Rawhide is an essential part of Stranded Deep. It is directly used to upgrade the Toolbelt (Pouch 2), but otherwise has no use outside of being crafted into Leather at a Tanning Rack. It's very useful at all stages of the game. It's not that common as it can be only obtained by Skinning Boars or by skinning any of the Sharks. All Sharks and Boars give rawhide when skinned. The Hog and the Great White Shark gives the most rawhide in game.