三种笼养灵长类活动时间分配的比较研究

采用焦点动物法和连续记录法对3种笼养灵长类活动时间分配进行比较研究。结果表明,川金丝猴Rhi-nopithecus roxellanae和熊猴Macaca assamensis用于休息的时间多于猕猴Macaca mulatta,移动时间则相反;川金丝猴和猕猴用于理毛的时间多于熊猴。不同性别年龄组之间的活动时间分配有差异,主要表现在川金丝猴母亲用于理毛的时间明显多于成年儿子,用于玩耍的时间则相反;猕猴成年雄性的移动时间和理毛时间多于成年雌性,玩耍时间则少于成年雌性;熊猴成年雌性的移动时间多于成年雄性,与成年个体相比,幼体花更多的时间用于玩耍,而相应的减少了其休息时间。     

社群大小的年变化、气候和人类活动对神农架自然保护区川金丝猴日移动距离的影响

作者于2001年4月至2003年1月研究了社群大小的年变化、气候和人类活动对神农架自然保护区千家坪地区一群川金丝猴(Rhinopithecusroxellana)日移动距离的影响。对该群金丝猴进行了8个季节的跟踪研究,每季连续跟踪30d。用社群直线距离法确定猴群的日移动距离,同时调查社群大小,记录人为活动和气象因子。研究结果显示:(1)两年间猴群的个体数增加了14%,但其日移动距离没有明显变化,说明社群大小的年变化对日移动距离没有影响。(2)猴群在人为活动影响下的日移动距离比没有人为活动影响时长。(3)多变量回归分析显示,各个季节中,猴群的日移动距离与一天中晴和有云但无降水所占时间的比例没有相关性;与春季和冬季日降雨或雪所占时间的比例呈负相关,但与夏季和秋季的没有相关性,说明降水缩短了冬春季猴群的日移动距离,这可能与川金丝猴的繁殖有关。人为活动对猴群是不利的;冬春季的长时间降水可能是川金丝猴的灾害性天气。     

拉沙山黑白仰鼻猴食物中单宁含量的变化

叶食性灵长类食物选择受食物营养及单宁等次生代谢产物影响,为了探讨单宁对黑白仰鼻猴食物选择的影响,通过磷钼酸-钨酸钠 (F-D) 比色法测定了拉沙山黑白仰鼻猴群 (Rhinopithecus bieti) 2010年4月 - 2012年3月间的食用植物 (192种) 和非食用植物 (188种) 单宁含量。结果表明,黑白仰鼻群全年食用植物中单宁含量低于非食用植物;春季食用植物中单宁含量高于其他季节,而其他季节无差异;不同取食部位单宁由高到低依次为芽、花、叶、果和地衣;不同季节,不同取食部位单宁有差异,春季芽的单宁含量最高,夏秋季果实单宁含量最高,冬季叶单宁含量最高;不同月份,食物单宁也不同,3月食用植物中单宁最高 (8.36% ± 6.22%),2月最低 (1.28% ± 1.19%)。因此,黑白仰鼻猴根据环境食物种类和供给时空特征,可能采取了从高蛋白纤维比/高单宁到低蛋白纤维比/低单宁连续谱觅食策略。     

成年雌性太行山猕猴活动时间分配的季节性变化:食物和温度的影响

活动时间分配是指动物根据环境和自身需求从事各种基本行为和活动的过程,受季节性变化的食物和温度等生态因素的影响。2013年3月至2014年2月,在太行山猕猴国家级自然保护区天坛山管护区,采用目标动物取样法,观察并记录了一个野生太行山猕猴群(WW-1群)内成年雌性个体的活动特征及其季节性变化,旨在了解成年雌性猕猴的日活动时间分配及其影响因素。结果表明:(1)成年雌性猕猴的活动时间分配表现出明显的季节性变化。春季,雌性猕猴花费52.9%时间于休息、19.5%时间于取食、11.8%时间于移动;夏季,用于休息、取食、移动的时间比例分别为53.4%、18.0%和11.3%;秋季,猕猴花费35.9%时间于取食、30.0%时间于休息,15.9%时间于移动;冬季,用于取食、休息和移动的时间比例分别为35.4%、39.7%和8.0%;(2)春季,成年雌性太行山猕猴主要取食种子(35.4%)和树叶(34.3%);夏季,树叶(73.5%)主导其每日食物组成;秋季,主要取食种子(98.1%);冬季,树皮(82.1%)则成为猕猴的主要食物;(3)当每日食物组成以草和树叶为主时,猕猴用于取食的时间增加,移动时间减少;当每日食物组成以种子为主时,则取食时间减少,移动时间增加;(4)随着气温降低,猕猴取食时间增加,而移动时间减少。总之,成年雌性太行山猕猴的日活动时间分配主要受季节性变化的食物资源和气温的影响,它们可通过日活动时间的调整以适应食物和环境温度的季节性变化。     

