Stars and Us...

So, it's out there, but apparently a cluster of local supernovas may be responsible for us walking upright (and everything that brought).

The supernovae caused an increase in certain kinds of ionizing radiation between 8 million and 2.6 million years ago.

This in turn caused an increase in forest fires in Africa, and in many places the forests never came back, leaving our ancestors forced to learn to live in the savannah. Standing upright (look at meerkats) is how you see over tall grasses...

Because the universe is weirdly interconnected.