Friday, November 26, 2010

Catching Some Rays

         
     Perhaps you’ve seen them lined up on a log sticking out from a lily pad covered beaver pond.  Maybe as you’ve floated down the river, waving your arms to maintain your balance and keep your beer can from dipping into the warm water, you’ve spooked some into plopping in from the overhanging branches with a splash.  A turtle’s domed shell enjoying the sun’s rays above the water is an iconic image.  As winter begins its snowy embrace, day dreaming about basking in the sunlight is not an unpleasant way to pass the time.

              Just about every species of turtle basks to soak up the sun.  Even highly aquatic turtles bask, like snapping turtles, but they do so without leaving the water.  These species may simply crawl into shallow water where they can benefit from the sunlight.  But, why do they go into all the trouble?

            One reptilian myth I’ve heard is that turtles must periodically crawl out of the water to dry off so they don’t become waterlogged and sink.  Well, this isn’t true.  Becoming waterlogged and sinking isn’t more of an issue for turtles than it is for fish.  As you might suspect, turtles bask to regulate their body temperature.

            Turtles are ectotherms, which means their body temperature is dependent on external forces.  The term, “cold blooded” has been largely abandoned because it gives the mistaken impression that these animals are relatively cool.  They’re not. In fact, some reptiles keep their body temperature warmer than we do.


            So, if the water’s cool, the turtles will climb out to warm up.  Warming their body helps them stay healthy and keeps their bodily functions running smoothly. For example, turtles tend to bask for longer periods of time after they’ve eaten a meal; they seek the added warmth to help their digestive system operate.

But, not just any basking spot will do.  Turtles often choose not to bask on structures too close to the shore; perhaps they perceive an increased risk of predation in these areas from animals such as raccoons or foxes.  They also prefer to bask in areas that allow them to have a clear view of their surroundings, to better see predators before it’s too late.  Another characteristic of basking spots include nearby deep water.  If a turtle is startled, it wants to be able to dive well below the surface, where it can wait until it’s safe.


            Who knew turtles could be so selective? With so many conditions about preferred basking areas, sometimes prime spots are in short supply.  And if there are a lot of turtles and only a few basking spots, it can get ugly.  Although many may picture a serene landscape of motionless turtles along logs when they imagine them basking, if you pay close attention you can watch turtles biting, crawling on top of each other, and even pushing their neighbors into the water!  Despite all the fierce competition among turtles, they actually benefit from sharing at least some of the space on their log.  More turtles means more eyes, and the more eyes there are, the more likely a turtle will spot any approaching predators.  If one turtle is startled, its neighbors will notice and they can all escape into the water together.

     This escape behavior has lead some to be concerned.  In many highly trafficked areas, where boats are a constant presence, turtles are often startled into the water while basking.  In some cases, disturbances are so frequent the turtle never feels comfortable basking at all.  This might affect the health of digesting turtles, or females with eggs inside.  Another basking-related concern is due to the questionable practice of “plinking”.  Plinking occurs when gunowners take target practice on basking turtles, maybe from bridges or boats.  For some rare species, plinking could deplete already small populations.  I'm not sure I understand the appeal of this activity and it's legal in several southern states.  Should it be?




Photos courtesy of Sean Sterrett.  For more information about river turtles and the conservation issues they face, the following book is a comprehensive review: The Ecology, Exploitation and Conservation of River Turtles (Enviromental Science)

Saturday, November 20, 2010

Knock Knock-Happy Holidays Edition



12/2/10 This tale has been confirmed as true by the parties involved, I include an update and additional photos below the original post.  Here's the story, in which yours truly is quoted.  The story has been picked up by numerous news outlets and is now being widely disseminated.  In all of them, I'm incorrectly identified as a "Florida graduate student".  Sacrilege!  War Eagle!


From an e-mail I received yesterday:

"Do you hang a wreath on your door?

(this was sent from someone in Slidell, La.):This is an unbelievable story!!! I opened my front door today to receive a FedEx package and as I shut the door I thought the wreath stuck me in the  head. After I shut the door I looked through the glass to see what it was that stuck me and was looking face to face with a 5’ snake. You can’t even see it as you walk up to the door. The wreath is over 5’ from the ground.  Still can’t figure out how it got up there??"  

  Perhaps you've also recently received this tale of holiday mirth and terror.  Unless you're a snake handler, this is probably not how you would prefer to celebrate Christmas. 

  In contrast to many "unbelievable" stories I receive via e-mail, I actually believe this one.  Perhaps I should clarify that I find the story feasible, I've grown far too skeptical to say with confidence that the described event actually happened. Let's put aside the questionable physics of opening a door and being bit by a snake on the other side and evaluate the biology, a topic closer to my area of expertise.

  The snake in the photographs is a Ratsnake (AKA chicken snake) of the genus Pantherophis (until recently it was considered Elaphe).  Those readers from the east coast may furrow their brow at this identification.  Although the snake looks superficially similar to the Black Ratsnakes (Pantherophis alleghaniensis) that reside north of Alabama and central Georgia and also similar to the Gray Ratsnakes (Pantherophis spiloides) that live south of this border, something seems off.  You're right. 


 You may notice that the blotches along this snake don't follow the same pattern observed in the above mentioned species.  In addition, although color is often a poor method of distinguishing closely related species (a single species of snake may have a lot of variation in color), the orangeish, light brown color of this Christmas snake is unique.  It's a Texas Ratsnake, (Pantherophis obsoletus).  Sometimes there are questions about where Ratsnakes can be found, but not in this case.  Despite its name, the Texas Ratsnake is found not only in Texas but also through Louisiana (including Slidell)

 Texas Ratsnakes, like all their Ratsnake brethren, are exceptional climbers.  They can easily navigate their way up and through the trees searching for potential prey, which include nestling birds or eggs or even perhaps the occasional lackadaisical squirrel.  Climbing a door, with its convenient window panes, would be no trouble at all.

