Friday, September 23, 2011

These Stories Bite

A "seven foot" Eastern Diamondback Rattlesnake

Yesterday, two similar news stories caught my attention. In north Georgia, a large Copperhead was killed after it bit a dog.  In Fort Myers, Florida, a large Eastern Diamondback Rattlesnake bit and killed a dog. The size of both of these snakes was grossly exaggerated to make the stories more sensational, but we’ll return to that later. Both of these instances were unfortunate and tragic. The question is, are they avoidable?

They say that an ounce of prevention is worth a pound of cure; I think the expression is very appropriate here. Wildlife, including animals that are potentially dangerous, are a part of our natural world. The best way to minimize conflict with potential dangers is to learn how to best coexist with them.

If we knew a child that rolled around in poison ivy when they went outside, we would teach that child that this was not a good idea. If the child had a tendency to engage in some illicit foraging behavior, we would teach them which berries and mushrooms they should avoid. And if the child didn’t listen, they wouldn’t be allowed outside, for their own safety. The same applies for our pets. If a dog or cat cannot restrain themselves from investigating, and especially attacking, wildlife, then they need to be trained otherwise, or spend their time indoors. The outdoors is not a sterile environment, and I don’t think anyone really wants it to be either. Therefore, we should prepare ourselves, and our children and pets, for the reality of living in a world surrounded by nature, and natural things.

A Copperhead's camouflage helps it avoid predators
All snakes in this area of the world are very familiar with bobcats, coyotes, and foxes, because these animals are major predators. To avoid these animals, snakes have evolved different defense mechanisms, some are heavily camouflaged and remain still, some spend most of their time underground, and some have the speed to try to escape. There is no reason a snake would initiate contact with a large predator, but once they feel they have been noticed and are threatened, they will defend themselves. Why wouldn’t they? They think they are about to be eaten and in many cases that is exactly what happens. There aren’t as many bobcats, coyotes and foxes prowling our neighborhoods as there used to be, but our pet dogs and cats sure act like them sometimes. A threatened snake will defend itself against these animals just as it would defend itself against their natural predators.

In justifying killing the copperhead, the woman in north Georgia said something interesting:

 “It was either me or the snake”

Let us imagine that the Copperhead, after being confronted by a Rhodesian Ridgeback (a breed of dog that has been used to hunt lions), and a woman with an axe, had somehow gained the ability to think and speak. If it were to say, “It was either her or me” I would believe it. It was true after all, that the snake ended up getting killed.

On the other hand, we walk past snakes all the time and we do not see them. They do not harm us, and they have no interest in harming us. On the rare occasions when we do actually see snakes in our yard, it is not a life and death situation, for us, at least. We have the ability to walk away.

Killing every snake you see in your yard is not a long-term solution. For every snake that is observed and deemed an imminent hazard, there are probably a dozen that are not seen, and these inconspicuous snakes are content to remain out of sight. What does killing a snake accomplish when we ignore the reason it was there in the first place?

Baby Copperheads have yellow tails
to help them attract something to eat
Accidents will always happen. There is a chance that even a well-trained dog will have unfortunate run-ins with local wildlife. Therefore, it’s probably more effective to make sure the area around your home doesn’t attract snakes. Brush and wood piles are a good start, don’t have them near the house. When walking through the woods, keep your dog on a leash, especially if they are known to attack wildlife.

OK, now let’s get to the descriptions of the snakes included in the news stories. The Copperhead in north Georgia was apparently four feet long. This would be a very big individual, but it’s not impossible to imagine a snake that huge. They can even get slightly larger, but these would be very large, and very rare snakes. But, the Copperhead in the picture doesn’t look that big at all. I should say, it does “look” big, but that is because of some relatively simple camera tricks. The snake is held on a rake several feet closer to the camera than the woman holding it, this is a common technique for making fish, snakes, etc, look larger than they really are.

So, I was surprised when the story suggested that not only was the Copperhead four feet long, but a Georgia Department of Natural Resources biologist said it was one of the largest in Georgia. I suspected that there had been some creative use of quotations by the journalist, so I contacted Thomas Floyd, the GA DNR biologist quoted in the article. He replied,

The dead North Georgia Copperhead
“I didn’t say,  ‘… the snake was one of the largest you'll see in Georgia.’ which would lead the reader to believe this was one of the larger snake species in Georgia or a record specimen copperhead.  Instead I said, ‘This is perhaps one of the larger specimens that may be encountered in the wild on average’.”  

