Whale Bone Genetics and the Extraordinary Closure of a Broch

A Fin Whale. Photo: Aqqa Rosing-Asvid. Creative Commons

New DNA results shed light on Iron Age use of whale bone and the remarkable process of ending a broch two thousand years ago.

Results of DNA investigations undertaken on a large collection of whale bone from the University of the Highlands and Islands Archaeology Institute Iron Age archaeological site of The Cairns, have afforded a glimpse into the complex relationship of Iron Age communities with whales.

In particular, the identification of multiple whale bones as belonging to a single large fin whale shows how its carcase was strategically and even ceremonially used and deposited during the ending of the monumental broch.

Vicki preparing one of the larger whalebone artefacts from The Cairns excavation. Photo: UHI Archaeology Institute

In the early Summer of 2019, Dr Vicki Szabo (Western Carolina University, North Carolina) and Dr Brenna Frasier (Saint Mary’s University, Nova Scotia) collaborated with Martin Carruthers (University of the Highlands & Islands Archaeology Institute), to examine the collection of whale bone artefacts recovered from The Cairns excavations, being undertaken by UHI Archaeology Institute, Orkney. The aim of the research was to obtain genetic information in order to provide an assessment of what species of whale, or cetacean, were present at the sites.

The research is part of a large international project funded by the National Science Foundation which is investigating the past use of whales in North Atlantic society. Brenna and Vicki are following up on work completed in Orkney in February 2018 where they examined the whales found at another archaeological site in Sanday, Orkney and other whale bone artefacts from The Orkney Museum.

The Cairns and the sea. Looking across Windwick Bay. Photo: Bobby Friel @Takethehighview

The project has sampled whale bones over a 1400+ year span, from Newfoundland, Greenland, Iceland, Faroes, Shetland, and Orkney. Orkney and Iceland are the primary centres of analysis, representing the Eastern and Western North Atlantic. Orkney offers exceptional assemblages of whale bone from many periods and sites, from the Neolithic to the Norse eras and thereafter. The types of objects produced in Orkney are remarkably stable over a long period of time, as well. The Cairns, though, has given Vicki and Brenna their first opportunity to sample at an ongoing excavation; with most of the other analysis undertaken on assemblages that were collected in the past.

The results from the study show that some of the whale bones that were uncovered at The Cairns were from very large types of whale including sperm whale, North Atlantic right whale, minke, grey whale, and humpback. This is fascinating as it raises questions about whether a site like The Cairns may have been able to stake a claim over the larger whale carcasses, and therefore if this is an indication of relative status and control of resources by the inhabitants of that site. One surprise, though, was the volume of bone belonging to fin whale species in the assemblage.

One of the larger pieces of Fin whale bone found at The Cairns Broch. Photo: Andrew Hollingrake

Fin whales are the second largest species on the planet, after the blue whale itself, and can grow to 27 metres in length. Interestingly, fin whales are also amongst the fastest whales in the sea, capable of bursts of 45KMH when hunting, or threatened, and they can dive fast and very deeply. Indeed, in the modern era, the fin whale was only really hunted in large numbers once the explosive harpoon was invented, and so it is unlikely to have been hunted in the Iron Age, but rather a stranded individual. That does not mean that other types of whale were not hunted, and the question of whether some whales were pro-actively sourced during the Iron Age remains unanswered.

In time, further study of patterns of whale bone and species recognition from sites like The Cairns may shed light on this.

The end of two giants: the broch and a Fin whale
The latest stage of the genetic project permits us to connect an entire array of whale bone items. The genetic and molecular study of 33 whale bone items shows that 20 pieces (vertebrae, ribs, scapulae, and other anatomical elements) were from the fin whale species. This is remarkable in of itself, however, 2 key mitochondrial haplotype regions of the genome of each bone were examined, and it is likely that all these fin whale items (except one) are from the same animal. This means that a single, large, fin whale may have been utilised during the last occupation and abandonment of the broch.

