
There are no native snake species in Ireland,Iceland, Greenland, Hawaii, New Zealand, part of Canada, northern Russia, or, predictably, Antarctica.
The temperatures in England and Ireland during the Ice Age were too low for cold-blooded reptiles like snakes to live there. However, 10,000 years ago, when the glaciers moved and land appeared to connect England, Ireland, and Europe, migration became possible. Brown bears, lynxes, and wild boars were among the animals that did make it to Ireland during this time. The territory between Britain and Europe was submerged 6,500 years ago, giving snakes more time to slither over, whereas the land between Ireland and England was covered over 8,500 years ago when the glaciers started retreating, according to Popular Science.
According to legend, St. Patrick not only introduced Christianity to Ireland but also put an end to all snakes on the Emerald Isle by driving them into the sea from a cliff where he had fasted for 40 days.