The T. rex's roar has struck fear into audiences from the days of King Kong to Jurassic World, but new research found that dinosaurs probably didn't sound anything like that. (Jenny Starrs/The Washington Post) 
 
 Picture, if you will, the mighty Tyrannosaurus rex. 
 
 The odds are good what you envision has been brought to you in part by “Jurassic Park,” a plastic toy or some other facet of pop culture. (Perhaps you’re a fan of stop-motion master Ray Harryhausen.) But what Hollywood won’t teach you is that T. rex may have had feathers. 
 
 After all, today’s birds are living dinosaurs. 
 
 Now listen closely to your fearsome and possibly feathered friend. If you imagine it roaring, as both Steven Spielberg and “The Valley of Gwangi” did, we are sorry to say that sound is complete fiction. The roar of “Jurassic Park”‘s CGI tyrannosaur can be traced to a sound studio rather than the fossil record. It was a witches’ brew of baby elephant cries, tiger chuffs and a gargling alligator, remixed into a cinematically terrifying but completely artificial aural blast. 
 
 Were a dinosaur to vocalize in defense of its territory — or as a mating call — it might have sounded like one of today’s birds, scientists say. In fact, a journal article published online Monday argues that the ancient reptiles made sounds closer to the coo of a pigeon or the mumble of an ostrich. Those are far cries from mammalian screams. 
 
 [Grooves in the ground may reveal a bird-like dinosaur mating dance] 
 
 According to the new research, dino sounds may be what scientists call “closed-mouth vocalizations.” Unlike the high-pitched chirps and tweets from the open beaks of songbirds, the closed-mouth sounds are low, throaty whooshes of air. A flesh sac called an esophageal pouch enables birds with proportionally large bodies — think pigeons or doves — to produce the low murmurs. 
 
 A cooing dove with its mouth closed. (Tobias Riede/Midwestern University) 
 
 The researchers figured out the common bird sound like this: First, they collected vocal data on all sorts of animals called archosaurs, which include birds and crocodiles. And, notably, the long-dead dinosaurs. Writing in the journal Evolution, scientists from universities in Texas, Arizona, Utah and Canada analyzed the noises made by many living bird and crocodilian species. 
 
 They divided the types of sounds into various groups, including the close-mouth noises. Roughly a quarter of 200 birds species analyzed emitted the bulging closed-mouth sounds. Small birds, like sparrows and finches, did not make the noise. But birds with proportionally larger body types — like doves, ostriches and the giant New Zealand cassowary — do. This, the researchers say, suggest large-bodied dinosaurs may have had similar vocal abilities. 
 
 “Looking at the distribution of closed-mouth vocalization in birds that are alive today could tell us how dinosaurs vocalized,” said study author and University of Texas biologist Chad Eliason in a statement. 
 
 [These chickens now have dinosaur legs — but that’s not as weird as you might think] 
 
 Moreover, because not all birds had the trait, the scientists say it evolved separately in different groups of animals. It appeared in 16 distinct animal lineages, including crocodiles and birds. The scientists feel confident it could have evolved in dinosaurs, too. 
 
 
 
 A model dinosaur at the recent International Tokyo Toy show. (Kazuhiro Nogikazuhiro Nogi/AFP/Getty Images) 
 
 “A cool thing about this work is the demonstration that closed-mouth behavior evolved many times,” Tobias Riede, Midwestern University physiology expert and lead author of the paper, said in a news release. “That suggests it can emerge fairly easily and be incorporated into mating displays.” 
 
 The researchers were handicapped in their study because vocal organs, made of soft tissue, do not fossilize the way dinosaur bones do. So it’s much easier to build a big scary creature than to reconstruct what it sounded like. 
 
 But there are a few other hints in addition to this study. Based on what scientists know about birds, dinosaurs likely did not have vocal cords — those tough membranes that vibrate when a lion roars or a human speaks. Instead, they had air sacs, and it is possible dinosaurs had a birdlike syrinx, too (an organ similar to our larynxes but two-pronged and lower in the chest). 
 