The Cairns broch looking across to the North Sea. Photo: UHI Archaeology Institute

The bones appear to relate to feasting that took place to mark the end of the broch. Some of the whale bones have chop-marks present showing signs of butchery and perhaps bone-working. Others are slightly singed from being subjected to direct heat. The fin whale bones were found in a range of contexts across the broch. Some of the bones were excavated from the uppermost floor deposits of the broch. Others were stuffed into gaps in its walls. Other fin whale bones came from the rubble that was used to infill the broch during the final abandonment.

The presence of this single animal, spread across these varied contexts, links these deposits very closely in time, much more tightly, in fact, than is currently possible with radiocarbon dating alone. It allows the excavators to closely connect several different contexts and stages within the finale of the broch and to appreciate what a relatively swift process the end was. The occurrence of the many bones from a single animal may also allow detailed consideration of the use of whale bone and how it was treated as a resource both physically and perhaps also symbolically.

The Fin whale vessel just outside the broch entrance. Photo: UHI Archaeology Institute

One of the bones of the giant fin whale is especially remarkable for its treatment. This was a large whale bone, which had been carved from a substantial vertebra to make a vessel. This vessel had been deposited just outside the broch door at the very end of the broch occupation. A remarkable assemblage of objects accompanied the vessel. Two shed red deer antlers had been propped against the outside of the vessel, and a very large grinding stone, or saddle quern, was also placed snuggly against the vessel as though to pin it firmly against the broch outer wall face. Inside the actual vessel, were the remains of two new-born lambs and, most remarkably, the jawbone of an elderly human. This entire collection of items was a very deliberate deposit that appears to have been part of the measures employed to perform an act of closure for the broch.

Martin Carruthers, site director of The Cairns and UHI lecturer in archaeology said: “It’s just amazing to be able to say with confidence that so many of these whale bones, including the vessel with the human jawbone, actually belong to the same animal, especially as we’ve recovered them from the site over a number of different seasons, not knowing all along that the spread of bone belonged to one huge beast. We had some suspicions that something particularly interesting was going on with the amount of whale bone that was emerging from end of our broch, but we’d never have managed to get to this level of specificity without the input and collaboration with Brenna and Vicki”.

When discovered, the whale bones are in a condition where they were cut-up or processed during the Iron Age. That often makes the original anatomical detail and form of the bones difficult to see clearly. Therefore, it can be challenging to identify them to species, let alone recognise bones belonging to a single individual. Martin continues: “One of the most important things, from my point of view, is how this research helps us to recognise the significant role that the treatment of the fin whale had in the dramatic procedures of deliberately ending of the monumental broch”.

What circumstances led to the use and deposition of the fin whale?
Whale bone seems to have been a highly important material for Iron Age communities. The appearance of these ocean giants on local beaches, when stranded, must have occasioned opportunities to recover a large volume of meat, oil (fuel for lamps), as well as a substantial resource for making objects. Whale bone-work clearly included things like our big vessel (The Cairns has also yielded several more whale bone vessels from across the site), but also tool-making (e.g. weaving ‘batons’, chopping-boards, ‘soft’ anvils, and much more), and even for architectural purposes such as large ribs used as roof rafters.

The whalebone distribution across the site which has been DNA tested. Credit: UHI Archaeology Institute

Indeed, it’s possible that a stranding of a major animal, like a massive fin whale, would have represented an exponential contribution to the community’s resources. Vicki Szabo suggests: “As a free and scavenged resource, whale provides a large volume of high value protein. Large whales are generally 14+% body weight bone, which means that a fin whale represents a massive quantity of soft tissue, meat and blubber at around 70%”.

This amount of food input may have served to energise productive capacity, providing additional assurance of a successful year for the community. Perhaps a stranding may have permitted endeavours and projects that might otherwise have been thought risky, making them more manageable. At The Cairns, this whale boon could have included support for a major undertaking such as ending the premier building, the broch, a structure that had dominated the local landscape and society for generations. It would have been no minor activity to demolish the upper parts of the massive and complex broch, and it is likely that the work of rendering it down would have had some serious consequences for the settlement, at the heart of which, lay the broch. It would have been a physically arduous and time-consuming process, probably involving many people, taking them away from other important tasks required of this busy farming group.