利用过夜地粪便估计白马雪山黑白仰鼻猴种群大小和组成

介绍了应用过夜地粪便来估计白马雪山黑白仰鼻猴群大小和组成的一种方法。该物种以单雄多雌单元和全雄组的形式在树上过夜。粪粒根据其大小可分为3种类型成年雄性的(最大)、成年雌性的(中等大小)和未成年个体的(最小)。2000—2001年,搜集了滇西北白马雪山国家级自然保护区北部南任村(99°04′E,28°34′N)附近黑白仰鼻猴群每个季节2个过夜地的粪粒。根据2001年11月猴群通过开阔地的数据来确定猴群组成。每个季节,由于单雄多雌单元的成年个体数与其粪粒数正相关,所以二者回归直线的斜率可以看作是每个个体每晚的平均排便量。由于该物种的栖息地主要为高山峡谷,而且能见度较低,因此,利用过夜地粪便比以前通过猴群活动痕迹来估计猴群大小和组成相对准确、可靠。从估计成年雌性个体数的角度看,利用粪粒来估计种群大约有9·4%的偏差。导致偏差的可能原因有杂草和灌丛对粪粒准确计数的影响、个体排粪率的差异以及成年雄性最小粪粒与成年雌性最大粪粒的混淆等。该方法适应于栖息地和主要食物与本文研究种群相似的其他种群。     

环境和社会因素对喀斯特石山猕猴日活动节律和活动时间分配的影响

2007年9月至2008年8月,以广西弄岗国家级自然保护区内的一大群野生猕猴为研究对象进行连续的跟踪观察,采用瞬时扫描取样法收集其食物组成、活动节律和活动时间分配的数据,旨在探讨影响石山猕猴活动节律及活动时间分配的环境和社会因素。结果表明：研究猴群的日活动节律表现为上午和下午的觅食高峰以及中午的休息高峰,这与白天温度和日照强度的变化有关。日活动时间分配中,休息42.1%,移动34.5%,觅食15.1%,玩耍2.0%,理毛5.2%,其他行为1.3%。猴群依据食物的变化调整活动时间分配,其中用于移动的时间与食物中果实的比例成显著的正相关性。不同性别年龄组个体的活动时间分配表现出显著差异,主要表现为成年雄性花费更多的时间休息,而成年雌性花费更多的时间觅食和社会性理毛,未成年个体则花费更多的时间玩耍。与同域分布的小群猕猴相比,本研究群花费更多的时间休息,较少的时间觅食。这些差异可能与盗食农作物有关。     

利用过夜地粪便估计白马雪山黑白仰鼻猴种群大小和组成

介绍了应用过夜地粪便来估计白马雪山黑白仰鼻猴群大小和组成的一种方法。该物种以单雄多雌单元和全雄组的形式在树上过夜。粪粒根据其大小可分为3种类型：成年雄性的(最大)、成年雌性的(中等大小)和未成年个体的(最小)。2000—2001年，搜集了滇西北白马雪山国家级自然保护区北部南任村(99°04′E, 28°34′N)附近黑白仰鼻猴群每个季节2个过夜地的粪粒。根据2001年11月猴群通过开阔地的数据来确定猴群组成。每个季节，由于单雄多雌单元的成年个体数与其粪粒数正相关，所以二者回归直线的斜率可以看作是每个个体每晚的平均排便量。由于该物种的栖息地主要为高山峡谷，而且能见度较低，因此，利用过夜地粪便比以前通过猴群活动痕迹来估计猴群大小和组成相对准确、可靠。从估计成年雌性个体数的角度看，利用粪粒来估计种群大约有9.4%的偏差。导致偏差的可能原因有杂草和灌丛对粪粒准确计数的影响、个体排粪率的差异以及成年雄性最小粪粒与成年雌性最大粪粒的混淆等。该方法适应于栖息地和主要食物与本文研究种群相似的其他种群。     

