#1. Who said they didn't?
There's plenty of "anomalous" finds. No proof, hardly
compelling evidence but some evidence just the
same. Erectus may have reached the Americas. Maybe
not.
#2. Define "Reaching the Americas"
If a single toe from a single erectus touched shore on
the Americas, does that count? I would think not. I
would think that be "erectus in the Americas" it's
meant that a sustained population existed for, I dunno,
some generations? But given how massive the expanse
that is the Americas -- north & south -- and the major
changes to the topography, would we even find them?
We find Clovis points, right? But what of the Clovis people?
https://news.ku.dk/all_news/2014/02/americas-only-clovis-skeleton-had-its-genome-mapped/
So even if erectus did reach the Americas we wouldn't
find per se, we'd only find tools they have left behind,
and this brings us back to point #1, above, because
there are anomalous finds that are claimed to be within
the age range necessary for erectus...
#3. Erectus wasn't cold-adapted
Erectus seems to be a tropical or very-near-tropical
people. We don't find them in Germany or the U.K.
at all, now do we? Their European adventures seem
to be limited to the southeast -- warmer Mediterranean
climates. Heidelberg man or "Antecessor" had to
evolve before they could start spreading north.
Maybe they lacked protected clothing?
Let's face it, if you're diving underwater then animal
skins are going to weigh you down. And even if they
didn't, frigid waters are NOT what you're going to want
to be diving into...
Homo erectus likely had very different mtDNA, a
lineage that wasn't producing the energy (warmth) it
needed to help them tolerate the cold.
This would not stop erectus from thriving in many
parts of the Americas, where it would be plenty warm
enough, but they'd have to reach them first. The route
through Siberia would certainly be out of the question.
Direct routes across the sea would be so difficult that
we could rule out anything other than accidental.. which
is NOT a good model for a sustained population at all.
In summation: Homo erectus didn't reach the Americas
because they were not cold adapted, and thus the only
routes open to them were not conducive to enough
individuals collecting in one area at one time to form a
breeding population.
::Discuss::
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https://jtem.tumblr.com/post/679904370902679552