Tortoises have similar digestive systems to other vertebrates, but they’ve adapted to extreme environments where food and water are limited.
So, tortoises use different parts of their digestive tract to glean extra water and nutrients from food and break down plant matter.
This process takes up to 3 weeks, depending on the size of their meal.
The digestive process of a tortoise begins in the mouth, where food is softened with saliva, passed down the esophagus, and enters the stomach.
The stomach walls secrete gastric acid to break down food with the aid of stomach muscles. There are two parts of the stomach, one that extracts nutrients and one that absorbs extra water.
After that, food passes into the small intestine, where enzymes break down the food further.
Food moves into the large intestines, where hindgut fermentation begins. This allows the tortoise to process its food slower but gain more nutrients. That also enables the tortoise to process a certain amount of cellulose, although it can’t digest fiber entirely.
Once the large intestine is done, the remaining waste passes through the cloaca and out to the anus, where it’s disposed of.
Tortoise Digestive System
A tortoise’s digestive system resembles most other animals but lacks mucous glands. Instead, they have salivary glands that produce saliva, which aids in the digestive process.
Likewise, tortoises have a slower digestive system compared to other vertebrates, and this adaptation allows for a comprehensive digestive and absorption process.
Here’s how your tortoise’s body processes food:
Mouth
Digestion begins when they use their mouth to ingest food. In the mouth is a tongue fastened to the bottom of the skull, enabling the tortoise to churn food before ingestion.
Unlike most vertebrates, tortoises don’t have teeth. Instead, the mouth is like a beak with a hard edge that crushes and tears food. Saliva is released to soften the food into mushier, easy-to-process pieces.
Esophagus and Stomach
Once the food is broken down into chunks that can be swallowed, it travels through the esophagus and into the stomach. The stomach of a tortoise has two regions, which are as follows:
- Cranial fundic region
- Caudal pyloric region
Although they’re both a part of one stomach, each of the two regions performs a distinct role. That makes them, in effect, two stomachs.
The walls of the tortoise’s stomach secrete gastric acid that breaks down food. As the name implies, this is a highly acidic substance that eats away at all parts of the food, making it easier for the rest of the digestive system to extract nutrients.
Once the stomach has performed this function, the food is passed through the pyloric sphincter at the end of the tortoise’s stomach, releasing it into the small intestines.
Small Intestine
The small intestine of a tortoise has three sections:
- Duodenum
- Jejunum
- Ileum
The different regions of the small intestine are indistinguishable from each other, so they’re identified based on their position in the digestive tract.
The duodenum is the uppermost region of the small intestine, and this connects the stomach of the tortoise to the ileum, which is the coiled middle section of the small intestine.
Within the ileum is a fan-like membrane; its function is to hold the folds of the small intestine together.
Bile from the liver and enzymes from the pancreas are released into the small intestine—these work to further break down food and complete the digestive process.
The lining of the ileum contains finger-like projections known as villi, which absorb nutrients and release them into the bloodstream of the tortoise.
All undigested material from the small intestines passes through the caecum. From there, it moves on to the main large intestine.
Large Intestine
The large intestine begins with the caecum, which isn’t an organ but a dilated opening at the top of the large intestine.
Once digestion has completed in the small intestine, any undigested or indigestible material is collected in the caecum, where extra nutrients are extracted.
The rest proceeds down into the main large intestine. The gastric content of the small intestine has a very mild pH balance.
This is where the tortoise begins fermenting leftover food to gain additional nutrients. This is designed to gain as much fiber as possible since tortoises are mainly plant-eaters.
This digestion process is completed using short-chain fatty acids, including:
- Acetate
- Propionate
- N-butyrate
Since tortoises have such a slow rate of digestion, this fermenting process isn’t as effective as with some mammals. For example, rabbits use ‘hindgut digestion’ to sustain their fast metabolism.
Since tortoises take so much time, the benefits are minor in comparison.
This point extracts almost all the nutrients. Nitrogen waste is released from the kidneys; along with all other waste, it’s passed on to the cloaca.
Cloaca
Tortoises have a cloaca, meaning the latter half of their digestive system shares one opening with their reproductive system.
Their bodies automatically shut off access to the digestive or reproductive systems, giving one priority, depending on the hormones in their body.
Before the mating process, the cloaca becomes exclusive as a sex organ. Here, it can accept sperm or, in males, dispense a penis-like appendage to administer sperm.
The cloaca allows the eggs to travel from the uterus during the egg-laying process. At all other times, the cloaca is used to pass waste.
Anus
Beyond the cloaca is the anus, also called the vent. The cloaca is often called the anus and vent, but they’re separate body parts.
All digestive and other metabolic wastes from the tortoise’s body finally leave the digestive tract through the anal opening, which is the end of the digestive system.
Do Tortoises Poop A Lot?
According to Chelonian Conservation and Biology, the amount of food a tortoise eats affects how quickly it digests it. Even if the same steps are taken within the digestive tract, it’s faster and easier to process a little food over a lot.
If you feed a tortoise a large meal, it may defecate once every few days. However, if you offer numerous smaller meals, it could pass waste several times a day.
