Pachyrhinosaurus was a large dinosaur that lived in the Late Cretaceous period.

It was as big as an elephant, and could weigh 4 tonnes and 8 metres long.

They lived in Alberta and Alaska 70 million years ago.

On the bony crest there were 2 horns pointing opposite directions.

At first, I thought its horns were used as defence, but when I watched a documentary, I discovered that  all Ceratopsians (Horned dinosaurs) used their horns to represent their age.

This is the documentary I watched.

https://www.youtube.com/watch?v=yfa6dBZS6-w

Here is a short video about Pachyrhinosaurus.