I think the number of species kept at Zoorasia is appropriate. A modern and naturalistic zoo without a large number of animals being squashed up in small cages or odd-looking ‘experimental’ exhibits, was the whole concept of ‘Yokohama’s new zoo’.
Ueno Zoo keep more than 500 species, whereas Zoorasia keep only just a little more than a 100, in a land four times as large as Ueno’s. I think the greenery and the valley serve fine as places for visitors to rest, also providing plenty of oxygen to the animals. Therefore, there is no need to utilise that area to introduce new animals.
Although Zoorasia’s collection is not huge, most of the exhibits are well-organised and the animals have enough space to show their real nature.
Zoos do not exist just for humans. I think Zoorasia’s collection size is fine as it is.