Snakes are cunning creatures.
They’ve slithered their way into almost every corner of the globe in their 150 million-odd years on our planet.
Saint Patrick, on the other hand, can’t take credit for eradicating our scaly companions from any of them.
Ireland, like almost every other country without snakes, never had them to begin with.
They can’t live in other parts of the country because it’s too cold. Few animals can survive too near to the poles, at least for now, because they are cold-blooded ectotherms who rely on their environment to regulate their body temperature.
The common garter snake, Thamnophis sirtalis, may reach the southern tundra boundary in North America (albeit its body fluids begin to freeze), but snakes are not found in the Arctic or Antarctic.
The northernmost parts of Russia, Norway, Sweden, Finland, Canada, and the United States, as well as the southernmost tip of South America, have no native snakes.
Alaska is one of only two states without snakes, the other being Hawaii.
Hawaii, being an island, exemplifies why most nations without snakes have been so fortunate: they are physically separated.
Of course, not all islands are snake-free.
Polynesia has a lot of them, Madagascar has a lot of them, and the Caribbean has a lot of them.
According to some estimates, Ilha da Queimada Grande, a little speck of land off the coast of Brazil, contains around one snake per square meter and is home to the golden lancehead viper, one of the world’s deadliest snakes.
Because it is so deadly there, the government hardly ever allows humans to visit.
However, all of those islands were formerly linked to bigger land masses or are close enough to other land masses for swimming snakes to inhabit.
For example, before increasing sea levels cut it off, Ilha da Queimada Grande was a part of the mainland.
Many of the islands in the Pacific and Indian Oceans are warm enough to host sea snakes (almost all of which are deadly), therefore they have already been colonized.
Some Pacific islands, such as Tuvalu, Nauru, and Kiribati, lack land snakes but do have native sea snakes.
However, the majority of those islands are quite close together.
Other island states, such as New Zealand, Greenland, Cape Verde, and Iceland, are too far away for snakes to have established themselves.
Hawaii, a far-flung volcanic archipelago, is in the same boat.
Ireland, unlike the others, is very near to the mainland and even had a land bridge that connected it to what is now the United Kingdom some 10,000 years ago.
That land bridge vanished 1,500 years later, but the land bridge connecting the UK and Europe lasted another 2,000 years, and it is this serpentine roadway that appears to have allowed snakes to into jolly old England.
The cold Irish sea appears to have kept these scaly intruders at bay, as no serpentine fossils have ever been discovered in the nation.
Even snake fossils from a warmer age have been discovered in northern Canada, where no snakes now live—a process that may repeat if global temperatures increase, reopening huge swaths of land to snake occupancy.
Of course, none of this guarantees that these areas will remain snake-free at all times.
Until World War II, Guam, one of the US possessions in the Pacific, had no snake species.
Brown tree snakes were unintentionally delivered to the island by cargo ships during the war, and they have since taken over.
By the 1980s, they had wiped out 10 of the 12 native bird species and prevented about 90% of new tree development by devouring the birds that would typically distribute the seeds in their droppings.
It is for this reason why having a snake is prohibited in Hawaii.
Because the chances of a few escaping and reproducing in the wild are so great, the Hawaiian government declared having or carrying a snake into the state a crime punishable by a $200,000 fine and up to three years in jail.
The prohibition occurs in other places as well: Even zoos in New Zealand are snake-free, and there are 20 trained snake handlers stationed around the nation whose duty it is to track down and catch any snakes attempting to enter.
Snakes are brought into New Zealand in a variety of methods, including stowaways on cargo ships, smugglers at airports, and daring swimmers.
Some sea snakes migrate across Australia every now and again, but most of the North and South Islands are too cold to maintain them on a long-term basis outside of the summer months.
There are lots of other areas without snakes if you want to be technical.
For example, because Vatican City is devoid of animals, it does not contain snakes.
Many small islands, ranging from Johnston Atoll to the Pitcairn Islands, are serpent-free—and generally human-free, as they are typically extremely small pieces of land that few people will visit.
However, with the exception of one dreadful Brazilian island, there aren’t many reasons to avoid a location just because of its snakes.
Even the most terrifying creatures have a vital role in their ecology.
Many of them are even pleasant to be around.
Some even conduct activities that directly help people, such as managing mouse populations.
We simply think it’s weird that they either crush their victim to death (assuming they don’t just inject it with venom) or devour it whole.
But this is simply another confirmation that snakes are amazing creatures.
It could be a good idea for us to quit attempting to avoid them.