The digestive systems that enable animals to use the food that is available to them are among the most complex of the organ systems. They are often especially adapted for the particular type of food or feeding behavior of the animal. That is certainly true of snakes.
All snakes are carnivorous, but they do not chew. They swallow their prey whole. They are specially designed with unique, flexible jaws that allow them to swallow prey larger in diameter than the snake itself. Since they consume such large meals, many snakes eat only occasionally.
Scientists studying the digestive systems of certain snakes, such as boa constrictors and pythons, have found some interesting design concepts. In these snakes the period of time between meals can be several weeks. It was found that during the long periods of fasting the lining, or mucosa, of the small intestine becomes atrophied, conserving the snake’s energy and resources.
Snakes such as these can consume animals ranging from 50% to as much as 160% of their own body weight. To accommodate such a large meal, the snake needs a fully functional digestive system. The scientists learned that feeding stimulates rapid growth of the intestinal lining. The weight of the small intestine can actually double in a few hours after a meal due to growth of the mucosa. One study demonstrated that the activity of the intestinal cells also increases after a meal.
After eating, the snake becomes dormant while its digestive system works. If a snake is threatened right after a meal, it may regurgitate the meal in order to escape from a perceived danger. If undisturbed, the snake’s digestive enzymes are able to completely digest and absorb the nutrients in the prey. Then the digestive system starts to atrophy as the snake becomes active again.
The digestive system of these snakes is well adapted to their intermittent feeding behavior. During times of fasting, the small intestine becomes less active and atrophied. Following a meal this organ quickly adjusts to the increased demands and enters into a period of rapid growth and increased activity. Highly specialized and efficient systems such as these clearly point to the wisdom of the One who designed them.
Nature, January 4, 1996, 379:23
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