How big should animal enclosures be?

The size of an animal enclosure should be in accordance with the need for movement and the social behaviour of that animal. For instance, social animals like chimpanzees should never be kept alone. Apes tend to grow depressed if they do not get enough mental and physical stimulation. Such measures are not that important for habitual loners like the lion that spends most of its day dozing. Also, lions do not require a lot of space because they do not hunt in the zoo. In contrast, animals like zebras, which like to move around in herds, need large areas for running and grazing. Animal enclosures must be designed in a way so that visitors can see the animals clearly.