Image: Andreas F. Borchert, Wikimedia Commons

The world's turning green for St Patrick's Day, which means it might be time dust off some enduring legends about the man behind the holiday – like his claim to the Emerald Isle's snake-free status. 

The legend goes that Saint Patrick chased Ireland's snakes into the sea in the fifth century after they attacked him during a 40-day fast atop a hill, leaving the isle free of slithering creatures once and for all. While it's true that the country is devoid of native snake species, just like a few other places around the globe (including Iceland, New Zealand and Greenland), Saint Patrick can't take the credit. 

"A lot of people think St Patrick banished snakes from Ireland ... well, there were never snakes in Ireland [in the first place]," historian Pat Liddy tells The Independent.

In fact, reptiles in general are in short supply. Ireland can lay claim to only a single native reptile, the common (or viviparous) lizard. As for any snake-resembling creatures, if you're in the Burren region in County Clare, you might just spot a slow worm (Anguis fragilis) – but it's believed that these limbless burrowing lizards were actually introduced in Ireland fairly recently.

Lacerta Vivipara Common Lizard 2015 03 17
The common lizard is Ireland's only native reptile. Image: Marek Szczepanek, Wikimedia Commons
Anguis Fragilis Slow Worm 2015 03 17
The slow worm Anguis fragilis, a type of burrowing lizard, was likely introduced to the country fairly recently. Image: Jonas Bergsten, Wikimedia Commons

So why the reptilian shortage? Blame geography and the Ice Age. Long, long before Saint Patrick's time, the last Ice Age kept the region far too chilly for reptilian comfort, and when warmer climes finally arrived some 10,000 years ago, the snakes' colonisation was stopped in its tracks when rising seas cut Ireland off from Britain. A few snake pioneers did make it as far as Britain, however: the grass snake, the smooth snake and the European adder (Britain's only venomous snake species).

It's not home to any native species, but Ireland's snake-free status might be changing. In recent years, escaped or abandoned exotic pets, from 15-foot pythons in suburban gardens to California king snakes lurking in vacant lots, have been slithering their way in.  

But how did the St Patrick legend come about? "[The myth] is kind of half true," explains Liddy. "The original word was "serpents". There were serpents in Ireland in the sense that the serpents we're referring to here are the druids and the pagan practices that Patrick banished from the life of Ireland."

So there you have it. Science may have tarnished his reputation as banisher of snakes, but with his honorary holiday gaining popularity around the globe (and beyond!), there are still plenty of reasons to celebrate St Patrick. 

Top header image: Jo Garbutt, Flickr