When the digestive process is complete, the food ingested by the tortoise is usually small in volume. Most of a tortoise’s diet has a high water content, which is easily absorbed in the gut.
The remaining content that’s absorbed into the bloodstream and utilized for energy is a small percentage of the total mass of food ingested.
Don’t be too concerned if your tortoise eats a large meal but only passes smaller stools.
How Many Stomachs Does A Tortoise Have?
Tortoises only have one stomach, but it’s separated into two parts. Each performs an important role, so many people casually refer to them as two stomachs.
It’s known as the hindgut system, which is composed of the following:
- Cranial fundic region: Food is broken down into nutrients, which are absorbed while the rest turns into waste.
- Caudal pyloric region: This absorbs any leftover moisture from the waste and distributes it into the body.
They ensure that the tortoise gains the most nutrients possible from its meals, which also helps the tortoise remain partly hydrated from its meals alone.
Since tortoises eat infrequently and can survive months without food, this complex stomach helps keep them healthy and energetic.
Tortoises that live in arid environments have an even greater need for water, and their digestive system accommodates it.
The kidneys process their urinary waste and absorb additional water stored in the bladder. The remaining waste, virtually free of liquid, is passed from their anus as insoluble uric acid crystals.
Do Tortoises Have Teeth?
Unlike most vertebrates, tortoises don’t have teeth. Instead, the tortoise’s mouth has a hardened, sharp edge that it uses to bite down, grind, and tear at food.
It’s similar to how a bird peck and shred its food before swallowing. This ensures that tortoises can still break their food down into chunks that are easy to swallow so that they don’t choke.
Do Tortoises Chew?
Tortoises use their jaws to bite their food but don’t chew it. They’re adapted to consume the food how it is or when it’s torn into smaller pieces.
Once the food is in the mouth, the salivary glands are stimulated to produce saliva. This will smooth the food down into a softer, sometimes gummy consistency, making it easier to swallow using the tongue.
How Long Does it Take for a Tortoise to Digest Food?
It can take a tortoise up to 3 weeks to digest food. This sounds like a hindrance, but tortoises use this time to glean far more nutrients from a meal.
Microbes need more time to break down plant matter and glean nutrients.
Furthermore, the slower rate of digestion enables the microbes in the tortoise’s digestive system to convert the compounds into more nutrients. These are absorbed in the large intestine of the tortoise.
Tortoises get more out of every meal than other animals, but the process takes much longer.
Can Tortoises Digest Cellulose?
Tortoises can’t digest cellulose. Like most other vertebrates, tortoises can’t produce cellulase, the enzyme responsible for cellulose’s breakdown. Instead, tortoises use their hindgut fermentation to glean what trace nutrients they can from cellulose.
It’s a long and difficult process, which is part of why fiber is so important for cleaning out the digestive system. Tortoises that get some of the nutrients to release from the cellulose need to absorb it using the microbes in the gut.
Younger tortoises practice coprophagy, which involves eating their own partially digested feces (or caecal pellets). They do this to develop the right gut microbes to make this possible.
Once old enough, tortoises stop this practice and avoid eating their own or other tortoise’s fecal pellets. They may still eat the poop of other animals to derive extra nutrients, but it’s less common.
Once they’ve developed the right gut flora, tortoises still can’t digest cellulose properly. However, they can glean more nutrients from it before.
Tortoise Digestive Problems
According to the Journal of Zoo and Wildlife Medicine, diseases are one of the main causes of population decline in tortoises. Most diseases that account for the high mortality rate affect the digestive system.
Be aware of the most common diseases and digestive problems that may affect tortoises. These include:
Stomatitis
Stomatitis (mouth rot) is an affliction that occurs when bacteria in the mouth attack an open wound, and this causes infection in the lining of the mouth and gums.
That can make it difficult for a tortoise to ingest food, thus affecting its nutrition and overall health.
Common symptoms of stomatitis include:
- Swelling or discoloration of the tortoise’s mouth and gums
- Loss of appetite
- Thick, whitish-yellow discharge around the mouth
If you suspect that your tortoise may have mouth rot, it’ll need antibiotics.
Constipation or Diarrhea
Tortoises can be afflicted by stomach problems that manifest as constipation and diarrhea.
In most cases, this is brought on by a poor diet. You’ll know a tortoise is constipated if it doesn’t poop every few days or at least once a week. If its toilet routine was consistent and there’s now a sudden, unexplained change, this can signify constipation.
If a tortoise has diarrhea, rethink the diet you’re feeding it. Ideally, you should provide a range of leafy greens and vegetables. Avoid iceberg lettuce since it contains little nutritional value besides water.
Intestinal Parasites
Intestinal parasites can latch onto your tortoise through its food or by interacting with the infected poop of another animal. Once parasites are inside a tortoise, they leech away its nutrients or damage the internal organs.
Different parasites require different treatments. Nematode parasites are one of the most dangerous, but intestinal parasites are relatively harmless to tortoises.
For example, pinworms are present in numerous species of tortoises and don’t pose any health risks. Likewise, certain types of protozoa are harmless to tortoises.
Tortoises digest their food much like other animals but take longer to process their meals and use microbes to break down the nutrients.
