Tuesday, July 31, 2012

Bring Your Boots to Arizona (or Texas)? Sure, But Not Because of 15-foot Rattlesnakes!

In the last week, I have received two e-mails about a large dead rattlesnake that I first wrote about years ago (thanks Brenda G. and Penny B.). These new e-mails claim that the animal in the pictures is a fifteen-foot Western Diamondback Rattlesnake (Crotalus atrox) recently killed near either Mesa, Arizona or Dallas, Texas (I'm sure there are other versions I'm not aware of, let me know in the Comments). An additional note has been added discouraging readers from looking for golf balls that are out of bounds.

If this e-mail is what brought you to this blog, let me assure you that the story is bogus for several reasons.

1) The snake is an Eastern Diamondback Rattlesnake (Crotalus adamanteus) not a Western Diamondback.

2) The animal was killed years ago in Florida.

3) Fifteen-foot rattlesnakes do not exist, an animal half that size would be huge. The best measurement we have for this snake is seven feet and three inches (and I've already written why I think even this measurement is exaggerated).

The e-mail also contains numerous "facts" about this snake, I include them below. They are all false.

"One bite from a snake of this size would contain enough venom to kill over 40 full grown men.

The head of this snake alone is larger than the hand of a normal sized man.

A bite from those fangs would be comparable to being stabbed by two curved, 1/4 inch diameter screwdrivers.

The knife being used to draw out the fangs for the bottom picture has a blade around 6 inches long. 
This snake is estimated to have weighed over 170 pounds.

Notice the girth of this snake as compared to the cop's leg in the first picture (and he is not a small man).

A snake of this size could easily swallow a 2 year-old child and dogs, pigs, etc). 

A snake this size has an approximately 5 1/2 foot accurate 
striking distance (The distance for an average size rattlesnake is about 2 feet).

This snake has probably been alive since George Bush Sr. was President."

Monday, July 23, 2012

Try Not to Step on Any Pythons

     Last spring, as I stood in a dry marsh on the border of Everglades National Park, I paused to study the vast landscape. I squinted my eyes to make out any movement in the endless sea of green before me, straining to see my quarry as the morning Florida sun rose and drew sweat on my forehead while simultaneously baking the dirt into my skin. I was looking so intently because I knew there were large pythons hiding in the grassy vegetation right in front of me, several of them, up to thirteen feet long. But there was no clue that these massive snakes were just a few steps away, they gave not even a hint of their presence. The only reason I knew they were there was because I had put them there and the beeping radio-receiver in my hand told me that they hadn’t left.

The people walking around in the study plot in front of me, probing the tufts of grass with various poking instruments, hadn’t had much luck either. For all they knew, there weren’t any snakes there at all. I looked to the adjacent study plot and noticed a black labrador retriever prancing and bounding enthusiastically. It had found a python.


             A few weeks prior, I had been thrilled when my friend and colleague Christina Romagosa offered me the opportunity to help out on a study she was coordinating related to Burmese Pythons (Python molurus) in Florida. Burmese pythons, as you are likely aware from their name, are not originally from Florida, but you can be sure that they are there now. How they became established in the United States is a matter of some debate and controversy, but the most plausible story I have heard suggests that the thousands of pythons that now roam southern Florida descended from a small group of individuals that were destined for the pet trade but ended up escaping (or were released) instead, probably sometime in the 1980s. Since that time, additional releases and escapees have supplemented the rapidly growing population.
Melissa (on right) showed us the ropes
   Most of the time when a species is introduced to a new area, they disappear into the forest or some backwoods swamp and quietly live out their lives, perhaps quickly eaten by a native predator that takes advantage of the new creature’s naïveté in the strange land. But every so often, an organism comes along that makes itself right at home. Perhaps they are able to outcompete native species and use up more than their fair share of a limited resource. Perhaps, on the other hand, they skip the competition bit and simply excel at eating up all the natives. These introduced species are considered invasive, because they wreak havoc on native ecosystems.

When it comes to species displaced to areas where they are not native, you can imagine that Burmese Pythons are not the quiet type. Biologists have been sounding the alarm for some time now, alerting everyone that would listen about the potential effects of an established python population in Florida. Concern was raised about all the animals they pythons were likely to consume, including endangered wood rats, key deer, even Florida’s iconic swamp king, the alligator. No amount of concern, however, could stop the ecological process that was already underway. A recent scientific article describes how encounters of medium-sized mammals in the Everglades have decreased dramatically, a decrease that coincides neatly with the increase in the numbers of pythons. Put two and two together, and the most logical explanation is that as the python population increases, they are eating everything else into oblivion.

