Human evolution: the discipline that can save the biosphere

orangutan

Understanding where we fit into the natural world and how, rather than rising above it, we depend on it like every other species, is a sobering realisation achieved through archaeological and anthropological research.

I recently wrote two articles for the Nature blog ‘Eyes on Environment’ arguing that this psychological revolution could be the only way to save the biosphere and ultimately, ourselves:

Part I

http://www.nature.com/scitable/blog/eyes-on-environment/human_evolution_the_discipline_that

Part II

http://www.nature.com/scitable/blog/eyes-on-environment/human_evolution_the_discipline_that_228236

Comments encouraged

Carpets of artefacts, mountains of baboons

DSCF8087

I must admit, I’ve slept in some pretty adventurous places…

And although I love spending the night on top of Mayan jungle temples and on Nicaraguan volcano-islands, I wouldn’t be the first to volunteer to sleep in the middle of a baboon hangout. But, for archaeology, anything….

I have arrived at my final few weeks in South Africa, but it has definitely not slowed down. It has in fact done the exact opposite. Since arriving back in January it has been almost non-stop excavations and surveying, from 500,000 year-old hominins on the shores looking out to Table Mountain, to rock-art searching in the beautiful Cederberg mountains, to Late Stone Age human burials in residential Cape Town, to trekking through the rivers and mountains of South Africa’s semi-desert: the Tankwa Karoo.

Here’s a brief impression of our time in the Tankwa Karoo in search of stone tools…

I was lucky enough to be invited to explore this incredibly beautiful yet very strange landscape in the hunt for tools made by humans both recent(ish) and ancient. Emily Hallinan, a PhD student with Cambridge, has been working in an area east of the Cederberg mountains for a little while now and recruited University of Cape Town collaborator Matt Shaw, as well as another UCT student and myself to venture through the never-ending valleys of the Tankwa to find artefacts.

The area that Emily has honed in on for this trip is a mid point between two sites of hers, one in the Cederberg mountains and the other further in the Karoo.

The team L-R: Matt Shaw, Candice Koopowitz and Emily Hallinan

The team L-R: Matt Shaw, Candice Koopowitz and Emily Hallinan

This is a really special place. Not only did we walk across landscapes so dense with Late Stone Age (~40,000 – 3,000 ya) stone tools that a ‘carpet’ is a accurate term, but they were lying right alongside those from the Middle Stone Age (~300,000 – 40,000 ya), as well as the Early Stone Age (~3.3m – 300,000 ya)! Unbelievable.

DSCF7986

A Middle Stone Age point

An Early Stone Age (ESA) hand-axe (1 million years old or older)

An Early Stone Age hand-axe (1 million years old or older)

DSCF8576

A Middle Stone Age radial core

DSCF8004DSCF8539DSCF8298

The artefacts Emily and Matt have found include stunning silcrete points made in a way not seen anywhere but north Africa…until now! (Have a read of their article for more details).

Surface scatters of lithics (stone tools) are rarely in their original archaeological context, however the bizarre intermingling geology of the Tankwa (sandstone, quarzite, diamictite and others) combined with a spectacularly low annual rainfall has created a ‘desert pavement'(as Emily has put it) restricting the movement of material.

The type of lithic you want to make is achieved by using certain types of rock, by knapping rocks together in very intricate ways, and by modifying the product further afterwards. The earliest lithics, now dated to ~3.3 millions years ago in Kenya, were very rudimentary involving smashing two rocks together. Over the following millions of years, techniques developed into much more precise and selective behaviours as a result of exploiting new environmental niches and the evolution of greater cognitive abilities. Over the two weeks of research, we saw this spectrum of technological development with our own eyes, coming across cruder Acheulean hand-axes (likely ~1m years old or more) up the valley from much more recently crafted blades and retouched points. We even found ostrich egg-shell beads and hunter-gatherer handprints on the cliff wall. Amazing.