He also added that if we were estimate that the tines on the rake were five inches long, the snake probably was around three feet long. A big snake, but not “one of the largest you’ll see in Georgia” as the news story suggests, and not even close to being even the biggest Copperhead. Unfortunately, the story did not provide a link to the brochure Thomas provided, which describes how to recognize, and learn about, the snakes of Georgia.

Although “giant” Copperhead pictures rarely appear on the internet, this is certainly not the case for rattlesnakes. I refer the reader to my previous post about how big rattlesnakes usually get and how camera tricks make them look bigger. In short, although Eastern Diamondback Rattlesnakes could conceivably reach seven feet long, this would be extremely unusual. The snake in the picture is much closer to the camera than the man holding it. Although the snake appears to reach a height above the man’s head, it is being held at an angle and the tail doesn’t come close to reaching the ground. Unless this guy is seven feet tall, there is no way the snake is as long as claimed.

The Eastern Diamondback Rattlesnake eats primarily small mammals like rats, when they grow larger they can feed on animals as large as rabbits. Although they were once found throughout the Coastal Plain of the United States (and nowhere else in the entire world), their populations have started to blink out. The main threat is habitat loss, they prefer open-canopy forests, but road mortality, incidental killings, and rattlesnake roundups are helping push them towards extinction. Some have recently suggested that the species should be considered for protection under the Endangered Species Act.  If this happens, protecting household pets won’t be a great excuse as to why an endangered species was killed, it’s probably best to figure out now, on our own, how we can best share the same landscapes with these reptiles.

How do you keep your pets from having dangerous encounters with local wildlife? Share your tips below.


Copperhead photos are provided courtesy of Bill Sutton.

Friday, September 16, 2011

Living Alongside Wildlife

A Softshell Turtle Found This Summer Outside
Everglades National Park
sciseekclaimtoken-4e7620cd64472  Yesterday afternoon, as I was driving home from the University, I noticed both a red-shouldered hawk and a belted kingfisher sitting on a powerline overlooking a large pond bordered on two sides by highway. As the cars raced around me to be the first to the next red light, I wondered if anyone had noticed these two animals. Neither represented particularly rare species, but they usually attract my attention when I see them. You can often hear kingfishers before you see them; they have a distinct rattling call that they may give as they fly over ponds and streams. They are most often found in these areas looking for fish, which they will dive into the water to catch. The kingfisher I saw was staring intently towards the water, surely looking out for its next meal.

            The red-shouldered hawk was also looking towards the water, but their hunting strategy is different. Although they are also often found near wetlands, they are most interested in feeding on the animals that can be found in wetland edges, such as small rodents or snakes.

            Just off the road, across from hotels, gas stations, and restaurants, some wildlife species have persisted in the midst of human development. I would like to think that we can eventually come up with a strategy of developing the landscape that allows all native wildlife to persist, rather than us just being content with the species that are able to hang on as we pave what we like. But in any case, until then, I try to appreciate the wildlife that is around.

            Of course, not everyone shares this sentiment. Earlier this summer I received a call asking for help getting rid of a large snake from a yard in a nearby neighborhood.  Upon arrival, I lifted an upturned garbage can to find a large and perhaps confused gray rat snake looking back at me. The homeowner had been doing some yard work when he came across the animal. After picking up the snake and showing it off, I began to deliver my talk regarding how these snakes were harmless and how they fill important roles in the environment. I pointed to the lightly wooded areas in the neighborhood and the small stream and tried to emphasize how fortunate the man was to be living in an area that still maintained some semblance of nature. He agreed with all the of the points I was making, but suggested that if the neighbors saw the snake they would kill it, regardless of his own personal enlightenment. After surveying the area and the proximity of the neighbors, I reluctantly agreed to relocate the snake.

The Pond, as seen from my patio.
            I often wonder how most of the residents of my condominium complex would react after hearing about the wildlife that can be found just outside. My unit overlooks a small pond that, although probably created for landscaping, has become an excellent spot for observing animals, like kingfishers, several species of herons, and even the occasional beaver. At night, I am serenaded by the calls of multiple species of frogs, depending on the time of the year I can hear Fowler’s toads, Green Tree Frogs, or Gray Tree Frogs, for some examples. The pond drains into a small creek that, although heavily impacted by the nearby road, still harbors some interesting creatures. I suspect some of the animals in the pond have crawled in from this nearby creek, which also intersects the University.

The Nesting Spiny Softshell Turtle, Taken From
a Distance to Avoid Disturbance
            A highlight occurred earlier this year, when I noticed some disturbance in the water. After some investigation, I managed to make out the shape of a large Spiny Softshell Turtle on the shore of the pond, at the edge of the closely mowed grass. It was digging a nest and flinging dirt into the nearby water, this was the small commotion that caught my attention. I could not believe that I was able to watch this turtle nest from my porch, minutes from downtown Auburn and in the midst of a housing development.  

