台灣獼猴(Macaca cyclopis)競爭人類餵食食物之模式-位階、食物區塊大小及品質之影響

食物豐富度、聚散程度，以及品質等因素，影響非人靈長類動物群體中的個體是否能同時食用該食物資源，以及覓食競爭的強度及形式，而群內覓食競爭被認為是形塑雌性個體間社會關係的重要因素，進而影響不同個體獲取之食物量。台灣近年來餵食獼猴風氣盛行，民眾所餵食食物之食物量較天然食物少，但具有較高熱量及分布較聚集之特性，可能會加劇猴群內的覓食競爭，使不同位階個體獲取食物量有所落差。本研究於2020年6月至2021年5月期間，觀察雲林縣林內鄉林北村接受人類餵食猴群之行為，選取猴群中高位階和低位階母猴各六隻，作為行為觀察對象，以特定行為取樣法(behavior sampling)及掃瞄取樣法(scan sampling)收集不同位階母猴進食餵食食物行為、進食期間發生之敵意互動，及活動模式資料，以檢視不同位階台灣獼猴競爭人類餵食食物之模式，以及面對餵食食物所採取之覓食策略。研究結果顯示，母猴在小型食物區塊進食直接餵食食物之時間長度與母猴位階、進食期間發生之敵意互動頻率、食物品質及餵食事件持續時間有關，當進食期間所發生之敵意互動頻率越高，母猴進食時間則越短，且在這樣的取食過程中，高位階母猴之進食時間顯著高於低位階母猴。而在大型食物區塊內，母猴進食直接餵食食物之時間長度與母猴位階和進食期間發生之敵意互動無關，但是當餵食事件持續時間越長，母猴進食時間也隨之增加。無論在小型或大型食物區塊內，高位階母猴進食直接餵食食物之時間長度均高於低位階母猴，而猴群進食高品質且聚集分布的餵食食物時發生之敵意互動頻率最高，且高位階母猴會比低位階母猴更頻繁發起敵意行為，以獨佔該類食物區塊。由此可知，人類分散餵食食物所形成之區塊大小對台灣獼猴食物競爭具有重要影響，母猴在小型食物區塊內具有掠奪式競爭，但在大型食物區塊內並未出現掠奪式競爭，高位階母猴獨佔小食物區塊的高品質餵食食物。相較於直接餵食的食物，被棄置食物的量較大且較分散，猴群會在一天內多次取食棄置的食物，且猴群在取食棄置食物時發生的敵意互動頻率較取食直接餵食食物時低。在低位階母猴進食餵食食物的總時間當中，進食食物量較多且低競爭性之棄置食物的時間比例高於直接餵食食物，且在進食天然食物資源的時間比例也相對較高位階母猴高，推論低位階母猴得以在食物量較多而發生敵意互動競爭頻率較低之區塊進食較長時間，以此覓食策略來彌補在覓食競爭中的劣勢。

關鍵字

食物競爭；餵食；覓食策略；敵意互動；社會優勢位序

並列摘要

Food abundance, patch size and quality are associated with within-group feeding competition in non-human primates that shape the social relationship among females in the group. Feeding macaques had risen in Taiwan in recent years. Macaques-groups feeding on provisioned foods may experience intensifying food competition and great disparity of foods among group members resulting from the clumped distribution of the high calories, but less abundant provisioned foods. Therefore, I conducted behavior observation on a Taiwanese macaque group at the Linnei area in Yunlin county, in order to investigate the pattern of feeding competition and feeding strategy of the adult females of different social ranks which primarily fed on provisioning foods. From June 2020 to May 2021, I recorded data on feeding behavior, agonistic interaction over provisioned foods with different quality and distribution, as well as all-day activity from 12 adult females by using behavior sampling and scan sampling. The results showed that the feeding time of female macaques on food handouts distributed in small patches was significantly associated with the social dominance rank, agonistic interaction over food, food quality and duration of the provisioning event. When the rate of agonistic interaction over food handouts distributed in small patches increased, feeding time of the female macaques decreased, over which high-ranked females spent more time feeding than low-ranked females. The highest rate of agonistic interactions occurred among the group members over the high-quality provisioned foods distributed in small patches, over which the high-ranked females initiated agonism to monopolize the food patch. These results suggested that the female Taiwanese macaques contested over provisioned foods that were distributed in small patch size. The high-ranked females managed to monopolize the high-quality provisioning foods within small patches by initiating agonism toward other group members. Deposited food to feed macaques was in a relatively great abundance and less clumped distributed compared to food handouts. The macaque group may feed on the deposited food for more than one round within a day, over which lower agonism rates occurred among the group members compared to that over food handouts. The results also suggested that the low-ranked females would allocate more time on consuming more abundant and less competitive deposited food, in order to compensate for their disadvantage on competing for high-quality food handouts that were distributed in small patches.