DSCF8296 DSCF8564

Most of the time we stayed in a stunning little house perched on the side of a river valley. We reached the start of our surveying hikes either through driving around the river or canoeing along it. The canoe trips were mind-blowingly beautiful, the river so glass-like that you could turn your head upside down and convince yourself you’re standing upright. In an unexpected, yet classic archaeology-fieldwork kind-of way, we discovered a hole in our canoe whilst paddling back one day, the boat filling up by the minute! In an act of self-sacrifice, I plugged the hole with my thumb, rewarded later with extra chocolate rations (thanks Emily!). The terrain of the surveying was incredible – vast valleys, endless rocky desert, or forests of stabbing 4-inch long acacias…DSCF8162DSCF806611110796_10153448525976874_5581473344415973029_o

To continue the craziness of the trip, we learned the house had been booked for the weekend. In the spirit of adventure, we thought it would be fun to camp on the porch of a derelict house in the middle of a dry river valley. The one small catch was that this happened to be the centre of baboon nighttime festivities.

DSCF8199 copy

We woke up sometime in the early hours to loud baboon barks behind the house, and a large male replying down the front path. I’m unsure how familiar you are with baboon dental morphology, but lets just say the canines are of an unfriendly size.

Having survived the night (largely through Matt honking the car horn, flashing the lights repeatedly, and revving the engine – maybe we could have hafted lithics to spears if we had the know-how), we were looking forward to staying in a house the farm owners had allocated for us. Unfortunately for us, it turned out to be the most bone chillingly, death-horror-movie worthy, no-one-can-hear-you-scream dilapidated house imaginable. Saying that, we had a great game of carcassonne and slept like babies.

All this drama was only in addition to the catastrophe of the car nearly rolling over down a hill potentially crushing Matt underneath it as it rolled the week before… And yes, there were groups of baboons surrounding us there too.

DSCF8197

We even managed to head over to the insane South African version of Burning Man Festival – Afrikaburn. Think thousands of hippies running around in the middle of the desert, setting fire to gigantic wooden sculptures, wearing florescent everything.

What a two weeks! But next time, I’m not partaking without a machete.

DSCF7978

South Africa: a home more ancient than anyone thought

To an archaeologist, anthropologist or geneticist, South Africa is irresistible

And to tantalise the scientific tastebuds even further, two studies which came out this week and last have found that South Africa holds an even more ancient human history than anyone thought.

1. Little Foot

Australopithecus prometheus

In case you didn’t know, it is this country which has yielded some of the oldest and most significant fossil humans (hominins) found to date. The majority of these human relatives have been unearthed from the cave systems in Sterkfontein, Malapa, Taung and Swartkrans in Gauteng – including the famous ‘Mrs Ples’ and ‘Taung Child’ (Australopithecus africanus), Paranthropus robustus, and Australopithecus sediba.  These extinct South African human species date back to early days in human evolution; from ~3 to ~1.2 million years ago, though were unlikely our direct ancestors (as indicated by the recent find of a 2.8myo jaw bone in Ethiopia belonging to our genus Homo).

In the 1990’s, a new Australopithecus specimen was dug up in Sterkfontein which didn’t fit into any of the Australopithecus species already described. ‘Little Foot’ (Australopithecus prometheus) as it’s been affectionately known, was dated to ~2.2myo (million years old) based on the flowstones in which the fossil lay, though this dating was controversial. 9 years later, a team has re-dated Little Foot to 3.67mya, indicating that this species of hominin lived 1.47 million years earlier than thought, and at the same time as the famous East African species Australopithecus afarensis (‘Lucy’). Clearly the early players in human evolution (the early australopiths) were far more wide-ranging and diverse than we thought. Though the oldest of the oldest hominins belong to east and central Africa, the South African hominin record gets pushed back further in time.

2. The San

The San, or bushmen, are thought to be one of the oldest human lineages, still practising a hunter-gatherer existence in the Kalahari desert of Botswana and Namibia (though they’re being horribly repressed by the Botswanan government).

