On St. Patrick's Day, most revelers don't remember the patron saint of Ireland for his role as a snake killer.

But legend holds that the Christian missionary rid the slithering reptiles from Ireland's shores as he converted its peoples from paganism during the fifth century A.D.

St. Patrick supposedly chased the snakes into the sea after they began attacking him during a 40-day fast he undertook on top of a hill.

An unlikely tale, perhaps—yet Ireland is unusual for its absence of native snakes.

It's one of only a handful of places worldwide—including New Zealand, Iceland, Greenland, and Antarctica—where Indiana Jones and other snake-averse humans can visit without fear.

But St. Patrick had nothing to do with Ireland's snake-free status, scientists say.

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