Assessments of the welfare status of captive and semi-captive animals often compare how their expression of natural behaviours differs from that of free-ranging conspecifics. Bukit Merah Orang Utan Island (BMOUI) is the only orangutan rehabilitation and conservation centre in the Malay Peninsula. We recorded and analyzed the activity budget and postural behaviours of orangutans moving freely in the enclosures on BMOUI to evaluate their welfare status. From December 2015 to December 2016, we observed three individuals: an adult male, an adult female and a subadult male, and collected 252 hours of focal data (84 hr/individual). Their activity budget was dominated by resting (60%), feeding (13%), playing (14%) and moving (9%). The study individuals heavily relied on the artificial foods (79.2%), and they spent majority of their time on the ground (85.1%) with occasional arboreal observations like using the wooden tree platform or a rope. Despite some significant individual differences, behavioural categories followed a similar trend: resting > feeding > moving > playing, except that the subadult male spent significantly more time playing (35%) than the two adults (3-4%). The most predominant posture was sitting (47.0%), followed by pronograde standing (29.4%), lying (10.5%) and clinging (4.5%). Our results suggest that orangutans on BMOUI engage in less feeding but more resting, and show less postural diversity, than free-ranging individuals. We propose that appropriate interventions to shift activity budgets, especially feeding vs. resting, and postural behaviours of captive orangutans towards those found in free-ranging orangutans might be beneficial for their welfare and survival; however, the conclusions we can draw are limited due to the small sample size, and thus until the captive behaviours of a larger number of orangutans has been described, these results must be considered preliminary and just a case study.

中文翻译：

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武吉美拉红毛猩猩岛上猩猩评估圈养大猩猩福利的活动预算和姿势行为

对圈养和半圈养动物的福利状况进行评估时，通常会比较它们的自然行为表达与自由放养的物种之间的区别。武吉美拉红毛猩猩岛（BMOUI）是马来半岛唯一的猩猩康复和保护中心。我们记录并分析了在BMOUI上围墙中自由活动的猩猩的活动预算和姿势行为，以评估其福利状况。从2015年12月到2016年12月，我们观察了三个人：一个成年男性，一个成年女性和一个亚成年男性，并收集了252小时的焦点数据（84小时/个人）。他们的活动预算主要由休息（60％），进食（13％），游戏（14％）和移动（9％）决定。这项研究的个体严重依赖人造食品（占79.2％），他们将大部分时间都花在了地面上（85。1％），偶尔会观察树木的树木，例如使用木制平台或绳索。尽管个体之间存在显着差异，但行为类别也遵循类似的趋势：休息>进食>移动>玩耍，不同的是，成年男性比两个成年人（3-4％）花费更多的时间（35％）。最主要的姿势是坐着（47.0％），其次是笔直站立（29.4％），躺着（10.5％）和紧贴（4.5％）。我们的研究结果表明，与自由放养的个体相比，BMOUI上的猩猩从事较少的觅食，但更多的休息，并且表现出较少的体态多样性。我们建议采取适当的干预措施来改变活动预算，尤其是进食与休息，将圈养猩猩的姿势行为转向自由放养的猩猩中的行为，可能对其福利和生存有利；