How Pythons and Other Animals Digest Bones

Nicole Jennings

Biology, Old Dominion University

BIOL 293: Cell Biology

Dr. Christina Steel

10/5/2025

How Pythons and Other Animals Digest Bones

While there are many carnivores in the food chain, very few can completely render their entire meal. Most eating only the flesh, fat and soft tissues. There are very few carnivores that can digest bone. However, snakes, especially large constrictors such as the Burmese python, are in fact one of those few animals that can completely digest their entire meals, including the bones. They not only digest the bones, but the bones are also a much-needed resource in their diets. One has to wonder however, just how they are able to do so when most carnivores cannot.

One reason may be their use of intestinal plasticity. Which is the ability to completely change the structure of their gut in response to their feeding. They can change both the size and function of their gut in response to eating their prey. They not only change the structure, but also the enzymes which they use to completely digest their meals (Secor 2018). Large snakes, such as the Burmese python, can have large fasting breaks between meals as they are more ambush predators than hunters. This means that their stomach and intestines, are in a different state during a fasting period compared to when they are finally digesting a meal. While waiting for a meal, they use very little energy, and their digestive tract is significantly smaller. Having reduced their metabolic maintenance, they are able to go long periods without a meal (Wood, 2025). However, once fed, their digestive tract goes into over-drive. Their ability to increase the mass and function of their digestive tract allows for energy to be maximized in the digestion of the meal. Allowing for large amounts of enzymes and acids to be excreted (Secor, 2018). Fast tracking the digestion of their food. It is through such an endeavor that the Burmese python is then able to prioritize not just the consumption of flesh, but also the intake of calcium and phosphorous that they receive through the digestion of the prey’s bones. A necessary resource for them. As it is with many animals such as carnivores.

Thoughts arise though as to how the snakes are able to regulate the amount of phosphorous and calcium they take in from their thoroughly digested meals. While also not allowing for an overabundance of both calcium and phosphorous. It may be in part due to parathyroid hormones, an 84 amino-acid single chain polypeptide (Aurbach, 1988) as well as calcitonin that regulates these levels in vertebrates. Keeping these levels in check. The parathyroid hormone controls calcium and phosphorous intake through many means. PTH controls calcium levels through its calcium-mobilizing factors. Allowing for control of calcium synthesis and intestinal calcium absorption. As well as stimulation of osteoclast activity and controlling renal phosphate excretions. PTH, through osteoclast activity, releases calcium and phosphates into the blood stream. The kidneys then reabsorb the calcium while the phosphates are excreted through renal means. While PTH takes more of a primary role, Calcitonin is also extremely significant in that it inhibits the reabsorption of calcium. The opposite of PTH. Calcitonin increases calcium and phosphate excretions allowing for lower levels of the two through inhibiting osteoclastic activities. While working against each other in the process of in-taking or excreting the extra calcium and phosphorous, they are in fact working together to achieve a homeostasis that keeps calcium and phosphorous levels in check. This kind of homeostasis helps vertebrates, including the Burmese python, with bone growth, muscle functions and metabolism (Wendelaar, 1991). Which are necessary for their existence.

Such findings, though, had to be achieved first through the study of the snake’s intestinal wall and enterocytes. Before we could understand the roles of calcitonin and parathyroid hormones, we first had to look at the bigger picture of how the snakes could absorb calcium through their intestines. This was done using light and electron microscopy. Electron microscopy is the use of electrons in the form of a beam to enhance the resolution of the microscopic specimens being studied, such as cells, and enhance them in a way to be easily studied. What could be nanometers in length is enhanced to a resolution that can be easily distinguished and used. However, to be extremely efficient in their research, other methods alongside electron microscopy are used. Such as Energy-Dispersive X-Ray or EDX. EDX is a technique used to detect elements and their amounts in the samples that are being examined using the electron microscope. Such techniques can be used to study nanoparticles, and elements that are accumulated in tissues (Scimeca, 2018). Much like the study of the Burmese pythons, EDX can be used in detecting both calcium and phosphorous in their bones and tissues, as well as the amounts of each element. Helping us to understand how they can digest their meals whole and absorb so much phosphorous and calcium through the ingestion of bones without over accumulating them.

We may now have a greater insight of how snakes, like the Burmese python, are able to not only digest bone but in fact find it necessary to do so. Through many techniques, such as EDX and electron microscopy, we can better understand their use of intestinal plasticity and its role in how these snakes digest bone. While also getting a deeper comprehension of how parathyroid hormones and calcitonin help keep the homeostasis and balance of these amounts these snakes take in through the absorption of bone. With more studies, there will undoubtedly be a better understanding of not just how snakes but other osteophagous animals consume and digest bone. As well as why such practices are necessary for the organism’s ability to live, thrive and reproduce.

References

Secor, S. M. (2008, December). Digestive physiology of the Burmese python: Broad Regulation of Integrated Performance. PubMed. https://pubmed.ncbi.nlm.nih.gov/19043049/

Wood, M. E., & Ruxton, G. D. (2025, January 15). A model of Optimal Digestive Strategy in Infrequently-Feeding Snakes. Springer Nature. https://link.springer.com/article/10.1007/s10682-024-10328-x

Wendelaar Bonga, S. E., & Pang, P. K. (1991). Control of calcium regulating hormones in the vertebrates: Parathyroid hormone, calcitonin, prolactin, and Stanniocalcin. International review of cytology. https://pubmed.ncbi.nlm.nih.gov/1917377/  https://core.ac.uk/reader/16107312?utm_source=linkout

Aurbach, G. D. (1988). Calcium-regulating hormones: Parathyroid hormone and Calcitonin. SpringerLink. https://link.springer.com/chapter/10.1007/978-1-4471-1437-6_3

Scimeca, M., Bischetti, S., Lamsira, H. K., Bonfiglio, R., & Bonanno, E. (2018, March). Energy dispersive X-ray (EDX) microanalysis: A powerful tool in biomedical research and diagnosis. European journal of histochemistry . https://pubmed.ncbi.nlm.nih.gov/29569878/