Legend says that St. Patrick cast all the snakes out of Ireland. In fact, snakes are very bad sea travelers and rarely manage to reach island homes, unlike many tortoises and lizards. At the end of the last Ice Age snakes slithered into England when it was still joined to Europe. But by the time they reached the west coast, the sea had melted, and Ireland was cut off, so the snakes were stuck in England, Wales, and Scotland.