 The dumbfounded e-mail also exclaims this reptilian caller was five feet long (about 1.5 meters).  This is also well within reason.  Ratsnakes may reach considerable lengths, a snake over seven feet long (about 2.2 meters) would be a very large individual, but they're out there.

 Perhaps the most questionable portion of the e-mail is the attack, which appears to have been unprovoked.  After handling many dozens of Ratsnakes, I've found that the species varies considerably in temperament.  When captured, some defend themselves vigorously with their mouth (their only weapon) while others seem perfectly content to be handled.  Although unlikely, I concede it's possible for an undetected Ratsnake to feel threatened by a human that gets too close, and then attempt to defend itself by striking.  Fortunately the species is not venomous and the resulting wound would be little more than a scratch.

  From the fancy footwork and "bite proof" glove displayed below (as well as the live snake), I assume the author of the e-mail had a relatively casual attitude about his visitor.  Perhaps he recognized the value of having a rodent-eating Ratsnake around and released the animal into the nearby woods.  Let's hope so.


12/2/10 Today I received an e-mail from the wife of the man in the pictures.  She notes the story is true and her husband was bitten by the snake as he sidestepped their incoming dog after going outside to receive the package.  Some additional photos are below.  We also have an answer as to the fate of this rat snake;  I'm afraid it's not a happy ending.  Again, here's the official story, which as I note, confirms the e-mail.









Friday, November 5, 2010

Announcing the Poise and Dignity Campaign


             Philosopher Alain de Botton has lamented the role of the pervasive advertisements we confront throughout each day of our modern lives.  These advertisements are conscious efforts to pervert and distort not only what we find valuable but what we should aspire to achieve and acquire in life.

            The media accosts us with stories and photographs they feel would be interesting to the general public.  They may not be deliberate attempts to guide our thought process, but are they not also conditioning us?   When we see, over and over, rattlesnakes killed or maimed and hoisted into the air as some macabre trophies, do we learn this is the appropriate way to interact with these animals (perhaps leading to event such as this)?

What happened to the animal that Dr. Robert Mount, in his seminal book, The Reptiles and Amphibians of Alabama, described as conducting itself with, “poise and dignity”?  Are they destined to serve simply as a thing to run over, hack with a shovel, and thrust towards the camera in some display of bravado?           

The Eastern Diamondback Rattlesnake is one of the top predators of the southeastern United States.  Their massive forms lay in wait around tussocks of wiregrass for potential prey like cotton rats.  Huge male snakes intertwine their bodies and reach towards the sky at right angles from the ground, engaging in ritual combat for mating opportunities.   As the weather begins to warms in the spring, snakes emerge from their winter refugia, such as a gopher tortoise burrow, the black and golden diamonds running down the length of their body appear in stark contrast to the sandy soils and sparse understory which typify their habitats.


Since I started this blog in April of 2009, my blog detailing commonly circulated pictures of dead rattlesnakes has received nearly 33,000 visits.   I’ve received 410 visits from people who have searched for the term, “large rattlesnake in florida”, 257 looking for information about a “giant rattlesnake”, 158 from those who’ve searched for, “largest rattlesnake ever killed”, 153 from those who typed “giant rattlesnake florida” into their search engine and 149 from those looking for information related to the “huge rattlesnake killed in georgia”.  Cumulatively, there are a lot of people interested in big rattlesnakes and when they look for information about these snakes, they find trophy shots of dead animals.

With this in mind, I announce the Poise and Dignity Campaign.  Let’s give all these people searching for information about giant rattlesnakes something to look at other than a mutilated corpse.  I’m soliciting high quality photos of rattlesnakes (of any species) demonstrating the poise and dignity these animals possess.  Photographs should not have evidence of human presence or interference and be accompanied by one to three paragraphs describing the encounter.  Once I have a number of stories submitted I will compile them (properly credited) and create a blog post to counter the dozens of trophy shots with which we’re bombarded.

            If you have an anecdote or story you’d like to share, please indicate your interest in the comments below and I will know to expect something from you.

12/10/10 Update: The compilation of stories has been published.  Now I'm collecting more for volume II!

Tuesday, November 2, 2010

A Giant Rattlesnake From Berkeley County, South Carolina




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Recently another large rattlesnake picture showed up in my inbox but without much accompanying information other than it was claimed to be from South Carolina. A quick internet search revealed some additional details.  Apparently, the snake was killed in Goose Creek, Berkeley County, South Carolina and measured six feet and seven inches long (~ 2 m).  It is now in the hands of a taxidermist.  I also read the snake was killed with jumper cables, which sounds like an odd and dangerous way of killing anything, let alone a large venomous snake.  Let's hope this part of the story isn't true, or at least that there's a rational explanation.

Although I can't confirm the details of the story, it generally appears plausible.  A snake this size is a huge individual but the length is within reason for a big, old, snake.  Today, the cotton rats have one less thing to be afraid of in their neighborhood.

Let's see how long it takes for these pictures to start circulating with a story about how it weighed 80 pounds and was ten feet long (and from your town!).


I've handled dozens of eastern diamondback rattlesnakes and have never been bitten.  It helps that I am extremely careful (and sober) whenever I do so.  This applies to dead animals as well, it's possible for your finger to nick a fang when moving around a dead snake.  Fangs may also poke out the side of the animal's mouth, so I'd advise against holding the snake as shown in the above picture.  With a little care and some distance, rattlesnakes don't pose much of a risk.  The safest strategy is always to leave these animals alone, particularly if all you have on you are jumper cables.