 [How to find the dinosaurs that hide inside modern birds] 
 
 If a non-avian dinosaur whooshed like a bird, with its throat puffed up, the scientists suggest it may have sounded like the most intimidating large-bodied birds of today: ostriches and cassowaries. 
 
 Though ostriches are imposing creatures, their hoots leave Hollywood-trained ears wanting. The ostrich mating call is a low buzz, a sound about as ferocious as the gasps from a dying vacuum cleaner. 
 
 That said, the sound-smiths behind “Jurassic Park” were able to call on the dinosaurs’ living cousins in a few tense scenes — just not for T. rex. 
 
 As designer Gary Rydstrom told Vulture in 2013, the sibilant velociraptors — specifically, the sounds emitted right before a certain clever raptor ambushes game warden Robert Muldoon — have avian influences. 
 
 “That’s a goose,” Rydstrom said to Vulture. “Birds make pretty raspy sounds, but geese are famous for being the nastiest. You’ve got to get a goose mad and then they hiss at you, and it doesn’t take much to get a goose mad because they seem to get mad at everything.” 
 
 [The most outlandish theory yet for what killed off the dinosaurs] 
 
 For creatures that so readily capture both popular imagination and scientific study, much remains unknown about dinosaurs. 
 
 The vast majority of dinosaur species have yet to be found, argued University of Pennsylvania researchers in 2006. “It’s a safe bet that a child born today could expect a very fruitful career in dinosaur paleontology,” said paleontologist Peter Dodson at the time, after he and his co-author estimated that humans had discovered only 29 percent of dinosaur genera — the taxonomic rank made of a bundle of many species. 
 
 Dino sounds are no exception to the mystery. It is safe to say dinosaurs made sounds, as American Museum of Natural History Mark Norell put it. But exact specifics — like certainty of dino whooshes, hoots or coos — died with the animals, 65 million years ago. ||||| This post originally ran in April 2013. We are rerunning it with Jurassic WorldÂ opening this weekend. 
 
 "If people knew where the sounds in Jurassic Park came from, it'd be rated R!" laughed Gary Rydstrom. The sound designer rang me up last week to discuss his work on the Steven Spielberg action classic, newly rereleased in 3-D; when the movie came out in 1993, it netted him two Academy Awards for sound design and mixing (he's been nominated an astonishing 17 times over his career, winning seven statuettes). Though the Jurassic job was fun, Rydstrom remembers it as a tall order: He had to create dozens of distinct dinosaur noises essentially from scratch, since no one really knows what these long-dead animals would have sounded like. His solution was to spend months recording animal noises — some exotic, some not — then tweaking those homegrown sounds to create something otherworldly but still organic. What recognizable animals did he use to mix together the raptor, the T. rex, and all of Jurassic Park's other dinosaurs? Read on, if you dare: As Rydstrom implied, some of the sounds are sorta smutty. 
 
 Velociraptors 
 
 The intelligent raptors appear to have their own simple language, and it turns out that it's the language of love. "It's somewhat embarrassing, but when the raptors bark at each other to communicate, it's a tortoise having sex," said Rydstrom. "It's a mating tortoise! I recorded that at Marine World … the people there said, 'Would you like to record these two tortoises that are mating?' It sounded like a joke, because tortoises mating can take a long time. You've got to have plenty of time to sit around and watch and record them." 
 
 Still, that wasn't the only animal element used to create the raptor noises. "When the raptor shows up in the door window in the kitchen, the breathing noise is a horse," said Rydstrom. "We used the horse in about three to four different dinosaurs." What about the hiss that raptor makes when it ambushes the game warden Muldoon (which prompts him to mutter, "Clever girl")? "That’s a goose. Birds make pretty raspy sounds, but geese are famous for being the nastiest. You’ve got to get a goose mad and then they hiss at you, and it doesn't take much to get a goose mad because they seem to get mad at everything. All you have to do is get close to one and stick a mic near its beak and you'll get that hiss, and that's the hiss that Muldoon hears before he dies." 
 
