Thursday, September 16, 2010

An Eight Foot Rattlesnake in Cameron Park, California?!

   I was recently made aware of an apparently giant rattlesnake that slithered up to a wastewater treatment plant in Cameron Park, California.  Although geographically distinct from any area I know well, the theme is one I'm intimately familiar with.  So, let's proceed with our usual protocol of examining this dead snake and explaining why the stated size is outside the realm of biological possibility.

   Wait a minute...What do you mean they didn't kill the snake?  You mean to tell me they let this murderous beast go free?  Don't they know a snake this big could terrorize local communities and eat your children?  Just ask the local concerned resident (and amateur herpetologist?) quoted here.

   I am, of course, being facetious, but the mindset of the individuals that came across this snake is in stark contrast to what the typical "giant" rattlesnake encounters when unfortunate enough to be found by humans.  When this California rattlesnake was noticed by treatment plant workers, it was fortunate to be relocated to a nearby unpopulated area, but not before the obligatory photograph was taken.

  One associated article notes this rattlesnake was estimated to be five to six feet long.  That's a large snake and probably an exaggeration.  That's not their fault though, most people tend to overestimate the size of rattlesnakes.  Even small animals can appear quite impressive when they puff themselves up, assume a defensive posture, and start rattling away.  But, the snake in the photograph is definitely a large and healthy adult snake, it could very well be upwards of five feet long.  However, posing the snake closer to the camera than the man holding it is a camera trick explained ad nauseum here.

  Identifying rattlesnakes in the western portion of the country is harder for me than when dealing with our southeastern animals because we only have a handful of different species and they are relatively distinct.  In addition, the resolution of the above photograph is relatively poor, but by examining the range of California rattlesnakes we can narrow it down.

   The snake in the photograph appears to have a black and white striped tail.  This is often associated with Western Diamondback Rattlesnakes, Crotalus atrox, (a species often killed and photographed), but the species doesn't range as far north as Cameron Park, California.  Another species, the Western Rattlesnake, Crotalus viridis, might appear in the area, but the coloration and patterning don't appear right.  I initially gave the snake a tentative identification of Mojave Rattlesnake, Crotalus scutulatus.  This species can be found in central California and also tends to have a similar tail.  But a reader more familiar with the species of the region suggested it was too far north for Mojaves and it was likely a Western Rattlesnake after all.

 The largest known Western Rattlesnake (I'm referring to a specific species here, Crotalus viridis) was a little over five feet long.  So, the lower end of the measurement on the scene is feasible (but would make this one of the largest known individuals of this species ever); but again, the measurement was an estimate (and it's a good thing, because I don't recommend taking reliable measurements on a live rattlesnake).

  But, eyeball estimates are usually accurate, right?  It's not like anybody is going to say this snake was....Oh, I don't know...Eight feet long, right?  Well, besides this newspaper.

Monday, September 13, 2010

7 Foot Diamondback Rattlers in Poulan, Georgia?

   This morning I noticed a news article describing the harrowing tale of a giant rattlesnake killed last week in Poulan, Georgia.  If you follow this blog, you'll know my interest in giant dead rattlesnake pictures and how many tend to exaggerate the size of these animals to gigantic proportions.  If you're curious why I didn't include this story as an update to my blog debunking these often outrageous claims, the associated pictures aren't being circulated as part of an e-mail hoax (yet) but there are still some red flags to discuss.

  The news story notes that the "normal" size of an eastern diamondback rattlesnake, Crotalus adamanteus, is five and a half feet long.  Well, this isn't quite true, of the hundreds of these animals I've observed, captured, or found on the road (all as part of ongoing research), I don't know that more than a couple were this large, if any.  Now, don't take this to mean they're not out there, they are...but a snake this long would be a very large snake.  This is likely what they meant to say in the news article, that is to say, the normal size of an eastern diamondback rattlesnake isn't five and a half feet long, but if you asked most snake biologists what they would consider a big snake, five and a half feet is a good figure.

   So, how big do eastern diamondback rattlesnakes get?  Well, it's possible for a snake to reach seven feet long.  But it's hard to stress how unusual that would be.  As I note above, a five and a half foot diamondback is a monster snake.  There are probably less than five individuals measured in the last few decades that have broken the seven foot barrier.  So, to find a snake this big would be an extraordinary event and we should insist on proof when it is claimed.  Interestingly, the news anchor does note a seven foot long is incredible indeed, but they do occasionally show up.  As proof, he notes there was a seven foot three inch eastern diamondback killed last year in St. Augustine, Florida.  I discussed last year why that "measurement" is also suspect.

  In reading the news story and watching the embedded video, it's clear reliable measurements are not yet readily available.  The title of the news story notes the snake is seven feet long but the text notes it was "nearly" seven feet long.  Similarly, the video segments describes the snake as seven and a half feet, then "about" seven and a half feet.  Small differences?  Perhaps, but if there was a reliable figure associated with the snake I would expect them to stick with it.  It sounds as if the length of the snake was estimated, which we know is a questionable technique.  In looking at the pictures provided in the news story and video, it's clear we have a big snake on our hands.  But seven feet?  What do you think?