How do sharks breathe?

How do sharks breathe?

How do sharks breathe? They do the same as other fish; sharks extract oxygen when water passes through their gills.

Shark gills are behind their heads, and they are not covered like most fish. However, for the water to pass through, some shark species have to be always swimming.

A shark’s breathing process is called ram ventilation. “In fish which have a reduced or no ability to pump water buccally, such as mackerel and sharks, perpetual swimming is required to maintain ventilation,” according to Encyclopedia.

Also, sharks do not have lungs. They get all the oxygen that they need through the gills.

Could sharks die if they stop swimming?

Now that you know how do sharks breathe, you should also know that some could suffocate if they stop swimming, but not all of them.

Obligate ram ventilators are sharks that must keep moving to receive enough oxygen from the water to live. They draw water in through their mouths and force them out through their gills.

Other sharks use a method called buccal pumping. They pull water through their mouth and force them out the gills using the cheek muscles.

However, some sharks do not need to move all the time to get their oxygen. These have special structures called spiracles to force water through their gills.

There are even other sharks that use both spiracles and buccal pumping.


What do sharks use their nose for?

We have explained how sharks breathe, but as you have learned, the nose has nothing to do about it.

A shark’s nose is used exclusively for the smell. It is also one of its most effective senses.

When a shark moves, water flows through two nostrils positioned along the sides of the snout. Then, “water enters the nasal passage and moves past folds of skin covered with sensory cells,” The Wildlife Museum explained.

Their sense of smell is so powerful that they can detect the smallest blood traces in the water. Also, the nasal cavities act like ears, so if the smell is coming from one side, either the left or right cavity will detect it first, before the other one does.

shark nose

How many gills do sharks have?

Gills are the respiratory organs sharks, and other fish have for breathing purposes. Water passes over them, and dissolved oxygen moves from the water into the bloodstream.

Then, water leaves the body again through the gill slits. However, some sharks also have spiracles, small openings on the shark’s head behind its eyes.

Those who have spiracles use them to allow water to enter their body, pass over the gills and then leave through the gill slits. These are sharks that rest on the ocean floor and do not have to move constantly to breathe.

But, exactly how many gills do sharks have? All shark species have from five to seven pairs of gill slits, depending on their species. Inside the gills, there are hundreds of feathery gill filaments.

What are gill filaments?

Each gill filament has “thousands of leaflike lamellae, or flaps, which contain blood vessels. The blood absorbs the oxygen from the incoming water, and the excess water flows back out the shark’s body through gill slits”, you can read in How Stuff Works.

This method can allow sharks to extract about 80% of oxygen from the water. Humans, for example, only take in about 25% of oxygen when we breathe.

shark gills

If they have to move all the time, how do sharks breathe and sleep at the same time?

You may be wondering how do sharks sleep if some of them have to be continually moving to breathe and stay alive. Do they even get to rest sometime?

Also, sharks do not have eyelids, so their eyes remain perpetually open. Their pupils are always monitoring the creatures swimming around them.

However, even if they have to move to breathe, they can still engage in periods of deep rest. They do not sleep the same way humans do.

Sharks that can rest while remaining stationary are the whitetip shark, the Caribbean reef shark, the wobbegong, the lemon shark, the reef shark, and the nurse shark.

Are the oxygen levels declining in our oceans?

Sharks depend on oxygen-rich water to survive, and according to, the oceans’ oxygen levels have been declining for more than 20 years. This consists of a threat to the entire marine life on the planet.

Low oxygen levels can reduce species that live in oceans. This also makes less food available for sharks to hunt.

What could also happen is for sharks to migrate to other areas where there are higher-oxygen surface waters. However, they will still need cooler, deeper waters to help regulate their body temperature.

If anyone asks you, “how do sharks breathe?” now you can give them a correct answer because you know that they use their gills to get the oxygen from the water. Also, not every shark needs to move to be able to breathe, but there are some that, if they stay stationary, will suffocate.

About The Author

Steph Copeland

I am a marine expert that has a passion for sharks and the preservation of the oceans. I would like to help people feel safe in the water so that they don’t fear sharks.