“In particular, the Neanderthal DNA that associates with chronotype consistently increases propensity to be a morning person.” Tony Capra, associate professor of epidemiology and biostatistics in the Bakar Computational Health Sciences Institute, University of California, San Francisco

 Well, that explains it.

Being a Neanderthal is why I wake up early.

 Archaic Introgression Shaped Human Circadian Traits 

Neanderthals were humans.

I'm continually amazed by all the news articles that say "humans" wiped out Neanderthals.  

Neanderthals were humans, and frankly, almost certainly members of the same species that we are members of.  They're simply a distinct subspecies. That's it.  Yes, they were different, but not that different.