Walter Tunnell Wilson ’20 Examines the Evolutionary Relationships Between Snake Species at University of Texas at Arlington in Arlington, TX

Hello, my name is Walter Thomas Tunnell Wilson and I am a junior here at Whitman College. This summer, I landed a sweet internship working with Doctor Eric Smith, a professor-researcher at the University of Texas at Arlington in Arlington, Texas, and one of his graduate students, Justin Jacobs. Here, we are using common technology in a cutting edge way.

You have probably heard the term “CAT scan” before, but less of you are likely familiar with the actual process or have thought about its use in reference to dead snakes. A single CAT scan involves taking an inconveniently large number of X-ray images from different angles around the subject in order to “see inside” without all the cutting that seeing inside something normally involves. This technology has fairly recently been used across the nation to look inside things other than the human body that are also undesirable to cut into, namely, preserved museum specimens.

Just like when you get an X-ray at the doctor’s, different parts of the animal absorb the rays at different rates. Using many slices, computer programs can not only build three dimensional models of the organisms, but also calculate the different densities of the materials the rays have penetrated. Therefore, one could see just the soft tissue of a really well-prepared specimen, or more commonly, the bones.

So this summer I am utilizing the same general idea as CAT scanning to look at snake bones in order to see how different snake groups are related. Here is how the process goes: first, we wrangle a specimen from either UTA’s extensive dead reptile and amphibian collection, or get a loan from another institution (like checking out a book except it is a dead snake). We then mount the snake on a stick in a very technical procedure involving much saran wrap and tape and load it into the computed tomography scanner, called Big Scandra  (by me just now). This ol gal churns out around 2,800 files per scan, which I sift through and convert into about 900 TIFF images. These are further packaged into other file types which are eventually loaded into a software (available to the public for free at:https://github.com/nci/drishti for those interested) that allows us to visualize the images in 3-D space. Then, I spend a couple or sometimes five hours separating one vertebrae from the rest, or movable bones in the skull from the stationary ones. However, the thing about bones, which the popular song highlights well, is that they often connect to other bones. These bones are the exact same density, which makes them particularly hard to isolate. It is painstaking stuff and exactly the kind of work that is perfect for summer interns. Additionally, our study involves around twenty snakes, so each of the aforementioned steps must be repeated at least twenty times, sometimes more because mess ups have been known to occur. Lastly, the vertebrae and skulls are examined and compared to all the others, and through the magic of the scientific method, certain evolutionary relationships can be discerned and described from those comparisons. After all this work has been done, we will probably publish a paper with our findings for the larger scientific community’s reading pleasure.

Although kind of tedious at many points, it has been really fun to learn not just about the snakes of the Lamprophiidae family, but also the various softwares we use, the scientific process “in practice,” and the inner workings of the field in general. Also, I can listen to audiobooks while working sometimes and that has been a really cool two birds one stone situation.


Experiences like Walter’s are made possible by the Whitman Internship Grant, which provides funding for students to participate in unpaid internships at both for-profit and non-profit organizations. To learn how you could secure a Whitman Internship Grant or host a Whitman intern at your organization, click here or contact Assistant Director for Internship Programs Victoria Wolff

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