4MacDonogh, Steve. The Dingle Peninsula. Dingle, Co. Kerry, Ireland: Brandon, 2000. 50-51.
In one souterrain what appeared to be a ventilation shaft may have had an additional purpose. Mary Hobson writes, "At Tavenahoney in Glenan I found the only vent or shaft I have seen, though I know of another. I am not sure that it was intended for ventilation, but rather incline to the idea that it is a speaking tube to give warning to those inside; a boy spoke to me through it. It was closed on the outside by a rough stone like thousands scattered over the hillside." (Hobson, Mary. "Some Ulster Souterrains." The Journal of the Royal Anthropological Institute of Great Britain and Ireland 39 January-June (1909): 223.)
According to NUI Galway Archaeologist Michelle Comber, the evidence suggests that "souterrains served at least two functions - refuge and storage. Features such as constricted passages, chambers on different levels, settings for internal gates or doors were clearly designed to prevent quick/easy access to some souterrains. In addition, some have exits, facilitating underground movement from one place to another (though not over huge distances as many local tales might suggest!). Excavation, however, has also shown that some souterrains, at least, were also used for storage. Their cool interiors were ideal for storing foodstuffs, and the remains of timber barrels have been found." (Comber, Michelle. "Other Purposes of Souterrains." Message to the author. 27 Feb. 2012. E-mail.)