There's only one species of humans in the world right now.  But there used to be several. The last of our human cousins, the Neanderthals, died out roughly 40 thousand years ago. 

And we tend to think of that extinction as a failure — reflecting their inferiority, and our superiority and inevitability. Well, that's a kind of thinking that we should be very suspicious of for all sorts of reasons in the 21st century.

But in any case, our clichéd picture of the Neanderthals as brutish, rag-clad primitives is just plain wrong. 

And all the reasons why it's wrong are described in a new book by archeologist and writer Rebecca Wragg Sykes, called Kindred: Neanderthal Life, Love, Death and Art. 

In the book, she describes the evidence for a species that persisted longer than modern humans have existed.  They were skilled hunters and accomplished tool-makers. They were artists, explorers, and they lived in a surprisingly rich culinary world. They lived their lives much as we did, and in fact left their mark on us, and a little of their DNA.

Bob McDonald spoke with Wragg Sykes about her bookKindred: Neanderthal Life, Love, Death and Art.Here is part of their conversation.

Where and when did Neanderthals live? 

Well, a lot of people might be thinking of them as European. Really they are Eurasian. They lived anywhere from between Wales, where I am, right through the Near East, up into Central Asia and across into Siberia. But in terms of their anatomy, they really begin emerging around 350,000 years ago in the fossil record. And then they continue right through until about 40,000 years ago, at which point they drop out of the fossil record. Nothing remains except their genetics.

How much do they look like us? 

We can see that Neanderthals are remarkably similar to us and they're not a missing link in anatomical terms between us and the common ancestor we share with chimpanzees, who are our closest living relatives. The Neanderthals emerge around the same time as early Homo sapiens, our ancestors, so we should really expect them to be looking much more similar to us. And yet there definitely are differences.

The size of their face is bigger. It's slightly more pulled forward. They had larger eyes and they had much bigger noses. The shape of the skull is also different. Their forehead is more sloping back. If you look at the rest of their physique, what would be most impressive is — even though they're a bit shorter than us — they would have been extremely well-muscled, very impressive.

You also say in your book that it's possible that Neanderthals lived in a richer culinary world than ours. What was on the Neanderthal menu? 

Well, what didn't they eat, really? The older ideas with Neanderthals is that they were sort of stuck in a rut, just eating big game. And certainly they did eat and hunt large animals like mammoth, woolly rhino, big extinct horses as well. But they took small game. They were after birds, rabbits, and if they're around the coast, quite often we see that they are taking shellfish.

   An exhibition at the Canadian Museum of Nature. (Nikola Solic/Reuters)

They certainly did eat a lot of meat, particularly fat and marrow, but plants were part of it, too. We can see, for example, from a site in northern Europe that they were eating water lily roots, which is not sort of an accidental thing. You have to go forage in a lake for that, and that's really quite sophisticated. 

What can you tell us about their sex and love lives? 

Well, maybe more than one might imagine. They probably were not living in bands of alpha males with lots of females. It's more like a monogamous pair bonding with a little bit of flexibility around the edges. But one thing we do know is that there was sex going on between Neanderthals and other hominids, including us, because we can see this from the genetics. It used to be theorized that we started to disperse and we basically replaced the Neanderthals without any interbreeding around 40,000 years ago.

Today we can see that the chronology for our own movement into Eurasia is way older than we used to believe. So the span of time over which there was potential to have interaction with Neanderthals and other more ancient Eurasian hominids is much larger. And certainly we see that in the DNA. It was only a decade ago that we got the first draft nuclear genome for Neanderthals, and that showed clearly that most living people today had a genetic legacy from Neanderthals. We now believe that the latest interbreeding event probably happened about 55,000 years ago. 

What we still don't know for sure is the social context of that, why were people having sex? Was it consensual or was it based around some kind of conflict? Probably a bit of both.

                                   Wragg Sykes holds a 55 thousand year old handaxe found in Lynford in the U.K. (Rebecca Wragg Sykes and Alison Atkins)

Neanderthals who had all the qualities that would seem to allow them to adapt to their environment, adapt to survival for so long, more than 300,000 years, and yet they went extinct. Do you think they could have coexisted with us for a longer period? 

We know that we did coexist with Neanderthals for 160,000 years or more. The question is, why did things change? It's very likely that Neanderthals and early Homo sapiens were living at really low population densities, there was hardly any of either population. And what we see is that Neanderthals appear to have been living in more socially isolated subpopulations.

So basically the breeding pool that they had available to them is smaller and probably they were less interconnected with each other, whereas we don't see that signal for those early Homo sapiens people. Again, there probably was hardly any of them, but they seem to have been in contact with each other more. 

You say that Neanderthals were never some sort of 'highway service station en route to real people, they were state of the art humans, just a different sort.' So what's the legacy of the Neanderthals to you? 

Well, I wrote that because I really wanted people to think about Neanderthals just on their own terms. They're so often viewed as a foil to us, like a sidekick. Or we just use them as a mirror to say something about us. I would like readers to take home with them that this is part of our great human story. They're our closest relatives in that sense, and they're still with us. That legacy is still here today. 

Q&A has been edited for length and clarity. Produced and written by Mark Crawley.