白马雪山黑白仰鼻猴(Rhinopithecus bieti)垂直迁移(英文）

2000-2001年间,在白马雪山国家级自然保护区南任村附近,通过在四个山坡每隔海拔100米的样带（宽5.0米）内搜集黑白仰鼻猴的粪便来研究猴群不同季节的垂直迁移模式。同时,通过在每个地区山脊上和山沟内搜集2.5米宽垂直样带内的粪便,来研究猴群不同季节对山脊和山沟的选择性。结果表明：猴群在海拔3500-4300米的区域活动。虽然猴群全年集中利用3900-4200米的林带;但是具有季节性差异：夏季最高（4200米）,依次是秋季（4100米）和冬季（4000米）,夏季最低（3900米）。另外,冬季山沟中的粪便多于山脊说明猴群在沟中停留时间长,这与沟中少风且温度高有关。不同海拔带上的粪便密度和松萝量间正相关,这意味着食物资源的垂直分布是影响猴群垂直迁移的重要因素。春季,猴群会下到低海拔采食嫩芽/叶,而冬季则下到低海拔处躲避首次大雪,这很可能导致猴群集中利用第二个海拔带。     

云南拉沙山黑白仰鼻猴交配行为和出生季节

灵长类的交配模式对于了解和掌握雄性的交配策略和社群的稳定机制非常重要,但是目前有关亚洲灵长类交配模式的数据较少;因此,该研究于2011年1—12月,分别采用全事件取样法和焦点动物瞬时扫描取样法收集了拉沙山黑白仰鼻猴群的交配行为和出生数据。猴群全年交配,有2个峰期,一个是繁殖交配高峰期(8一10月);另一个在出生季节,但其非繁殖交配的生物学意义尚不清楚。雌性通过俯卧/注视雄性或跳落邀配。爬跨射精比为8.8,射精交配稀少(11.4%),这说明雄性并非每次交配都射精,因而支持黑白仰鼻猴交配模式的主体为多次爬跨射精或处于从单次爬跨射精到多次爬跨射精连续谱上段的观点。雄性邀配的射精爬跨多于雌性,说明多次爬跨射精不仅是雄性的一个交配策略,而且可以决定交配模式在连续谱的位置。交配时间后延6~7个月,交配频次与婴猴出生率相关。拉沙山猴群出生模式为严格的季节性,这进一步证实了前人的观点。婴猴出生具有一定的同步性,且不同猴群婴猴出生的同步模式不同。     

黑白仰鼻猴肠道寄生虫感染调查

为了解黑白仰鼻猴野生种群的肠道寄生虫感染现状,对分布于云南塔城境内的一群90只个体的黑白仰鼻猴种群进行了粪便虫卵检查。共采集了225份样品,记录了粪便供体的性别、年龄、所在单元和采集时间,分别采用水洗过滤沉淀法、饱和盐水浮聚法和改良加藤氏厚涂片法进行检查。实验结果表明该猴群感染的寄生虫种类有灵长类肠道常见寄生虫毛首线虫Trichuris sp.,感染率在不同年龄段间存在显著差异;钩虫Ancylostoma sp.和结节线虫Oesophagostomum sp.在黑白仰鼻猴中的感染存在季节性,旱雨季差异性显著;同时粪便样品中还检出了少量的肝毛细线虫Capillaria hepatica和蛔虫Ascaris sp.。     

Effect of Group Size on Time Budgets of Sichuan Snub-Nosed Monkeys (Rhinopithecus roxellana) in Shennongjia National Nature Reserve, China

Group size influences intragroup scramble competition, which in turn influences time budgets in some primates, and may impact age–sex classes differently. There is a great deal of debate about whether folivorous primates, e.g., colobines, experience significant feeding competition. Unlike most colobines, Sichuan snub-nosed monkeys (Rhinopithecus roxellana) live in extraordinarily large groups and eat mainly lichens supplemented by seasonal plant food. We examined the effect of group size on time budgets in this species by studying two groups of different sizes in the same habitat in Shennongjia National Nature Reserve, China (study periods: August 2006–July 2008 for the larger group, November 2008–July 2009 for the smaller group). Results showed that the distribution of activities throughout the day did not differ between groups, but that time budgets did differ. Specifically, the monkeys spent more time moving and less time resting in the larger group than in the smaller group. Intergroup comparisons for each age–sex class indicated that adult females (but not adult males or juveniles) in the larger group spent more time moving and less time resting, and tended to spend more time feeding compared to those in the smaller group. The results suggested that increased scramble competition was occurring for adult females in the larger group. We provided preliminary evidence for the existence of intragroup scramble competition in Rhinopithecus roxellana.     

