Orangutans as a model for humans

Source: nu.nl
Orangutan teeth and molars strongly resemble those of our ancestors. Researchers say we need to understand orangutan diets in order to comprehend how our own teeth have developed.
A group of evolutionary anthropologists from Dartmouth College (USA) studied the orangutans on Borneo for five years. Their results were published this week in the online journal Biology Letters.

The study focused on the orangutans’ diet and how they digest their food, especially the way the orangs cope with scarcity in their food supply. Unfertile soil and a harsh environment result in frequent food scarcity on Borneo. Trees bear fruit only once every few years, and then all at once. In those years, the apes gorge themselves on fruit, thus storing up calories in fat reserves. In the lean years, the animals’ ration consists of hard seeds and starchy tissues from trees.

Orangutans on Borneo were separated from others of their species about 400,000 years ago. The selective pressure of eating hard foods has led to the development of larger molars and more powerful jaws than orangs elsewhere.

Study of wear patterns of early hominid molars revealed that these early ancestors frequently ate hard foods as well. The comparison with orangutans can teach us more about how early hominids coped with food scarcity and about adaptations that helped them to survive. For evolution, say the researchers, it’s not so important what the regular diet was. The lean times are much more interesting.