For a python, every meal is like Thanksgiving

For millions of Americans, Thanksgiving is an excuse to gorge on turkey, stuffing and pumpkin pie, despite the warnings that overeating, even for a day, can be incredibly unhealthy. But for a Burmese python, enormous meals are the norm. These huge snakes — they can reach up to 6.7 meters in length — may go weeks or months without eating, so they have to make their meals count. And they have many adaptations that let them consume quantities of food that would be impossible for a human to take in.

Captive Burmese pythons live on a diet of small animals, like snakes and rabbits, but in the wild, they’ll eat animals as large as deer and alligators. Pythons swallow their meals whole, a feat made possible by a jaw that can separate, allowing the snake to chow down on a creature four or five times as wide as its head.

Researchers X-rayed a snake digesting an alligator and watched as the gator’s soft tissues got eaten way (which took three days) and its body completely dissolved within a week. To digest such a big meal, the python’s body must undergo enormous change. As soon as it ingests its prey, the snake’s gut tissues begin secreting digestive acid and enzymes. The stomach produces large amounts of hydrochloric acid, and gut pH drops from a slightly alkaline 7.5 to a very acidic 2.

The python’s metabolic rate increases dramatically, reaching a spike within the first 48 hours and not returning to normal until digestion is finished. And the bigger the meal, the faster the snake’s metabolism. If the python has eaten something equal to its own weight, the snake’s metabolism will increase to 44 times faster than its rate at rest.

Cardiac output ramps up, reaching levels higher than what is seen even when the snake is on the move. Blood flow to the gut increases. And the heart muscle itself also gets bigger, with its mass increasing by 40 percent in just two days. It’s not the only organ to increase in size; the pancreas, liver and kidneys grow as well. And the cells that line the small intestine — the ones that absorb nutrition from the digesting meal — increase in volume by 50 percent.

Digesting this meal takes a lot of energy, and as much as 37 percent of the energy derived from the meal goes to the digestion process itself. By the time the snake poops out what it can’t digest — about one to two weeks after it first consumed the meal — its intestine and the rest of its digestive tract have returned to their normal, fasting states.

This knowledge won’t help any of us survive overeating on Thanksgiving, but scientists hope that it may one day lead to medical therapies for human heart disease. Enlarged hearts may be normal for Burmese pythons, but they are a real problem for people.