Ireland is an island and it is surrounded by the Irish Sea which is over 50 miles wide. This vast stretch of water makes it unlikely for land animals like snakes to reach Ireland by swimming. Even sea snakes, which live in warmer tropical waters, wouldn’t survive the frigid Atlantic crossing. St. Patrick rid Ireland of snakes in the fifth century by driving them into the sea. The truth is that Ireland never had snakes in the first place.
While the United Kingdom (U.K.) is also an island and has snakes, neither Britain nor Ireland had snakes for a long time. During the Ice Age, the islands were too cold for reptiles to survive. Their cold-blooded bodies require warmth from the surroundings to function properly.
When the glaciers retreated about 10,000 years ago, a land bridge between Europe and Britain, and another between Britain and Ireland, emerged, allowing animals to migrate. The land bridge to Ireland disappeared around 8,500 years ago, while Britain’s land bridge remained for another 2,000 years. This gave animals from Europe more time to colonize Britain, but there is no evidence of snakes in Ireland’s fossil record.
Apart from Ireland, other islands like New Zealand, Hawaii, Greenland, Iceland, and Antarctica also lack native snakes. Despite the global pet trade, the absence of snakes on these islands is remarkable, considering snakes’ potential to become invasive species.
In Guam, the invasive brown tree snake has caused significant damage to the island’s native bird and lizard populations. To combat this, authorities resorted to drastic measures, such as dropping dead mice laced with acetaminophen from helicopters to kill the snakes. While this method has been temporarily effective, it has not eradicated the snake population entirely. The U.S. Department of the Interior allocated millions of dollars to address the issue further.
In Ireland while pet snakes are legal and became popular during the economic boom of the late 1990s, many people released their snakes into the wild during and after the 2008 recession. Despite some sightings in random places there has not been widespread establishment of snake populations in the wild. It’s crucial to prevent snakes from establishing themselves in Ireland.
