The valley and the caricature
In 1856 quarrymen clearing a cave in the Neander Valley near Düsseldorf turned up a skullcap and bones too robust and beetle-browed for comfort — three years before Darwin’s Origin gave anyone a framework for them. Named Homo neanderthalensis in 1864 (the first fossil human species ever recognised), the Neanderthals promptly received the caricature they spent a century wearing: the shambling ape-man — an image cemented by an early 20th-century reconstruction of a skeleton that happened to be an arthritic old male. The caricature has since been dismantled bone by bone.
What they actually were
Neanderthals descended from earlier Homo populations in Eurasia and lasted, through repeated ice ages, from roughly 400,000 to 40,000 years ago — a run several times longer than Homo sapiens has yet managed. They were shorter, vastly stronger, cold-adapted, and carried brains as large as ours or larger. The archaeology credits them with composite tools hafted with manufactured birch tar (a multi-stage chemical process), controlled fire, coordinated big-game hunting that took mammoth and rhino at close quarters (their skeletons carry rodeo-rider injury patterns), burial of their dead, care of the disabled — individuals survived for years with crippling injuries, meaning others fed them — plus pigment use, eagle-talon ornaments, and, if the dating of certain Spanish cave paintings holds (it is contested), art. A hyoid bone and genetics suggest speech capacity; a mysterious ring of stalagmites built deep inside Bruniquel cave 176,000 years ago suggests things we have no word for yet.
The genome and the merger
The revolution came from ancient DNA: Svante Pääbo’s team sequenced the Neanderthal genome (draft 2010; a Nobel in 2022), which delivered the headline that reframed the species: they are not entirely extinct. Modern humans leaving Africa met and interbred with them — repeatedly — and today most people of non-African ancestry carry about 1-2 per cent Neanderthal DNA, influencing skin, immunity (including, researchers found, some COVID-19 risk variants), and more. The related Denisovans, known almost entirely from DNA in a Siberian cave, added their own contribution in Asia and Oceania.
The disappearance
Around 40,000 years ago — within a few millennia of sapiens’ arrival in Europe — Neanderthals vanished as a distinct population. The suspects are argued with vigour: absorption into larger modern-human populations (partly true by definition — the DNA survives), demographic arithmetic (small, scattered groups against more numerous newcomers), climate whiplash, subtle edges in technology or networks; simple violence has the least direct evidence and the most persistent appeal. The honest summary is that our closest relatives ended not as the caveman punchline but as a long-successful human species that met us — and that everyone reading this sentence outside Africa is, slightly, them.