How Dinosaurs Communicated: Sounds, Signals, and Display Structures

Dinosaurs ruled the Earth for over 165 million years, living in herds, raising young, competing for mates, and defending territories. None of this would have been possible without communication. But how did animals that went extinct 66 million years ago “talk” to each other? While we can’t hear their voices, the fossil record preserves remarkable evidence of their communication methods—from resonating head crests to colorful feathers, from booming low-frequency calls to visual threat displays.

Sound: The Voices of Dinosaurs

Parasaurolophus: The Built-In Trombone

The most spectacular evidence for dinosaur vocalization comes from Parasaurolophus, a hadrosaur with a long, curved crest extending over a meter behind its skull. CT scans reveal that this crest contained complex hollow tubes connected to the nasal passages.

Scientists have digitally reconstructed the sound this crest would have produced:

A deep, resonating foghorn-like call at approximately 30-120 Hz
Audible over distances of several kilometers through dense Cretaceous forests
Each species had a differently shaped crest, producing a unique frequency—allowing individuals to identify their own species by sound alone

This is not speculation—the physics of sound resonance through tubes of known dimensions gives us reliable estimates of the frequencies produced.

Other Hadrosaur Crests

Parasaurolophus wasn’t alone. Other hadrosaurs had their own acoustic equipment:

Dinosaur	Crest Shape	Likely Sound
Parasaurolophus	Long, curved tube	Deep foghorn, 30-120 Hz
Corythosaurus	Helmet-shaped, hollow	Mid-range resonance
Lambeosaurus	Hatchet-shaped, hollow	Different frequency range
Edmontosaurus	No bony crest (inflatable nasal sac?)	Bellowing calls

The diversity of crest shapes within the hadrosaur family strongly suggests these structures evolved primarily for species-specific acoustic signaling—each shape producing a distinct sound that helped individuals find mates and stay with their herds.

Sauropod Infrasound

Giant sauropods like Brachiosaurus and Argentinosaurus may have communicated using infrasound—sound frequencies below the range of human hearing (below 20 Hz):

Their enormous body cavities and long tracheas could have produced extremely low-frequency sounds
Modern elephants use infrasound to communicate over distances of 10+ kilometers
A 30-meter sauropod could theoretically generate even lower frequencies, potentially audible to other sauropods across vast distances
These sounds would have traveled through the ground as well as the air, detected through the feet (as elephants do today)

Theropod Vocalizations

What did T-Rex sound like? Probably not the iconic roar from Jurassic Park:

Birds (living dinosaurs) and crocodilians (their closest living relatives) both produce sounds using a closed mouth—deep booming, cooing, and hissing rather than open-mouthed roaring
T-Rex likely produced low-frequency booming calls felt as much as heard, similar to modern cassowaries and alligators
Velociraptor and other smaller theropods may have produced higher-pitched calls, hisses, and chirps
Some theropods like Cryolophosaurus had hollow crests that may have served as resonating chambers

Visual Communication: Colors, Crests, and Display

Head Ornamentation

Many dinosaur groups evolved elaborate head structures that served as visual signals:

Ceratopsians (horned dinosaurs):

Triceratops had three horns and a large neck frill
Styracosaurus had a frill ringed with long spikes
These structures varied dramatically between species, suggesting they were used for species recognition and mate selection
The frills were likely brightly colored or patterned, as seen in modern lizards with display structures

Pachycephalosaurs:

Pachycephalosaurus had a thick skull dome surrounded by bony knobs
These may have been used in head-butting contests (though this is debated) or simply as visual displays of fitness

Theropod crests:

Cryolophosaurus had a distinctive fan-shaped crest
Carnotaurus had prominent horns above the eyes
Dilophosaurus had paired crests on its skull
These structures were too fragile for combat, suggesting they were purely for visual display

Feather Displays

The discovery of feathered dinosaurs has revolutionized our understanding of dinosaur visual communication:

Microraptor had iridescent black feathers—scientists determined this by analyzing preserved melanosomes (pigment-containing structures) in the fossils
Anchiornis had black and white feathers with a reddish crest—the first dinosaur whose full color pattern was scientifically reconstructed
Yutyrannus was covered in filamentous feathers that may have been displayed during courtship
Oviraptor had feathered arms that it spread over its nest—a behavior preserved in multiple fossils, suggesting it displayed feathers to protect eggs and possibly to signal to mates

Modern birds use feather displays extensively for courtship (think of a peacock’s tail), and there is every reason to believe feathered dinosaurs did the same.

Tail Displays

Stegosaurus had large back plates that were likely flushed with blood for temperature regulation AND visual signaling—turning bright red or pink as a display
Ankylosaurus had a massive tail club that could have been used in visual threat displays as well as combat
Amargasaurus had a double row of tall neck spines that may have supported a colorful skin sail for display

Body Language and Behavioral Signals

Posture and Intimidation

Like modern animals, dinosaurs almost certainly used body language:

Making themselves look bigger: Theropods may have raised their arms, spread feathered wings, or stood tall to intimidate rivals
Tail positioning: A raised or lowered tail could signal dominance, submission, or alertness
Head movements: Ceratopsians may have lowered their horns as a threat display, similar to modern horned animals like rhinos and bison

Footsteps as Communication

Large dinosaurs couldn’t help but communicate through the ground itself:

A walking Argentinosaurus (70+ tonnes) generated seismic vibrations detectable from hundreds of meters away
Herds of hadrosaurs or ceratopsians moving together would have created a constant “ground hum” that helped the group stay together
Foot-stamping, as seen in modern elephants and ungulates, may have been used as deliberate warning signals

Chemical Communication

While impossible to confirm from fossils, dinosaurs almost certainly used scent-based communication:

Modern birds and crocodilians both use chemical signals
Dinosaurs likely marked territories with scent (urine, feces, or glandular secretions)
Scent may have played a role in identifying herd members, locating mates, and detecting predators
Some dinosaurs had enlarged olfactory bulbs (the brain region processing smell), suggesting scent was important—T-Rex had exceptionally large olfactory bulbs

Frequently Asked Questions

Q: Could dinosaurs roar like in the movies? A: Probably not. Based on their closest living relatives (birds and crocodilians), dinosaurs likely produced closed-mouth vocalizations—deep booming, cooing, hissing, and bellowing. The open-mouthed mammalian roar is specific to animals with a larynx, not a syrinx (the bird vocal organ).

Q: Did baby dinosaurs call to their parents? A: Almost certainly. Modern crocodilians call from inside the egg to signal that they’re ready to hatch, and their mothers respond by digging up the nest. Baby birds call constantly to their parents. Given that many dinosaurs showed parental care, vocal communication between parents and offspring was very likely.

Q: How do we know what colors dinosaurs were? A: By analyzing melanosomes—tiny pigment-containing structures preserved in fossilized feathers. Different melanosome shapes correspond to different colors (rod-shaped = black, round = reddish-brown, etc.). This technique has revealed the colors of several feathered dinosaurs with scientific accuracy.

Q: Did dinosaurs sing like birds? A: Modern birdsong is produced by the syrinx, a vocal organ unique to birds. The oldest known syrinx fossil dates to about 66 million years ago (from a bird called Vegavis). Non-avian dinosaurs may have lacked a syrinx and instead vocalized using other structures, producing simpler sounds than modern birdsong.

The world of the Mesozoic was far from silent. From the haunting foghorn calls of Parasaurolophus echoing through ancient forests to the ground-shaking footsteps of sauropod herds, from the iridescent flash of Microraptor’s feathers to the colorful threat displays of horned ceratopsians—dinosaurs communicated in rich, diverse ways that we are only beginning to understand.