It is always explained to me that men used to hunt and women used to gather but how do we know that this always happened like this? Are there any examples of male gatherers or female hunters? How can we be certain that this never occured? I could for example see a benefit in older or less fit men being gatherers. A combination of both could also benefit the population. ( for example a women spotting a rabbit while picking berries )
While there is overlap of posters, this is more of a pre-history question, so you would be well served X-posting to /r/AskAnthropology as well!