Bonekickers

History behind ‘Warriors’: Bone Stable-isotope Analysis

The analysis of bone, shown in Bonekickers, works on the principle that ‘we are what we eat’ and that our chemistry, particularly the collagen in our bones, reflects our diet.

In particular, stable isotopes of carbon and nitrogen provide very distinctive signatures that can be analysed by archaeologists. In the case of carbon, photosynthesis converts atmospheric carbon dioxide into carbon compounds with three or four carbon atoms; the plants produced in this way are known as C3 and C4, and they can be measured by the ratio between the isotopes ¹²C and ¹³C.

C3 plants include wheat, barley, and rice, but also tubers such as cassava, potato and yams.

C4 plants are mostly sub-tropical plants such as maize, sugarcane, millet and sorghum. In the case of our potential ‘slaves’ it would be expected that the diet would be heavily balanced towards a C4 diet, whereas Europeans are more likely to have a C3 diet.

The proportion of ¹⁵N in bone is also a useful indicator of a diet of seafood - which might for example indicate consumption of salt-cod by the slaves.