 Gallimimus 
 
 If the Gallimimus flock recalls a stampede of wild horses, there's good reason for it. "I remember recording a female horse, and the male horse came right by her and she squealed because she was in heat," laughed Rydstrom. "A lot of animals in heat make a very unique sound, and she squealed at this male because he got a little too close and she was excited about the male, I assume. And that’s the squeal the Gallimimuses make when they’re passing by, and the squeal one makes when it's getting eaten by a T. rex. One of the key elements of the raptor screams was a boy dolphin in heat, so you can see a pattern here!" 
 
 Tyrannosaurus rex 
 
 The fearsome Tyrannosaurus rex is one of the biggest animals in Jurassic Park, but some of its key noises came from Rydstrom's tiny Jack Russell terrier, Buster. "The way they animated the T. rex was very doglike, especially when it grabs the Gallimimus and the lawyer and shakes them to death," said Rydstrom. "Every day I would see my dog playing with the rope toy and doing exactly that, pretending like he's killing his prey." Was Buster's Jurassic Park cameo an isolated incident? "No, I use my pets all the time," laughed Rydstrom. "In Terminator 2, I recorded the sound of Buster eating puppy chow, and that became the crunch when the T-1000 spiked that guy’s eye socket." 
 
 "One of the fun things in sound design is to take a sound and slow it down: It becomes much bigger," he continued. "That was inspired by Ben Burtt, the great sound designer from the Star Wars movies and a mentor of mine: He did the Rancor beast in Return of the Jedi by slowing a chihuahua sound down. It's one of the secrets of sound design that if you slow something down, something small, it brings out elements of the sound that you could probably never get if you recorded something big." 
 
 As for that bone-shivering, theater-shaking T. rex roar: "The key element of the T. rex roar is not a full-grown elephant but a baby elephant," said Rydstrom. "So once again, a small animal making a small sound slowed down a little bit has more interest to us than what a big animal might do." 
 
 Brachiosaurus 
 
 "The brachiosaur’s singing is one of my favorite sounds in the movie because it’s beautiful, but like all good sound design, it's made from a non-beautiful source, which is donkeys," said Rydstrom. "You think of donkeys, and they kind of yodel, you know? There's this pitch shift in donkey vocals, and if you slow them way down, you get almost a hooting, songlike quality. That's the brachiosaur when it’s in its splendor mode." And what about later in the movie, when it's in its sneezing mode? "That's a whale blowhole and a fire hydrant." 
 
 Triceratops 
 
 "I work at Skywalker Ranch, which has a lot of cattle around, so I used a lot of cows for the triceratops," said Rydstrom. "But the main sound of the sick triceratops is its breathing — this long, slow inhale and exhale — and that's actually one of the only elements of the movie that isn't an organic sound. I used this long cardboard tube with a spring in it, a reverb device that makes sounds seem stretched out and deeper and weird. So when Sam Neill puts his ear right up to the chest cavity of the triceratops and listens to its breathing, there's a lot of cow in there, but the key element of the breathing is mostly me breathing into a tube." 
 
 Rydstrom admitted that he did sneak one other human voice into the movie: his friend Dietrich. "He was visiting me and I turned on the mic and said, 'Can you make any weird sounds?' And he did this phlegmy, guttural growl. In the kitchen attack scene, there’s a close-up of the raptor slowly opening its mouth when it's about to attack Lex as she's hiding in a cabinet, and that sound is mostly my friend Dietrich doing this weird guttural growl. At the time, it felt like cheating when I would use myself or any other human to make a dinosaur sound — I felt like I was cheating the sound-design gods!" 
 
 Baby Raptor 
 
 The sounds Rydstrom used to animate the newly hatched dinosaur are just as adorable as the creature itself. "It's just been born, so at first it’s really squeaky and cute, and we recorded a lot of baby animals: baby owls, baby foxes, and things like that," he said. And no, your ears aren't deceiving you: When Sam Neill finds out that the cute baby dino is actually a vicious velociraptor, the sounds it emits become more … unsettling. "That's exactly right; as soon as he asks, 'What kind of dinosaur is this?' you start hearing these raspier baby owl sounds," said Rydstrom. "I already knew what the adult raptor would sound like, that it would have this screechy, raspy sound, so I tried to find a baby animal that has that rasp in it." 
 
