St. Patrick, patron saint of Ireland, is best known for bringing Christianity to the Emerald Isle, but his story is chock-full of other legends and miracles, too.
It’s been said that the missionary raised dozens of people from the dead, for example, and even banished all of Ireland’s snakes into the sea following a 40-day fast. Unfortunately, and perhaps unsurprisingly, the science doesn’t quite back up this latter claim.
While it’s true that the Irish don’t have any snakes to deal with, St. Patrick can’t take the credit. In fact, no one can — because there’s no evidence in the fossil record that the slithering serpents ever lived there at all.
Why Are There No Snakes in Ireland?
Plenty of islands have them, of course. Ilha da Queimada Grande, or “Snake Island,” located some 90 miles off the São Paulo coast, has as many as one snake per square meter. So why did they never make it to the Emerald Isle?
Researchers point to the most recent ice age.
Blame the Ice Age
During this last glacial period, spanning between about 120,000 and 10,000 years ago, both Ireland and the island of Great Britain were far too cold for snakes and other reptiles. After the ice retreated, two land bridges were revealed: one connecting Ireland to Britain, and the other connecting Britain to the rest of Europe.
Around this time, a number of new species, including three different snake species, colonized Britain. But as melting glaciers caused sea levels to rise further, the land link to Ireland became impassable — some 2,000 years before surrounding seas cut off the bridge to Britain.
The prevailing theory is that snakes simply didn’t have enough time to make the last stint of the journey to the Emerald Isle. To this day, the island has only a single native terrestrial reptile: the common or viviparous lizard, which must have arrived sometime in the past 10,000 years, following the end of the ice age.
Where Else Are There No Snakes?
You might be surprised to learn Ireland is in good company. The major islands of New Zealand, Iceland, Greenland, Hawaii and Antarctica are all serpent-free as well — and therefore great vacation destinations for those of us with ophidiophobia.
Risk of Invasion
Many of these governments ban the import and possession of snakes to ensure they stay that way (even pet lizards and turtles are illegal in Iceland). After all, invasive snakes have been known to wreak havoc on island ecosystems; look no further than Guam, where the invasive brown tree snake is infamous for killing native lizards and birds.
But reptile enthusiasts can rejoice because no such laws exist in Ireland.
In fact, pet snakes were considered a status symbol there as recently as the early 2000s. They’re also found in zoos, including the National Reptile Zoo in Kilkenny City, the country’s only reptile zoo.
This is because there’s little fear that abandoned or runaway snakes will become invasive there. Because the creatures are cold-blooded and unable to keep themselves warm, they rely on heat from the sun — something that’s too rare to sustain a healthy snake population in the Emerald Isle.
In other words, there’s no need for a modern-day, snake-slaying St. Patrick … for now, at least.
Read More: 10 of the World’s Deadliest Snakes