Monday, July 31, 2017

Gulf Coast Toads in Alabama? Yep, Confirmed.

    It was dreadfully dry in the Southeast last fall, and many animals were hard to come by that season. But on a weekend hike with his family in Montgomery, Alabama, Roger Birkhead discovered something new and noteworthy.

    I’m sure they were relishing that day in true Birkhead form – tromping through the forest, rolling over logs, and catching many odd little beasts that they happened to encountered. And when Roger flipped over an old and desiccated board, they sure did find an odd little beast. It was a toad, but not any regular Alabama toad. After a quick double-take, Roger’s internal herpetology alerts fired off, and he recognized that it wasn’t one of the four usual Alabama toads. This particular one was strange. it had irregular and bold crests on its head, with dark pigmentation dotted in lines across it’s body.  Roger, being the keen natural historian that he is, collected it for further study at the Auburn University Museum of Natural History, and this is the story of how the first Gulf Coast Toad (Incilius nebulifer) was recorded in the state of Alabama.

    The Gulf Coast Toad has a pretty massive geographic distribution, which extends from basically Mexico City, Mexico, north along the Gulf Coast into Texas, and as far east as barely reaching into southern Mississippi. Now, one might think – “How did a Gulf Coast Toad doing in central Alabama, so far from the species’ native range in Texas, Louisiana, and Mississippi?!” Could this be a non-native population that has recently been introduced into Alabama? Potentially, yes. But also maybe not. While Montgomery is a considerable 300 mile stretch from the closest known populations in Mississippi, 300 miles isn't really that far of a gradient of ecological change for a species which spans latitudinal habitat from Mississippi all the way to Mexico City. 

    With this alternative viewpoint in mind, I can think of three hypothetical scenarios to explain the presence of this toad in Alabama. That specimen could have been: (1) a single, errant, non-native specimen, which jumped off a truck (or some-such random mechanism) and which does not represent a native breeding population, (2) a specimen which does represent a breeding population, but which is not native to the area and was recently established, or (3) a specimen which represents a breeding population, which is actually native, and has been here all along – and nobody ever noticed it! To eliminate one or more of these hypotheses, we need more data!

    Thus, my guy Roger was keeping his eye on the weather this past spring for a good rainy night to return to Montgomery and try his luck for more Gulf Coast Toads. And with weather forecasts predicting rain on May 12, Roger put out the call, and Craig Guyer and I joined in for the fun.

    The rain never came, but we gave it a good effort. Near the original forest locality from 2016, we heard a large and diverse chorus of the summer-breeding frogs – Green and Bird-voiced Treefrogs dominated the soundscape, but Banjo, Bull, and Cricket Frogs contributed as well. And we saw a big old cottonmouth: as always, more fearful in appearance than disposition. We visited a few such wetlands, striking out on toads, and settling instead for the occasional Dewberries.

    But the first locality wasn’t the only card we had to play. We had recently gotten a tip from an Auburn herpetology student, Dani Douglass, who had recently photographed a Gulf Coast Toad hopping around her suburban neighborhood, a few miles away from Roger’s spot. So, we shifted gears and tried our luck at the neighborhood.

    As soon as we pulled in, we scored our target and found a Gulf Coast Toad in the middle of the road. This toad was dead, a recent victim of traffic mortality, but we were pleased to be off the schneid with our mission for the night. We bagged it, and kept on hunting. We explored the neighborhood a bit, and then moved to an old field nearby – a classic country dump, with garbage and beer bottles all over the place (Roll Tide). And that’s where we found the third and fourth specimens – a pair of big, mature Gulf Coast Toads hanging out beneath a wooden palette.

    Now let’s think back to the three hypotheses I proposed earlier. These accumulating observations are now suggesting that there are certainly multiple populations of Gulf Coast Toads living around Montgomery, which reasonably eliminates the first scenario. Given that these toads appear to represent a reproducing population living in pretty sub-optimal habitat in and around neighborhoods, which most native species avoid, we are thinking that these toads represent a non-native species that has been recently established (the second scenario). This is consistent with other studies which have found Gulf Coast Toads to be invasive in human-modified habitats in Louisiana and Mississippi, where they have been outcompeting and displacing a native species, the Fowler’s Toad. In this non-native and invasive scenario, Gulf Coast Toads might be exerting negative effects on the native toad assemblage.

    But it’s hard to eliminate the third scenario. Perhaps the Montgomery toads represent a native, disjunct population, which has just overlooked all along. To be clear, I am very skeptical of this hypothesis, given what we know about the species being invasive in other states. But we now have tissue samples from the specimens, and it’s possible to perform a genetic analysis to determine whether (A) the populations are genetically linked to populations elsewhere in the species’ range, or (B) if they represent a population with it’s own unique evolutionary history. The former result would suggest a human-mediated introduction of Gulf Coast Toads to the herpetofauna of Alabama, while the latter would suggest that the Gulf Coast Toad is a native and overlooked species in the state. An intrepid undergraduate or high school student should take up this project!

