You may like hanging out with your mates - well it seems Tyrannosaurus Rex and his relatives also did!
Scientists have found out that the top dinosaurs hunted in bloodthirsty gangs, which included young and older members.
T Rex are often portrayed as dim-witted loners, but new evidence shows that the massive creatures were highly intelligent and liked to hunt together.
The new idea comes after experts studied 24 skeletons of T Rex's cousins - Tarbosaurs - found in Mongolia.
It looks like the faster, young dinosaurs would do the chasing while the adults would kill them with their huge mouths.
Prof Philip Currie thinks T Rex hunted in groups
"Tyrannosaurids, I believe, were far more complex and more dangerous than we ever could have imagined," said lead scientist Prof Philip Currie.
"I believe these tyrannosaurids hunted in deadly, bloodthirsty packs. It's definitely time to rewrite the dinosaur books."
Tarbosaurus lived about 70 million years ago, was a two-legged hunter about 12m long weighing five tonnes.