 Dilophosaurus 
 
 When we first meet the Dilophosaurus, it cocks its head at Dennis Nedry and lets out an appealing trill. "Made from a swan," revealed Rydstrom. "Swans make a cute hooting sound, so the cute version of the Dilophosaurus sounds like a swan, for the most part." He chuckled. "Part of the fun of doing these kind of jobs is that I had no idea what a swan sounded like before!" 
 
 Of course, things quickly escalate with the Dilophosaurus as it grows a fearsome cowl and expectorates all over its prey. "When it's the scary spitter, there’s definitely a rattlesnake sound in there as it fans out its canopy around its head, and the raspy sounds in its voice are from a hawk," said Rydstrom, adding with a laugh, "Whenever I give lectures to people about getting sounds for movies, one of the key things I tell them is that when you’re recording dangerous animals like lions and alligators and rattlesnakes, then you have your assistant do it! On Jurassic Park, I had an assistant, the lovely Chris Boyd — who's still alive — and if we needed a rattlesnake, I’d say, 'Chris, please record the rattlesnake.' And I’d record the dogs and the kittens!" ||||| This is a set of web collections curated by Mark Graham using the Archive-IT service of the Internet Archive. They include web captures of the ISKME.org website as well as captures from sites hosted by IGC.org.These web captures are available to the general public.For more information about this collection please feel free to contact Mark via Send Mail ||||| Most birds vocalize with an open beak, but vocalization with a closed beak into an inflating cavity occurs in territorial or courtship displays in disparate species throughout birds. Closed‐mouth vocalizations generate resonance conditions that favor low‐frequency sounds. By contrast, open‐mouth vocalizations cover a wider frequency range. Here we describe closed‐mouth vocalizations of birds from functional and morphological perspectives and assess the distribution of closed‐mouth vocalizations in birds and related outgroups. Ancestral‐state optimizations of body size and vocal behavior indicate that closed‐mouth vocalizations are unlikely to be ancestral in birds and have evolved independently at least 16 times within Aves, predominantly in large‐bodied lineages. Closed‐mouth vocalizations are rare in the small‐bodied passerines. In light of these results and body size trends in nonavian dinosaurs, we suggest that the capacity for closed‐mouth vocalization was present in at least some extinct nonavian dinosaurs. As in birds, this behavior may have been limited to sexually selected vocal displays, and hence would have co‐occurred with open‐mouthed vocalizations. ||||| Colors show probability of each branch being an open-mouth vocalizer (blue) or a closed-mouth vocalizer (red). Pies show the probabilities that the ancestors of birds and crocodiles, palaeognath birds, and neognath birds used closed-mouth vocalization. Tobias Riede 
 
 AUSTIN, Texas — Dinosaurs are often depicted in movies as roaring ferociously, but it is likely that some dinosaurs mumbled or cooed with closed mouths, according to a study posted online in the journal Evolution that will be published in the August print issue. 
 
 The research examines the evolution of a specialized way birds emit sound — closed-mouth vocalization. The study emerges from a new collaboration, funded by a grant from the Gordon and Betty Moore Foundation, to understand the origin and evolution of the unique vocal organ of birds and the large array of sounds it can produce. Because birds descended from dinosaurs, the research may also shed light on how dinosaurs made sound. 
 
 
 
 X-ray image of a ring dove (Streptopelia risoria) producing cooing sounds with a closed mouth. Tobias Riede 
 
 Closed-mouth vocalizations are sounds that are emitted through the skin in the neck area while the beak is kept closed. To make them, birds typically push air that drives sound production into an esophageal pouch rather than exhale through the open beak. The coos of doves are an example of this behavior. Compared with sounds emitted through an open beak, closed-mouth vocalizations are often much quieter and lower in pitch. Birds making closed-mouth vocalizations usually do so only to attract mates or defend their territory. At other times, they emit sounds through an open mouth. 
 
