圈養台灣黑熊幼獸行為發展及親子關係

外文標題: 
Infant Behavioral Development and Mother-Young Relationship of Captive Formosan Black Bears (Ursus thibetanus formosanus)
校院系所: 
屏東科技大學野生動物保育研究所
指導教授: 
黃美秀
出版年份: 
2007年
主題類別: 
摘要: 

台灣黑熊(Ursus thibetanus formosanus)為晚熟型物種,親代照顧對於幼熊的生長發育及行為發展有重要影響。本研究旨在瞭解圈養台灣黑熊母子於幼熊1歲之前的幼熊成長發育,以及親子行為隨年齡的變化。本研究針對1對壽山動物園及2對特有生物保育研究中心的黑熊親子,利用監視數位錄影系統與現場觀察的方式記錄24小時行為模式,共取樣145天。
幼熊於1月齡眼睛張開,1.5至2月齡能爬行,2月齡之後可以行走,母熊在2月齡之前亦較少離巢,親子日活動程度在2月齡之前均最低,之後逐漸上升。在幼熊1歲之前,不活動與遊戲佔親子一天時間比例的最多與次之,在母熊分別是77.7%與5.7%,幼熊的不活動與遊戲則是67.3%與13.6%。親子以日行性為主,但晨昏時段活動稍高,母熊日、夜間活動比例分別為37.6%與8.6%,幼熊日、夜間活動比例53.2%與14.2%。親子身體接觸的互動比例在5-6月齡之前均高50%,由此可看出在5-6月齡之前親子間關係似乎較親密。
1歲齡之前親子平均每天哺乳次數8.8(±2.7)次,每天哺乳時間42.9(±11.3)分鐘。親子每天哺乳次數與總時間呈現前(<4月齡)、後期(9-12月齡)高,中間期(5-8月齡)偏低的趨勢。後期哺乳時間與次數較中期高,推測受飼糧所限,幼熊轉向母熊索取能量來源—乳汁、食物—的機會隨之增加,如此也引發了親子之間的衝突,因為進食而引發的親子敵對行為,以及母熊對幼熊索奶的敵對反應,均隨幼熊年齡而有增加的趨勢。
單胎、雙胎的每天哺乳次數與時間並沒有顯著差異,然雙胎的遊戲或與其他熊遊戲的日出現頻度(20.1%,15%)皆較單胎高(17.3%,9.6%);雙胎幼熊相互遊戲的頻度(7.7%),明顯高於幼熊與母熊之間遊戲(2.2%)。雙胎親子間的身體接觸顯著高於單胎(64.4% vs. 49.7%),單胎親子的無互動佔47.8%顯著高於雙胞胎的19.3%,可看出雙胎親子關係較單胎親子密切。
圈養黑熊親子對於其他成熊叫聲的反應程度與吼叫音量皆有顯著正相關,顯示面對潛在威脅壓力時,親子會出現不同程度防禦或躲避的本能反應。黑熊親子於於飼糧供給量較多、環境大且豐富的親子,進食時間比例較高,期待餵食及母熊刻板行為的時間比例均較低。於24小時活動模式上,親子上、下午均各有一活動高峰,但在圈養環境豐富、空間較大且無門禁的個體,上午活動高峰較早出現。本研究顯示黑熊親子行為及互動受圈養環境及管理方式影響。

外文摘要: 

Formosan black bear (Ursus thibetanus formosanus) cubs are late-maturing, making maternal care important for cub growth and behavioral development. My objective was to document cub growth and the mother-young relationship in captive Formosan black bears during the first year of cubs’ lives. I videotaped and made on-sight observations of one and two pairs of mother-cubs, for a total of 145 24-hr observation days, at the Shoushan Zoo and the low altitude experimental station of the Endemic Species Research Institute, respectively.
Bear cubs started to open their eyes at one-month old, crawl at 1.5-2 months and walk after two months old. Mothers seldom left dens until cubs were two months old. Both mothers and cubs were very inactive in the first two months, and then their daily active proportion increased over time. For both mothers and cubs, inactivity and play accounted for the largest (77.7% vs. 67.3%) and the second (5.7% vs. 13.6%) proportions of the daily activity budget, respectively. Both mothers and cubs were mainly diurnal, with activities peaked at dawn and dusk. Activity levels of mothers during daytime and nighttime were 37.6% and 8.6%, respectively, and those of cubs were 53.2% and 14.2%. Mother-cub body contacts were >50% during the first six months of a cub’s life, indicating an intimate relationship between them during this period.
The daily average nursing bouts of bears were 8.8 (±2.7) for a total of 42.9 (±11.3) minutes. Daily nursing bouts and time were greater when cubs were 3-4 and 9-12 months old than 5-8 months old. This might be related to restricted supply of artificial food during the 9-12 month period, which may drive cubs to demand more food and milk from their mothers. Both feeding-related mother-cub agonistic behaviors and mother agonistic reactions toward cub’s begging for milk increased with cub’s age. The parent-offspring conflict was therefore asserted.
There were no significant differences in daily nursing bouts and time between the single cub and the twin. However, the twin spent more of each day playing and playing with other bears (20.1% and 15%, respectively) than the single cub did (17.3% and 9.6%, respectively). Besides, the twin played more with siblings (7.7%) than with their mother (2.2%). The single cub had less body contact (49.7%) and more no-reaction (47.8%) with the mother than the twin (64.4% and 19.3%, respectively), indicating a more intimate mother-cub relationship for twins than for single cubs.
Mothers and cubs showed different levels of defence or avoidance when facing potential threats, indicated by other adult bear’s vocalizations. The mother and cub kept in environmentally more complex and larger space provided with more food spent more time foraging, and less time in feeding anticipation and stereotypes. Additionally, bears kept in spatially richer environment and without a curfew started their activities earlier in the morning. My study suggested that both mother and cub behaviors and their interaction were affected by physical environment and management.