Sunday, August 22, 2010

Mambas on the Loose in Minnesota

    A couple weeks ago an interesting news story about a snake in Minnesota caught my attention.  A family from Sauk Centre received a scare when a five foot long black serpent was spotted outside their home.  What happened next nearly defies belief.

     Black Rat Snakes range throughout the eastern United States.  One of the biggest species within this country, a large individual can span up to eight feet (2.4 m) long.  Harmless to humans, rat snakes feed on, you guessed it, small mammals such as rats and mice.  They’re also important predators of birds.  As they’re highly arboreal, the species spends much of their time crawling through bushes and trees and swallowing any bird eggs or nestlings they can track down.  Controlled studies have suggested rat snakes cue in on adult birds flying to and from a particular area to zero in on the location of bird nests.

    In the southeastern United States, the closely related Gray Rat Snake is commonly encountered crossing the road, lounging in trees adjacent to wetlands or taking up residence around farms.  Although they may not be a welcome guest within the chicken coop, many value the species for rodent control around barns and other buildings.

   Perhaps it’s because snakes are less common overall in more northern climates, but for some reason, although rat snakes are easily recognized as a normal component of the local fauna in the south, those in the northeast and Midwest often freak out and do very strange things when confronted by one.  I think people have a hard time accepting that such a large reptile could possible be a normal resident of their state, blanketed by snow through so much of the year.  Shouldn’t big snakes be found in Florida instead?

    But the fact is, big snakes do actually occur in areas that experience harsh winters, they just take up different strategies to cope with the cold.  For example, Black Rat Snakes, Timber Rattlesnakes, and Black Racers, all large snakes that can be found up and down the east coast, tend to hibernate in underground caverns and rocky caves.  Often, the different species can be found huddled together, perhaps due to a lack of suitable hibernation spots.  In this way they pass the winter months, while their cousins to the south enjoy much longer activity seasons and seldom find the need to escape the frost by engaging in a deep slumber.

   Black Rat Snakes are native to Minnesota, although the state is the limit of the species’ range and they are only found in the southeastern counties.  You may have guessed by now the snake found in Sauk Centre was a Black Rat Snake, but nobody there knew it.  I’ll spare you the details of this encounter, which ended poorly for the snake, but some on the scene were convinced it was a Black Mamba, a highly venomous species ranging through the nations of eastern Africa.  Despite their confidence in their identification skills, I doubt many there knew Black Mambas are actually green (unlike the Black Rat Snake before them).  Other theories suggested the snake was an escapee from a carnival that had passed through recently.

   In any case, when confronted with what some felt could be a highly dangerous animal (i.e. the Black Mamba), a particularly adventurous individual decided to kill it with an ice pick.  As an aside, if you’re ever walking through the wilds of Africa and suddenly come across what actually is a highly venomous snake, do not, under any circumstances, try to kill it with a handheld kitchen utensil.  Just walk away.

   The snake attracted more attention when it was dead than when it was alive, and I first heard of it in a news article that included a plea to contact the newspaper if the snake could be identified.  I responded, and after being provided additional photographs, confidently identified the species as the harmless Black Rat Snake I initially suspected.  The follow up story, in which yours truly is quoted, is here.

   As I mentioned, the Black Rat Snake is native to Minnesota (although only the southeastern corner) and this snake was found a couple hundred miles away from the nearest known population.  When I contacted the Minnesota Department of Natural Resources to ensure they knew of this possible range extension, I was informed their stance was this snake was captured elsewhere and released by someone in Sauk Centre.  To support their position, they noted that appropriate habitat didn’t exist in the area where the snake was found and the snake had subtle color differences that suggested it was from a population outside of Minnesota.  Although I didn’t find their conclusion particularly satisfying, considering how little we know about reptiles and how easy it is to overlook a species that was there all along, I concede I know just a small fraction of what they do about their local wildlife.  We’ll just have to wait and see if more rat snakes show up in the area.  If they do, I hope they’re spared the ice pick.

The first three pictures are of Gray Rat Snakes.  The final picture is of the Minnesota snake itself.


Bernard Brown said...

This story had me slapping my forehead too.

Anonymous said...

Black Mambas are actually green? Who wrote this story? Just one piece of advice, "research".

David Steen said...

A google search for black mamba images will reveal their color. Thanks for providing your insights.