Sleeping Cave Selection,Activity Pattern and Time Budget of White-Headed Langurs

We describe the activity patterns and time budgets of white-headed langurs that were confined to about 4 km² of Longlin habitat in Fusui County, Guangxi Province, China. Between February and December 1996, we observed 6 langur groups monthly via group focal sampling and continuously recording the behavior of a focal group. Our results indicate that the langur groups selected stone caves on cliffs as sleeping sites. The daily activity pattern outside caves had 8 stages: (1) leaving the cave in the early morning; (2) moving and resting; (3) morning feeding; (4) moving a long distance; (5) resting at noon; (6) afternoon feeding; (7) moving back to the cave, and (8) entering the cave. Over the year, langurs spent a daily average of about 11.5 h outside caves and about 12.5 h inside caves. Moving accounted for 7% (spring), 7% (summer-autumn) and 13% (winter) of the time budget, and langurs spent 9% (summer-autumn) and 14% (spring) to 20% (winter) of their time feeding. Resting accounted for 79% of the time budget in spring, 84% in summer-autumn, and 57% in winter. Sunbathing only occurred in winter and accounted for about 10% of the time budget. One-way ANOVA and multiple range tests demonstrated that time budgets differed significantly among seasons. Langurs spent significantly more time feeding and moving in winter than in spring and summer-autumn, but significantly less time resting in winter than in spring and summer-autumn.     

Test of the ecological-constraints model on ursine colobus monkeys (Colobus vellerosus) in Ghana

For group-living mammals, the ecological-constraints model predicts that within-group feeding competition will increase as group size increases, necessitating more daily travel to find food and thereby constraining group size. It provides a useful tool for detecting scramble competition any time it is difficult to determine whether or not food is limiting. We tested the ecological-constraints model on highly folivorous ursine colobus monkeys (Colobus vellerosus) at the Boabeng-Fiema Monkey Sanctuary in Ghana. Three differently sized groups were followed for 13 months and two others were followed for 6 months each in 2004-2005 using focal-animal sampling and ranging scans; ecological plots and phenology surveys were used to determine home-range quality and food availability. There was relatively little difference in home-range quality, monthly food availability, diet, adult female ingestion rates, and rate of travel within food patches between the groups. However, home-range size, day-range length, and percent of time spent feeding all increased with group size. We performed a single large test of the ecological-constraints model by combining several separate Spearman correlations, each testing different predictions under the model, using Fisher's log-likelihood method. It showed that the ecological-constraints model was supported in this study; scramble competition in this population is manifesting in increased ranging and time spent feeding. How costly this increased energy expenditure is for individuals in larger groups remains to be determined.     

湖北石首麋鹿昼间活动时间分配

为探讨性别、年龄和季节对麋鹿(Elaphurus davidianus)行为的影响,2006年9月-2007年10月,作者采用焦点取样法和瞬时记录法,将麋鹿昼间活动归为采食、饮水、运动、休息、警觉、其他行为等六大类型,每月6-8 d对湖北石首麋鹿国家级自然保护区麋鹿种群的昼间活动时间分配进行了跟踪观察.结果表明:麋鹿有晨、昏两个采食高峰和一个午间休息期,各种行为类型所占比例依次是:休息53.40％(±5.59％)、采食22.36(±8.34％)、运动11.23％(±0.63％)、警觉5.03％(±1.76％)、其他行为4.42％(±2.06％),饮水2.65％(±0.74％).不同季节,时间分配变化明显.非参数Kruskal Wallis H检验结果显示(n=120),季节、年龄和性别显著影响麋鹿的活动时间分配.除运动行为(x2=16.856,df=3,P＞0.05)和饮水行为(x2=7.667,df=3,P＞0.05)无显著差异外,采食(x2=15.657,df=3,P＜0.01)、休息(x2=13.173,df=3,P＜0.01)、警觉(x2 =13.887,df=3,P＜0.01)和其他行为(x2=16.317,df=3,P＜0.01)在不同季节所占时间百分比均有极显著差异.对不同性别年龄组的活动时间分配采用两个独立样本的Mann-Whitney U检验,各性别-年龄组间的运动行为所占时间比例有极显著差异(P＜0.01),雄鹿与雌鹿之间的警觉行为有极显著差异(P＜0.01),雄鹿花较多时间用于警觉.幼鹿与成年鹿及亚成年鹿之间的采食行为时间有极显著差异(P＜0.01).不同性别、年龄组在不同季节的昼间活动时间分配的差异采用方差(ANOVA)分析后发现:所有年龄组,夏季与冬季饮水、春季与夏季警觉均存在显著性差异(P＜0.01);成体和亚成体麋鹿,春季与冬季警觉、夏季与冬季运动均存在显著性差异(P＜0.01).     

