The first draft of the Neanderthal genome, published in 2010, came with some titillating news. It showed that 50,000 years ago, these ancient hominids interbred with the ancestors of many modern humans. If you have European or Asian ancestry, an estimated 1 to 4 percent of your DNA came from Neanderthals.

On the off chance that your mind hasn’t gone there, allow me: Our ancestors, looking pretty much like we do today, had sex with the short, extremely muscular, big-nosed, big-browed, big-headed Neanderthals. Were the differences between the two species mostly physical, with shared intellectual and cultural pursuits the subjects of their pillow talk? Or were Neanderthals violent, mute, and stupid, as so often depicted in