It wasn't that our extinct relatives could smell scents undetectable to humans, or vice versa. Instead, the Denisovan turned out to have a more sensitive nose than humans, while Neanderthals seemed to have weaker noses — especially, in one group, for stinky body odors.

— Read more in Some Neanderthals couldn't smell their own stink, suggests a new study recreating early humans' noses at Business Insider.