 To understand when and how closed-mouth vocalization evolved, researchers with The University of Texas at Austin, Midwestern University in Arizona, Memorial University of Newfoundland and the University of Utah used a statistical approach to analyze the distribution of this vocal ability among birds and other reptilian groups. In total, the researchers identified 52 out of 208 investigated bird species that use closed-mouth vocalization. 
 
 “Looking at the distribution of closed-mouth vocalization in birds that are alive today could tell us how dinosaurs vocalized,” said Chad Eliason, a postdoctoral researcher at The University of Texas Jackson School of Geosciences and the study’s co-author. “Our results show that closed-mouth vocalization has evolved at least 16 times in archosaurs, a group that includes birds, dinosaurs and crocodiles. Interestingly, only animals with a relatively large body size (about the size of a dove or larger) use closed-mouth vocalization behavior.” 
 
 Tobias Riede, a physiology professor at Midwestern University and the study’s first author, said the association with large bodies is a matter of physics. 
 
 “The inflation of an elastic cavity could present a size-dependent challenge,” Riede said. “The lung pressure required to inflate a cavity depends on the tension in the wall of the cavity, and this tension increases for smaller body sizes.” 
 
 Researchers still are not certain about how the ancestors of modern archosaurs vocalized. But the occurrence of closed-mouth vocalization across birds and crocodiles — the two surviving groups of archosaurs — indicates that closed-mouth vocalization can emerge in diverse archosaur species depending on behavioral or environmental circumstances, Riede said. 
 
 “A cool thing about this work is the demonstration that closed-mouth behavior evolved many times,” Riede said. “That suggests it can emerge fairly easily and be incorporated into mating displays.” 
 
 An ostrich inflates its neck to make closed-mouth vocalizations. Credit: Ryan Mayock 
 
 Because dinosaurs are members of the archosaur group, and many had large body sizes, it is likely that some dinosaurs made closed-mouthed vocalizations in a manner similar to birds today, perhaps during mating displays. However, at this point in time, no direct fossil evidence exists to reveal what dinosaurs sounded like. 
 
 Julia Clarke, a professor at the Jackson School of Geosciences and co-author, said the study offers clues. 
 
 “To make any kind of sense of what nonavian dinosaurs sounded like, we need to understand how living birds vocalize,” she said. “This makes for a very different Jurassic world. Not only were dinosaurs feathered, but they may have had bulging necks and made booming, closed-mouth sounds.” 
 
 Future research by this collaboration will integrate information from fossils, experimental physiology, gene expression and sound modeling to understand the sounds that extinct early avian species, and perhaps their dinosaur ancestors, produced.
– Dinosaurs may have been much more like modern birds than we knew—and not just because some had feathers. A new study suggests that mighty dinosaurs of yore didn't roar, contrary to every dinosaur movie you've ever seen. Instead, they made a decidedly less scary sound called a "closed-mouth vocalization." Think of a dove cooing or perhaps an ostrich doing this grunting thing. As the scientists explain in the journal Evolution, per UT News, the sound actually comes out of the neck area after air is pushed through an esophageal pouch. In fact, the animal's mouth is shut the whole time. Lots of birds do this today, and because birds descended from dinosaurs, scientists suspect they may have communicated in a similar way. The fossil record can't prove it, though the Washington Post notes that previous research meshes with the idea, including the belief that dinosaurs had air sacs instead of vocal chords. “A cool thing about this work is the demonstration that closed-mouth behavior evolved many times,” says the lead author. “That suggests it can emerge fairly easily and be incorporated into mating displays" among different types of animals. A co-author says the study gives the impression of "a very different Jurassic world. Not only were dinosaurs feathered, but they may have had bulging necks and made booming, closed-mouth sounds." But if so, the makers of Jurassic Park didn't get it all wrong: The hiss of the film's velociraptors came from a goose, per Vulture. (Scientists have grown chickens with dinosaur legs.)