Mechanismfeeding figure

Physiology of feeding

Orangutans prefer to eat fleshy fruit. However, fruit is only available part of the year with a certain level of annual variation (mast fruiting years are difficult to predict, but are significant in determining feeding behavior). As a result, orangutans alter the time spent feeding in relation to fruit availability and appear have developed highly efficient mechanisms of energy storage (5). The figure to the right represents time spent feeding in male and female orangutans.

Storing Fat

In times of energy stress, when fruit is no longer available, orangutans rely on fat storage. In captivity, orangutans have higher rates of obesity than other great apes (10). Although the detailed mechanism of orangutan energy storage has not been investigated, the results from captivity suggest orangutans have a more efficient storage system than other apes.Wild Feeding

Feeding and Reproducing

Variation in feeding and energy intake, in turn, effects hormone levels throught the year, and may determine when orangutans engage in reproductive behavior. It is common in many primates (including humans) to reproduce only when there is sufficient energy stored internally.