The Orang Utan: Solitude and size
Female Orang Utans are about half the size of their mates but they too are solitary animals and travel through the forest accompanied only by their young. This preference for solitude may well be connected with their size. Orang Utans are fruit-eaters, and being so big have to find considerable quantities of it every day to sustain themselves. Fruiting trees, however, are uncommon and widely scattered through the forest, at widely varying intervals. Some only bear fruit once every twenty-five years. Others do so almost continuously for about a century but only on one branch at a time. Yet others have no regular pattern and are triggered irregularly by a particular change in the weather such as the sudden drop in temperature that proceeds a heavy thunder storm. Even when they do produce fruit, it may only be on the tree for a week or so before it becomes over-ripe, falls or is exploited. So the Orang Utans have to make long journeys, continually searching, and may well find it more profitable to keep their discoveries to themselves.