St. Patrick’s Day is one of the year’s more popular celebrations. Though the percent of Americans planning to celebrate has increased from 44% in 2009 to 49% in 2021, the total spending has gone from $3.29B to an anticipated $5.14B for the same years, according to the National Retail Federation. People across the world plan to wear green and drink a pint (or more) of Guinness, which happens to be this American of Irish descent’s favorite.
There are as many ways to acknowledge the day as there are shades of green found on the Emerald Isle and one is to recount Irish stories. Possibly one of the more well-known associated with Saint Patrick is how he banished all snakes from Ireland. This one goes back centuries and was first mentioned in print in Topographia Hiberniae by Gerald of Wales. Gerald showed skepticism when he wrote:
Some indeed conjecture, with what seems a flattering fiction, that St. Patrick and the other saints of that country cleared the island of all pestiferous animals; but history asserts, with more probability, that from the earliest ages, and long before it was favoured with the light of revealed truth, this was one of the things which never existed here, from some natural deficiency in the produce of the island.
-Giraldus Cambrensis, The Historical Works of Giraldus Cambrensis, trans. Thomas Forester (London: H.G. Bohn, 1863), 48.
Nevertheless the legend has persisted and there have long been songs that mention it in their lyrics, like Saint Patrick was a Gentleman!
To get to the truth of the matter of a snake-free Ireland we need to look back to the most recent Ice Age. The Quaternary glaciation period began around 2.6 million years ago and is, surprisingly, ongoing. At the moment we’re living in an interglacial period, where the ice sheets have receded but have not fully disappeared. These fluctuations in the freezing and unfreezing of ice cause sea levels to lower and rise, which in turn reveals or submerges land masses. During the current glaciation period, Ireland has been covered intermittently with ice sheets which made it pretty inhospitable to cold-blooded fauna due to low temperatures. When the latest round of ice receded, the Irish landscape had been remodeled and was left as an island as sea levels rose which further prevented many animals from being introduced.
As with other islands in similar situations during past glaciations, such as New Zealand and Greenland, and extreme north or south landmasses like most of Canada, Siberia, and Antarctica, snakes are not native to Ireland. The only known land reptile species that is native to Ireland is the viviparous lizard, which makes its home across the Eurasian landmass.
Ultimately, though Saint Patrick may not have banished the snakes from Ireland, it still makes for a good toast on March 17th! Sláinte agus táinte!
Further reading on Ireland:
- A History of Ireland by Mike Cronin and Liam O’Callaghan (2001).
- The Natural History of Ireland by William Thompson (1849-1856).
- Secrets of the Irish Landscape, edited by Matthew Jebb and Colm Crowley (2013).
Further reading on climate and environment:
- NOAA Paleoclimatology Data
- Geology and Archaeology: Submerged Landscapes of the Continental Shelf edited by Jan Harff, G. N. Bailey, and Friedrich Lüth (2016).
- Quaternary Glaciations – Extent and Chronology: A Closer Look edited by Jürgen Ehlers, Philip L. Gibbard, and Philip D. Hughes (2011).
Further reading on snakes:
- Snakes of Europe, North Africa & the Middle East: A Photographic Guide by Philippe Geniez (2018).
- Herpetology of Europe and Southwest Asia: A Checklist and Bibliography of the Orders Amphisbaenia, Sauria and Serpentes by Kenneth R. G. Welch (1983).
- Snakes of Europe by J. W. Steward (1971).
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Driving out the snakes is a metaphor for forced conversion of the Irish people by this English monk, including burning sacred groves, thereby driving out the “pagan” and druid gods and practitioners.
While this post is intended to focus on the natural history behind the lack of snakes, I do appreciate you taking the time to add some context on the significant impact that English and religious imperialism had on Ireland’s population.
Thanks to lentigogirl for a concise explanation. Metaphors often seem to have a colloquial status so I wonder if this particular one was in use prior to St. Patrick?