The effect of social and ecological factors on the time budget of wild vervet monkeys

Animals often have a limited time to perform different fitness‐enhancing activities, such as the trade‐off between socializing versus foraging in group‐living species. Many previous studies have focused on how ecological and social factors influence activity budget at the individual or group level in various species. However, few primate studies have focused on multiple study groups living within a similar habitat. Here, we analyse group, season and sex effects on the individual activity budget of wild vervet monkeys (Chlorocebus pygerythrus) living in four groups with overlapping home ranges. Generally, our findings support previous studies on primates. Our results indicate that intragroup competition may force larger groups to spend more time feeding and less time resting. We also found that seasonal variation, and therefore food availability, has a strong influence on the monkeys’ activity budget. Females, which are the philopatric sex in vervet monkeys, spent more time socializing while, in general, males spent more time resting. However, we did not find any difference on the time spent socializing between groups. Since there is evidence that not only time constraints and habitat quality but also group size influence individual behaviours and ultimately group living, we advise that future studies should focus on multiple groups of the same species living in the same habitat in order to better understand how all these variables are interlinked.     

Enclosure environment affects the activity budgets of captive Japanese macaques (Macaca fuscata)

Individuals adapt to changes in their environment, such as food availability and temperature, by adjusting the amount of time spent in different behavioral activities. These adjustments in behavior should vary across age-sex class according to specific physiological and social needs. We studied the activity budgets of three social Japanese macaque groups inhabiting either vegetated or nonvegetated enclosures in order to compare the effects of access with vegetation, as both food and substrate on resting, feeding, grooming and moving activities over a 12-month period. Daily access to natural foods for monkeys in the vegetated enclosure seems to be largely responsible for the differences in daily time budgets of these three groups. Resting time in all three groups was longer than the time devoted to other activities. Resting and moving time in the two nonvegetated enclosures was significantly longer than in the vegetated enclosure. In contrast, feeding and grooming time was significantly longer in the vegetated enclosure. Seasonal variation in time spent feeding, resting and grooming was significantly effected by enclosure type. In all three enclosures, immatures, particularly females, spent more time feeding and moving, whereas adults spent more time resting. Significant monthly variation in time spent by age-sex class was noted only for feeding and resting. Interestingly, in the vegetated enclosure, time spent feeding on natural vegetation was equal to the amount of time spent feeding on provisioned food. This suggests that factors other than energetic and nutritional needs may be important determinants of the activity budget of the species. These results have important implications for the enrichment of captive primates and our understanding of the maintenance of activity patterns by primates in the wild.     

Scramble Competition Among <Emphasis Type="Italic">Colobus vellerosus</Emphasis> at Boabeng-Fiema,Ghana

We investigated the occurrence of scramble competition among Colobus vellerosus at Boabeng-Fiema, Ghana. If scramble competition had an impact on feeding efficiency among females, we expected a positive relationship between group size and the proportion of time spent feeding, day journey length, or home range size assuming resource availability is similar among the groups compared. We collected focal data on the feeding behavior of adult females and males over 11 mo (September 2000–August 2001) on 2 study groups: WW (n = 31–33 individuals) and B (n = 8–16 individuals). We also collected ranging data on group movements at half-hour intervals. The large group (WW1) had a significantly longer day journey length than the small group (B1), and females in the large group spent a significantly greater proportion of time feeding in the wet season, a period of low food availability, which suggests it may be a bottleneck period when food resources are scarce and Colobus vellerosus is close to being energy limited. The proximity data suggested females may be able to reduce or adjust for competition by having fewer neighbors when they feed and by spreading out when in a larger group. However, we found no relationship between home range size and group size or that females spent a greater proportion of time feeding than adult males did. Our results highlight the need to factor in differences in food availability when investigating scramble competition. Though equivocal, our results suggest scramble competition occurs among Colobus vellerosus, leading us to suggest there was a match with the potential competitive regime, i.e., food distribution.     