    Somehow these animals have found a way. As I think of all the snakes I have been asked to relocate from nearby neighborhoods, and all the turtles I have moved off of the road adjacent to the pond, I wonder if we have lost ours.

A newly-hatched Florida Softshell Turtle


This is my 100th blog post. Thanks everyone for reading.

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Monday, September 12, 2011

Rat Snake Freakout: Paradise Coast Edition

Photo Courtesy of Fingerprinceprints.com

For the last few days I have been monitoring a news story in Naples, Florida about an apparent python on the loose. First, a man spotted a large snake on his doorstep and assumed that it was a Burmese Python. A helpful neighbor noted that, "It kills." Mysterious flyers began to appear, warning residents of the python; that someone was putting up flyers suggested that the beast had escaped from a worried owner, but nobody could figure out who had posted them. Then, we started hearing about how pet owners were concerned about how the giant snake might eat their dogs.The Sheriff's office and the Florida Fish and Wildlife Conservation Commission were on the scene, but couldn't find the snake or confirm who had put up the flyers.


I was skeptical about this evolving story and I had some suspicions...now, they have been confirmed, kind of.

Upon further investigation, the "8 to 9 foot" snake was yellow. And, the flyers were not posted by a concerned owner looking for their pet, they were posted by the Homeowner's Association, and the Homeowner's Association had been tipped off by the people who had originally seen the snake. Everything leads back to the snake on the doorstep...the yellow snake.

Is it possible that there is a large yellow python on the loose in the neighborhood? I suppose so, pythons have established themselves in south Florida and made a problem for themselves (but they would never be mistaken for yellow). And, pet breeders have created lots of strange looking animals (including ones that may appear yellow), but they are expensive and it is unlikely that someone would have let their snake escape without putting up a fuss.

Photo Courtesy of Fingerprinceprints.com
What I think what we have here is another Rat Snake Freakout. The Rat Snake that can be found throughout peninsular Florida can reach 7 feet long and is commonly called...wait for it...the Yellow Rat Snake. If you have already read my other posts on hapless rat snakes confronted by angry and confused people, you will know that even though rat snakes are common throughout eastern North America, even though they are completely harmless to people, even though they are considered beneficial because of their habit of eating rats and mice, their large size inspires some very strange reactions. These reactions often included mistaking Rat Snakes for pythons, boas, mambas, you name it. I think it is just very hard for many people to accept that big snakes are a normal (and harmless) component of our native wildlife fauna.

So, I could be wrong, but I think Naples can come off of high alert and relax in the knowledge that the snake rampaging through the neighborhood is probably just a Yellow Rat Snake looking for somewhere to hide out. I hope that everyone curious about native snakes decides to visit Corkscrew Wildlife Sanctuary, in Naples, where you can find Yellow Rat Snakes, or maybe spend a little time reading about all the other snakes that can be found in the area. Like I said, I could be wrong, if that is the case I apologize in advance to everyone, but until someone brings up some bona fide evidence of a yellow python, I think everyone in Naples can tell their grandchildren they don't need to cancel their visit.

It sounds like people have started coming to their senses.



Got a story that you think is a case of a Rat Snake Freakout? Let me know.

Friday, September 9, 2011

Things That Creep in the Night

I. inornatus

         Earlier this year, I found myself in a tropical downpour, surrounded by a Central American jungle, and with my nose running like a faucet.  I was afflicted with what my advisor had dubbed, “Black Elk Disease”, resulting in my words turning into grumbling sounds that seemed to emanate from the depths of my stomach. I tried to shake my grogginess off; I was supposed to head into the forest that night to look for snakes crawling through the dense shrubs and trees. So far, I would imagine this sounds like Hell on Earth for many people. But, it was actually an incredible opportunity.

            I had returned to La Selva in Costa Rica to conduct a study that aimed to determine how two closely related and superficially similar species of snakes could inhabit the same area. One of basic foundations of ecology (i.e., the study of factors that influence the distribution and abundance of organisms, and my area of interest) is that species compete for resources. If two species eat the same type of food and live in the same type of habitat, then one species will eventually be outcompeted (assuming that there is a limited amount of these resources). What happens next is a tricky question, but the answer probably occurs over a long period of time. In some cases, the lesser competitor could go extinct. Another potential is that the lesser competitor eventually evolves to reduce competition. The classic example of this type of change, often dubbed Character Displacement, is that of the Galapagos finches. Finches evolved different beak shapes that allowed them to feed on unique seeds (and other items). By each species using a different resource, they were all able to thrive; this resulted in a high diversity of species in one area.

