Aquatic Hadrosaurs

"If it looked like a duck, then it probably swam like a duck..."

For more than a century after their discovery in the 1850s, hadrosaurs were thought to have been semi-aquatic animals that lived in swamps and ate aquatic plants. There are a few factors that led to this (ultimately disproven) hypothesis. For one thing, their generic name "duck-billed dinosaurs" comes from their broad and flat rostral bones which are similar to a duck's bill (most prominently seen in Edmontosaurus, also known as Trachodon, Anatosaurus, or Anatotitan in older works), which may have led to the assumption that they fed on aquatic plants, although it's now known that the rostrum was not actually "duck-billed" in reality, because there was a squared-off keratinous beak attached in life. The interpretation also came about in part due to a sustained misinterpretation of hadrosaur teeth, believing they could not tackle anything sturdier than the softest water plants without breaking off; even when a hadrosaur was preserved with terrestrial vegetation in its gut, it was written off as merely being a possible dietary supplement. Better fossils revealed they actually had thousands of sophisticated grinding teeth packed tightly in their mouths (known as dental batteries) clearly used for pulverizing tough, fibrous vegetation, and would've been way over-engineered for soft water plants.

The hadrosaurs also lacked the horns and spikes of some of the other big herbivorous dinosaurs, leading to questions about how they defended themselves from predators, and the idea that they could escape by swimming into deeper water (where predators supposedly couldn't follow) seemed like a solution. Another thing is the presence of soft tissue that was believed to be webbing for the fingers but turned out to be a deflated fleshy pad, built for walking on dry land. It was also thought that they could have used their flattened tails for propulsion, but their vertebral columns were connected by ossified tendons, rendered their tails too stiff for any sort of paddling. Last, but not least, some hadrosaurs sported head crests that were hypothesized to have functioned as some kind of snorkel or air-storage space; however, they lacked a hole in the crest and the stored air wouldn't be enough for animals of their size, making both theories unlikely. Instead, their crests functioned like resonating chambers used to amplify their calls but may have also been used as a visual signal and for display.

As it is now known that they were terrestrial animals similar to modern ungulates, this is largely a Discredited Trope, but it may still pop up in media now and then.

A Sub-Trope of Artistic License – Paleontology. In older works, this overlaps with Science Marches On. For another trope pertaining to the general family hadrosaurs belong to, see Social Ornithopod. Compare Aquatic Sauropods, which addresses outdated aquatic depictions (although for different reasons) of herbivorous dinosaurs such as Diplodocus, Brachiosaurus or Brontosaurus.

---

Examples:

Arts

• Charles R. Knight, a paleoartist who lived from 1874 to 1954, has a few paintings where he depicts hadrosaurs according to the classic portrayal. This example◊ includes two Edmontosaurus individuals, one of which feeds on aquatic plants.
• Rod Ruth's Album of Dinosaurs, released in 1972, includes a picture of three Edmontosaurus. Two of them are depicted swimming, one of which feeds on submerged plants.
• This piece of art◊ by the paleoartist Rudolph F. Zallinger depicts Corythosaurus and Parasaurolophus swimming. Their crests are likely supposed to act like snorkels.

Comic Books

• DC Comics: In this panel from◊ Wonder Girl, a pair of Corythosaurus-like hadrosaurs can be seen on the background munching on the aquatic plants of a river.

Films — Animation

• The "Rite of Spring" segment from Fantasia features several species of hadrosaurs, namely Parasaurolophus, Corythosaurus, Edmontosaurus, and Kritosaurus. They are depicted as swamp animals feeding on aquatic plants and run away in the water when a T. rex approaches.
• The The Land Before Time series is a major offender of this trope, as while Ducky and the other hadrosaurs featured in it do spend a lot of their time on land and browsing trees, they are also depicted as skilled swimmers and frequently shown eating water plants like a reptilian moose (which goes hand in hand with the series often merging antiquated Charles R. Knight-esque depictions of dinosaurs with more modern ones associated with the Dinosaur Renaissance). Ducky frequently utilizes her swimming skills to help her friends and her mother saves Spike from drowning in the eighth movie. This is also emphasized as their kin’s special talent (like pterosaurs being able to fly, ceratopsians being tough and ramming things, sauropods being gigantic and having whip-like tails, etc.), with “swimmer” even being the usual term used for duckbills in the series (the first film uses the term "bigmouth" but it didn't stick).

