How were the cairns used?
For obvious reasons, we cannot say, with any degree of certainty, how Orkney’s chambered cairns were used. But, from the evidence, we can make educated guesses.
Where remains were found inside the cairns, the bones were noted to be in very different states.
Some chambers contained complete skeletons, while many others simply held piles of jumbled bones. Sometimes, the bones were in a disorganised heap, while other cairns had neatly-organised piles, in which skulls were in one area, leg bones in another etc.
Some cairns, such as Isbister, contained only a few bones that had been taken from a number of different people.
Handling the dead
From these different arrangements of remains, it has been suggested that each community had its own way of handling its dead. Some would place the corpse into the cairn, where it was left to decompose. This explains the complete skeletons.
Others left the corpse outside the cairn until decomposition had stripped the flesh from the bone. In these cases, the communities may also have relied on the local wildlife to assist in the excarnation process - laying out the corpse until the birds had picked the bones clean. Then the disarticulated bones were gathered up and deposited inside the cairn.
Again, we can’t say for certain, but the importance placed on excarnation could indicate that the Neolithic Orcadians believed that a person’s soul, or spirit, was only released once the flesh had decayed. At this stage, the spirit was perhaps free to join the ancestors in the "house of the dead".
Here, the veneration of the ancestors didn’t even require that the remains of each corpse be kept separate. In most cases, they were swept together into one pile or sorted into distinct piles. Were these communal piles of bone more important as a representation of the individual community and their shared origin?
Once the remains were placed in a cairn they were not simply left.
With some chambers being used for up to 800 years, the communities they served had to implement systems to maintain and organise the physical remains of their predecessors.
Interacting with the spirits
We know that the cairns were not like the mausoleums of today, where bodies are interred and then left. The Neolithic cairns were a vital part of the community and entered on a regular basis. It may have been that the dead were still regarded a part of the community - although they now resided in a structure reserved specifically for their kind.
The interaction between the living and the dead may have been a part of this tradition.
An interesting theory is that a slot above the entrance of the recently-discovered Crantit cairn, outside Kirkwall, was specifically to allow the living to confer with the spirits of the dead.
Along similar lines, calculations at Maeshowe have shown that there would have been a gap at the top of the stone that sealed the entrance, thus allowing contact with the "spirits" at all times.
At the end of their use the cairns were generally sealed, in some cases filled with earth or rubble. At some sites the level of rubble was complete, almost reaching the roof whereas others were only partially filled. The Wideford Hill cairn, for example, was discovered to be two-thirds full when excavated.
What was the reason behind this last ritual act? To protect the remains of the ancestors? To prevent access by anyone else? Did their religious practices or traditions change and the tombs were filled simply to prevent further use?
Again, like all other aspects of the life of the Neolithic people of Orkney, we simply do not know.