⚠️This fact has been debunked
This is a common misconception. While penguins are the most famous flightless swimming birds, they are not the only ones. Other flightless birds that can swim include flightless steamer ducks of South America, flightless cormorants in the Galápagos, and the now-extinct Great Auk. Additionally, several island-dwelling ducks and geese have evolved to be flightless swimmers.
The penguin is the only bird that can swim, but cannot fly.
Are Penguins the Only Birds That Swim But Can't Fly?
Walk into any trivia night and someone will confidently declare that penguins are the only birds that can swim but can't fly. It's one of those "facts" that sounds right—penguins are so iconic in their tuxedo waddle—but it's actually a myth. While penguins are certainly the most famous flightless swimmers, they've got company in the bird world.
So who else traded wings for flippers? Let's meet the club.
The Flightless Swimmers
Flightless steamer ducks of South America are powerful swimmers that use their wings like paddle wheels to propel themselves through the water, literally looking like miniature steamboats. There are four species, and three of them never learned to fly. Instead, they "steam" across the water's surface at impressive speeds, thrashing their wings to escape predators.
The flightless cormorant of the Galápagos Islands also gave up flight for a life in the ocean. With wings about one-third the size they'd need to fly, these birds are expert divers, plunging deep to hunt fish and octopuses. No predators on their volcanic islands meant no need to escape into the sky.
Then there's the tragic story of the Great Auk—the Northern Hemisphere's answer to penguins. These flightless seabirds once thrived in the North Atlantic, swimming with penguin-like efficiency. Sadly, they were hunted to extinction in 1844, but they prove that penguins weren't unique even in their heyday.
Why Give Up Flight?
Here's the evolutionary trade-off: good flippers don't fly very well. To be an excellent swimmer, you need dense bones for diving, heavy muscles for propulsion, thick fat layers for insulation, and tightly packed feathers. All of that makes you too heavy to get airborne with short wings.
Penguins chose the ocean. Their bodies are essentially underwater missiles—they can dive over 500 feet deep and swim up to 22 mph. That's worth giving up the sky for.
The Penguin Myth Persists
- Of 11,000 known bird species, only about 60 are completely flightless (roughly 0.5%)
- 18 of those are penguin species, making them the largest group of flightless birds
- Their dominance in pop culture (think: Happy Feet, nature documentaries) cemented the myth
- Most people never hear about steamer ducks or flightless cormorants
So while penguins are the poster birds for flightless swimming, they're not flying solo in that category. Nature is full of birds that decided the ocean was more appealing than the clouds—and honestly, watching a steamer duck power across the water like a tiny motorboat, it's hard to argue with their choice.