Films — Live-Action

• Jurassic World Dominion: When the flaming locusts inadvertently cause a forest fire across the BioSyn Valley, several Parasaurolophus take to the water for protection from the blaze.
• King Kong (2005): The corpse of a Ligocristus, a fictional lambeosaurine dinosaur, appears. According to the film's companion book, The World of Kong, it's noted to swim to small islets to lay its eggs during dry seasons. They are skilled swimmers, using this as a way to escape land predators. Possibly justified by the fact that it's not a prehistoric hadrosaur, and that most of the evolved dinosaurs were designed to evoke outdated reconstructions as an intentional Genre Throwback to the 1933 original.
• March of the Dinosaurs: Averted. Edmontosaurus are depicted as mostly terrestrial creatures. The herd only ends up in water by accident after the ice beneath them breaks under their weight, and while they are capable of swimming, the lake isn't a safe place for them because of the Mosasaurus.
• Star Wars: Kaadus, the primary riding animals used by the Gungans, resemble slender, armless hadrosaurs, live in swamplands, and are established in supplementary materials to be agile swimmers and divers. The Gungans themselves also somewhat resemble anthropomorphic hadrosaurs, save for standing upright and lacking a tail.

Literature

• After Man: A Zoology of the Future: While no actual dinosaurs appear, the trope is referenced in the page about the hornheads (a group of future antelopes which have evolved a pseudo-beak structure from extensions of the horns for browsing coniferous branches). The water hornhead is a wading species that feeds on waterweeds with a particularly wide, duck-like snout which the text explicitly states "in its way of life, must surely resemble the hadrosaurs — the duckbilled dinosaurs of the latter part of the Age of Reptiles". Yeah, not so much (the book was written in the late 70s/early 80s, when the idea was still widespread).
• The New Dinosaurs: An Alternative Evolution features the Bricket, a lambeosaurine hadrosaur that lives in dense woodlands. However, as ticks and other sorts of parasites tend to live off from them, Brickets would often submerge themselves in watery bodies to wash said parasites away from them.^note This wouldn't actually work in real life in the same way just bathing your dog with plain water doesn't get rid of its fleas; skin parasites can survive being submerged for a long time. It is also when submerged in water where Brickets mate with one another.
• Tales of Kaimere: The spirit of this trope is reflected in the spirit drakes, a branch of thescelosaurs (who took over the niche of hadrosaurs in Ni'Kar after the Dynastic Extinction wiped out almost all hadrosaurs) that are proficient swimmers and can even walk on the river bottom for food. Notably, they are more predatory compared to other thescelosaurs and hadrosaurs of this trope, with fish and small games making up 50 percent of their diet. And for the larger drakes like the Jugashen, "small" game includes people.
• Tyrannosaurus Drip, a Julia Donaldson picture book, has the duck-billed dinosaurs live in a river environment, similar to actual ducks.
  And they hooted "Up with rivers!" And they hooted "Up with reeds!"
  And they hooted "Up with bellyfuls of juicy water weeds!"

Live-Action TV

• Walking with Dinosaurs: Briefly mentioned in "Death of a Dynasty", when it's stated that hadrosaurs evolved in lush swamps, subtly suggesting the idea that hadrosaurs were semi-aquatic. The Anatotitan in the episode itself are only ever shown on land, however.
• Prehistoric Planet.
  • Downplayed where not averted altogether with the actual hadrosaurs, which are generally shown as fully terrestrial, and the "Deserts" episode shows two hadrosaur species, Barsboldia and Secernosaurus, migrating across arid dunes in herds resembling those of wild camels. In the episode "Ice Worlds", a herd of unnamed hadrosaurs do cross a cold, rapidly-moving river during a spring thaw, and while even the juveniles seem like reasonably competent swimmers, it's not something they do lightly, finding the narrowest possible place to ford before entering the water. Even then, not all of them survive the crossing.
  • This trope is invoked in the "Freshwater" episode with the Deinocheirus, whose duck-like bill is specifically pointed out in the narration, and is depicted wading through the wetlands like an immense moose, chomping down water plants - but he's wading, not swimming, and Deinocheirus was not a hadrosaur^note It was actually part of the ornithomimimosaur group, including the much smaller Dromiceiomimus and Gallimimus. Still, the scene has a lot of the imagery you might expect in an older depiction of a hadrosaur feeding.
  • The dinosaur whose actual swimming ability is most heavily emphasized in the series is actually Tyrannosaurus rex, with the first episode opening on a father rex taking his kids to an island where they can hunt sea turtle hatchlings.

