In addition, the pendulous laryngeal sac, when inflated, increases the resonant tone of the voice. Excellent binocular vision. Their ability to brachiate and even hang upside-down enables them to retrieve fruit. When on the ground, they walk on all four limbs, using the knuckle pads on the back of the digits on the hands. Less social than the other apes.
Mature males appear to be totally intolerant of each other.
They tend to be quiet, relatively shy and spend most of the day eating and resting. They can solve problems related to arboreal travel and food processing, trained to perform tricks and communicate with sign language to ask for items of interest, such as food and contact. Comments about the orangutans of the Fort Worth Zoo. The current orangutans are from Indonesia. For more clarification, a hybrid orangutan's DNA is the makeup of both a Bornean and Sumatran orangutan's genes.