A pair of month-old Sumatran tiger twins have become inseparable playmates with a set of young orangutans, an unthinkable match in their natural jungle habitat in Indonesia's tropical rainforests. The friendship between 5-month-old female baby primates Nia and Irma, and cubs Dema and Manis, has blossomed at the Taman Safari zoo where they share a room in the nursery. After being abandoned by their mothers shortly after birth, the four play fight, nipping and teasing each other, and cuddling up for a shared nap when they are worn out. "This is unusual and would never happen in the wild," said zoo keeper Sri Suwarni, bottle-feeding a baby chimp on Wednesday. "Like human babies, they only want to play." The four have lived side-by-side for a month without a single act of hostility, she said.