One of the great mysteries of early human evolution is what happened to extinct hominin groups like the Neanderthals and Denisovans.
"Neanderthal, also spelled Neandertal, the most recent archaic humans, who emerged between 300,000 and 100,000 years ago and were replaced by early modern humans between 35,000 and perhaps 24,000 years ago. Neanderthals inhabited Eurasia from the Atlantic regions of Europe eastward to Central Asia and from as far north as present-day Belgium southward to the Mediterranean and southwest Asia. Similar human populations lived at the same time in eastern Asia and Africa. Because Neanderthals lived in a land of abundant limestone caves, which preserve bones well, and where there has been a long history of prehistoric research, they are better known than any other archaic human group.Consequently, they have become the archetypal “cavemen.”
The fossil evidence for the few hundred thousand years leading up to the time of the Neanderthals shows a gradual decrease in the size and frequency of anatomic characteristics of Homo erectus and an increase in features more representative of Neanderthals. A gradual emergence of the Neanderthals from earlier regional populations of archaic humans can be inferred, probably across their entire geographic range. The changes between Neanderthal ancestors and the Neanderthals themselves highlight their characteristics. Brain size gradually increased to reach modern human volumes relative to body mass, although Neanderthal brains and braincases tended to be somewhat longer and lower than those of modern humans. Neanderthal faces remained large and especially long, similar to those of their ancestors, and they retained browridges and projecting dentitions and noses and had receding chins. Their chewing teeth (premolars and molars) were small like those of early modern humans, and their chewing muscles and cheek regions had shrunk accordingly. Their incisor and canine teeth, however, remained large, like those of their ancestors, indicating continued use of the teeth as a vise or third hand.The bodies of the Neanderthals changed little from those of their ancestors. They retained broad shoulders, extremely muscular upper limbs, large chests, strong and fatigue-resistant legs, and broad, strong feet. There is nothing in their limb anatomies to indicate less dexterity than modern humans or any inability to walk efficiently. The details of their hand bones, however, do suggest greater emphasis on power rather than precision grips. All these features appear to have been maintained from their ancestors. Neanderthal [Credit: Encyclopædia Britannica, Inc.]Then, in 2010, a team led by geneticist Svante Paabo announced stunning news. Not only had they reconstructed much of the Neanderthal genome—an extraordinary technical feat that would have seemed impossible only a decade ago—but their analysis showed that "we" modern humans had interbred with Neanderthals, leaving a small but consistent signature of Neanderthal genes behind in everyone outside Africa today. In "Decoding Neanderthals," NOVA explores the implications of this exciting discovery. In the traditional view, Neanderthals differed from "us" in behavior and capabilities as well as anatomy. But were they really mentally inferior, as inexpressive and clumsy as the cartoon caveman they inspired? NOVA explores a range of intriguing new evidence for Neanderthal self-expression and language, all pointing to the fact that we may have seriously underestimated our mysterious, long-vanished human cousins.