Do Dolphins Have Gills:7 Facts You Should Know


It is a well-known fact that fishes breathe through their gills. But do dolphins have gills as well? Let us find out.

Dolphins don’t have gills but have other organs to breathe smoothly. They are instead equipped with lungs that allow them to breathe without drowning. There are several steps that dolphins follow to breathe. Dolphins are not the only marine creatures that breathe through their lungs; even whales have lungs to breathe, just like mammals. 

Needless to say, there is a lot of speculation about how dolphins breathe. Let us look at some of the most commonly asked questions and try to understand the breathing process.

Image Credits: “Dolphins” by Nico Kaiser is licensed under CC BY-SA 2.0.

Why don’t dolphins have gills?

You may be wondering why dolphins lack gills even though fishes have them. Allow us to tell you more in this regard.

Dolphins, like whales, are mammals and therefore do not have gills. Mammals have lungs to breathe and do not rely on gills as fishes do. This is because they are warm-blooded animals, and it would not be possible for them to extract sufficient oxygen from the water via gills. 

It is also important to add here that the cardiovascular and respiratory system of mammals is so designed that it facilitates the presence of lungs but not gills. Despite the development in science, restructuring the mammalian cardiovascular system is not possible to give gills to dolphins and whales. 

How do dolphins breathe without gills?

Image Credits: “Dolphins” by Sean MacEntee is licensed under CC BY 2.0.

Curious to know how dolphins manage to breathe without gills? Let us tell you all about this topic. 

Dolphins breathe without gills with the help of their lungs. Gills allow fishes to take in oxygen from surrounding water and also expel carbon dioxide. In dolphins and whales, this function is performed by the lungs. Dolphins breathe through their nostrils, and they move to the water surface to take in air which then travels to their lungs. 

Unlike fishes, dolphins cannot breathe underwater due to the absence of gills. Therefore, despite spending most of their time underwater, they travel to the surface when they have to breathe. 

Do dolphins breathe underwater?

Since dolphins live underwater, it is common to assume that they may breathe underwater as well. But is it true? Let us find out. 

No, dolphins cannot breathe underwater. This is because they lack gills, which gives fishes and sharks the luxury of breathing underwater. However, dolphins are equipped with lungs, like mammals and whales, and travel to the surface to breathe. They have a blowhole through which they inhale fresh air and expel out used air. 

In fact, the blowhole of dolphins is equipped with a flap that firmly seals the dolphin’s nose when they are underwater so that water does not enter their lungs. There have also been instances of dolphins learning how to breathe through their mouths. 

How do dolphins breathe?

Dolphins have a very streamlined breathing process. Let us take you through it step by step. 

Dolphins breathe through their nostrils (also called blowholes) in a very systematic manner. Here is the list of steps they undertake:

  • Dolphins travel to the surface to breathe since they cannot breathe in water.
  • Dolphins first exhale out air filled with carbon dioxide and clear out the water that might be resting on their blowhole.
  • In the next step, they breathe in oxygen-dense air from the surface.
  • Dolphins breathe in through their blowhole while the rest of their body remains submerged in water. 
  • The blowhole has a flap that closes when the animal is underwater. Therefore, water cannot enter the dolphin’s lungs. 
  • The air the dolphins breathe through their blowhole travels straight to their lungs from where it is transported to the rest of their body, and this process is fairly similar to the respiration process of humans.
  • Dolphins usually need to breathe 8 to 12 times per minute on average, and this process is repeated often. 

Although this may look like a very complicated procedure, dolphins have been accustomed to doing this since birth, just like humans and whales. 

How long can dolphins hold their breath?

Image Credits: “Common Bottlenose Dolphins, near Santa Cruz Island, Channel Islands National Park, California (10)” by Ken Lund is licensed under CC BY-SA 2.0.

Since dolphins spend a lot of time underwater, you may want to know how long they can hold their breath. Let us find out. 

On average, dolphins can hold their breath anywhere between 8 to 10 minutes. That being said, dolphins are like mammals and need to breathe frequently, and since they do not have gills, they cannot breathe underwater. Instead, they travel to the surface, and most active dolphins need to breathe 8 to 12 times a minute. 

Dolphins and whales are extremely intelligent animals who have the unique ability to manipulate their respiratory system and hold their breath for sufficiently long durations. This gives them the chance to travel deeper into the water in search of food. 

How do dolphins breathe when they sleep?

Image Credits: “Sleeping dolphin” by Brian Sloat is licensed under CC BY 2.0.

Curious to know how dolphins manage to breathe while sleeping? Let us tell you all about it. 

When dolphins are sleeping, you can find them resting on the water surface motionlessly (either in a vertical or horizontal position). In shallow waters, they manage to sleep on the seabed in order to travel frequently to the surface to breathe. Another way in which dolphins breathe is by continually swimming slowly close to the surface

In the last instance, even though the dolphin is sleeping, it continues to swim so that it can keep breathing. We must add here that dolphins keep one-half of their brain awake at all times, and as such, even though they may be sleeping, the ‘awake’ part of their brain allows them to keep breathing. 

How often do dolphins breathe?

Wondering how often dolphins breathe? Let us find out more in this regard together. 

On average, when dolphins are active, they travel to the surface often and breathe around 8 to 12 times in a minute. When on the surface, they take quick breaths, but they can also dive deep into the water in search of food and hold their breath for around 7 to 10 minutes. However, when resting, dolphins breathe 3 to 7 times a minute. 

Needless to say, dolphins need to travel to the water surface periodically since they do not have any alternate breathing mechanism. They rely on their lungs to breathe and need to inhale air from the surface since they cannot derive air from the water like fishes do.

How do dolphins breathe in the rain?

The rain can be quite an obstruction to dolphins and their breathing. Let us together learn how they breathe in the rain. 

Dolphins, like most cetaceans, have a blowhole located on top of their head and can easily control it. This blowhole has a seal that closes to prevent water from entering the lungs of the dolphins while it is raining. Thus, the dolphin can inhale air from the surface without worrying about water entering its lungs. 

The air is also exhaled from their lungs through the blowhole. Any water that might accumulate around the blowhole is cleared out by the dolphin before they breathe in the fresh air.

Can dolphins stay out of water?

It is a well-established fact that dolphins cannot breathe in water. But can they stay out of the water like humans? Let us find out. 

Yes, dolphins can stay out of the water, but it is conditional. Dolphins can only survive outside water if they are kept cool and wet since they need to have a certain body temperature to survive outside water. Although they can breathe outside water, regulating their body temperature becomes a huge task for them, and therefore, dolphins usually live in water. 

Despite being highly adaptable, dolphins do not thrive outside water since they become dehydrated quickly. Although they may stay outside water for a few hours if they are kept wet, it is not possible to replicate the ocean environment outside for them. Therefore, they must remain underwater. 

Conclusion

Various amphibian creatures such as fishes and sharks have gills that allow them to pull oxygen from their surrounding water. However, dolphins cannot breathe in the aquatic environment since they do not have gills, and therefore they have to rise to the surface periodically to inhale oxygen for their survival. If dolphins try to breathe underwater, they are likely to drown, like humans. 

It is interesting to note here that dolphins are not capable of breathing through their mouths like humans can since their trachea is not connected to their air passage. This allows them to only expose their blowhole and inhale oxygen instead of constantly keeping their head above the water surface. 

Sehrish

I am Sehrish , I love writing about animals. I like exploring the different aspects of the animal kingdom and aim to present the information to the readers in an interesting, easy-to-read format. The world of animals is full of undiscovered, intriguing facts and stories and there is nothing I enjoy more than delving deeper into it.

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