     That pythons are eating things is not a controversial suggestion. Where and when they will stop doing so is another matter. Scientists have tried to predict how far the python invasion will spread, as the giant snakes eat and slither their way across Florida, but different predictions (i.e., models) have led to different results. There was even a study done in South Carolina to determine if Burmese Pythons could survive the winter in areas less tropical than Florida (the verdict: not really). But, in any case, what we can all agree on is that today, southern Florida, and most notably, the Everglades National Park, is overrun with exotic giant pythons.

    However, determining if there are any pythons in any specific spot can be a tricky matter. Snakes are exceptional at camouflage and in being inconspicuous in general. Christina wanted to know how good we can be at finding pythons, and by extension, evaluate our ability to determine when and where the population was spreading. We are at a disadvantage though, when compared to canine searchers. Dogs are well known for their ability to sniff out drugs and bombs; but recently, biologists have taken advantage of their exceptional sense of smell and trained some dogs to find things like snakes. Large study plots in the grassy areas just outside the border of Everglades National Park were to be filled with zero to three pythons. My job (for the week) was to help keep track of how long it took people to find the snakes (or, sometimes, how long it took them to tell me that they gave up) and, separately, keep track of how well detector dogs fared in other plots.

A typical study plot. See the pythons? Me neither.
On my first day, I was skeptical. The study plots reminded me of somebody’s freshly mowed front yard. How in the world, I imagined, could a ten-foot (or larger) animal escape detection for more than 30 seconds in this type of habitat? The answer, it turned out, was quite easily.

In the morning, before the searchers (both humans and canine) arrived, we drove through the study plots and dropped pythons out of the back of a pickup truck. It was necessary to do so because otherwise the dogs would have cued into our scent, leading them right to the snake. I watched with amazement as the pythons uncoiled themselves, took survey of their surroundings, and then just disappeared into the undergrowth.

Trying to remember how radio-telemetry works
The pythons we were using for the study had all been captured in and around Everglades National Park. And, as you can imagine, there was some concern that the pythons would escape and crawl right back. So, each snake was implanted with two radio-transmitters (one a back-up in case the first failed) that allowed us to keep track of its location. Before any searchers began looking for the snake, I walked the perimeter of the study plot with the radio-receiver, confirming that the snake (or snakes) was still within the boundary.

The highlight of the experience for me was when I was supervising two individuals tag-team a study plot. They were covered in expedition gear, looking like a combination of Crocodile Dundee, Steve Irwin, and the Predator.

Bagging a python at the end of the day

 They confidently strode through the grassy study plot, chatting and occasionally investigating a shrub or two. When they finished, in record time, they pronounced their disappointment at being assigned a plot with no snakes.

“Would you be surprised if I told you that there was a python in this study plot?”           

Surprised? They wouldn’t believe me, they said.

I admit I took great pleasure in then leading them around the study plot and showing them not one, not two, but three pythons hiding among us. I don’t know how they avoided stepping on any of the great snakes, which together measured about thirty feet.

At the end of each day, my partner and I retreated to the Key Largo cabin we were provided for helping out on the project. While eating on the dock and drinking margaritas as the waves lapped against the shore or kayaking around the bay as storm clouds gathered in the distance, I imagined that I was finally getting to enjoy one of the perks of being a field-biologist, that is, helping out and doing field work in exotic and tropical locations. The thrill, however, was somewhat diminished by the 4:30 am wake-up calls. It was necessary, after all, to drive into the park and set up the study plots with pythons before the searchers arrived (at a much more reasonable hour). Exhausted by the sun and our schedule, we stayed awake to explore the Everglades only once. The manatees cooperated and revealed themselves to us, on the other hand, the American Crocodiles (Crocodylus acutus) did not.

            Monitoring plots wasn’t the only task at hand. Christina was also interested to know whether people and dogs could find pythons in areas that more closely resembled the habitats that pythons preferred, that is, the canals that crisscross much of South Florida. The brush and vegetation surrounding many of these canals were dense and overgrown, perfect hiding spots for snakes, which occasionally slip into the water to hide.  Because of concerns about live pythons disappearing into the drink, these trials involved us hiding a thawed out (and very dead) python.

