Here's the raw truth: we know so little about our very own human history - when you consider it as a whole, not just the last two thousand years or so - and even less about the evolution of the human species itself. What did our ancestors look like, and how did they live?

Sometime in the deep past, one or more hominid species started down an evolutionary path that would eventually lead to us: how exactly did that happen? Now, a recent piece of research on hungry orangutans has contributed something to the discussion.

According to the study carried out by anthropologist Nathaniel Dominy and his colleagues, the island of Borneo is not an easy place to live in. Borneo's land is not particularly reliable: seeds rarely ever germinate when they're expected to, trees can go up to five years without producing fruit, and they all tend to go on strike at the same time. For the orangutans, this means long periods of forced abstinence.

Being the smart creatures they are, orangutans know to tighten their metaphorical belts when the lean years come around. In other words, they eat whatever they can find - even hard seeds and the starch-rich tissues beneath tree bark. In this way, they obtain enough protein to avoid excessively depleting their body fat reserves (or they could, if Borneo's forests weren't quickly vanishing due to unchecked logging and land clearing). For added efficiency during the lean season, the orangutans have evolved large molars and strong jaws, two adaptations that are unnecessary in the case of their customary soft, juicy diet, but crucial when it comes to the tough foods they consume in times of scarcity.

Given the resemblance between the teeth of pre-human apes and those of modern orangutans, it's possible that a similar logic can apply to the evolutionary history of hominids. Our ancestors' teeth appear to have developed in order to adequately process hard foods, but maybe these didn't constitute a large part of their diet, nor a frequently exploited resource.

Further research is needed on this subject, of course - but if the comparison with the orangutans is valid, we need to fundamentally rethink our ideas on hominid subsistence patterns as well as their ability to adapt and evolve. The full study was published online, in The Royal Society journal Biology Letters.