"among placental mammals this species-wide premature birth situation
is unique, I believe."
I put that very poorly indeed! I think what I was thinking at the time
was just wrong. There certainly aren't any other species with so slow
a ramp up from birth to the first stages of autonomy, but there
certainly are placental mammals born with a level of immaturity
similar to humans. I was thinking of the former, but expressed
something contrary, on the face of it, to the latter.