Theme Parks

• Jurassic Park River Adventure: Parasaurolophus play an almost entirely aquatic role, with the one that (according to the ride narrative) bumps the riders' boat off course being seen neck-deep in water when it briefly surfaces after bumping against the boat. It being portrayed as aquatic is for the sake of practical reasons regarding hiding the machinery of the animatronics.
• At Walt Disney World, a herd of Edmontosaurus are present in the Primeval World Diorama segments of Universe of Energy (and its later retool Ellen's Energy Adventure) bathing under a waterfall and likewise positioned in a small pool of water.

Video Games

• ARK: Survival Evolved: The Parasaurolophus are better swimmers than the other dinosaurs, using this as a means of protection.

Web Original

• Serina: The scrunge is a member of a family of birds that evolved into cold-blooded lizard-like animals that has adapted to live in the expansive marsh known as the soglands by becoming a large, scaly omnivore with as blunt beak and escapes from predators by running on their hindlegs. It is even described as resembling "some fusion of a muskrat, and a rather outdated depiction of a duckbilled dinosaur".

Western Animation

• 64,000,000 Years Ago: The educational short film was made before the idea was discredited, and it depicts Edmontosaurus with webbed feet, paddle-like tails, duckbilled snouts, and fleeing from a Tyrannosaurus by diving into water.
• Darkwing Duck: In Extinct Possibility, the trio travel back to the Cretaceous and the first dinosaur they see is a cartoon Hadrosaur in a pond. Subverted when it turns out the hadrosaur is intelligent, wears clothes, lives on land and was just bathing at the time.
• Dinosaur Train: Discussed briefly in the Corythosaurus-centered episode. When the main characters are learning about the function of its crest, Buddy asks Cory if it's used for breathing underwater, Don, due to being more of a Cloudcuckoolander, asks her if it's a crown, and Tiny asks her if it's related to the music they make. Cory denies the first two questions and affirms the third one.
• Gigantosaurus: Inverted with Rocky, a Parasaurolophus. His friends can swim just fine, but he's shown to be afraid of water because he can't swim (although he later learns to). Interestingly, he has a hole in his crest, even though the lack of one is one of the very reasons why the theory about his species being aquatic was disproved.
• Go, Diego, Go!: In the episode "Diego's Great Dinosaur Rescue", Maia the Maiasaura is shown to be a good swimmer. In the episode, Alicia tells the viewers that "Maiasauras and a lot of dinosaurs swim", which unfortunately isn't true.
• Il Était Une Fois...: In the first episode of Once Upon a Time... Man, an Edmontosaurus/Anatosaurus jumps into a lake in order to escape from a Tyrannosaurus.
• Jurassic World: Camp Cretaceous: Played straight by the Parasaurolophuses that live in the underground river area. Given that they also have bioluminescent patches that are wildly implausible, it's likely they were genetically modified to be semi-aquatic. The Ouranosaurus also qualify when they attack the campers' yacht ^note Though they aren't techically hadrosaurs, they are close relatives, belonging to the Hadrosauriforme group.
• Valley of the Dinosaurs: In "Test Flight", the group comes across an Edmontosaurus wading in a river, and it dives deep into the water when Lok scares it off.

Real Life

• While not exactly a hadrosaur (though it was a relative, part of the clade Hadrosauriformes), Lurdusaurus appears to have been the closest real-life equivalent to this. Based on its body proportions, palaeontologist Tom Holtz speculated that it may have had a semi-aquatic lifestyle similar to a hippopotamus. Additionally, fossils of giant crocodiles and fish-eating spinosaurs have been found in the same area as Lurdusarus, suggesting that its environment was a wetland.
• While not a dinosaur by any stretch of imagination, Atopodentatus◊ essentially looks like old hadrosaur reconstructions. It was a real life "duck billed" herbivore scrapping the sea floor for algae.
• Eretmorhipis was another marine reptile that looked like an old hadrosaur reconstruction, being "duck billed" and aquatic. Still, it was actually a crustacean eater probably more similar to platypodes ecologically.
• Deinocheirus was a large ornithomimosaur that possessed a hadrosaur-like skull. Deinocheirus remains were discovered in a formation that was once a wetland and fossil evidence suggests that it possessed an omnivorous diet consisting of aquatic plants and animals.
• In real life, Edmontosaurus would have lived in a swamp-like environment due to remains of one species E. annectens being found in a formation (Hell Creek) that was once a wetland complete with crocodilians, turtles, amphibians and fish. Downplayed in that it still would have spent most of its time on land, but likely would've been acquainted enough with water to swim when it needed to.

---