Neandertal diet was not dolphin-safe

Chris Stringer and colleagues (including Finlayson and Barton) have a paper in the current PNAS early bin describing Neandertal exploitation of marine mammals in the Gibraltar caves (Vanguard and Gorham's). The Neandertals left some seals and dolphin bones with cutmarks behind, along with a lot of mollusk shells.

When I pulled up the paper, it sounded very familiar to me, like I'd written about it before. And indeed, I had, although I hadn't posted the results. A couple of years ago I was doing some research on the Gibraltar caves and I ran across a website from Oxford covering the Gibraltar excavations. The page (at the time) included this passage:

As a result of the research project, we have been able to compare and contrast the distinct records of these caves to show that Middle Palaeolithic Neanderthals in Mediterranean-type environments occupied relatively small home ranges, that they focused on local estuarine wetland and marine habitats and had a highly omnivorous diet. This is revealed in exceptionally well-preserved occupation levels, by the presence of plant foods and shellfish, and cut-marked bones of small (e.g. tortoise, bird, rabbit) and large (red deer, ibex) vertebrates. Vanguard cave has also revealed the first evidence of Neanderthal processing of marine mammals, and this very important finding is the subject of a paper now being prepared for Science.

That sounded pretty interesting, so I filed it away and did some more reading about marine resource exploitation.

It's often hard to explain to people why it takes so long for us to learn new things about Neandertals, and why it's so exciting that today's genetic information is progressing so rapidly. This sequence of marine exploitation from Neandertals is a good example. Stiner (1993:191ff) documented shellfish remains in the Middle Paleolithic strata of Moscerini Cave, Latium, Italy. One of the interesting elements of the Moscerini shellfish remains was a fluctuation over time between two kinds of shellfish: mussels and smooth-shelled sand clams. These two kinds of bivalves live on different substrates -- mussels attach to rock, while sand clams, well, bury themselves in sand. Distinct pulses of alternating mussel and sand clam remains occurred in the site, and Stiner interpreted these as a consequence of local abundance of these different bivalves, which may have changed over time due to local sedimentation, sea levels, or other hydrological factors.

But this fluctuation raised a point about the Neandertals: they weren't carrying the clams or mussels very far. They left in the cave a small fraction of the species variety of shellfish in the environment; the two kinds of bivalves are approximately equivalent in calories and nutritional yield.

Their choices of which shellfish to bring into Moscerini appear to have been guided foremost by locational convenience: one kind of shellfish patch, on rock or in sand, may have been closer to the cave entrance at any given time in the past. The case of Moscerini, contrasted with the lack of much evidence for shellfish exploitation at neighboring Mousterian caves only slightly farther inland, indeed suggests the influence of this simple energetic principle. Assuming that transport distance is generally limited by the relatively low caloric yield of these bivalves, regardless of substrate source, hominids may have been willing to carry the shellfish to shelter only from the closest patches before eating them. Otherwise, hominids might have preferred to eat the shellfish where they found them (Stiner 1993:191).

So far, so good -- Stiner documented something very interesting about the way that Neandertals exploited marine resources, and that might tell us about Neandertal foraging patterns more generally.

In the face of that old result, it was hard to understand the excitement that accompanied last year's paper by Curtis Marean and colleagues (2007), who found evidence for shellfish exploitation at Pinnacle Point, South Africa. The press reported the result as if there were a shell midden, with abundant evidence for consumption. But actually the number of shells is fairly small -- all the shells from all the layers reported weigh less than a kilogram. That looks similar to the pattern of exploitation that Stiner had reported for the Neandertals at Moscarini, and more or less like the pattern at Vanguard and Gorham's Caves.

Into this context comes the evidence of marine exploitation from Gibraltar. The marine mammals showed up in the faunal list of Finlayson et al. (2006), which along with the web material means that there are no surprises here. But the progression of this story has built upon several recent papers that have placed marine exploitation squarely in the the Pinnacle Point paper, as well as year's giant clam paper and the earlier research by Walter et al. (2000) in Eritrea. That paper included this quote:

Regardless of which hominid species made the tools at Abdur, or at the more tenuously dated sites in South Africa, the pressing question is: what caused such an apparently sudden and widespread coastal marine adaptation by early humans by the last interglacial period? Climate changes leading to hyper-arid conditions in Africa and the Red Sea basin during the penultimate glaciation (150 kyr) and at the peak of the last interglacial may have been severe enough to pressure early humans to migrate from once stable interior habitats to exploit coastal marine habitats for survival. As opposed to shrinking freshwater environments during these times (for example, East African rivers and lakes), human adaptation to marine shoreline environments might have been further influenced by the lack of competition from other terrestrial mammals for coastal marine food resources. It is likely, however, that during extreme hyper-arid conditions marking the peak of the penultimate glaciation, that the Red Sea basin itself was virtually uninhabitable (Walter et al. 2000:69).