Mitochondrial DNA is an amazing piece of wizardry that evolutionary geneticists can use to track past population movements. Using mtDNA, previous studies have found that the San lineage broke off from that of every other human around 150,000 years ago, however a new study has re-analysed this date finding that the distinct San haplogroup (the unique mitochondrial DNA group that the San belong to) ‘L0d’ diverged from the main human line ~172,000 years ago. That’s incredibly old! Considering that our species (Homo sapiens) only evolved ~200,000 years ago, you can see how ancient the San lineage is. It is, in fact, the oldest offshoot from the main human lineage (of those analysed in this study).

And so although South Africa may not be the ancestral land of all modern humans, it has sure been a hospitable host to evolving hominins for at least 3,670,000 years

500,000 year-old humans and me

DSCF6968

This is what you will find 45 minutes up the west coast from Cape Town

As beautiful as this landscape is, its what’s under the sand that is truly valuable.

Dig down even only 20cm through the white dune sand and you’ll find the start of a deep red layer of sand. This is an ancient landscape of history frozen in time.

The site was originally discovered by workmen at the nearby nuclear power plant, who’s accidental unearthing of fossilised animal bones attracted Stanford archaeologist Richard Klein. After arriving on the scene and doing a fair bit of surveying and excavation, Klein et al. found that the find wasn’t an isolated stroke of luck – the site yielded wheelbarrows full of fossilised bones. Macro- and micromammals were present in their findings, ranging from the Egyptian mongoose (H. ichneumon), black rhino (D. bicornis), and the extinct long-horned African buffalo (Pelorovis antiquus), to the hairy-footed gerbil (G. paeba), Cape golden mole (C. asiatica), and Krebs’s fat mouse (S. krebsii), to name but a few. And that’s just the mammals! Bird species from the jackass penguin (S. demersus) to the spotted eagle owl (B. africanus) have appeared from the depths, as well as species of frogs and toads.

mnw2_buf_ill

P. antiquus (Image: E. Esterhuizen)

 

The incredible (and unexpected) biodiversity found in this stratigraphy is only really comparable to that in an Ace Ventura movie.

The abundance of bones from fresh water-dwelling animals (including hippos) reveal that this area, now vast dry sand dunes, was once a marshy wetland, with the high frequency of fauna that graze rather than browse (like buffalo), and fossilised pollen in hyena poo, indicating that the area was vast grasslands (full paper here).

However, the most exciting finds were those directly made by humans. Hundreds of stone tools have been gradually exposed in the form of flakes (and their debris), hammerstones and cores, showing that humans were living alongside this oasis of life. The Klein team conducted ‘optically stimulated luminescence dating’ on the sand surrounding the upper layer, arriving at a date of ~270,000 years ago. Tools have been found in lower layers too that go back even further in time – perhaps even ~500,000 years ago, or older. This would instantly get any archaeologist, anthropologist or biologist excited, as these humans were therefore pre-Homo sapiens (us). Most likely Homo erectus or Homo heidelbergensis, this realisation has transformed this site into a sought-after hominin site, allowing us to peer directly into the lives of our half a million year-old ancestors.

Cruz-Uribe et al., 2003

Cruz-Uribe et al., 2003

H. heidelbergensis

H. heidelbergensis

H. erectus

H. erectus

In a stroke of luck, I managed to get on board with a team carrying out new excavations at this same site, and what treasures we have found… Unfortunately I can’t reveal most of them, but I’ll provide a brief flavour to give you an idea.

The frequency of faunal finds only increased since we started, with a fossilised rhino tooth, antelope jaw, and possible extinct long-horned buffalo horn. Of greater significance in relation to humans, we’ve found lots of stone tools thereby confirming that hominins were hunting and living in this exact area.

