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What Bird Can Swim but Not Fly? Get the Facts Here!

Written by Clinton Atkins / Fact Checked by George Dukes

what bird can swim but not fly

Unlike most, some species of birds cannot fly, including steamer duck, ostrich, kiwi, takahe, and more. But what bird can swim but not fly?

Well, among them, the only bird that can swim is the Penguin (Sphenisciforms). Antarctica is home to a vast range of bird species, whether flying or not, and the penguin is a flightless Antarctic bird with unique characteristics.

Read on to know more about this fascinating species.

Why Do Penguins Not Fly?


Birds that cannot fly are called a flightless bird. The most common species of flightless bird name that you may hear about is the penguin.

Scientists have discovered a total of 18 species of this animal, but none of these species of penguins can fly.

Unlike other birds, they can be easily identified due to their unique appearance. Penguins are unable to fly, but they are excellent swimmers and can reach incredible speeds in the water.

Penguins Cannot Fly for the Following Reasons


1. Penguins Weight

Penguins also have heavy bodies, which would make it difficult for them to fly. Unlike common birds cannot fly images, they have a layer of fat under their skin that helps keep them warm while swimming at high speeds through the water.

The fat also acts as insulation against the cold water around them. The fat in their body makes it difficult for them to get off the ground when they tried to flap the wings.

With all of their fat reserves and dense feathers, they don’t need a light body weight to stay buoyant in water. So they have no problem carrying around excess fat while diving underwater and walking along beaches or the following fish in shallow waters.

2. Their Wings

Penguins don’t fly because their wings are too short. The penguin wings or flippers are actually quite large, so they wouldn’t be able to carry enough weight to take off.

But it’s spectacularly efficient under the water, where it would be useful for swimming and flapping to stay afloat.

Penguins use their wings for maneuvering through the water as they swim. When diving underwater, penguins can close their wings and allow them to act like fins as they move through the water. This gives them a smoother ride through the water than if they were using their feet alone.

3. Their Bones and Muscles

Penguins do not fly because they don’t have the right body shape or wing structure.

In detail, their bones are too small and weak to support their weight in the air. They lack muscle strength and bone density required to support their weight in the air for a significant amount of time.

The foot bones of penguins are very thick with little flexibility, which makes them more effective at walking than other birds with thinner feet.

Penguins’ ribs are very strong to withstand the pressure generated by their swimming. Penguins can dive down to the bottom of the sea quickly and without difficulty, thanks to their strong and thick bones.


I believe that you already know the answer to what bird can swim but not fly after reading this article. The main point here is that some species of birds don’t have the ability to fly. Penguins are one among them.

I hope this article has helped you to learn new things about flightless birds and their fascinating characteristics.

Besides, you also can refer more to other topics of flying birds:

5/5 - (2 votes)

Clinton Atkins


Hi, I'm Clinton. Rocky and I became friends after a birdwatching trip with our new group. And we have been enjoying every adventure together. When he told me the idea of establishing a site that shares our experiences and fun, I immediately agreed. After trials and errors, here we have Thayerbirding.

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