Can you excavate twins?

While most mammals have multiple offspring at a time, in humans the phenomenon is fairly rare. The rate of multiple births varies from 1.3 to 3.5% by country, although these have increased slightly in the past decade with the introduction of artificial reproductive techniques. Attitudes towards multiple births varies by culture, from being a sign of fortune, a source of shame, or fascination. Americans do seem to have a fascination with multiple births, especially those that have six or more children at a single time like Jon and Kate plus 8 or the octo-mom hype. However, this has not extended to our interpretations of prehistory. As Flohr argues in a new publication “the rarity of evidence might be that the suspicion that two or more buried individuals are twins is commonly not aroused, and hence, a systematic search for traits that could support this assumption is not conducted”. In this article, he argues that a burial from Iron Age Germany may potentially be the remains of a set of twins rather than two coinciding burials.

Two perinatal skeletons were recovered from an excavation near Ochtendung, Germany. The remains were found near the post holes for a pit house, and appeared to be buried without a formal burial. This is evidence by a lack of grave goods and shallow burial. A large portion of the bones of both individuals were recovered, and preservation was fairly good, only a small amount of erosion damage was found on the cranial bones.Using measurements of the bones as well as presence of tooth crowns, they were able to determine age at death between 36 and 40 weeks. One of the individuals was aged slightly older than the other, a difference of only a week or two. Based on the similar burial, Flohr argues there is suspicion of a twin burial, and combined with similar ages it is a high possibility. Comparison of morphological traits in the bones and teeth revealed further similarities. He argues that the discordance in age between the two individuals is due primarily to a 5-10% difference in measurements throughout the skeleton. However, this could also support the twin hypothesis as they are usually different sizes at birth. The attitude towards the potential twins is unknown, since there is no correlating cemetery with the settlement that could compare these against ‘normal’ burials.

A similar type of burial was discovered by Crespo et al. (2011). They recovered two perinatal individuals who were interred at the same time at a 4th to 2nd century BCE site near Barcelona, Spain. The remains were found near a metal workshop and their lower extremities were intertwined. Of the 11 perinatal burials found at the site within the settlement, only these two were buried together. One was aged at 39 weeks and the other at 40 weeks based on the measurements of the bones. Like Flohr, they argue that the discordance in size is a common feature of twins and therefore doesn’t disprove the possibility. They were unable to do genetic studies, and morphological assessment was inconclusive as to whether there was a genetic relationship or not.  They conclude that given the double internment and comparison against other perinatal burials at the site, as well as the intertwined legs, same age at death and burial at the same time, these likely represent twins.

The question is whether we can really conclude that double burials with individuals of similar ages are twins. There is a lack of evidence beyond circumstance that leads to this conclusion. Given the age of the individuals, it is also extremely to difficult to see potential morphological variation. Further, the discordance in size, while possibly due to the difference between twins, is more likely attributed to different ages. Twinning is a rare phenomenon that is only more frequent now due to artificial birth methods and later ages of pregnancy. It is more likely these burials represent two different individuals. A recent re-study of the conjoined perinatal twins from Angel mounds using DNA studies proved that not only were they not twins, but they weren’t even related on the mother’s side (Marshall et al. 2011). On the other hand, we cannot discount the possibility of twins. Regardless, it is something that we need to consider to some extent if within the constraints of the evidence.

Works Cited

ResearchBlogging.orgFlohr, S. (2012). Twin Burials in Prehistory: A Possible Case from the Iron Age of Germany International Journal of Osteoarchaeology DOI: 10.1002/oa.2236

Crespo, L., Subirà, M., & Ruiz, J. (2011). Twins in prehistory: The case from Olèrdola (Barcelona, Spain; s. IV II BC) International Journal of Osteoarchaeology, 21 (6), 751-756 DOI: 10.1002/oa.1169

Marshall, C., Tench, P., Cook, D., & Kaestle, F. (2011). Brief communication: Conjoined twins at angel mounds? an ancient DNA perspective American Journal of Physical Anthropology, 146 (1), 138-142 DOI: 10.1002/ajpa.21557

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