Tuesday, July 25, 2017

Researchers are Using Vibrators to Give Turtles Boners

Hey all, I hope you've had a chance to read my first article for Motherboard: Researchers are Using Vibrators to Give Turtles Boners that featured the research of Donald McKnight, a Ph.D. Candidate at James Cook University. If not, go check it out! The article is pretty short so there was a bunch from my interview with Donald that got cut out; I decided to publish the rest of the exchange here. When you're done reading the Motherboard article come on back here for more!

How did you come up with the idea to use a vibrator to sex turtles?

For my MSc, we were working with a population of western chicken turtles that appeared to have a very skewed sex ratio (far more males than females), and very few people have worked with chicken turtles in that part of their range, so we weren’t convinced that the published methods for sexing chicken turtles worked for our population. Thus, we began looking for alternatives, but because of the conservation status and relatively small size of our turtles, most methods were out of the question, so we began looking for alternatives. That’s when I came across a paper by Lefebvre, Carter, and Mockford, where they used vibrators to get male turtles to ejaculate for sperm studies. It seemed reasonable to us that if you could use a vibrator to make a turtle ejaculate, then you should also be able to use it to make a male turtle show you his penis, which would then allow us to distinguish males and females.

Your paper notes that certain techniques worked better than others and that the appropriate technique might vary by species or individual. How do you recommend future researchers evaluate their technique and figure out how to modify it?

It’s really going to be trial and error. When you have a relaxed turtle and you start to vibrate it, it is usually pretty obvious if you do something that it doesn’t like, because it will pull its tail up tightly against the body and tense up. In contrast, if you’re in a good spot, it relaxes even more and, often, you can see fluid forming around the cloaca. So when trying a species for the first time, researchers really just need to experiment with lots of different positions and techniques, and it should be obvious which ones are working and which ones aren’t.

Given the variety of available vibrators, are there certain features of vibrators that you think would make them more effective at sexing turtles?

I certainly suspect that some will work better than others, but I haven’t had a chance to experiment with anything other than the generic silver bullet vibrator that we used in the study. It did appear though that we got a better response when the vibrator had fresh batteries and was on its fastest setting, so I suspect that high speed ones will work better than slower ones. 

When you decided to publish the study, were you concerned that the paper would be criticized by people that were not biologists? Why or why not?

I was a little bit concerned because people often react irrationally and emotionally anytime that animals are involved. So, I think that it is really important to emphasize that we didn’t do this because of some perverse personal desire. Rather, we did this because we were looking for a non-invasive way to easily sex turtles in the field. The current alternatives include things like taking the turtles to a veterinarian to open them up surgically and look at their gonads, which is obviously far more traumatic for the turtle than simply vibrating it for a few minutes (surgery is potentially fatal). So, this really was driven by a desire to minimize our impact on these animals, and I hope the general public will realize that.

Are you planning any follow-up studies to refine the technique and increase its utility?

At this particular moment, no. We talked about trying to expand our methods and species before publishing, but I’ve moved on to work on my PhD and just don’t have time at the moment. So, we decided to just go ahead and publish what we have and let the rest of the scientific community move forward with it. I’d certainly be open to revisiting it in the future though.

Can you think of any other sex toys that may have applications for biology and conservation research?

I don’t personally have any ideas at the moment, but I think that there is definitely potential there, and biologists are a pretty creative, innovative group. So I don’t think this will be the last sex toy study.

Enjoy what you read and learn here? 

Sunday, July 23, 2017

Snake Identification Challenge of The Week: A Few Snakes Crawling Through the Heat of Summer

I am in McCormick, SC, and today I came upon this snake trapped down by our basement window. I allowed it to escape, and now I am hoping it is a water snake, but I wanted to check as it was very aggressive. 

Thank you so much,

Mea S.
South Carolina

I've got another snake for you to identify, if you have a chance.

My friend came across this one on the weekend while camping on the Bruce Peninsula (Lake Huron), a couple of hours north of Toronto.  Any idea?

Dan D.

What Are These Snakes?

Snake Identification Post Ground Rules

-Guesses are welcome and encouraged. Don't worry if you're not an expert, wrong guesses allow us to talk about how to distinguish between the various species and that's why I run these posts.

-If you can't explain why you think a snake is a particular species, go ahead and just say what you think it is. But otherwise please do let us all know how you identified the animal. If you're wrong, we can explain why. If you're right, this helps everyone learn how to identify snakes, which is the point of these posts.

-This is not a pop quiz, any kind of research is encouraged and I hope you will engage with other commenters to try to figure these snakes out. I will eventually chime in with my thoughts.

-Assume I know what kind of snake is in the picture. I run these posts because they are outreach opportunities. Please don't send me private e-mails with your guesses, include them below.

-Remember, the person that sent me the picture is probably reading your comments. Although it is frustrating to know that many of these snakes have been killed, these people do want to learn more about them. More snake knowledge will lead to fewer snakes being killed. Don't hate, educate.

Enjoy what you read and learn here?