How Snakes Digest Their Food, Animal Sake

Snakes are often found to go hungry for long intervals. That behavior is mostly seen after they have eaten a huge meal. Here are some interesting facts about how snakes digest their food.

Snakes have long, narrow, limbless bodies. Because of this body shape, their internal organs are arranged in a straight line. The digestive system of a snake runs through almost the entire length of the body. It starts from the buccal cavity (the mouth) and extends all the way to the anus. The system is well adapted to how these animals feed.

Most snakes often exhibit an intermittent feeding behavior, with long gaps between meals. Those gaps may span from a few days to weeks, months, and even years in some cases. Here's an interesting fact: when an infrequent feeder snake gets active and goes hunting, its digestive system actually remains inactive. After the meal, the snake turns inactive, but the digestive system gets active. Snakes have specialized digestive systems that undergo rapid growth to cope with the increased demands of digestion. Once the meal is fully digested, the activity slows back down. The digestive system shrinks in size and turns dormant. Let us take a look at how snakes digest their food.

Digestion in Snakes

Intake

The digestive system of a snake starts from the mouth, which is highly modified to swallow prey whole. The jaws, as well as parts of their skulls, are flexible enough to swallow large prey. Another interesting fact is that, in most cases, the prey is swallowed headfirst, without any chewing. This way, the prey's horns, limbs, hair, feathers, or spines do not get stuck and cause injury to the snake. However, such injuries can still happen in some cases.

The process of digestion begins in the mouth, as the prey is coated with saliva that contains digestive enzymes. The process of swallowing may take several hours or even days.

Digestion

Diagram showing the digestive system of a snake from mouth to cloaca — The digestive system of a snake runs nearly the full length of its body, from the buccal cavity to the cloaca.

The long tube-like structure that connects the mouth with the stomach is called the esophagus. In snakes, the esophagus is muscular as well as lengthy. It may measure one-quarter to one-half the body length of the snake. The organ is highly distensible (meaning it can stretch wide) to allow large prey to move down to the stomach. It is the contraction of the muscles on the walls of the esophagus that pushes the prey toward the stomach.

The cells on the stomach walls produce strong digestive juices that help dissolve the prey. Even the small intestine produces some secretions that help with digestion.

The small intestine is a tube-like structure that absorbs nutrients from the food. The liver produces bile, which is stored in the gallbladder. The bile is sent through the duodenum to the small intestine to break down fat. The pancreas also produces some digestive juices. The food is sent to the large intestine through the cecum. Compared to other parts of the snake's digestive system, the large intestine is the least muscular and has the thinnest walls. The large intestine ends in the rectum, which opens up to the cloaca, the single opening that leads to the outside of the body. Everything except the claws and hair of the prey is digested by snakes.

Factors that Affect Digestion

Temperature

A snake basking in warm sunlight on a rock to aid digestion — Snakes bask in the sun after a big meal to warm their bodies and speed up digestion.

This is one of the most important factors that affect the digestive process in snakes. Their internal body temperature is affected by the air temperature around them, and they need warmth for proper digestion. That's why snakes are often found basking in the sun after a very large meal. Another technique is to coil up the body to conserve heat.

It is said that a temperature range of 28 to 30°C (82 to 86°F) is ideal for digestion in snakes. Sometimes, a snake may expel swallowed prey if the temperature drops too low. A considerable drop in temperature may also be the reason why some snakes fast from late fall to early spring.

According to a study conducted on Indian pythons, it took four to five days for a snake to completely digest a rabbit when kept at 82°F. A drop in temperature to 71°F extended the time taken for digestion to seven days. When the temperature was further lowered to 64°F, the prey was still sitting in the snake's stomach even after two weeks.

Body Size

A green tree python wrapping around and beginning to consume prey — A green tree python beginning to eat. Larger snakes can tackle much bigger prey, but digestion takes longer.

The size of a snake's meal depends largely on its own size. The larger the snake, the larger the prey it goes after. Even big species, like pythons, feed on small animals like mice when they are juveniles. The adults feed on antelopes, donkeys, deer, and other large animals.

Unlike humans, most snakes consume food that is around 25% of their body weight (when unfed) in a single meal. Certain types of pythons are able to swallow prey that weighs 65 to 95% of their own body weight. The larger the prey, the longer digestion takes.

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Feeding Intervals

While some snakes feed frequently, others have large meals at longer intervals. In other words, there are frequent feeders and infrequent feeders. Compared to frequent feeders, infrequent feeders have very slow digestion. Infrequent feeders have a low metabolic rate, along with lower organ mass and a low rate of nutrient absorption. However, after feeding, their energy rates and organ mass shoot up.

According to the latest studies, the liver, intestines, and heart of an infrequent feeder snake all enlarge as a result of the metabolic spurt. While the size of the intestines increases by three to four times, even the cellular lining thickens threefold, within 24 to 48 hours of food consumption. The liver also displays tremendous cell growth. All of this requires so much energy that the oxygen intake of the animal increases 60 times. An average snake spends more than one-third to half the energy it gets from a single meal just on digestion. Once the food moves out of the large intestine, it takes around a week for the digestive system to return to its normal state, where it stays until the next feeding.

Regurgitation and Vomiting

Both terms refer to the action of expelling food that the snake has swallowed. Forceful expulsion of partially digested food from the stomach is called vomiting. In regurgitation, undigested food is expelled from the esophagus instead. The most common causes for food expulsion are stress, very low temperature, prey that is too large, and underlying health problems. A prey animal that carries foreign microbes may rot inside the snake's body, causing distension, which could also trigger vomiting.

This is only a brief overview of the process of digestion in snakes. They are highly adapted to their feeding behavior, with a digestive system that can remain active or inactive depending on their feeding habits.

Term	What it means
Esophagus	The muscular tube that connects the mouth to the stomach. In snakes, it can be one-quarter to one-half the body length and stretches wide to move large prey.
Cloaca	The single opening at the end of a snake's digestive system, through which waste passes out of the body.
Distensible	Able to stretch and expand. A snake's esophagus is highly distensible, it can widen enough to pass a whole rabbit or even a small deer.
Regurgitation	Expelling undigested food back out through the esophagus and mouth. Different from vomiting, which involves partially digested food from the stomach.
Metabolic rate	How fast an animal uses energy. Infrequent feeder snakes have a very low metabolic rate between meals, it surges dramatically right after eating.
Buccal cavity	The mouth and oral cavity. In snakes, digestion begins here as saliva with digestive enzymes coats the prey.

You'll Be Stunned to Know How Snakes Digest Their Food