各地都有不同的圈養繁殖計劃，但最近的一項研究發現，一些圈養繁殖的動物在身體或行為上出現變化，放歸野外後可能會減低牠們的生存機會。 例如，圈養獅子的頭骨形狀與野生的不同，咬合力較弱； 圈養帝王蝶的翅膀形狀有變異，而且無法辨別南方； 圈養繁殖的雄性攝政吸蜜鳥的歌聲變得較短，相信更難吸引到雌性。
There are different captive-breeding programs around the world, but a recent study found that some animals bred in captivity developed physical and behavioral changes and might harm their survival chance after released into the wild. For example, captive-bred lions have different skull bone shape with weaker bite force; monarch butterflies in captivity have different wing shapes and unable to posit south; captive-bred male regent honeyeaters’ songs are shorter and less attractive to females.
