And, of course, they are all extinct - except us - why? Brains or braun? Time or unforeseen occurence.?.or bloody murder?
I reckon it might have been disease. Or something us humans were able to tolerate that our cousins just wern't. Like if we had no knowledge of fire and we all started eating raw meat. We'd quickly get sick and a lot of us would perish. The meat eating animals however would be fine. Something may have happened the other way round, disease, parasites, change in climate... who knows?