In driving to one of these canals, we were all surprised when a silver streak jetted across the dirt road in front of us. Both the labrador and their trainer, Bart, (who were walking the road while we followed slowly in the air-conditioned truck) were shocked motionless as the streak appeared from one side of the road and, just as quickly, vanished into the other. Before we could get our bearings the creature appeared once again and disappeared into the brush from where it had first emerged. It was an incredible feeling to realize I had just seen (albeit briefly) a tegu, a large lizard distantly related to the racerunners found throughout the Southeastern United States. I didn’t expect to find them here, far from their native range in South America. Stocky and voracious predators, tegus are yet another emerging and invasive threat in Florida.

Driving back to Auburn after the week in South Florida, I reflected on how the dogs were exceptional at finding hidden pythons. Humans, on the other hand, performed decently. Would either be able to accurately inform us about the spread of pythons through the wilds and swamps of Florida? It’s unlikely we have enough dogs, or people, for that matter, to accomplish that feat.

Any story mentioning the Everglades must include photographs of alligators

Want to learn more? Check out these scientific articles:

Dorcas ME, Willson JD, Reed RN, Snow RW, Rochford MR, Miller MA, Meshaka WE Jr, Andreadis PT, Mazzotti FJ, Romagosa CM, & Hart KM (2012). Severe mammal declines coincide with proliferation of invasive Burmese pythons in Everglades National Park. Proceedings of the National Academy of Sciences of the United States of America, 109 (7), 2418-22 PMID: 22308381

Pyron RA, Burbrink FT, & Guiher TJ (2008). Claims of potential expansion throughout the U.S. by invasive python species are contradicted by ecological niche models. PloS one, 3 (8) PMID: 18698351

Rodda GH, Jarnevich CS, & Reed RN (2011). Challenges in identifying sites climatically matched to the native ranges of animal invaders. PloS one, 6 (2) PMID: 21347411

M.E. Dorcas, J. D. Willson, & J. W. Gibbons (2011). Can invasive Burmese pythons inhabit temperate regions of the southeastern United States? Biological Invasions, 13, 793-802 DOI: 10.1007/s10530-010-9869-6

J. D. Willson, M. E. Dorcas, & R. W. Snow (2011). Identifying plausible scenarios for the establishment of invasive Burmese pythons (Python molurus) in Southern Florida Biological Invasions, 13, 1493-1504 DOI: 10.1007/s10530-010-9908-3

Tuesday, July 17, 2012

Snakes Are Born This Way

   A friend recently forwarded me this video clip of a second-grade class demonstrating what they had learned about snakes in an excellent parody of a pop song that may sound familiar to you. Not only is the parody catchy-but they manage to throw in some great snake natural history information-including how snakes escape predation and how males engage in combat for access to females. From now on, you can rest assured knowing that I will be sending this video to everyone that tells me that they are afraid of snakes. We certainly don't have to be terrified by these animals. But you don't have to take my word for it...

Monday, July 9, 2012

Conserving endangered species means weaving together science, policy, education, and public participation

The following article is a guest post by Kyle Barrett. Kyle is a Postdoctoral Research Associate at the University of Georgia. His research addresses how large-scale environmental stressors such as urbanization and climate change influence the abundance and distribution of vertebrates. His current projects range from habitat conservation planning in the northeastern US to an assessment of sea level rise effects on marsh birds along the Atlantic coast of the southeastern US. Kyle received a B.S. from Middle Tennessee State University, an M.S. from Missouri State University, and a PhD from Auburn University. When not working Kyle enjoys good books, running, hiking with his family, and drinking beer.

  There are few among us who do not delight in experiencing wild things – a beautiful spring flower blooming on the forest floor, a chorus of frogs mid-summer, or even a foraging squirrel observed from the comfort of the dining room table. There are even fewer who would not at least take pleasure in watching formerly wild things play, eat, and roam in the zoo or in an aquarium. In short, our species seems to be pretty partial to nature. It is this partiality that leads us to want to leave some space for wild things to remain in the wild. But sometimes, of course, the way we use our natural lands and resources is incompatible with the needs of wild things. That’s where the Endangered Species Act (ESA) comes in. In the United States, the ESA is our sole means of legally mandating conservation efforts. Although many aspects of the ESA are controversial, one survey of public opinion revealed that over 80% of the general public would like to see the ESA remain as written or even strengthened.