I. cenchoa
            The snakes I was interested in are both considered blunt-headed vine (or tree) snakes that are in the same genus (Imantodes). Both species are extremely slender, similar sized, arboreal, and their head shape (which can be an indication of what a species eats) looked identical. The only difference between them seemed to be their coloration: one species tended to be light brown with dark spots and the other was yellowish. At first glance, you might expect that these two snakes competed for everything, but the fact that they were both able to occur in the same jungle suggested that there was more to these snakes than their appearances.

            My hunch was that these two species, although they seemed to be in the same forest at a large scale, actually divided up their habitats at a smaller scale, which allowed them to reduce competition between them. To test this hypothesis though, required finding the snakes and comparing their locations, hence my trip to Costa Rica.

            Fortunately, my sickness was temporary, and I was able to head out most nights to look for snakes. Accompanied by my advisor, the protocol was to slowly walk along the extensive trail system of La Selva while shining our headlamps into the leaves and branches that enveloped us on all sides. It was slow going; the snakes were so slender that they can easily blend into the dense vegetation. We were required to spend a lot of time hiking around before we could find many snakes. In the meantime, I tried to convince myself that the occasional noises we heard emanating from the forest were unlikely to be from a jaguar stalking us (although they are known from the site).

I. cenchoa
Kinkajous, which are nocturnal and terribly curious animals, were frequently noticed as they crashed through the tree canopy above us to get a better look at the herpetologists below. Kinkajous are in the same family of animals as raccoons, but these fruit-eating creatures look more like a cross between a ferret and a lemur. Shining my headlamp into the trees above us would occasionally reveal the eye-shine of a kinkajou looking back down at me.

            Preliminary research had suggested that one of the species, Imantodes inornatus, is found more often in swamps while the other species, Imantodes cenchoa, occurred more often in dryer portions of the forest. This could be the key difference in behavior that resulted in reduced levels of competition. Once we had found a snake, we would record its location. This location would later be placed on a map of the site and by measuring the distance to the nearest swamp, we could determine whether the different species were located closer to swamps than we would expect than if they were found in random locations.

I. inornatus
In addition, the previous study had suggested that the two species of snakes might prefer to eat different things. Since snakes investigate scents by flicking their tongue, it is possible to know how interested a snake is in a particular item by counting how many times they flick their tongue. So, we also captured various lizards and frogs we encountered during our night hikes and later in the study we would rub a Q-tip across one of these animals and put it in front of a particular snake. If one of snakes flicked its tongue at one type of scented Q-tip more often than expected, we could conclude that the snake prefers that prey type.

We were only able to find about ten or so snakes after about two weeks at La Selva, not a particularly good haul and not enough to come to any firm conclusions, but our preliminary data did seem to support the suggestion that although the two species appeared very similar, they are probably using different resources. On my last day in La Selva, as I released all the animals we had captured, I considered how amphibians and reptiles seem to be declining overall at the site and I wondered if our inability to catch more snakes could be attributed to this trend. It is difficult to know.

In any case, I am looking forward to my next study at the site: I will be trapping mud turtles in a few La Selva swamps and comparing my results to some old data to determine how their populations have changed over the last few decades. Of course, I’ll also be keeping an eye out for more blunt-headed snakes.

Not all of the snakes I found were harmless. Rainforest Hognose Pitviper
 --------
Much of what I write is based on my own experience, but I also rely on the research of others.

Whitfield SM, Bell KE, Philippi T, Sasa M, BolaƱos F, Chaves G, Savage JM, & Donnelly MA (2007). Amphibian and reptile declines over 35 years at La Selva, Costa Rica. Proceedings of the National Academy of Sciences of the United States of America, 104 (20), 8352-6 PMID: 17449638

Wednesday, September 7, 2011

A 25-pound rattlesnake in South Carolina? Unlikely.

The reportedly 5.5 foot long, 25 pound rattlesnake
This morning I was made aware of a large Eastern Diamondback Rattlesnake that had been captured on Hilton Head Island in South Carolina. This in itself isn't too surprising, the species can range up to North Carolina and are often found on barrier islands. Although, there isn't much habitat left for snakes on these islands because they are popular tourist areas.

In any case, the articles describing the snake's capture note that the animal was five and a half feet long. This is a very large individual but well within reason. However, the weight of the snake is particularly puzzling: 25 pounds. This is well beyond the mass of any rattlesnake I have ever heard of, regardless of length.