So obviously we need a reminder that Neandertals shared the same marine exploitation patterns as early modern humans. Now Stringer et al. (2008) have provided it: Neandertals were like Africans in that they exploited marine resources. The systematic exploitation at Abdur may be beyond that present at any Neandertal site, but that goes to a question of motives and foraging patterns, certainly not the recognition of marine resources as useful foods. And we must not forget that most of the Pleistocene coast is now far underwater. If people tended to forage according to the Neandertal pattern, not carrying their shellfish far from the point of acquisition, then we should never expect to find evidence of any marine exploitation where the ancient coast was further from a short distance from the present coast. Littoral ecosystems may have been highly valuable to all these ancient humans.

This story parallels the pace of discovery about pigment use. Pinnacle Point is mainly notable for its pigment blocks:

There are 57 pigment pieces (93.4g total) and most are from the LC-MSA Lower. Forty-six are iron-rich fine-grained sedimentary materials, and most have a pinkish-brown or reddish-brown surface colour. Streak colour (Natural Colour System) shows the majority (n = 31) as intermediate reddish-brown, followed by saturated reddish-brown (n = 10), and saturated very red (n = 7, high chroma values and75% redness). All can be classified as 'red ochre'. Ten pieces were definitely used (eight ground and two scraped) and two pieces were probably used (both ground). Most ground pieces are moderately to intensively ground on one principal surface (Fig. 2). Saturated very-red values are disproportionately represented among used pieces, suggesting preferential use of the reddest, most chromatic ochre (Supplementary Information) (Marean et al. 2007:906).

But as I discussed earlier this summer, there is now clear evidence that Neandertals used pigment crayons. The numbers at Pech de l'Azé are much more extensive (although later) than the Pinnacle Point remains. Again, the evidence is that Middle Paleolithic Neandertals did the same things as MSA Africans.

In a commentary accompanying Stringer et al. (2008), Pat Shipman points out the message of behavioral similarity:

Thus, these excavations have yielded excellent evidence of four behaviors usually cited as hallmarks of modern human behavior: the exploitation of a wide range of terrestrial resources; the exploitation of marine resources; the use of small scale resources; and seasonality or scheduling in the use of resources (11-13). That modern human subsistence behaviors would show up among archaic humans like Neanderthals, even as late as 28,000 B.P., is startling.
...
If behavior did not separate "us" (modern humans) from "them" (Neanderthals), what did? Why did Neanderthals go extinct if they and modern humans used similar subsistence strategies in Gibraltar? Answers to these questions are likely to be elusive. But more research into carefully chosen, meticulously excavated, and thoughtfully analyzed sites may be one way to begin to find them (Shipman 2008:14242).

It is the theme of current research: "behavioral modernity" appeared piecewise in Late Pleistocene humans, including the Neandertals.

References:

Barton RNE, Currant AP, Fernandez-Jalvo Y, Finlayson JC< GOldberg P, Macphail R, Pettitt PB, Stringer CB. 1999. Gibraltar Neanderthals and results of recent excavations in Gorham's, Vanguard and Ibex caves. Antiquity 73:13-23.

Finlayson C, and 25 others. 2006. Late survival of Neanderthals at the southernmost extreme of Europe. Nature 443:850-853. doi : 10.1038/nature05195

Marean CW and 13 others. 2007. Early human use of marine resources and pigment in South Africa during the Middle Pleistocene. Nature 449:905-908. doi:10.1038/nature06204

Scholz CA and 18 others. 2007. East African megadroughts between 135 and 75 thousand years ago and bearing on modern human origins. Proc Nat Acad Sci USA 104:16416-16421. doi:10.1073/pnas.0703874104

Shipman P. 2008. Separating "us" from "them": Neanderthal and modern human behavior. Proc Nat Acad Sci USA 105:14241-14242. doi:10.1073/pnas.0807931105

Stringer CB, Finlayson JC, Barton RNE, Fernández-Jalvo Y, Cáceres I, Sabin RC, Rhodes EJ, Currant AP, Rodríuez-Vidal J, Giles-Pacheco F, Riquelme-Cantal JA. 2008. Neanderthal exploitation of marine mammals in Gibraltar. Proc Nat Acad Sci USA 105:14319-14324. doi:10.1073/pnas.0805474105

Stringer C. 2002. New perspectives on the Neanderthals. Evol Anthropol Suppl 1:58-59. DOI link

Walter RC and 11 others. 2000. Early human occupation of the Red Sea coast of Eritrea during the last interglacial. Nature 405:65-69. doi:10.1038/35011048