Monday, April 16, 2012

Humans and their Tall Tales of Snakes: Science to the Rescue

                Snakes.  Personally, I am quite found of them.  I like the large venomous ones that have a built in rattle.  I like that they can periodically refresh themselves with a good skin shedding that keeps them looking as young and vibrant as ever.  I like how their scales cover their surface like a roll of sequins.  Snake fondness could be the next fad with a little help from everyone, and science can help.
                I was just reading a study called “Defensive behavior of cottonmouths (Agkistrodon piscivorus)” by Whit Gibbons and Mike Dorcas and am reminded how we scientists can put myths to the test quite literally.  It’s one thing for snake lovers to say that people shouldn’t worry about venomous snakes and how unlikely they are to actually bite a person.  But people seem very confident that venomous snakes, in particular, are prone to chase a person down for a little venom therapy, just for funsies.  Sure, we can say “Approximately 8000 of the 310,000,000 people in the US will be bitten by a venomous snake—or ~0.026% of the population.” Or that “There are typically 12 or fewer deaths in the US per year for venomous snakes, or ~12/310,000,000, which is 0.0000039% of the population.”  Or even in our most confident voice “In contrast, there are roughly 40-50 deaths by lightning strike and 90 deaths by motor vehicle crashes each year in the US.  Come on people, evaluate the risks properly.”  But, nothing is quite as convincing as a nice hypothesis-driven study.  And, the study by Gibbons & Dorcas (2002) suggests that you are most likely to be bitten (and therefore in some unlikely cases die) by a venomous snakebite if you pick up and harass the snake.  So, I had to share the data:

                They had three treatments:  1) stand beside a snake (in snakeproof boots) while touching its body; 2) step on the snake midbody without injuring the snake; or 3) pick up the snake midbody with a pair of snake tongs that look like a human-hand and arm.  (Would love to see a picture of those, personally.)  And these (above) were the results they found.  Most of the snakes that bit were picked up with the human-like hand and had also been stepped on—so the more harassment, the more likely the snake was to bite.  Even still, 60% of the snakes did not bite when picked up.  None apparently chased the researchers when they were done with the study.  NONE! 
                So, if you do not want to be bitten by a venomous snake, then do not harass them or pick them up or kill them, just stand back and admire them.  Every living creature could use a little more admiration.  Myself included (husband, are you listening?). 

Friday, April 13, 2012

Just a Couple of Nice Days in the Field

We are having such gorgeous weather in wild & wonderful Ohio this week.  (I know weather is the stuff of old people, but I turned 40 this week and, therefore, must speak of gorgeous blue skies.)  Yesterday, I was out with my herpetology class looking for, well, herps, of course.  There’s a good crop of herpers in this group (too bad they are not reading this, because I’m sure that comment would give them a warm, fuzzy feeling).  We saw a few lovelies including the southern two-lined salamander, which we saw in all sizes, small larvae to big and chunky adult.  Such a lovely surprise to turn over a rock and find a salamander or snake.  Of course, we are turning rocks over for this very reason, but it’s still kind of like buying a lottery ticket…you don’t win every time. 

We also found a few snakes under some of those rocks—queen snakes and small northern water snakes.  A number of snake whisperers in class this year that seem to find them no matter where we are, but these were all hanging out at the water’s edge. 

Today I was out in the field for a bit checking my terrestrial pens. Notice anything?

I raised these northern leopard frogs from tadpoles in ponds and then placed them in these terrestrial pens.  As tadpoles, they were exposed to an insecticide at 2, 4, 6, or 8 weeks after hatching and we’re following them in the terrestrial environment to see if there are long-term effects from early life exposure.  The pens are only about 6 feet by 6 feet, but these frogs are hiding Houdini’s in the grass.  I’ll hop into a pen and see a frog, but I think they have a secret hidey-hole or two.  Fortunately, there’s one nice big hidey-hole, which we elegantly call “the central pit,” and when they are in there I can catch them better than a frog can catch a fly.  Aren’t they gorgeous?  This is the last part of a very long three year study, which has had more than the normal numbers of snags.  I’m keeping my fingers crossed for something really, really, really interesting.  However, even if it’s really, really, really not interesting, they still had me out on a nice 60 degree F day working my Jedi reflexes to catch these lovely beasts.  Science is good!