Uncommon Heavy Hide
Rare Heavy Hide
It can be gathered from plants in tier III-VII maps with an Expert's Skinning Knife (requires Expert Animal Skinner unlocked in the Destiny Board).
Exceptional Heavy Hide is the main resource in Steppe biomes, the secondary resource in Forest biomes, and the tertiary resource in Swamp biomes.
Gathering Exceptional Heavy Hide counts toward unlocking:
Gathering Exceptional Heavy Hide counts toward leveling: