The myth of St. Patrick tested by science

On St. Patrick’s Day, most holidaymakers do not remember the patron saint of Ireland for his role as a snake hunter.

However, legend has it that the Christian missionary cleared the Irish coast of these reptilian crawls as he converted the pagan peoples of Ireland in the 5th century AD.

When he undertook a forty-day fast on the top of a hill, St. Patrick is said to have driven out the attacking serpents and brought them back to the sea.

An unlikely story, especially when you know that Ireland is distinguished by the fact that it is not home to native snakes.

It is one of the few places in the world – along with New Zealand, Iceland, Greenland and Antarctica – where you can wander fearlessly if you have a deep aversion to snakes.

But scientists say St. Patrick’s Day has nothing to do with it.

As curator of the Department of Natural History at the National Museum of Ireland in Dublin, Nigel Monaghan has explored the vast collections of fossils and other available records listing Irish animals. “At no time was the presence of snakes in Ireland mentioned, so St. Patrick had nothing to hunt for,” Monaghan said.

So what happened?

Most scientists point to the last ice age, which kept the island at temperatures too cold for reptiles until about 10,000 years ago. After the ice age, the surrounding seas may have prevented snakes from colonizing the emerald island.


Once the ice caps and woolly mammoths retreated north, the snakes returned to northern and western Europe, extending to the Arctic Circle.

Britain, which had a land bridge with continental Europe until about 6,500 years ago, was colonized by three species of snakes: the venomous snake, the grass snake, and the smooth-crowned snake.

But the land link between Ireland and Britain was cut off about 2,000 years earlier by sea inflation due to glacier melting, Monaghan notes.

Among the animals that came to Ireland before the sea became an insurmountable barrier were rough bones, wild boars and lynxes, but “snakes never got that far. Snake populations are slow to colonize new areas, “he added.

Mark Ryan, director of the Louisiana Poison Center at the Louisiana State University Center for Health Sciences in Shreveport, agrees that the timing was not right for expanding the reach of these sensitive reptiles. and cold-blooded.

“There are no snakes in Ireland for the simple reason that they could not get there, the weather was not conducive to their presence,” he notes.

The other reptiles did not reach the island either, except for the gray lizard. The only native reptile in Ireland, this species must have arrived in the last 10,000 years, according to Monaghan.

So unless Saint Patrick knew how to distinguish a snake from a lizard, where does this legend come from?

Specialists are prone to allegory. Snakes are symbols of evil in Judeo-Christian beliefs, like the serpent that causes Adam and Eve to fall.

These animals were also linked to pagan practices, so St. Patrick’s act of eradicating snakes can be seen as a metaphor for their Christianizing influence.


Irish people looking for snakes to hunt and repel will probably have to settle for the fragile slow worm, a non-native species of legless lizard that is often confused with a small snake.

First recorded in the early 1970s, the species was thought to have been deliberately introduced to the west of Ireland in the 1960s, according to the Irish Environmental Protection Agency.

However, the reptile does not appear to have spread beyond a region of biodiverse limestone in County Clare known as the Burren.


In the future, it is entirely possible that snakes may be seen in Ireland, especially pet snakes deliberately released by their owners.

“No alien species is safe for native wildlife,” says Monaghan. “The isolated nature of an island population makes Ireland very vulnerable to any introduction, whether well-intentioned or wrong.”

Henry Kacprzyk, a reptilian curator at the Pittsburgh Zoo and the PPQ Aquarium, believes Ireland’s native wildlife would not be prepared for the introduction of snakes. Invasive snakes such as the irregular bug have already wreaked havoc on Guam and other island ecosystems.

Getting rid of these unwanted creatures would not be as easy as the legend of St. Patrick suggests.

“I don’t want to completely break the St. Patrick’s myth,” Kacprzyk says. “I want to keep him partially alive.”

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