Loathed at First Sight : Sex appeal is important . . . ask the Neanderthals

When scientists first found their bones in Germany’s Neander tal, or valley, in 1856, Neanderthals were touted as early ancestors of man. Appearing in Europe perhaps 200,000 years ago, the thick-boned, barrel-chested creatures were thought to be a missing link between an earlier hominid and Homo sapiens.

That notion has faded in recent years and has now been debunked persuasively in a study of Neanderthal DNA that concludes the species was an evolutionary dead end. Rather than interbreeding and slowly evolving into humans, the study found, Neanderthals were an entirely separate species that vanished abruptly about 30,000 years ago, just as modern humans were becoming the dominant hominid.

The study raises two mysteries. The first is why Neanderthals, which probably lived near humans for tens of thousands of years, did not interbreed with them. The Neanderthals’ reproductive systems are not believed to have been different enough to preclude interbreeding. But theorists speculate that their facial expressions were. Mating in nature always begins with an attraction. In dogs this is scent and in birds it is song, but in humans it’s overwhelmingly visual and centered on the face. While human faces are able to express a gamut of emotions, the Neanderthals’ facial muscles were rigidly cast into one beetle-browed expression, with a great projecting nose, puffed-up cheekbones and large, rounded eye sockets.

The second mystery is why Neanderthals vanished so abruptly. Conventional wisdom has long held that they died off because they were unintelligent and had no family structure. Archeologist Lewis Binford, for instance, has said that the Neanderthals suffered a “lack of planning depth,” a failure to anticipate and arrange for future needs. Other research, however, has shown that the Neanderthals were not the oafish boors that their name has come to denote. In fact, they buried their dead with flowers, may have been the first to feel religious stirrings, became relatively sophisticated tool users and cooperated during hunts.

A more plausible theory is that humans killed off that species with the inscrutable face. Unable or unwilling to make love to the Neanderthals, our ancient ancestors may have decided to make war on them instead.