A black bear is seen in Beijing Zoo.(File photo)

In order to promote animal welfare, Beijing Zoo has launched a massive environmental enrichment movement by constructing additional infrastructure.

Most facilities have completed early stage plans, according to local newspaper Mirror on Friday. One highlight is that "Animals have the right to be seen as well as not to be seen" in the words of a zoo official.

In addition to freedom from hunger and thirst, freedom from discomfort, freedom from pain, injury, and disease, as well as freedom from fear and distress, animals should also have the freedom to express normal behavior, which, according to the official, is a tricky one.

To make takins, who are expert jumpers and climbers, feel more at home, zoo keepers connect the roof and floor with wooden ladders to simulate the animal's natural home in the mountainous Himalayas.

Bears used to be housed in open air enclosures and were vulnerable to visitors feeding them unregulated food. Now a glass wall has been erected, so nothing can be thrown at them.

In order to stimulate a lion's hunting nature, zoo keepers offer them ball-shaped toys made of grass, which contain droppings from herbivores they would hunt in the wild.

Animals easily become distressed after prolonged confinement in the unnatural settings of a zoo. An environmental enrichment movement aims to add "natural elements" to animal enclosures to incite the animal's natural instinct.

Beijing zoo is continuing to add animals while allowing them the freedom to "not to be seen". The plan is so effective that some unknowing tourists have even been "tricked" into complaining that the zoo has fewer animals than previously.