[metallic tapping against rock] -[Narrator] In the wilderness of Northern Alberta, scientists are excavating the bones of the unique horned dinosaur, Pachyrhinosaurus.

In an effort to do something truly unexpected, reconstruct their brains.

Surveys of the ancient rock in Pipestone Creek show its home to one of the biggest dinosaur herds ever found.

With the Pachyrhinosaurus living in colossal groups.

-[Emily Bamforth] It could be literally hundred of thousand maybe even millions of bones and so we estimate the size of the Pipestone Creek herd at 40,000 animals.

-[Narrator] So what enabled these one and a half ton herbivores to live in such enormous numbers, seventy-three million years ago?

To find out, paleontologist Emily Bamforth wants to get inside their heads.

-[Emily] Even though the brain is long gone, [deep bellowing] if we look into the, the skulls of these long extinct animals, what could better help us understand what the structure of herding animal brains actually looks like and how that might have informed the behavior of the animal.

-[Narrator] Pachyrhinosaurus brains were protected by a thick solid shell known as the brain case.

Today, Emily is bringing one of these brain cases, still inside a skull to a specialized imaging facility in Edmonton, Alberta.

She’s investigating a theory that the brains of herding dinosaurs would be physically different to those that were on their own.

Because of the demands of living in a group.

-[Emily] Herding dinosaurs versus solitary animals might have various parts of the brain that are developed differently because they need to focus on certain behaviors over others.

-[Narrator] So to understand more, she’s using a CT scanner normally reserved for human patients to create x-ray images of the shape inside the brain case.

-[Emily] CT scanning gives us a really clear idea of what the shape of the internal bones are.

The brains themselves are not preserved, what we get is the space in the skull where the brain was.

-[Narrator] Once the scan is completed, scientists Max Scott and Natalia [indistinct] can use the images to reconstruct the brain’s shape.

It’s a painstaking process, tracing the shape slice by slice to build a full 3D model.

-[Max] You can see the brain structures, there’s a lot of, lot of density in here, just all really great things.

-[Narrator] It paints a clear picture of how Pachyrhinosaurus brains were adapted to life in the herd.

-[Emily] They have structures in their brains that are found in herding animals today.

Things they probably would have used for individual identification.

-[Narrator] Pachyrhinosaurus herds are thought to have consisted of thousands of smaller family groups, so they had to be able to spot each other in a crowd.

And the scan suggests parts of their brain was specialized to identify each individual’s unique frill.

-[Natalia] There’s structures and they’re closely associated with pattern recognition.

-[Emily] Every frill is different and parts of the Pachyrhinosaurus brain are better developed so they can recognize each pattern.

At a distance they could see who was who.

-[Narrator] But the results also show their brains were adapted for more than finding friends.

They were built for dealing with foes.

Living in large social groups meant that the males had to fight for the pick of the mates and Pachyrhinosaurus brains appear to be wired for handling these one-on-one battles.

-The vestibula apparatus is rather enlarged and it’s what strongly controls that eye stabilization so they’re able to track movements around them.

-[Emily] The organ that is used for, for balance seems to be more developed in Pachyrhinosaurus.

Having good balance would be a better way to withstand individual to individual combat which would be more common in a herd environment.

[guttural grunt] -[Narrator] For Emily and her team, this cutting-edge research has given them new insight in to these unique dinosaurs.

And with more discoveries being made all the time it’s revealing an unprecedented picture of what life was life in one of the biggest dinosaur herds in Earth’s history.