That is not to say that the stranding of a single large whale led to the ending of the broch. There is growing evidence that the period around the 2nd Century AD was a time when many brochs were coming to their end, at least in their initial form as high-walled, tower-like buildings. There is a sense, therefore, that things were changing, more generally, in Iron Age society across Northern Scotland at that time, which the waning importance of monumental broch architecture is a part of. However, we may still wonder if occurrences, such as the stranding of a significantly large whale, might encourage a community, perhaps already considering a radical break with the past, to go for it.

Just some of the whale bone unearthed at The Cairns. Photo UHI Archaeology Institute

There was a very practical bonus to be had in the harvesting of a very large whale, but we may also wonder if the appearance of such a large beast stranded on the foreshore meant more to Iron Age communities than just a resource. In many non-Western societies, and, indeed, many ancient European ones, sudden natural phenomena such as the highly prominent death of a significant type of animal may be seen as a conspicuous indication of arcane and esoteric forces, taken as a sign, an auspicious, or inauspicious, omen. Even though stranding may have been more common with a larger population of whales thought to exist in prehistory, it might be that both the practical impact, and the potential ideological and psychological effects of the appearance of a big stranded whale created the critical timing and final motivation for major change.

Other Animal Offerings? Animal Bone Groups at The Cairns
Whales are not the only animals present in interesting circumstances during the final stages of the occupation and abandonment of the broch. Indeed, across the site there are what are known as animal bone groups (ABG’s) present that date to the period of the broch and afterwards. These are articulated animals, or articulated parts of animals, apparently deliberately deposited. These derive from cattle, sheep, and red deer as well as cat, pig, otter and even, in one case, an articulated seal flipper!

To date, around twenty such ABG’s have been recognised from The Cairns. Probably many more await discovery. In many, or most, cases they may well be butchered joints of meat. It may be that these ABG’s are indeed portions of meat, but they are not discarded in middens as one might normally expect and seen elsewhere on the site. Instead, they were left in certain locations within the buildings of the site and across floors, and infills, as if they were actually posed. Indeed, many look like they have been displayed. Some of the bones reveal traces of weathering on the surface of the bone, indicating a period of exposure prior to being covered in soil, rubble or new house floors.

Whale bone from The Cairns…showing cut marks. Photo UHI Archaeology Institute

Why formally place animal bones?
What did these deposits mean for the people of the Iron Age? Martin Carruthers says: “At the Cairns, I wonder if many, or all, of these deposits followed on from activities that celebrated the end of the broch and the beginning of new things for the community, who by no means just disappeared thereafter”.

Human occupation of the site lasted at least another 800 years after the end of the broch. Carruthers continues: “they might also be acts of propitiation, an assuagement of the decision to end a major building that had been highly valued for so long, by many previous generations of inhabitants. Perhaps the inclusion of our elderly human jawbone as part of the process was also a nod in the direction of the past of the broch, when it was in its hey-day? When that person was in their youth the broch would still have been the major symbol of authority in the landscape, and the jawbone may well have belonged to someone who had been a member of the broch household”.

A further possibility is that the formality and recurrence of all these depositional acts were themselves a source of comfort and reconciliation, especially in the face of major transitions underway on site, and in wider society, a response to crisis that drew comfort from the long-standing tradition of deposition.

Whatever the truth of the mentalities and motivations, the process of ending the broch was measured, carefully planned, required resources of people as well as of materials, was physically difficult, as well as probably not a little dangerous. It also seems to have entailed serious ideological input and consideration, not least indicated by the deposition of human remains like our jawbone inside the fin whale vessel.

The end of the broch seems also to have involved the butchery and perhaps sacrifice of animals, feasting, and especially, perhaps, reflection on the past, present, and future of the community.