The Grizz often pulled out this skull to scare the Sabertooth soldiers into following orders. It's actually made of hollow wood but they wouldn't know the difference.
― In-game description[src]
The Sabertooth Skull is a treasure found in Sly Cooper: Thieves in Time. It is worth 154 coins, and it has a time limit of 30 seconds to be returned to the hideout.
Description[]
It is a skull that is made of hollow wood, featuring blue gems serving as the eyes.
Location[]
You will find this treasure on a tiny ledge to the west, above the icy river. To get there, it's best if you take the path from Grizz's statue, going north.