What blew my mind after hours scraping away in a 1 x 1 meter hole however, was finding stone tools in situ myself. It’s hard to describe the feeling when you take it out of the sand, brush it off, hold it in your hand, and know that the last person to hold it was an extinct species of human living ~500,000 years ago. And boy are they incredibly beautiful! Flakes of silcrete, quartzite and quartz that I’d just pulled out of the sand after lying there for an unimaginable time-span were still sharp, and with a careful eye it’s easy to see where the maker had hit it off the stone core (and sometimes where they had missed), as well as where they had touched up the edges to make it as sharp as possible (a ‘retouched flake’). These materials are not available in the immediate area, and so, along with river pebble tools we’ve also found, these hominins were fetching specific lithic material, bringing it back to this site, and knapping away. Debitage and flake chips that have turned up in our excavation pits in abundance, confirm that these early humans were sitting exactly where I was, creating sharp tools, but ~500,000 years earlier.

I found, and still find this fact absolutely unfathomable.

DSCF6956 DSCF6958DSCF7403DSCF7405DSCF7382

The lead researcher, Dr Deano Stynder’s, research interests in the site are centered on reconstructing the palaeoenvironment through faunal and floral proxy material in order to infer what the landscape in which Middle Pleistocene hominins were living was like (particularly whether the biome was C3 or C4 dominated). Through this, he hopes to gain a greater understanding of the environmental pressures which shaped the ecology and behaviour of these early humans.

In addition to the excavation (and bucket carrying, and endless sieving), Dr David Braun (Uni of Cape Town & George Washington Uni) turned up to carry out some aerial photography by literally attaching a camera to a kite. This is a nice technique to get a broader view of your site and a spatial context of where you’ve excavated…and more importantly where you haven’t.

Further excavations at this unique treasure trove of human evolution will take place through the hottest part of the summer, potentially leading to the faunal bones found 500,000 years from now being those of dehydrated archaeology students…

The Cederberg: mountains and rock art

Having just returned from a week-long workshop in a small town within the Cederberg mountains, it seems unfair to not share its natural and archaeological wonders…

  An area of ~700km² encompasses the Cederberg Wilderness Area, made up of mountains, desert fynbos, and little Afrikaans towns. In this land of leopards and meerkats lies significant palaeontological finds, including a fossil fish from the Ordovician (~450 million years ago).

DSCF6823

More relevant here though are the wealth of archaeological finds: shell middens (hunter-gatherer rubbish dumps), artifact scatters, and most noticeably, incredible rock art. In fact this area is one of the best places to see rock art in the world, with more than 2500 individual sites found (so far)! These consist of carefully drawn animals (mostly eland and kudu) and people, as well as handprints. Rock art is really hard to date, but these were most likely were drawn between 5,000 – 1,500 years ago

DSCF6811DSCF6806DSCF2104DSCF2113

Dating some of the paintings has been successful including this piece which goes back to at least ~3,600 BP

Picture1

Although these paintings are far from the oldest (this title currently goes to those in France and Indonesia at ~40,000 years old), they represent a later point on this fascinating shift from behaviour which is purely essential for survival (why waste energy on something which isn’t going to directly enhance survival chances) to that which we would call ‘art’. It’s a really interesting thought that there came a point where our hunter-gatherer ancestors had enough spare time or cognitive capacity to produce things which were purely symbolic or abstract. In case you missed it, the earliest evidence of this has very recently been pushed back almost 5 times further than previously thought with ~450,000 year old Homo erectus shell engravings.

The Cederberg has also yielded rock art painted by not just the indigenous San hunter-gatherers and migrating Khoi pastoralists, but also the Dutch colonisers

Picture3StompiesfonteinDutchmanDutchcart

The San paintings presumably reflect what was most important to the artists at the time – animals (and a few other things). Clearly the hunter-gatherers had (and indeed still have) a very close relationship to the animals that share their land, and the respect they show their prey before and after death is truly admirable and sobering. The Dutch art, on the other hand, represents mostly people and transport, with some animals which are being shot and put to work.

There are of course thousands of other examples (if interested get hold of John Parkington’s book ‘Cederberg Rock Paintings‘), but these show just how you can get a fascinating snapshot into the minds of people many thousands of years ago.

South Africans, be proud of the San!

