The bare mininum intake of water should be at least 64 oz. Now if you live in hotter states like me who live in AZ in the summer months you will want to increase that intake to about 96-128 oz per day. Of course your activity level and how much you spend outside will be a factor as well.
Neanderthals were a separate species from modern humans, and became extinct (because of climate change or interaction with modern humans) and were replaced by modern humans moving into their habitat between 45,000 and 40,000 years ago.
For decades, the overwhelming scientific consensus has held that sometime between 100,000 and 50,000 years ago, Homo sapiens left Africa in search of more space and new habitats to exploit. En route, they inevitably met up with the Neanderthals occupying the Middle East and southern Europe.