Effect of Group Size on Activity Budgets of Colobus vellerosus in Ghana

Group size influences foraging efficiency in several primates. We examined the activity budgets of 3 groups of Geoffroy's pied colobus (Colobus vellerosus) at the Boabeng-Fiema Monkey Sanctuary in Ghana to determine whether larger group size induces scramble competition. We studied 2 groups (B1; N = 7-8 and WW; N = 31-33) occupying slightly overlapping home ranges from August to November 2000. We observed the third group, B2 (N = 15-16), comprising B1 and 7 male invaders in the same home range as B1 from August to November 2001. By comparing groups belonging to the same population and occupying sligthly overlapping or similar home ranges, we were able to control, to a certain extent, for differences in food distribution. We recorded a total of 3353 scans, yielding 14,886 activity records, over 73 days. As with other black-and-white colobus, resting was their most common activity (59%). Intergroup comparisons suggest that time spent feeding, resting and moving did not vary in relation to group size. However, intragroup comparisons between the sexes show that females in the large group spent more time feeding than males did, whereas this was not the case in the small group, which suggests that scramble competition may be occurring among female Colobus vellerosus at BFMS. It is also possible that this may be due to greater nutritional requirements because of a higher proportion of infants in the large group. In fact, the proportion is quite similar between the two groups, lending support to the idea that females in the two groups had comparable nutritional demands due to lactation. This suggests that increased feeding in females in the large group was partly an effect of scramble competition. Group size and group composition also influenced the frequency of social behavior. There was more grooming in the large group, and it was performed mostly by females. The distribution of activities throughout the day was similar to the pattern reported for other black-and-white colobus.     

Costs of Mate Guarding and Opportunistic Mating Among Wild Male Japanese Macaques

A trade-off relationship between mating and feeding effort is important when considering reproductive strategies of long-lived species. I compared the influence of male sexual activities, female mate-choice behaviors and the daily activity budget on male mating success among males in a group of wild Japanese macaques (Macaca fuscata yakui) on Yakushima Island. The 1st-ranking male, which had immigrated into the troop at this rank, more frequently approached peri-ovulatory females, spent more time grooming peri-ovulatory females and in mounting series and spent less time feeding than subordinate males did. The 1st-ranking male attained the highest mating success as a result of his high expenditure of time and energy in sexual behaviors directed toward peri-ovulatory females. Mating success of subordinate males did not relate to the amount of sexual effort, but instead to the frequency of female approaches, female rush toward males and the number of peri-ovulatory females within the group. The pattern of intermale competition shifted from nearly contest competition to scramble competition as the number of peri-ovulatory females in the group increased. Feeding time of subordinate males did not vary between the days when they copulated and the days when they did not. The findings demonstrate that mate guarding in the 1st-ranking male is a high-cost mating tactic, while opportunistic mating in subordinate males is a low-cost mating tactic. The differences in male mating tactics are probably related to male life history and to the formation of groups with a high socionomic sex ratio.     

Interference competition and group size effect in sika deer (<Emphasis Type="Italic">Cervus nippon</Emphasis>) at salt licks

Competition has long been considered as a confounding factor of group size effect but the understanding of interference competition is rudimentary for the difficulty in disentangling interference competition from scramble competition adequately. Here, we analysed remote-camera video records of wild sika deer (Cervus nippon) at salt licks in southern China from March 1, 2006 to November 30, 2008 to investigate how interference competition and predation risk interacted on vigilance behaviour. Scramble competition is negligible at salt licks; therefore, we could focus our interest in interference competition. We used linear mixed model to compare vigilance, licking and aggression behaviours among females with and without fawn as well as males with different group sizes to identify the primary role of vigilance behaviour in sika deer. In total, 168 individuals were recorded and observation time was 2,733.04 min. We found that deer spent much time on vigilance and scanned frequently in spring and winter, and females with fawn spent more time on vigilance than females without fawn, suggesting vigilance for predation risk. Aggression ratio increased first and then decreased, while scan frequency continued to decline and then slightly increased when group size increased from two to seven, implying vigilance for interference competition. Our results suggested vigilance in sika deer was influenced by both predation risk and interference competition, but was mainly driven by predation risk even at sites with intense interference competition. Our results of interference competition shed some light on finding the underlying mechanism of group size effect in wild populations.