Question answered by Dr. Chuck Peterson, Biology Professor, Idaho State University
Yes, their stomachs are big enough to hold an entire rodent. Sometimes they eat multiple rodents which extend up into their esophagus. It will take multiple days for the rodents to be digested.
All snakes are carnivorous (meat-eaters). Snakes do not chew their food or even bite it into pieces; they just swallow their food whole.
Once the rattlesnake identifies its prey, it begins by biting the animal. When it bites, the rattlesnake’s fangs act as hypodermic needles and inject venom into the prey. Rattlesnake venom works by breaking down blood, which begins the digestive process and paralyzes the prey. Once the prey stops moving, the rattlesnake swallows it whole.
As the rattlesnake eats, the food is pushed from the mouth into the esophagus. This tube, which is up to half the snake’s total body length, has folds within it which permit snakes to consume large prey. Once the food is in the esophagus, it is pushed down by two kinds of movements. One of the swallowing movements is peristalsis, the same movement as in many animals, including humans. The second movement relies on the spine and body. The spine and body bend and make the snake’s ribs push in against the food. If you were to watch a snake eating, it would look as though the snake is crawling its body over its food. The snake continues these two swallowing motions until the food has reached its stomach.
The stomach is where most of the digestion occurs. The stomach secretes gastric juices and digestive enzymes that break down the prey. Once most of the digestion is completed, food passes into the small intestine where more digestive enzymes continue to break down the prey for absorption. Food enters the large intestine where much of the remaining water is reabsorbed. The snake then excretes the remaining waste as feces.
After eating, snakes become inactive while they digest their food. Digestion is an intensive activity, especially after the consumption of very large prey. Because of this, a snake disturbed after recently eating will often regurgitate its prey in order to direct energy away from digestive functions and put it toward escaping a predator.
Snakes digest almost everything. The only things snakes can’t digest are keratin-based products, like hair, claws and feathers etc. They pass through the digestive system and are ejected as waste material.
The esophagus is a long muscular tube that leads to the stomach. Food doesn’t travel by gravity; rather it is pushed by a wavelike contraction of muscles known as peristalsis.
The esophagus makes quick work of this job. In humans, it can squeeze food to the stomach in seven seconds.
This activity will simulate how the esophagus works.
Materials: Long, thin balloon, cooking oil, bread
- Cut the end off the balloon so that it makes a long, flexible tube.
- Pour 1 teaspoon of cooking oil into the balloon. The oil represents saliva, which acts as a lubricant in the esophagus.
- Tear off ¼ of a slice of bread and make it into a ball about the size of a marble.
- Stick the bread ball into one end of the balloon.
- Squeeze the balloon behind the ball of bread with one hand. Keeping that hand in place, cross your other hand over the first hand, continue squeezing to move the bread down the balloon.
This activity simulates peristalsis, the rhythmic, wavelike contractions of the muscles that line the digestive tract.