For bunny owners, few behaviors seem as bizarre as a rabbit nibbling on its own poop. However, behind this unusual habit lies an ingenious evolutionary adaptation. Unlike most mammals, rabbits have a unique digestive system that produces two types of droppings. While fecal pellets can be ignored, rabbit owners should look closely at the consumption of cecotropes – the nutrient-rich “night feces” that holds the keys to understanding the rabbit digestive process. Get ready to hop down the rabbit hole into the fascinating world of cecotrophy! This intriguing behavior not only uncovers secrets of the remarkable rabbit GI system but also reveals why healthy rabbits eat poop as a normal, healthy behavior. Let’s explore why rabbits eat their own poop!
How Does a Rabbits Digestive System Work?
Rabbits have a unique digestive system that allows them to obtain nutrients from fibrous, low-quality foods. Here is an overview of how a rabbit's digestive system works:
The rabbit's digestive tract consists of the mouth, esophagus, stomach, small intestine, cecum, large intestine, and anus. Food first enters the mouth where chewing begins the mechanical breakdown of food. From the mouth, food travels down the esophagus to the stomach.
The stomach is relatively small and food does not spend much time here. Some enzyme breakdown of food begins in the stomach but minimal nutrient absorption occurs. Food passes quickly from the stomach into the small intestine.
The small intestine is where the majority of nutrient absorption occurs. Here, enzymes break down food into simple compounds like amino acids and sugars which can be absorbed into the bloodstream. The small intestine is the only site of protein and fat absorption in rabbits.
At the end of the small intestine is a dead-end pouch called the cecum. The cecum contains a large population of beneficial bacteria and fungi which ferment fiber that cannot be digested by rabbit enzymes.
Fermentation breaks down fiber into volatile fatty acids that can be absorbed and used by the rabbit as energy. The cecum is the site of water absorption and absorption of vitamins produced by microbes like vitamin K and B vitamins.
The cecum empties into the large intestine where further water absorption occurs. The large intestine ends at the anus where fecal pellets known as hard feces or fecal pellets are eliminated.
However, some material from the cecum is not excreted as hard feces. Instead, this material passes as a soft, greenish fecal material called cecotropes or "night feces". Cecotropes are eaten directly as they exit the anus. This is called cecotrophy.
Eating cecotropes allows rabbits to maximize nutrient absorption from their food. Cecotropes contain microbe-produced vitamins, protein, and rezidual undigested plant matter. Consuming cecotropes gives rabbits a second chance to absorb nutrients.
What Is Hindgut Fermentation in Rabbits?
Hindgut fermentation refers to the process of microbial fermentation that occurs in the cecum of rabbits. As mentioned above, the cecum is a blind-ended pouch located at the junction between the small intestine and large intestine.
The cecum contains a high density of beneficial bacteria and fungi that breakdown and ferment fibrous material that cannot be digested by the rabbit itself. These microbes break down fiber, starches, and proteins into short-chain fatty acids, gases (CO2, CH4, H2), ammonia, amines, and vitamins.
The main short-chain fatty acids produced are acetate, butyrate, and propionate. Butyrate provides the primary energy source for cells lining the cecum wall. The other acids and gases are absorbed into the bloodstream and utilized by the rabbit. The microbes themselves can also be digested as a protein source.
Some key features of hindgut fermentation in rabbits:
- Occurs in cecum pouch after small intestine
- Involves symbiotic microbes – bacteria and fungi
- Breaks down fiber indigestible by rabbit's own enzymes
- Produces short-chain fatty acids, vitamins, amino acids
- Allows digestion of a high fiber, low quality diet
- Makes cecotropes rich in nutrients, vitamins, protein
Hindgut fermentation enables rabbits to extract nutrients from plant fiber. This allows them to thrive on a high-fiber, low-quality diet. The hindgut fermentation process is why rabbits reingest cecotropes to obtain nutrients synthesized by cecal microbes.
How Do Rabbits Know Which Poop to Eat?
Rabbits produce two types of feces – fecal pellets and cecotropes. They eat only the cecotropes while allowing the fecal pellets to pass out of the body. This raises the question – how do rabbits know which type of poop to eat?
There are a few key factors that enable rabbits to identify cecotropes and distinguish them from regular fecal pellets:
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Time of day – Rabbits usually produce cecotropes late at night or very early morning, while fecal pellets are produced throughout the day.
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Location – Cecotropes are excreted directly from the anus and often get stuck to the rabbit's fur around the anus area. This makes them easy to locate and directly ingest.
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Odor – Cecotropes have a distinct musky odor that is thought to help attract rabbits to eat them. Fecal pellets have little odor.
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Texture and moisture – Cecotropes are soft, wet, and sticky compared to relatively firm and dry fecal pellets.