To determine if it is conceivable for a 25 pound rattlesnake to exist, I looked through some snake data I had from Alabama and Georgia. Over the many years of trapping represented in my data, not a single rattlesnake reached 5.5 feet, so it wasn't possible for me to directly compare. However, there was one large rattlesnake that was 5.3 feet long. This snake weighed only 6.5 pounds. Using this information, I tried to crudely estimate how much I would expect a 5.5 feet long rattlesnake to weigh. A 5.5 foot snake is only 1.03x larger than a 5.3 foot snake, but I decided to be extra-cautious and estimated that it would weigh 50% more. As an analogy, this is like saying if a man that is 5 foot 9 inches tall weighed 180 pounds then a six foot tall man (someone about 1.04x taller), would weigh 270 pounds (180 pounds plus 90 pounds, which is 50%). Just three inches taller but 90 pounds heavier.  I think we can all agree this is probably a generous estimate.

Using these rough and crude numbers, I estimated that a 5.5 foot long rattlesnake would weigh 9.75 pounds (again, this is probably way, way more than it would really weigh, I just wanted to know if there was any chance of finding a 25 pound rattlesnake). Well, we are still about 15 pounds under. Not even close. Okay, but you might argue that a snake's weight can be influenced by a recent meal. I agree. So let's try to factor that in.

The largest prey item a big rattlesnake could eat is probably about the size of a rabbit. But, a big rabbit only weighs about four pounds. So, our theoretical snake, which was already morbidly obese at 9.75 pounds, would have to eat about four rabbits at once to reach 25 pounds. This just doesn't seem realistic and I am going to conclude that the reported weight is bogus. All of these estimates of course, assume that the length of the snake wasn't exaggerated. If the snake was actually smaller it would be even more of a stretch to say it weighed so much (off the record, the snake in the picture does look like it would be smaller than 5.5 feet long, but I can't say with certainty how long it was).

A large rattlesnake from southwestern Georgia
But, I only had a small sample size of snakes to examine and I wondered if it was possible that others may have data for larger snakes. So, I looked through a recent paper that reported the weights of the biggest Eastern Diamondback Rattlesnakes that were brought into Alabama and Georgia rattlesnake roundups each year for the last few decades. In these roundups, prizes are awarded for the largest snake, so there is a big incentive for people to bring in the biggest and baddest snakes they can find. Since 1959, the biggest rattlesnake was only about 15 pounds (this must have been a massive and impressive animal) and on average, the snake that won the prize for being the biggest in a given year was less than about 11 pounds.

I am going to read between the lines and hope that this South Carolina rattlesnake story has some good news. It sounds as if accurate measurements weren't made for the snake possibly because it was relocated alive elsewhere and nobody wanted to take the chance of measuring a large and ornery rattlesnake. In that case, let's cut some slack to all those involved. Perhaps the snake is growing heavier as we speak.

Added 9/9: For reference, here's an Eastern Diamondback Rattlesnake that is about 5'6" long (perhaps slightly larger) captured as a component of a research project in southwestern Georgia. The snake weighed less than nine pounds


D. B. Means (2009). EFFECTS OF RATTLESNAKE ROUNDUPS ON THE EASTERN DIAMONDBACK RATTLESNAKE (CROTALUS ADAMANTEUS) Herpetological Conservation and Biology, 4 (2)

Monday, September 5, 2011

Readers Write In: Name That Snake

Snake #1 (bonus points for describing the behavior)
Over the past year or so, numerous people have taken me up on my offer to answer their wildlife-related questions. A common theme is that of the mystery snake; these e-mails are from people who have spotted a snake in their yard and are curious to know what species the animal represents. Some of these folks tend to be shoot-first-ask-questions-later types, but I appreciate their interest. Many do realize that not every good snake is a dead snake, but do not want to take the chance of having a venomous snake around their home, particularly if there are children or pets present.

Snake #2 (bonus points for describing the behavior)

So, although I answer all the e-mails I receive directly, I wanted to post the pictures here so that others can learn how to identify the snakes and determine whether they are venomous. The purpose of this blog post is two-fold; I recently integrated a new commenting system and I want to know if it works well (for you and me). You'll notice you can now sort comments and 'reply' or 'like' specific comments.




Snake #3
I am looking for your participation. For each picture, please identify the snake, share some interesting natural history information or perhaps a relevant personal anecdote , tell us how to determine whether the snake is venomous or not, and how it can be differentiated from similar looking snakes (particularly venomous ones). If you are an earlier commenter, please leave some pics for others to address. And let me know if you like/dislike the new commenting system.

To everyone curious about snakes and other wildlife, keep the pictures and questions coming.

Snake #4

Snake #5

Snake #6

Snake #7