Thursday, 31 July 2014

Evidence for Neolithic dairy farming in Finland

Lipid residues from prehistoric sherds reveal transition around 2500 BC 

It has long been debated whether Neolithic farming economies were ever established at the limits of modern agriculture around the 60th parallel north. Thanks to the warming effects of the Gulf Stream, sustainable farming economies were established slightly to the south, in Britain, southern Norway and Sweden. In Finland, however, agriculture is problematic even today due to lower temperatures and a snow cover for several months of the year.

Corded Ware was a pan-European phenomenon during the third millennium BC. Corded Ware reached Finland, but despite the firm association of this culture with pastoral farming elsewhere in Europe, there is no evidence for it in Finland. A problem for archaeologists is the poor survival rate of archaeological remains in the acidic soils of the region.

Fortunately, these same conditions favour the preservation of certain classes of ancient biomolecules such as lipids in the walls of ancient ceramic cooking vessels. Carbon isotope analysis can then be used to determine the origins of such organic residues.

In a new study published in Proceedings of the Royal Seciety B, researchers took advantage if the availability of abundant sherds representing prehistoric cooking vessels to investigate the economy of prehistoric hunter–fisher–foragers using so-called Comb Ware, and possible early farmers associated with Corded Ware, Final Neolithic Kiukainen Ware, and Early Metal Age people.

Seventy prehistoric sherds were investigated, from sites in southern and southwestern Finland; 19 yielded residues amenable to analysis. Residues recovered from Comb Ware dating from 3900 to 3300 BC were found to be associated exclusively with marine products suggesting specialised subsistence strategies and/or the storage of marine commodities for exchange. By contrast, residues recovered from Corded Ware dating to around 2500 BC display isotopic signatures suggesting fats of ruminants. While these could indicate either domestic cattle or wild elk or reindeer, around half the residues are from milk, suggesting the former possibility. Notably, these milk residues were found in drinking beakers rather than storage amphorae. Only one Corded Ware vessel was found to contain residues of a marine origin despite the proximity of the sites investigated to the coast.

Unlike the other two, Final Neolithic Kiukainen Ware sherds revealed a mixed-economy of marine and ruminant products. Possibly marine elements were reintroduced to the economy as a hedge against deteriorating climate. The Early Metal Age residues were exclusively of dairy origin, suggesting the intensification of agriculture despite the continued deterioration of the climate.

The sharp contrast between the marine products associated with Comb Wares and domesticated products associated with Corded Wares supports the view that Corded Ware pottery represents the successful introduction of farming into Finland and also places the origins of farming and milk consumption at this northerly latitude at 4,500 years ago.

References:

1. Cramp, L. et al., Neolithic dairy farming at the extreme of agriculture in northern Europe. Proceedings of the Royal Seciety B 281 (2014).

Link:

http://rspb.royalsocietypublishing.org/content/281/1791/20140819.full

Friday, 11 July 2014

Chimpanzee gestures decoded

Study may throw light on origins of human language

The use of gestures by chimpanzees was first demonstrated by field studies carried out in the 1960s and 1970s, and work on captive animals has shown that these gestures are part of an intentional, goal-orientated behaviour common to all the great apes. While this behaviour overlaps with human language, it is absent from most animal communication systems and evidence for it is also lacking for the vocalisations of great apes.

There has been considerable interest in a potential common origin of great ape gestures and components of human language and, therefore, in the actual meaning of the gestures. Surprisingly, little work has been carried out in this area. In a new report, published in the journal Current Biology, researchers Catherine Hobaiter and Richard Byrne from the School of Psychology & Neuroscience, University of St Andrews, have presented the first systematic study of meaning in wild chimpanzee gestural communication. They have found that individual gestures have specific meanings, independently of who is making them, as is the case with words in human language. They have also provided a partial ‘lexicon’.

The field studies were conducted in the Budongo Forest in Uganda, and more than 80 chimpanzees were observed. The researchers recorded the interactions of the chimpanzees and analysed 4,531 instances of gestural communications between the animals, noting the motions they used and how other chimpanzees responded. Some 36 gestures were analysed, and some 15 different meanings were identified.
Some of the gestures are unambiguous: for example ‘leaf-clipping’ is only used to signal sexual attraction. 

However, many are associated with up to three meanings: for example, ‘grab’ is used for ‘stop that’, ‘’climb on me’, and ‘move away’. This ambiguity may be apparent rather than real, and may arise in part from the difficulty for human observers in discerning subtle variations in the nature of the gesture. It is evident to a human recipient whether or not a gentle touch is intended to make them move or stay where they are, but such distinctions are very difficult to perceive visually. Gestures were also employed towards two or three very similar outcomes:  for example, ‘push’ is used for both ‘move away’ and ‘stop that’.

Researchers found considerable variation in whether an intended meaning was signalled by a single gesture type or several gestures of apparently equivalent meaning. This was particularly common in social negotiations, where a degree of persuasion was required. By contrast, meanings typically conveyed by a single gesture were often well defined: for example ‘initiate grooming’ is signalled by a big loud scratch.

References:
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1.  Hobaiter, C. & Byrne, R., The Meanings of Chimpanzee Gestures. Current Biology 24, 1-5 (2014).
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