Thursday, March 17, 2016

Snakes - A St. Patrick's Day Tradition

It's time for my St. Patrick's Day tradition - sharing a photo of snakes.

A Northern Water Snake training for the future invasion of Ireland.

Legends says that Ireland has no snakes because St. Patrick chased them off of the island.  The story is that St. Patrick was involved in the middle of a forty day fast when he was attacked by snakes.  This angered Patrick so greatly that he chased the snakes into the sea and banished them from the island forever.  To this day, Ireland has no native population of snakes.

The truth is that there were never any snakes on Ireland for St. Patrick to chase away.  Ireland has been covered with glaciers during more than one ice age.  During the last glacial maximum, which occurred about 11 thousand years ago, three-quarters of Ireland was buried under a thick layer of ice.  The remainder of the island was too cold and inhospitable to support snakes and most other species of wildlife.

When the glaciers retreated, Ireland was temporarily connected to Great Britain and the rest of Europe by a land bridge.  This connection allowed some species to repopulate Ireland, but snakes did not make it across before the connection was severed by rising sea levels.  This isolation is the true reason for Ireland's lack of snakes, not an angry fifth century saint.

Michigan was affected by the same glacial periods as Ireland.  It also was scoured clean by a thick layer of ice.  However, Michigan remains attached to the rest of North America and snakes have repopulated both the Upper and Lower Peninsulas in the past 11,000 years.  A total of seventeen snake species currently call the state home.  I am glad that they are here.  They play an important role in the ecosystem as both predators and prey.

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