The orang utans have become almost synonymous with the Singapore Zoo, led by Ah Meng, the Sumatran orang utan which was confiscated in 1971 from a Chinese family (which had illegally kept her as a pet) and subsequently found her home in the zoo. She soon became a celebrity, both locally and internationally, hosting the famous 'Breakfast with an Orang Utan' programme of the zoo. She has been featured in over 30 travel films and 'interviewed' by more than 300 writers. In 1992, Ah Meng received a special award from the Singapore Tourism Promotion Board, in recognition of her contribution towards tourism in Singapore.

Today, the Singapore Zoo displays a large social group of 24 orang utans in a spacious naturalistic enclosure. The zoo has bred a total of 33 orang utans to-date. Ah Meng alone has borne five children in the zoo, and she also became a grandmother in 1990.

Orang utans are arboreal mammals who spent most part of their lives eating, sleeping and travelling in the trees. They feed on fruits, leaves, seeds, bark and insects of the rainforest. There are two species of orang utans, namely the Bornean and the Sumatran. The Sumatran orang utan has a longer face, and lighter, longer hair. The males also develop longer beards. Conversely, the Sumatran has a rounder face and darker, shorter hair. The males have shorter beards. Generally, the hair colour varies from dark orange to brown or maroon. Currently, the population of Bornean orang utans in the world is estimated at 55000, and they are classified as an endangered species. Their counterpart, the Sumatran orang utans, are even more critically endangered, with an estimated population of only 7500 left in the wild.