Penguins in fiction tend to be given attributes of ducks due to the historical unfamiliarity of penguins. Since penguins are both waterbirds and considered exotic to either writers and/or audiences, work creators tend to substitute in attributes from better-known, more familiar animals. It also helps that penguins also walk with a waddling motion, like ducks. Subtrope of Informed Species.
Fictional penguins may have more rounded beaks like a duck's bill while real penguins have sharp beaks. Fictional penguins might make quacking sounds, when in reality they do caws or squawks — Emperor penguins have a very distinctive call that can be heard for miles, and is probably the most recognisable noise produced by any penguin species, while African penguins are nicknamed "jackass penguins" because their calls sound remarkably like the braying of a donkey. Penguins in fiction also tend to have orange, flat webbed feet with no claws, much like a duck's feet.
In terms of Linnaean taxonomy, penguins and ducks are only together up until Aves, the class that all birds belong to. When you get to the next lowest classification, order, that's where they split. Ducks are in the order Anseriformes with other waterfowl like geese and swans, while penguins are in the order Sphenisciformes. In terms of cladistics, penguins and ducks are similarly very distant relatives; they are together up to the Neognathae infraclass, which contains all modern birds short of the most basal ones.note Their lineage split during the Late Cretaceous when non-avian dinosaurs still ruled the world. Millions of years ago. They are so long-diverged that ducks are more closely related to chickens than to penguins, and penguins are closer to albatrosses than to ducks.note Nonetheless, a real-life animal did approach this trope: Bambolinetta, a flightless wing-propelled duck occupying a similar niche to penguins.
This trope may be related to the fact that both penguins and ducks are often considered humorous.
Subtrope of Artistic License – Ornithology, Informed Species, and Cartoon Penguin. Compare All Flyers Are Birds, Zebras Are Just Striped Horses, White-Tailed Reindeer, and All Animals Are Dogs. May overlap with Flying Flightless Bird if the penguin is shown flying.
- KC Penguin, the mascot of Kid Cuisine, has many duck-like features, especially his bill.
- Pleasant Goat and Big Big Wolf depicts penguins with yellow or orange beaks, when in real-life penguins' beaks and feet aren't always that color. They also have webbed feet, when real-life penguins have claws.
- During the duration of Bloom County, Opus the penguin has seen his beak change from a somewhat more pointed duck-like version to a full-on puffin-like schnozz. Lampshaded in a Sunday comic where Binkley, "burdened with an awesome clarity of vision," takes it upon himself to enlighten the other cast members with hard truths.
- The character Duke from Boner's Ark has a broad, flat bill like a duck. His beak in fact looks a lot like that of Dr. Quack, who is a duck.
- Batman Returns has several penguins living in the Absurdly-Spacious Sewer of an American city. There have been news stories about people rescuing ducks trapped in sewers in real life, so you would certainly expect to see ducks instead in an urban area. The penguins also occasionally quack (particularly in the Penguin's death scene), although they also sometimes make more realistic penguin sounds. The Penguin himself has a vehicle made to look like a giant yellow duck. While this is probably more to reflect his Psychopathic Manchild personality, it's still telling that a penguin-themed supervillain is associated with a duck.
- As played by Burgess Meredith, The Penguin, a recurring villain in Batman, sometimes makes quacking sounds like a duck at the end of sentences. However, the "Wauugh Wauugh" may not have been intended originally to evoke a duck's quack — he'd improvised the laugh on the spot to cover a coughing fit he was having so he could save a take (Meredith had quit smoking years earlier but was called upon to smoke on screen as The Penguin, and obviously his throat and respiratory system were having none of it). The director liked it and said Throw It In as part of the character's quirks.
- Club Penguin: The penguins all have orange or orangish-yellow beaks and feet that are soft and rounded. While the feet aren't quite like those of any bird in real life, the beaks and feet are still closer to those of a duck than a penguin.
- King Dedede is implied to be a penguin, yet he resembles a duck more due to his feet, his beak being rounded (although they sometimes resemble lips), and just like Kirby, he can fly by inhaling enough air.
- Pengies, penguinlike enemies, play with this trope. Their beaks have large throat pouches resembling those of a completely different bird: the pelican.
- LEGO Batman: The Videogame: The Penguin can summon dynamite-wielding penguin minions that make quacking sounds.
- Madagascar: The penguins don't actually act this way, but the Zoohunter in the first game and many humans in the second game do refer to them as ducks (the sailors in the first game instead call them kitties), and Skipper takes offense to this.
Zoohunter: Now hold on there! This is the end of the line for you ducks!
Skipper: Did he call us ducks? Get him!
- Puyo Puyo Chronicle: Expediguins, explorer penguins who serve as one of the game's enemies, have yellow beaks.
- Spelling Jungle: The penguins in the sequel Spelling Blizzard make a quacking sound instead of regular penguin noises.
- Super Mario Bros.: Bumpties, a species of penguins appearing in the Yoshi's Island and Paper Mario games, are often depicted with long, ducklike bills. This◊ artwork from Yoshi's Story, however, makes a Bumpty's beak look ducklike in a different way, by having it almost resemble lips.
- The website Debate.com (sadly defunct now) had a debate on whether or not penguins actually are ducks. "No" won, but not by much. Those who claimed "yes" cited all sorts of reasons why penguins are the same as ducks, most of which involved hilarious Insane Troll Logic. Arguments include: because they evolved similarly, because you can't say otherwise unless you've actually seen a penguin in real life, or even simply because they're both birds.
- The penguins in Adventure Time are often heard making quacking sounds. Of course, the show is set After the End, so they could have simply mutated.
- The penguins from the 1934 Disney short Peculiar Penguins have webbed feet and bills shaped like that of a duck's. While they don't make actual quacking sounds, their noises sound closer to that of ducks than penguins.
- Inverted in Peep and the Big Wide World, wherein Quack is a duck who's stylized to look more like a penguin.
- Pingu zig-zags this trope with the beaks, as sometimes penguins are shown with pointy bills and sometimes they are shown with round ones. Their feet also don't resemble feet of any real-life bird but look more like duck feet than penguin feet.
- Half-averted with the Avenger Penguins. They have comical two-toed feet but do have the pointy beaks.
- Wild Kratts: Lampshaded in "Mystery of the North Pole Penguins" where Martin refers to a family of emperor penguins stranded by Donita in the Arctic as sitting ducks, only to then point out that penguins are not ducks but more closely related to albatrosses, loons, and petrels.
- At the end of The Simpsons episode, "Simpson Tide" has Homer talking to the penguin crew of a ship from Antarctica by saying "Quack quack quack".