內布拉斯加州林肯兒童動物園中的白頸狐猴（Varecia variegata）正在窺視鏡頭。PHOTOGRAPH BY JOEL SARTORE, NATIONAL GEOGRAPHIC PHOTO ARK

伊利諾州布隆明頓的米勒動物公園中呆愣的紅領狐猴。PHOTOGRAPH BY JOEL SARTORE, NATIONAL GEOGRAPHIC PHOTO ARK