“Whilst the Mayans were building temples, Egyptians constructing pyramids, and Babylonians designing ziggurats, why were our guys still rubbing two sticks together?”

Although this may seem like a perfectly decent question, the woman who asked me this at a charity dinner last week after discovering I work in the archaeology department, is greatly underestimating southern Africa’s indigenous population.

So, I’m going to enlighten her here, by exploring the ingenuity of this amazing indigenous group

Let’s start with a bang

All architectural designers have the San to thank

Cave art found in South Africa, though largely remaining undated, is not very old. It is unlikely that it compares in age to those of Chauvet Cave in France or the recently published hand stencils and animal drawings from Sulawesi in Indonesia, both dated up to ~40,000 years old. Granted, indigenous southern Africans probably weren’t the first to decorate cave walls. However, a prerequisite for art (that includes music, complex language, writing…) is thinking in an abstract and symbolic way, and the earliest evidence for this is from, you guessed it, South Africa.

Blombos cave on the south coast 300km from Cape Town has yielded ochre pieces with intentional patterns – showing the makers had symbolic intent. These have been dated from between 70 – 100,000 years old. 100,000 years old! That is doubly as old as the recently found Neanderthal engravings in Gibraltar! Engraved ostrich egg shell found in the Western Cape”s Diepkloof cave falls within the same time period.

Blombos

Blombos engraved ochre

Diepkloof ostrich eggshell

Diepkloof ostrich eggshell

We’re talking about the very emergence of key modern human behaviour here! Abstract and symbolic thought as evidenced here was the precursor for any sort of art, music and indeed architectural design…like that of the Egyptians. Recent genetics has established when the ancestors of the San headed south – around 150,000 years ago – so these engraving are remnants of the San and their ancestors.

No agriculture = No builders

As brilliantly conveyed by Jared Diamond in Guns, Germs and Steel, the advent of agriculture brought huge changes to almost every part of the human world. Suddenly, foraging and hunting for food didn’t have to dominate the daily lives of everyone; the ability to produce a greater quantity of food allowed for the stratification of society, leading to those specialising in writing, building, developing medicine and all the job specialisations you see around you today. Thus, no agriculture, no pyramids.

Why wasn’t agriculture developed in southern Africa as it was in the several other points of origin around the world? To cut short pretty much the whole of Diamond’s book, no plants or animals have proved suitable for domestication. Though southern Africa has far more than its fair share of indigenous floral and faunal species, it takes a rather unique species to pass the strict entrance requirements for domestication (i.e. zebra’s just don’t like being told what to do).

The isolated location of southern Africa, separated from the rest of the world by desert, ocean, and jungle, formed an impenetrable barrier to the movement of agricultural peoples from the ‘Fertile Crescent’ (now the Middle East), inhibiting the spread of agricultural knowledge. Livestock and crops domesticated in North/Central Africa and the Fertile Crescent couldn’t survive in the vastly different climate of southern Africa. And so agriculture only arrived here in full force ~1000 years ago.

The relevance of all this? Due to the geographical position of the San and their ancestors, agriculture did not arrive in southern Africa until much later than Egypt, Babylon and Mesoamerica, and so they were hunting and gathering away without growing a darn thing. If this were different, world history would have surely not played out the same; as Jared Diamond puts it…”Africans mounted on rhinos would have trampled any European invaders, but it never happened”

rhinoCAT_450x300

…or did it

Hunter-gatherers for 150,000 years (and counting)

Here’s an interesting idea for you: being a hunter-gatherer isn’t so bad.

Sure, a large proportion of your time is spent searching for food which restricts  time to do other things, but anthropologists experiencing the day-to-day life of the San have noted that they actually have quite a bit of spare time. This time is essential in groups without writing as a chance to pass stories, wisdom and techniques from one generation to the next. Perhaps the brilliantly abundant rock art all around South Africa is a testament to this spare time…

DSCF1975

Even after agriculture had become established in South Africa, most of the hunter-gatherers here didn’t enthusiastically grab the nearest shovel and start planting next year’s sorghum harvest. No, they continued living as hunter-gatherers.