  I had cause to reflect on the ESA, and conservation of species in general, when I recently made a visit to several mountain bogs in northern Georgia to see Bog Turtles (Clemmys muhlenbergii). This is North America’s smallest turtle, and it’s federally endangered (that is, protected under the ESA) in the northern portion of its range (it is listed as endangered by the state of Georgia, which affords it additional protections within the state). This secretive species inhabits mountain bogs in the south (but can be found in other wetland habitats at lower elevations further north). Bog Turtles are rare mainly because of habitat loss (due to draining of wetlands for land development, habitat inundation from water impoundment, or similar issues) and because they are often collected for pets.

  Over the last year, I’ve had the pleasure of working with a very 

talented student at the University of Georgia who is extremely passionate about these little turtles. Theresa Stratmann has spent years keeping track of these animals at bogs throughout the Georgia mountains. She, and several others in the state, work tirelessly during the summer to collect data that will help us learn more about the species. Research is an essential component of species conservation, as we cannot conserve what we do not understand. And while research is extremely important to keeping wild things in the wild, it is certainly not the only means to this end. I envision conservation as a patchwork of contributions - research, public participation, education, and policy being the primary contributors to the integrity of the fabric.

Bog Turtle Habitat

  As I drove through the winding mountain roads this week, we stopped at a few bog sites that were owned by either the US Forest Service or the state of Georgia; however, we stopped at many more sites that were privately owned. These lands were owned by individuals who were willing to maintain bog turtle habitat on their land, and even more than that, they were willing to allow Theresa and others to work with the animals on that land. Such
public participation in conservation efforts, especially related to federal threatened and endangered species, is vital. It’s been estimated that up to 80% of federally protected species occur, at least in part of their range, on private lands (Schwartz 2008). Without the participation of these landowners, recovery efforts would be greatly hampered. 

  There is a sentiment among some that having a federally listed species on their land might result in property use restrictions that could
inhibit economically-beneficial development. But, these concerns aren’t necessarily true; in fact, the ESA now allows for the creation of Habitat Conservation Plans (HCPs). These plans maximize benefit to provide private landowners and species alike by providing the landowner a guarantee that they can continue to use their land in certain ways, ways that are compatible with the needs of the rare species. As the National Audubon Society reports, these plans vary greatly in both the amount of land and the amount of time they cover. At one extreme an HCP permitted the construction of a residence on one-half an acre in Texas where the endangered Golden-cheeked Warbler resided, while another HCP in Washington State address 170,000 acres and hundreds of species for 100 years. An assessment of such HCPs in Georgia recently indicated they do not have any significant negative influence on land values. The landowners that allowed us onto their land this week were giving up very little to promote the long-term persistence of a special species.

Representative Bog Flora

  Why do some landowners agree to give up their ability to do whatever they want to their property and agree to participate in the conservation of rare plants and wildlife? There is little doubt that the education and experiences of these cooperative landowners influences their willingness to contribute to conservation efforts. Positive interactions with wildlife and an understanding of wildlife-habitat relationships can promote an individual’s willingness to contribute to the persistence of wild things through donations of money, time, or simply permitting the wild things and the people that study them to share their land.

  The goodwill and hard work of landowners, conservationists, and researchers are, in some cases, insufficient to save species on the brink of extinction. In these situations policy can provided additional resources to extremely rare species requiring urgent intervention. Such intervention might take the form of habitat management, human-assisted movements of species (away from development or toward breeding opportunities), or mitigation of threats to the species. Strong legislation, such as the ESA, can provide a platform for all of these types of actions.

  For legislation such as the ESA to be enacted, the citizenry must be educated and they must be supportive. The needed education is informed by research and the research is facilitated by public engagement. Conservation is an interwoven fabric of professions, experiences, and personalities. Conservation is informed by science, but it is propelled further by individual passions for species such as the bog turtle. All of us – landowners, scientists, policy makers, voters, teachers, and lovers of nature can readily contribute to the patchwork. The persistence of bog turtles, and the many other wild things that we live alongside, depends upon us making those contributions. 


Want to Learn More? Check Out These Scientific Articles:

B. Czech, & P. R. Krausman (1999). Research Notes Public Opinion on Endangered Species Conservation and Policy Society & Natural Resources: An International Journal, 12 (5), 469-479 DOI: 10.1080/089419299279542

C. Langpap, & J. Kerkvliet (2012). Endangered species conservation on private land: Assessing the effectiveness of habitat conservation plans Journal of Environmental Economics and Management, 64, 1-15 DOI: 10.1016/j.jeem.2012.02.002

M. Schwartz (2008). The performance of the endangered species act Annual Review of Ecology, Evolution, and Systematics, 39, 279-299 DOI: 10.1146/annurev.ecolsys.39.110707.173538