Recently, incidents of people falling victim to pythons have repeatedly captured attention in Indonesia. Pythons are known to swallow people whole. Unlike most carnivorous animals that consume only the flesh of their prey and cannot digest bones, snakes swallow their prey whole and digest the bones. Scientists have identified specialized cells responsible for bone digestion in snakes.
An international research team, including Montpellier University and the University of Alabama, announced on the 9th (local time) at the International Conference on Experimental Biology in Antwerp, Belgium, that they discovered a new type of intestinal cell in the Burmese python (scientific name: Python bivittatus) that had not been previously recognized. The research results were published in the international journal Journal of Experimental Biology on June 5.
The reason snakes eat bones is to intake calcium. Calcium, the main component of bones, is an essential element in a snake's diet. A pet snake that only eats boneless food can suffer from calcium deficiency. However, excessive calcium absorption can lead to problems with internal balance.
Jehan-Hervé Lignot, a professor at Montpellier University, explained the motivation for starting the research, saying, "I wanted to find out how snakes process and regulate such enormous amounts of calcium."
The research team examined the intestinal wall cells (intestinal cells) of the Burmese python using optical and electron microscopes. They also measured the snake's blood hormone and calcium levels at the same time.
As a result, they discovered a new type of intestinal cell that differs in form from existing intestinal cells. This new cell is much narrower than typical intestinal cells, has shorter absorptive projections (microvilli), and contains a recessed space at the top. Large particles composed of calcium, phosphorus, and iron formed within this space.
Subsequently, the research team offered the snakes three different diets to confirm the role of the new intestinal cells: a typical rodent diet, a boneless rodent diet, and a boneless rodent diet with calcium supplemented by injection.
When feeding the snakes boneless food, no particles formed in the newly discovered intestinal cells, but when they consumed food containing bones or calcium supplements, calcium, phosphorus, and iron particles appeared inside the intestinal cells. Unlike the existing intestinal cells that primarily absorb nutrients, the new cells play a crucial role in completely breaking down and absorbing the bones of the prey.
The research team explained, "The newly discovered intestinal cells seem to help fully store necessary nutrients while regulating excessive calcium absorption."
The newly discovered intestinal cells have also been found in other pythons, boas, anacondas, and monitor lizards, in addition to the Burmese python. This suggests that these intestinal cells may have evolved before the species diverged or evolved separately in various animals.
In this regard, the research team noted, "Animals that swallow their prey whole and eat bones may provide clues to the origins of these cells," adding that "it's likely that similar cells exist in marine predators that consume bony fish or aquatic mammals, as well as in birds like the bearded vulture."
References
Journal of Experimental Biology (2025), DOI: https://doi.org/10.1242/jeb.249620