Sharks have to eat to stay alive, and just like us or any other animal, that means something is going to come out of the other end. So, the answer to “do sharks poop” is definitely, yes!
Headlines like “Superpredator!”, “Feeding Frenzy!”, “Eating Machine!” and others make it easy to think about sharks only in terms of eating. Such is the conjured-up imagery it’s natural to forget about anything else. But, sharks possess fairly straightforward digestive systems meaning that, like other fishes, they too poop.
We’re going to look into how shark digestion works and how they poop. We’ll also consider how the varied diets of different sharks might affect what their poop contains.
So, read on, and discover everything you ever wanted to know about shark poop!
The Sharks Digestive System
Sharks have a digestive tract that follows the characteristics found in most animals. However, they possess a few unique features that make them stand out.
Typically, sharks don’t chew their food. Shark mouths are designed to tear off large lumps to be gulped down. They’ll even swallow their food whole if it’s small enough.
Unlike humans, for example, sharks don’t have saliva and so don’t digest carbohydrates or anything else in their mouths as we do.
A shark’s mouth is one of its sense organs, and they will often use it as a last option to try and work out what something is. It’s scant consolation to anyone unlucky enough to get bitten, but the most likely reason it happened was that the shark was curious and, unfortunately, didn’t have hands to feel you!
A Shark’s Stomach
Food that the shark has bitten off is gulped down through the esophagus into the shark’s stomach.
Sharks have U or J-shaped stomachs filled with a gastric juice cocktail of acids and enzymes that chemically digest the food into a kind of rich soup.
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In some sharks, it is said that the gastric acid is so strong it could dissolve metal.
Inside the stomach, there are ridges called rugae, enabling the stomach to expand as needed for a substantial meal.
The digested food will pass onto the spiral intestine for absorption, but we can look at a fascinating ability that shark stomachs have before we get to that.
The stomach’s chemical digestion is pretty effective. However, some undigested materials inevitably build up from time to time and irritate the fish. This could be bones, bird feathers, or other debris like garbage that the shark has perhaps accidentally swallowed.
To get rid of this waste, many sharks can temporarily eject their stomachs, inside out, through their mouths in a process called gastric eversion.
Like turning out your trouser pockets, everything inside the stomach is dramatically dumped back into the ocean. The empty stomach is then sucked back in, and the shark continues as if nothing had happened.
As well as clearing out waste, sharks will also exhibit this behavior when experiencing high stress levels.
The fish may use it as a final way to try and scare off a perceived threat or to clear a full stomach so they can enter an effective fight or flight mode.
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The Spiral Intestine
The nutrient-rich soup from the stomach enters the spiral-shaped intestines via the pyloric sphincter to be absorbed.
Like humans, the first intestine stage is the small intestine (duodenum), where nutrients are absorbed. Shark intestines are relatively short.
However, the spiral shape gives a corkscrew-like twist configuration, increasing the available absorption time and nutrient take-up efficiency.
The shark’s colon is similar to our large lower intestines and is where water is absorbed.
How Do Sharks Poop?
So how do sharks excrete waste? Once the shark has digested its food in the spiral intestine and colon, whatever is left passes to the rectum. When it’s ready, the shark’s poop is expelled out into the sea via the cloaca opening.
So, if asked do sharks poop in the sea, we can say that yes, they do, and they do it in a very similar way to many other animals. In bursts, as they need to.
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Scientists and scuba divers have observed some sharks making unusual movements with their bodies as they poop. It is believed that this up and down motion encourages the movement of the poop and helps it exit the shark completely.
When the shark poop, it’s common to see small fish rushing towards it to eat any remaining particles.
You might wonder do sharks poop through their skin, but this isn’t the case. All the shark’s poop comes out via the cloaca. This confusion might arise from hearing about how do sharks pee, and we’re going to explain that a bit later.
Do Sharks Fart?
Some people ask do sharks fart? This might seem like a funny question. However, the answer is yes, they can! Well, sort of.
The shark’s gastric process doesn’t produce gas as cows or humans might. However, when sharks swallow food at the surface, they may gulp air at the same time.
Sucking air into their stomachs will mess up the shark’s buoyancy, so they need to get rid of it.
Some may be spat back out, perhaps by gastric eversion, but more commonly, so as not to waste valuable food, the air gets squeezed out through the digestive tract and pushed out of the cloaca, making it look as if the shark is farting.
What Does Shark Poop Look Like?
A shark’s poop is primarily liquid, but there can be some solid matter also. When the bowel movement is observed being pushed out of the shark’s cloaca, it’s often quite dramatic and looks like a cloud of color on the water.
So what color do sharks poop? Well, typically, it appears as yellow or green plumes. Remember, this is the digested remains of the “soup” made in the stomach, so you shouldn’t expect to see anything recognizable.
The poop color comes from the digestion process. Muscle and blood pigments from the shark’s food that have been broken down combine with the green-colored bile.
The yellowish shade comes from waste products from the shark’s liver, particularly from bilirubin produced when old red blood cells are broken down.
If you were to observe a shark pooping underwater, the color you see might be affected by the water depth in the fish.
Water absorbs light of different colors at different rates, so the color observed may not be the actual color when you are deeper underwater.
