasexual fights for dominance and access to females. In group-living species characterized by endurance rivalry, however, factors contributing to male reproductive success are less well understood. In such species, particularly seasonally breeding ones with low sexual dimorphism and seniority-based rank, age and social factors other than rank may prove important. In the absence of genetic data, male mate guarding or consortship can serve as an indicator of male reproductive success. To evaluate the contribution of age and intragroup sociality to male consortship rate, I collected behavioral data during one nonmating and one mating season in two social groups of free-ranging rhesus macaques that experience no predation or food scarcity. Higher-ranking males, younger males, or males that exhibited lower rate of intrasexual aggression had higher consortship rates. Male–female dyads that groomed outside consortship did not form consortships as often as dyads that did not engage in nonconsort grooming. This is the first study to identify the significance of male–male aggression and male–female affiliation to male consortship rate in a species characterized by endurance rivalry, high male rank stability, and strong female mate choice. Social behaviors and male age may be particularly important in determining male reproductive success in populations experiencing high food availability and a lack of predation, which are typical of an increasing number of vertebrates in areas densely populated by humans.     

Interactions Between Third Parties and Consortship Partners in Tonkean Macaques (<Emphasis Type="Italic">Macaca tonkeana</Emphasis>)

Sexual competition is potentially disruptive for the cohesion of social groups because stress and conflicts can extend to other group members. The displays and interactions of sexual partners are liable to influence the behavior of group-mates, which may need to observe them to anticipate possible consequences. We studied 2 captive groups of Tonkean macaques (Macaca tonkeana) to test whether group-mates pay more attention to consort partners, modify their activities and social interactions, and exhibit signs of stress during periods of sexual consortships. We found that group-mates approached the top-ranking male more frequently and were more frequently oriented toward the consort pair at the time of consortship than at other times. Group-mates spent less time sleeping, and devoted less time to manipulating the environment and more time to monitoring during consortship. This indicates that consortships may incur costs in individuals not involved in sexual competition. However, Tonkean macaques did not exhibit any signs of increased stress during consortship periods, as their rates of scratching and yawning did not differ between consortship and nonconsortship periods. This study shows that not only direct competitors but also other individuals monitor the behavior of sexual partners. It is likely that group-mates obtain information this way about ongoing action, and take decisions accordingly.     

Sex differences in sexual partner acquisition, retention, and harassment during female homosexual consortships in Japanese macaques

Female Japanese macaques (Macaca fuscata) in certain populations are unusual in that they exhibit male-typical patterns of mounting behavior and sexual-partner preference. The goal of this study was to determine whether female Japanese macaques, from one such population, employ male-typical behavioral tactics to disrupt existing homosexual consortships, as well as to acquire and retain same-sex sexual partners. "Harassment" of homosexual consortships occurred when a sexually motivated, third-party male or female interrupted a consorting female couple by displacing or aggressing them. Sexual harassment was a male-typical strategy for disrupting existing homosexual consortships, but was rarely performed by females. "Intrusions" occurred when a male or female competitor attempted to acquire exclusive access to a female engaged in a homosexual consortship by targeting that female as the focus of competition and her partner as his/her competitor. "Sexual coercion" occurred when one individual alternately sexually solicited and aggressed another individual as part of the same behavioral sequence during an intrusion. Males employed consortship intrusions and sexual coercion when they attempted to acquire female sexual partners that were already engaged in homosexual consortships, but females rarely did so. However, females did employ male-typical patterns of aggressive competition and sexual coercion to retain same-sex sexual partners when confronted with male competitors' attempts to usurp those partners. These results indicate that female sexual activity during homosexual consortships is not uniformly "masculine" in expression, but rather is a mixture of male- and female-typical behaviors.     

