Triceratops’ Oversized Nasal Cavities Played Roles Far Beyond Smell, Paleontologists Find
For decades, representations of Triceratops and his parents were led by bones alone. Now Japanese paleontologists have mapped the soft tissue anatomy of these horned dinosaurs, revealing unexpected structures that could explain how they regulated temperature and breathed.
Triceratops‘nasal cavity. Image credit: K. Sakane.
Horned dinosaurs (Ceratopsia), including the iconic Triceratopswere among the most diverse and successful dinosaur groups of the Late Cretaceous.
Their skulls are among the most elaborate ever produced by vertebrate evolution, combining beaks, a variety of horns and frills, an enlarged nasal region, and a compact dental battery designed to handle tough vegetation.
Because these distinctive features likely underlie the group’s ecological dominance on land, scientists have long focused on the functions of their cranial structures, particularly the horns, beak, and ruff.
In contrast, the biological significance of their enlarged nasal region has remained largely unexplained.
“I have been working on the evolution of reptilian heads and noses since my master’s degree,” said Dr. Seishiro Tada, a paleontologist at the University of Tokyo Museum.
“Triceratops in particular, I had a very large and unusual nose, and I couldn’t figure out how the organs fit into it, even though I remember the basic patterns of reptiles.
“This led me to become interested in their nasal anatomy, its function and its evolution.”
In the new study, Dr. Tada and his colleagues examined several cranial specimens from Triceratops.
“Using X-ray based CT scan data from a Triceratops“Together with our knowledge of contemporary reptilian snout morphology, we found unique features in the nose and provided the first comprehensive hypothesis of soft tissue anatomy in horned dinosaurs,” said Dr. Tada.
“Triceratops had unusual “wiring” in their noses. In most reptiles, nerves and blood vessels reach the nostrils from the jaw and nose. But in Triceratopsthe shape of the skull blocks the passage of the jaw, so the nerves and vessels take the nasal branch.
“Basically, Triceratops tissues evolved this way to support his big nose. I realized this while assembling 3D printed objects. Triceratops skull pieces like a puzzle.
The researchers also identified a structure specialized in Triceratops‘nose known as the respiratory turbinate, an anatomical feature almost unknown among other dinosaurs but common among their living descendants, birds, as well as mammals.
These thin, curved nasal surfaces increase the contact area between air and blood, helping to regulate temperature through heat exchange.
Triceratops It probably wasn’t entirely warm-blooded, but scientists believe these structures helped keep temperature and humidity levels in check, since its large skull would have been difficult to cool otherwise.
“Although we are not 100% sure Triceratops had a respiratory turbinate, as most other dinosaurs have no evidence of this, some birds have an attachment base (crest) for the respiratory turbinate and horned dinosaurs also have a similar crest at a similar location in their nose,” Dr Tada said.
“That’s why we conclude that they have respiratory turbinates like birds.”
“Horned dinosaurs were the last group to have soft head tissues subject to our type of investigation, so our research has filled in the final piece of this dinosaur-shaped puzzle.”
“Next, I would like to address questions around the anatomy and function of other regions of their skull, such as their characteristic frills.”
The team’s paper was published in the journal Anatomical file.
_____
Seishiro Tada and others. Nasal Soft Tissue Anatomy Triceratops and other horned dinosaurs. Anatomical filepublished online February 7, 2026; doi: 10.1002/ar.70150
