Dinosaur Brains and Senses: What Skull Scans Can Reveal

The short answer

Scientists use skull anatomy and CT scans to investigate dinosaur brains and senses. They can reconstruct internal spaces associated with the brain, nerves, and inner ear. These clues help test ideas about smell, hearing, and balance, but they cannot reveal a dinosaur's thoughts or provide a dependable IQ score.

The most important distinction is between a preserved brain and the cavity that once held it. Most dinosaur brain studies examine the latter.

Looking inside without breaking the fossil

CT scanning records many X-ray views that can be combined into a three-dimensional digital model. Differences between bone and surrounding material help researchers trace internal structures.

This approach can reveal areas hidden inside a delicate skull. Researchers can then share, measure, and compare the digital reconstruction without cutting the original specimen apart.

The Ohio University account of spinosaur research describes the use of scans to reconstruct brains and inner ears in Baryonyx and Ceratosuchops.

What is an endocast?

An endocast represents the internal space of the braincase. It can be a natural filling, a physical cast, or a digital reconstruction.

It is not automatically a perfect model of the brain itself. Blood vessels, membranes, and other tissues may have occupied part of the space. The relationship differs among animal groups.

Scientists compare extinct animals with living relatives to estimate what the cavity can reveal. Preservation also matters: crushing or missing bone may distort the outline that must be reconstructed.

Smell leaves anatomical clues

Regions associated with processing smell can be investigated through the braincase and nasal anatomy. Relative proportions may suggest that smell was important to an animal's life.

The Natural History Museum's discussion of spinosaur scans explains how researchers compared particular regions rather than simply labeling the whole brain “advanced.”

A large smell-related region does not tell us exactly how far an animal could detect a meal under every weather condition. Wind, habitat, odor type, and behavior also affect real-world sensing.

Hearing and balance have different structures

The inner ear contains structures linked to hearing and balance. Their size and shape can be compared with those of living animals.

Those comparisons can support inferences about sensory abilities, but they require careful calibration. An internal canal is not a preserved recording of what an animal heard.

Nor does strong hearing establish one specific lifestyle by itself. A proposed nocturnal hunter, for example, needs evidence connecting hearing with vision, anatomy, and ecology rather than relying on a single impressive feature.

Why brain size is not a simple intelligence score

Body size, brain organization, neuron density, and the relationship between brain and braincase complicate comparisons. Living animals also express different kinds of learning and problem solving.

A University of Bristol discussion of T. rex intelligence claims explains why estimates of neuron numbers cannot carry an entire behavioral reconstruction. Multiple lines of evidence are needed.

A bigger dinosaur brain was not automatically “smarter” than a smaller one, and a comparison with a living animal should identify the actual feature being compared. Sensory specialization and general cognition are different questions.

Digital models need interpretation too. A boundary visible in a scan may be incomplete or obscured by mineral filling, so researchers must decide where a structure begins and ends. Comparing reconstructions and documenting those choices helps other scientists check whether a sensory conclusion depends on one uncertain region.

Better questions for a dinosaur skull

Instead of asking only “Was it clever?”, ask which senses its anatomy emphasizes. Could it detect relevant smells, maintain balance, or respond to particular sound frequencies?

Then ask how directly the fossil supports the answer. Some structures are well preserved; others require reconstruction. Clear uncertainty makes the result more informative.

For a family activity, compare a skull illustration with an endocast image and identify what each represents. Avoid treating an empty eye socket as the exact size of a living eye.

Read our T. rex facts, compare Irritator, and explore dinosaur sounds. Anatomy reveals useful sensory clues without granting access to a dinosaur's mind.

Sources

• Ohio University: Spinosaur brains and inner ears
• Natural History Museum: Spinosaur brain scans
• University of Bristol: Limits of dinosaur intelligence estimates

Research reviewed: 7 October 2026.