The best I can come up with is a dual answer - a search for better living conditions, i.e. better food sources, and/or some innate drive for variety, exploration, investigation. Because not everyone did migrate from Africa, there must have been something different about those who did. Maybe they were drawn to new areas out of a developing curiosity, a nascent interest in new things. It would seem that aside from a need to feed and protect the tribe or family, there must have been some inner drive to explore new areas among those who did move away. What are some current ideas on WHY our ancestors migrated all over the globe, or at least out of Africa, while others stayed behind?
Pretty much all animal migrations ultimately come down to competition for food sources, or externalities (natural disasters, new predation, etc.).
Well, in the historical period, migration has most commonly resulted from changes in the availability of resources, unsupportable population growth, and warfare, with those holding control over resources and military power the most likely to stay put.
I think you are picturing migration happening in a faster and more purposeful way than it actually did. Migration out of Africa likely happened over many thousands of generations. It could have been as simple as a tribe ranging only a few miles further north in a decade, and over many hundreds or thousands of years they end up in the Middle East. Groups of people may have been following animal migration, climate changes, or distribution of plant life. If one group goes north to find more tubers and another group goes south, it doesn’t mean the north-going group was somehow more intelligent or industrious.
A lot of it is just kind of random drift, not conscious, destination-oriented “migration,” just tribes rambling further out from more populated areas over the generations.
A tribe reaches a place with a certain amount of resources. Its population expands until the level of resources no longer suffices. To avoid starvation, part of the tribe wanders a few miles until they reach a place where there aren’t any humans. Repeat for 100,000 years.
Right, it wasn’t a group or series of groups “leaving” Africa, it was populations just ending up there after generations and generations of drift.
It should be noted that they probably came from somewhere in or around modern Kenya. That means they had farther to go to colonize the rest of Africa than they did to leave it.
Plus, at some point, they’d have found the Nile, and their drift would have followed that, which would naturally have taken them very close to the Sinai Peninsula.
If they’d started out in, say, modern-day Liberia, it might have taken dozens of millennia longer for them to reach northern Europe, eastern Asia, and the Americas.
The people whose ancestors move furthest (over many thousands of years) were the Tierra del Fuegans and the Tasmanian Aborigines. What did they have in common? Well, it turned out that they became relatively isolated from the main centres of innovation and invention, so when they were discovered by Europeans, they had relatively primitive technology.
As the last few posters have pointed out, “migration” is probably a misnomer for what actually happened. Migration implies a directional movement toward (or away) from a specific area. It’s better to view the movements of early humans as dispersal, or a spreading out.
To avoid competition for resources with other humans, a band of humans is likely to move just far enough so that they are out of the foraging range of other bands. They usually don’t want to move completely out of contact, because they probably have kin in other bands and also want to maintain trade and social bonds. So that any movements are likely to have been only a few dozen miles per generation at most. They are unlikely to have been over hundreds or thousands of miles.
In terms of overall migration rates, humans moved thousands of miles over tens of thousands of years. That’s actually pretty slow most estimates of migration rates are in the ballpark of a mile per year. You could imagine that some tribe moves a few tens of miles towards better conditions, once every generation.
According to “Before the Dawn” by Wade, genetic research shows that our ancestors migrated out of Africa by crossing the Red Sea/Gulf of Aden and establishing colonies along the coast. Over thousands of years they expanded east as the population in a given colony would expand until a group of people would break off to establish a new colony. Eventually they reached India, China, the Phillipines, Australia. These coastal colonies had to compete with established neaderthals and other early primitives - but obviously in all areas they were able to ‘push’ inward and eventually take over. It took a long time.
They left Africa, likely near Ethiopia/Eritrea/Somalia, probably because the crossing to the Arabian peninsula is doable in simple watercraft. There are some islands to hop to as well. I would guess they were fishing based communities and were headed somewhere where the current inhabitants where either non-existant/few or less advanced and able to be pushed aside.
neanderthals were already there??? If you’re talking about pioneer populations, there wouldn’t already be neanderthals there, now, would there? Besides, I thought neanderthals were a European species.
The current inhabitants were non-existent? This line of thinking reminds me of a classic student remark: “It’s so cold in certain parts of Alaska that the inhabitants have to live elsewhere.”
From this chart off wiki: We are not descended from neanderthals. Neanderthals came a little earlier - had much of Europe settled - but we’re wiped out by competition from Homo Sapiens that originated in Africa.
Pioneers usually don’t come upon uninhabited land.
The OP didn’t specify which ancestors. Some of our ancestors were the first to leave Africa.
The relationship between Neanderthal and other hominids is still in question. And we weren’t wiped out, we just maintain a low profile.
It’s not clear from the OP what you mean by “our” ancestors, whether the first modern humans (Homo sapiens) to leave Africa, or earlier populations.
The earliest human species to leave Africa has long been thought to have been Homo erectus. However, some recent discoveries, including the archaic features of the “hobbits” of Indonesia (Homo floresensis), suggest that their were earlier ones.
The range of Neanderthals included the Middle East as well as Europe. The first modern humans to leave Africa would have found Neanderthals already there.
However, some recent research indicates that some of the genes of modern non-African populations are of Neanderthal origin, implying that there was some interbreeding.
People simply like to wander. It is what we tend to do.
It’s getting too damned crowded around here. Urk, Grawk, Thag - get your shit, we’re moving to the suburbs.
To explore strange new continents. To seek out new food, and start new civilizations. To boldly go where no proto-man had gone before.