Specialized Bone-Digesting Cell Discovered in Burmese Pythons

Research into the digestive system of Burmese pythons has identified a previously unrecognized cell type that enables these snakes to fully absorb the skeletons of their prey. While most carnivores avoid eating bones or pass them undigested, many snakes and reptiles consume their prey whole, including bones. The biological processes behind this ability had remained unclear. 

Snakes require bones in their diet to avoid calcium deficiencies. However, absorbing all the calcium from a skeleton could lead to excessive calcium in the bloodstream. Jehan-Hervé Lignot, senior author of the study published in the Journal of Experimental Biology, explained, “We wanted to identify how they were able to process and limit this huge absorption of calcium through the intestinal wall.”

To investigate, Dr. Lignot and his team from CNRS examined the enterocytes—intestinal lining cells—of Burmese pythons using both light and electron microscopy, as well as blood calcium and hormone measurements. Their analysis uncovered a new type of cell in the intestine that produces large particles composed of calcium, phosphorus, and iron.

Dr. Lignot described, “A morphological analysis of the python epithelium revealed specific particles that I’d never seen in other vertebrates.” These particles were located within an internal “crypt” of specialized cells, which differed from typical intestinal cells. He added, “Unlike normal absorbing enterocytes, these cells are very narrow, have short microvilli, and have an apical fold that forms a crypt.”

To determine the function of these cells, the researchers fed pythons three diets: whole rodents, boneless prey, and boneless rodents supplemented with calcium. They found that only diets containing bone or added calcium led to the production of the calcium- and phosphorus-rich particles. No bone fragments appeared in the snakes’ feces, indicating complete digestion of skeletons.

This specialized cell has also been found in other python and boa species, as well as the Gila monster. Dr. Lignot noted that other carnivores, such as marine predators and bone-eating birds like the bearded vulture, may possess similar adaptations.