My guilt over being too swallowed up by other obligations to post for this past week (a state of affairs that will probably continue for another day or two, alas) compels me to offer something today, even if it’s just a few visual morsels. And so, in keeping with that “from the belly of the beast” theme, behold: medical scans of pythons eating rats!
Above is a 3-D computer tomography (CT) image of a Burmese python (Python molurus) shortly after it has eaten three rats; you can see the bundles of rodent bones clustered at various distances along the snake’s digestive tract. Kasper Hansen of Aarhus University and his colleagues created it as part of their study of the adaptations that allow snakes and some other reptiles to binge on large, whole animal meals, then go without food for days, weeks or even months. They presented this work in Prague last June at the annual meeting of the Society for Experimental Biology.
To visualize the animals’ anatomy in detail, the researchers combined CT scans, which are good for showing the positions of bones, with magnetic resonance imaging (MRI) scans, which are better for showing soft tissues, in conjunction with injected contrast agents that helped to differentiate tissues from one another. The abstract of their presentation (available for download here) notes:
We were in hours able to produce high resolution 3D digital models of animal soft and hard tissue anatomy in quality similar or superior to time consuming dissection, and we therefore advocate MRI and CT as valuable tools in future studies of animal anatomy in research and education.
Fun (and, dare I say, beautiful) as the isolated images are, perhaps the most fascinating of their python images is the time-series below that reveals what happens inside the python as it digests its rat meal. The images show parts of the snake’s digestive tract an hour before it eats, then at intervals of two, 16, 24, 40, 48, 72 and 132 hours afterward. As one would expect, the rat’s body gradually disappears inside the intestines, which expand and then contract to accommodate its bulk. But other organs also shift in volume: according to reports, the gall bladder shrinks (perhaps because it has emptied itself of digestive bile?), while the heart swells by 25 percent (perhaps because the displacements of blood vessels in the stretched tissues changes the hydraulic forces within the circulatory system?).
Amazing. But if you truly want to experience the full glorious detail of the techniques that Hansen and his colleagues developed, scroll down through this large image of a rat nestled inside a python. Warning: you’ll be scrolling for some time!
For a wonderful gallery of these python images and those of other animals under study, go to LiveScience.
Corey Binns at Life’s Little Mysteries also has some related fascinating information about how snakes eat challengingly large animals.