The shark’s food can affect what the poop looks like. Some sharks are apex-predators, while others are filter feeders.
Scientists actively study shark poop as it can tell them a lot about the animal’s diet. In fact, whale shark poop was referred to as “scientific gold” by scientists studying this vast shark.
Residual DNA found in poop samples is analyzed to determine what the fish ate.
Scientists can use this to work out where the animal may feed and understand the ecosystem’s health. By studying a shark population over an extended period, changes in diet can be observed and assessed.
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It’s also possible to use recovered intestinal cells in sharks’ poop to study the animal’s stress and sex hormones.
Unfortunately, scientists have found microplastic waste in the feces of sharks. This may have come from the shark eating food that had itself digested the plastic, or it could have been inhaled with seawater when the fish was feeding.
Shark poop is also known to be an essential food source and has been proven to provide sustenance to coral reefs by transferring enough carbon, minerals, and nutrients from off-shore waters.
So, while it may not be evident at first glance, shark poop is an essential part of the nutrient cycle in the ocean and can tell scientists a lot about the health of the animal.
What Do Great White Sharks Eat and What Is Their Poop Like?
The great white (Carcharodon carcharias) is by far the most famous shark species.
It is probably also the most studied by science. Great white shark poop is some of the most dramatic that you could expect to see. The resulting green cloud might resemble cow manure if it was sprayed into the water.
Great white sharks cruise the oceans looking for protein-rich marine life, often including sea turtles, seals, squid, octopus, dolphins, sea lions, large fish, and other sharks.
The great white has razor-sharp teeth designed to tear off lumps of flesh to swallow or grab the prey and gulp it down whole.
Bones, teeth, and other inedible parts of their food will be spat back into the ocean after the rest has been digested in the great white’s stomach.
What About Tiger Sharks?
Tiger shark (Galeocerdo cuvier) poop will contain the remains of the tiger shark’s diet, which is said to be just about anything this predator can find to fit in its mouth.
Tiger shark poop hasn’t been observed by scientists very often. However, it is thought to produce a green cloud in the water that looks very similar to a great white.
While a tiger shark’s everyday food will include crabs and lobsters, birds, rays, turtles, seals, smaller sharks, dolphins, and porpoises, they have been found to have eaten bottles, cans, vehicle license plates, and other kinds of random debris.
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Like many sharks, once the tiger shark has digested the food, it can vomit whatever remains, so even though they might have gulped down something pretty strange, it typically doesn’t cause them any lasting problems.
The tiger can concentrate on just eating whatever comes by, knowing that it’s gastric eversion can deal with anything that isn’t nutritious.
How About Whale Sharks, the Largest of All Sharks?
The whale shark (Rhincodon typus) is a filter-feeding species rather than a predator, unlike the previous two sharks.
Whale sharks are the largest known fish species. They are relatively slow-moving and cruise ocean currents looking for huge meals of plankton.
The whale shark can get food in two ways. It can actively swim forward with its mouth open, which pushes water and the food it contains inside (ram filtration). Alternatively, it can open and close its mouth in a stationary position, which sucks large amounts of water inside (active suction feeding).
Whichever method it uses, the water passes through the gill rakers, where food particles are separated to stay in the mouth and swallowed.
Whale sharks eat plankton and small fish in huge quantities. Studies have scientifically proven that juveniles need to eat at least 21 kg of plankton a day.
A typical whale shark diet may include algae, krill, shrimp, larvae, and jellyfish. Tiny fish could include anchovies, sardines, tuna, and mackerel.
Unfortunately, because they eat particularly indiscriminately, whale sharks can easily ingest plastic waste in the ocean. Microplastics have been found to be present in whale shark poop by scientists who have analyzed its contents.
Whale sharks pooping near the surface were first observed from the air by scientists. They saw a long green cloud of whale sharks poop that stretched several meters behind them.
How Do Sharks Pee?
While we’re considering how do sharks excrete waste, we can complete the picture and find out that sharks don’t pee conventionally. In fact, it can be said that sharks pee out of their skin.
Sharks produce urea in their livers and deliver it to their tissues to prevent their bodies from dehydration by the saltwater environment. Without the urea, the high-salt concentration surrounding the shark would suck essential water out of it.
Some urea is continually lost into the sea as the shark goes about its everyday life. The liver constantly replaces this.
So, do sharks pee out of their skin? Yes, they do!
So the answer to “do sharks poop?” is definitely yes. Sh sharks eat a lot, no matter the species, and what goes in must come out!
The shark’s digestive system produces considerable amounts of waste once it’s done digesting. The result is typically a thick green cloud in the water that can be enjoyed by small fish and filter feeders, including corals.
Scientists can study shark poop samples to determine what it’s eaten and assess the animal’s health. They can even use it to measure feeding habitat changes and track microplastics’ impact in the ocean.
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British-born Dan has been a scuba instructor and guide in Egypt's Red Sea since 2010.
Dan loves inspiring safe, fun, and environmentally responsible diving and particularly enjoys the opportunity to dive with sharks or investigate local shipwrecks.
When not spending time underwater, Dan can usually be found biking and hiking in Sharm's desert surroundings.