Why Do Some Animals Eat Poop? Explained in 3D
When humans are extremely hungry, they may eat almost anything they can find. But there is one thing humans instinctively avoid: feces. This strong aversion exists either because we feel a deep natural disgust toward it, or because we know feces can contain harmful germs and diseases.
However, in the animal kingdom, this rule does not always apply. For many animals, eating feces—scientifically known as coprophagy—is not strange at all. In fact, for some species, it is an essential survival strategy.
So why do some animals eat poop? Is feces really as dangerous as we think? The answers may surprise you.
Is Feces Always Dangerous?
One major reason animals eat feces is that feces are not always harmful—especially when they come from healthy individuals.
Feces from sick animals can contain dangerous bacteria, parasites, or viruses. But in healthy animals, feces mostly consist of:
Water
Undigested food
Harmless gut bacteria
In recent years, even modern medicine has recognized the value of healthy gut bacteria. Doctors now use fecal microbiota transplants (FMT)—sometimes called “poop pills”—to treat serious intestinal infections like Clostridioides difficile. These treatments use stool from healthy humans to restore good bacteria in sick patients.
This alone shows that feces are not always toxic waste—they can sometimes be biologically valuable.
Watch the Full 3D Animation
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Undigested Nutrients: A Hidden Food Source
Another key reason animals eat feces is nutrition.
During digestion, the body does not always extract all nutrients from food. This is especially true for animals that eat plants. Plant material is difficult to digest, and a significant portion of nutrients can pass through the digestive system unused.
Studies show that herbivores lose nearly one-third of the nutrients they consume through feces. This makes feces a rich secondary food source.
Because of this:
Many insects like beetles and flies survive entirely on animal dung
Feces recycle nutrients back into ecosystems
Some animals directly consume feces to reclaim lost energy
In ancient times, humans even built toilets above pig pens, allowing pigs to survive on human waste because it still contained enough nutrients.
Why Do Dogs Eat Poop?
Many pet owners have witnessed dogs eating feces, a behavior that often causes alarm and disgust. But dogs have their reasons.
Dogs have an extremely strong sense of smell. They can detect:
Specific vitamins
Digestive enzymes
Nutritional deficiencies
Sometimes, dogs eat feces because they are lacking certain nutrients, especially B-vitamins or enzymes. In other cases, it may be instinctual behavior inherited from their wild ancestors, who ate feces to eliminate food traces that could attract predators.
While it’s unpleasant for humans, this behavior often has a biological explanation.
Gorillas and the Second Meal
Gorillas are powerful plant-eating animals, but their digestive systems cannot fully break down all food components.
When gorillas eat hard seeds, their digestive systems often fail to extract all the fats and minerals inside. To compensate, gorillas sometimes eat their own feces to:
Re-digest undigested seeds
Absorb remaining fats and sodium
Maximize nutritional intake
This behavior helps them survive in environments where food quality may vary.
Cassowary Birds: Digestion on Fast-Forward
The cassowary, a large flightless bird found in tropical forests, has a very short digestive tract. Because of this:
Fruits often pass through its body partially undigested
Valuable nutrients remain in the expelled feces
When cassowaries notice this, they may turn around and eat their feces again, giving their bodies a second chance to absorb nutrients.
This behavior is less about habit and more about efficient digestion.
Animals That Must Eat Their Own Feces to Survive
For some animals, coprophagy is not optional—it is essential.
Rabbits: A Perfect Example
Rabbits eat grass like cows, but unlike cows, they do not have complex multi-chambered stomachs. Their digestive systems cannot fully break down plant fibers in one pass.
To solve this problem, rabbits produce two types of feces:
Soft feces (cecotropes) – rich in nutrients and beneficial bacteria
Hard pellets – the final waste product
Rabbits eat the soft feces directly from their anus. This process allows them to:
Absorb vitamins (especially B and K vitamins)
Reintroduce beneficial bacteria into their gut
Fully digest plant material
Only after this second digestion do rabbits pass the familiar dry pellets.
Without this behavior, rabbits would not survive.
Coprophagy Is Not Filthy—It’s Functional
From a human perspective, eating feces seems revolting. But in nature, survival matters more than disgust.
Coprophagy helps animals:
Recover lost nutrients
Maintain healthy gut bacteria
Survive on low-quality or plant-based diets
Adapt to digestive limitations
Evolution does not care about social taboos. It only rewards what works.
Why Humans Don’t Do It
Humans evolved with:
Highly efficient digestion
Cooking and food processing
Cultural norms around hygiene
We also face high risks from pathogens due to dense populations and shared environments. Over time, natural selection reinforced our strong psychological disgust toward feces as a protective mechanism.
So while humans can benefit medically from processed fecal bacteria, eating feces directly offers us no survival advantage.
Final Thoughts
Eating poop may sound shocking, but in the animal world, it is a smart biological strategy. For many species, feces are not waste—they are an opportunity.
Understanding coprophagy helps us appreciate how diverse and ingenious nature can be. What seems disgusting to humans may be life-saving for another creature.
Nature doesn’t follow human rules. It follows efficiency.
And sometimes, efficiency looks… messy.
Watch the full process in action!
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Useful Links : Coprophagia