What Drove Homo Erectus Out of Africa? (2021)

Nomads did not traveled for the fun of it. They moved either because of business - buys stuff here, move over there and sell them. Or because of environment - the sheep have better environment here in summer and over there in winter. And places where we could stay all the time are already taken and they guard them, so we have to move.

When nomads find a place where they can settle stably, they overtime tend to stay.

Were they nomads? I'm not sure that there is too much evidence for that, is there?

Intra-species competition would also have been my first guess. Homo erectus seems to have been quite a successful species, given the archeological evidence. And given the time frame of the migration, I'm betting on a slow but steady expansion as the families and tribes grew larger and split to explore new territories.

I wouldn’t expect them to study that. This article is about second-order change in population density coinciding with the rate of environmental change.