As mentioned in Diamond’s The Third Chimpanzee, a San bushman said simply,

“Why should we plant, when there are so many mongongo nuts in the world?”

Despite European and Bantu colonialism, discrimination by contemporary African governments, and wide-scale environmental degradation of hunting lands by external forces, there are San living a hunting and gathering lifestyle in southern Africa to this day.

The Mayans were amazing; I’ve climbed up (and slept on) their temples in the middle of the Guatemalan rainforest myself. The downfall, however, of this complex civilization can be attributed to a whole host of factors, but as many archaeologists have speculated,  these were ultimately based on over-exploitation of their environment. As Dorothy Hosler, Jeremy Sabloff and Dale Runge originally proposed, the most likely scenario is that a steady increase in monument construction (to please the gods) necessitated ever more workers, which required ever more food but in less space and with fewer farmers; they were essentially trying to increasingly intensify agriculture in ever depleting productive land (see a nice review here). Over-intensification echoes through the decline of other great civilizations too…

So don’t get me wrong, I’m not attempting to discount the innovation, intelligence and architectural brilliance of ancient civilizations, I’m just trying to point out what seems rather obvious: throughout the rise and fall of these empires, San hunter-gatherers have been surviving perfectly well, as they and their ancestors have done for ~150,000 years, without over-exploiting their environment.

Maybe we should be asking them for some advice

A window into 16,000 years ago

Although the skeletons found at Faraoskop (our current site) were all buried ~2000 years ago, the site itself shows evidence of occupation dating back to over 16,000 years ago.

This we know by discovering artefacts over different stratigraphic layers, and these you can date with radiocarbon dating.

Only a small part of the Faraoskop rock shelter has been excavated, but despite this we’ve found some amazing artefacts. These were excavated in different layers, and so date back to different times, though unfortunately before UCT archaeologists could arrive at the site, the farmer had dug up a fair amount of material and so the date of these is more difficult to attain. None the less, they all reveal a lot about how these hunter-gatherers were surviving…

Here are some which I stumbled across the other day;

Reed arrows (note how one is fletched and the remnants of plant fibre wrapped around the top)

WP_20141006_001WP_20141006_003WP_20141006_005

…and the bone arrow tips (showing remnants of red ochre). These were attached with mastic (tree resin)

WP_20141006_016

Antelope leather stitched together to make material (layer 1, ~670 years old)

WP_20141006_008

Ornamental beads made from bone and seeds (found in all layers: from ~670 to ~16,500 years ago)

WP_20141006_009

String made from plant fibres (found in layer 1, ~670 years old)

WP_20141006_012

Bone ‘spatulas’ used in cooking (note how they’ve been smoothed and a groove made in the middle)

WP_20141006_018

So Faraoskop was occupied multiple times over the last ~16,000 years, by different generations and groups of San. Clearly these groups were actively hunting, cooking (there’s also evidence of fire use), making clothing and other materials, decorating themselves with ornamental jewellery, and crafting string. Not mentioned here are the numerous stone tools (found up to the deepest layer ~16,000 years old), pottery, decorated ostrich eggshell, mussel shells (used as scrapers), and animal bones also found. The change in the species of animal over the layers can reveal changes in climate – we’ve found a shift from large grazers (like buffalo) to small browsers (like bushbuck) over 16,000 years, indicating the decline of grassland and proliferation of fynbos bushes and trees (so cooler to warmer temperatures).

Finding these sorts of artefacts allows us to peer into the life of southern African hunter-gatherers from the late Pleistocene to recent times. But Hominins have been crafting material items since at least 2.5 million years ago (though probably longer – see this and this), gradually gaining the cognitive and technical ability to dream up and make ever more complex tools (such as these bone spatulas and fletched arrows). So our findings represent only the very end of an incredibly long object-manipulating process that has slowly been perfected since the hominin and chimpanzee lineages split ~6.5 million years ago.

Faraoskop tool evolution

Aren’t we amazing?