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Color – Cecotropes are dark green to brown, while fecal pellets are lighter brown and dry.
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Taste – It is thought that cecotropes likely have a distinct taste compared to fecal pellets.
Rabbits learn from a very young age to identify the unique features of cecotropes so they can find and consume them. By relying on factors like odor, texture, and timing, rabbits are able to zero in on just the cecotropes to re-ingest.
What Are the Two Types of Rabbit Poop?
As mentioned, rabbits produce two types of feces – fecal pellets and cecotropes. The key features of each are:
Fecal pellets:
- Small, round-to-oval dry pellets
- Formed in the large intestine
- Contain indigestible fiber, ash, and dried mucous
- No nutrients, vitamins, or proteins left
- Rabbits do not eat these
- Produced in larger quantities throughout day
- Light brown color when fresh
Cecotropes:
- Elongated, softer, wet clumps with mucous coating
- Formed in the cecum pouch
- Contain nutrients, vitamins, proteins synthesized by cecal bacteria
- Significant calories and nutrition remaining
- Rabbits selectively eat these
- Produced at night and in early morning in smaller quantities
- Dark green to brown color when fresh
The differences between the two allow rabbits to identify and selectively eat only the cecotropes while allowing fecal pellets to pass out of the body. This enables them to fully utilize nutrients from their food.
Why Is My Rabbit Not Eating Cecotropes?
It can be concerning for rabbit owners if they notice their rabbit is not eating its cecotropes as expected. There are a few possible reasons a rabbit may stop eating cecotropes:
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Dental disease – If the rabbit has tooth spurs or dental pain, it may avoid chewing cecotropes. Rabbits with dental issues need a thorough oral exam and dental treatment.
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GI tract issues – Diarrhea, intestinal blockages, or other intestinal issues can prevent proper cecotrope formation. Appropriate diagnosis and treatment of GI issues is needed.
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Pain – Any condition causing pain in the rear legs, back, or abdomen can cause a rabbit to avoid assuming the proper position to eat cecotropes. The source of pain should be identified and treated.
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Obesity – Overweight rabbits may have difficulty reaching and properly consuming cecotropes. Weight loss may be indicated.
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Arthritis – Elderly rabbits with arthritis may stop eating cecotropes if they have trouble moving into position. Pain control and physical therapy methods can help improve mobility.
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Fur soiling – Soiled fur around the rear end caused by urinary incontinence, diarrhea, or excess cecotrope accumulation can deter a rabbit from eating cecotropes. Keeping the rabbit's rear end clean can help.
If a rabbit stops eating cecotropes, a veterinary visit is recommended to identify and address any underlying medical issues. This helps ensure the rabbit resumes this important nutritional behavior.
Why Is My Rabbit Eating Poop (Not Cecotropes)?
In some cases, rabbit owners notice their pets eating normal fecal pellets or eating their litter in addition to cecotropes. Reasons a rabbit may start eating fecal pellets or litter include:
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Nutrient deficiency – Deficiencies in nutrients like fiber, protein, or vitamins may cause a rabbit to eat non-cecotrope droppings trying to find lacking nutrients. Diet adjustment is needed.
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GI tract disorder – Diarrhea or slowed GI motility may prevent proper absorption, causing a rabbit to seek more nutrients from poop. Medical treatment of GI issues is required.
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Dental disease – Rabbits with tooth problems may not chew and digest food properly, leading to nutritional deficiencies and poop eating behaviors.
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Fear or anxiety – Stress may cause some rabbits to eat fecal pellets or litter in an instinctual attempt to hide signs of their presence from perceived threats. Address sources of stress.
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Boredom – Inactive, lonely rabbits with inadequate enrichment may eat poop or litter out of boredom. More exercise, toys, and interaction is beneficial.
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Medical side effects – Some medications, like antibiotics, can eliminate intestinal microbes needed for cecotrope production and nutrition. Probable medication causes should be evaluated.
While cecotrope consumption is normal, eating other feces or litter can signal an underlying issue. Consulting an exotics veterinarian to determine and treat the cause is recommended.
In summary, rabbits eat their own poop as a normal behavioral adaptation that benefits their digestive health. Cecotrophy allows rabbits to maximize nutritional intake from their food. Understanding cecotrophy and differentiating it from abnormal poop-eating behaviors helps rabbit owners support proper digestive health. Monitoring appetite and poop habits aids in early detection of issues. With attentive, informed care and veterinary guidance, rabbit owners can support the natural cecotrophy behavior in their pets.
References:
https://rabbitbreeders.us/questions-and-answers/why-do-rabbits-eat-their-own-poop/
https://www.rabbitsforsale.com/questions-and-answers/why-do-rabbits-eat-their-own-poop/