These solitary and placid creatures are frugivores and spend their time foraging in the trees for the fruits that are in season. The fruits can be quite scarce therefore it makes sense for the orangutan to travel alone or in small groups. When there is an abundance of food they have been known to eat and travel together over a few days. They are known as gardeners of the forest as they drop the seeds from their meals over different areas, these seeds are then spread as they travel. Fruit availability has a huge impact on all aspects of their wellbeing, including their health, social and reproductive behaviour and their ranging patterns due the seasonal fruits. Over 500 plant species have been recorded in their diet! They can also eat insects and palm stems, sometimes even tree bark.
They are an important part of the forest biodiversity and they also need the trees to move through and to use to make their nests every day. They make these bowl like nests most evenings, by twisting branches and leaves and making the nest in to a comfy seat. You may have seen photos of orangutan cleverly shielding themselves from the rain with large branches, much like we would with an umbrella. They spend their day foraging for food and finding a place to sleep. They tend to go through the smaller trees in the middle canopy and this saves energy, they are rather large and cannot swing through the branches like a gibbon does!
The orangutan males have a very distinctive long call that they use to attract females to them. This is also to warn other male orangutan who might be trying to encroach on their territory. Another sound commonly heard is the kiss squeak. This is usually made when an orangutan is agitated or nervous, and might be accompanied by the breaking and throwing of branches down on to the offending person! The babies make a whiny sound when moved from their mother and can scream hysterically if away from her for too long.