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。
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。
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.