Social relationships between adult male and female rhesus macaques: II. non-sexual affiliative behaviour

The social relationships of adult male rhesus macaques (Macaca mulatta) in Group I of the Cayo Santiago colony were studied over a period of 14 months. Relationships were found in which adult males and sexually mature females were persistently close to one another in nonsexual contexts, both within and across seasons. Males of long tenure and high dominance rank tended to have more female partners, and more persistent relationships, than more recent immigrants of lower rank. Correlations with length of tenure were stronger than those with dominance rank. Closely-related females tended to have persistent relationships with the same male. In most cases the female was primarily responsible for maintaining proximity in non-sexual contexts. Dyads which were persistently within 5 m of each other in the birth season were more likely to form a consortship in the subsequent mating season than those which had a brief relationship. A similar tendency was apparent in the 1 m data but it was not statistically significant. There was no association between persistent proximity during the birth season and the occurrence of long, or multiple consortships, nor with the maintenance of proximity or direction of grooming between consort partners. The pattern of consortships was not closely related to the formation of persistent relationships in the subsequent birth season. Females occasionally received protection from their male partners and, in some cases, spent more time in the feeding corral with them than did other females. Affiliative relationships can be very enduring and may have long-term benefits that were not apparent during the study period.     

Male competition and its hormonal correlates in Assamese macaques (Macaca assamensis)

In polygynous mammals, where males compete over access to females, the potential of males to monopolize reproductive females largely depends on the spatio-temporal distribution of reproductive females. We investigated mechanisms of male reproductive competition and its hormonal basis in a cercopithecine species with reduced contest potential owing to female reproductive synchrony and concealed ovulation. Over 16 months including two mating seasons we collected 1218 h of observational focal animal data and 1254 fecal samples of 11-12 adult and large subadult male Assamese macaques (Macaca assamensis) living in their natural habitat in Thailand. Androgen output along with aggressive behavior showed a seasonal pattern, with highest values being obtained by all males during the mating season and by those males experiencing acute social challenges, e.g. rank change and dispersal. Individual androgen levels and rates of attacks were linked across the study period, suggesting a promoting function of androgens for aggressive behavior. Dominance rank predicted neither mating success nor androgen levels consistently, indicating a reduced selective advantage of high social status for general mating access. However, high ranking males engaged in extended consortships with reproductive females. Distribution of consortships across males followed a priority of access distribution, with the two top ranking males accounting for 75% of consort activity, suggesting that high social status also carries fitness benefits in a species characterized by low contest potential.     

Close bonds and social rank similarities favor non-random mating in captive stump-tailed macaques (Macaca arctoides)

Assortative mating is non-random mating by the mutual choice of phenotypes or behavioral types. In polygynandrous species, competition for mating by social rank can lead to assortative mating. However, although not an individual trait, social bonds also influence mating opportunities resembling assortative mating. Stump-tailed macaques form long-term close bonds and organize in a linear dominance–subordination hierarchy. Therefore, we studied whether the strength of the social bond and rank closeness influenced mating decisions and increased mating opportunities, particularly for low- and middle-ranking animals. Firstly, we observed whether females directed proceptive behavior to close-bonded or adjacent rank males. Secondly, we measured whether successful copulations were related to the strength of social bonds and close ranking. Thirdly, to ensure that copulations owed mainly to the aforementioned factors, we also evaluated whether sexual coercion was unrelated to social bonds and rank similarities. Finally, we assessed whether close bonds mediated agonistic support to females. The study subjects were 12 adult female and 11 male captive stump-tailed macaques. We monitored daily females' reproductive status by vaginal cytology. Sexual behavior was recorded by all occurrences sampling and scan sampling to collect the agonistic and affiliative instances required to calculate social ranks, social bond strength, and agonistic support. The results indicated that the probability of females displaying proceptivity increased during the follicular phase toward close-bonded and high-ranking males. Copulation chances increased with male–female social bonds and rank closeness. Forced copulation decreased in close-bonded individuals, while agonistic support increased in close-ranking strong-bonded animals. In conclusion, close social bonds and similar social rank result in non-random mating in stump-tailed macaques.