Location: The Hideaway (ship)
Petitioner: Clive's Reading Table
Unlocked: Complete Letting Off Steam
Reward: Cavall's Fang, 50 Sharp Fangs, 20 Renown, 800 gil
In order to unlock this side quest you need to progress far enough into the main story to reach Out of the Shadow. The majority of Out of the Shadow consists of three sub-quests, all called Letting Off Steam. Complete the three parts of Letting Off Steam, unlock the next area, and visit it once to gain access to all of the side content, including A Bone to Pick.
If you check Clive's Missives at his Reading Table you'll find a letter from Charon, expressing grudging concern for Torgal. Answer her summons, then head to Charon's Toll. Apparently Torgal isn't interested in Charon's treats, and that's cause for worry. Visit Harpocrates and he'll suggest that Torgal, who is now magical in nature, requires a new diet to keep himself going.
Fast Travel to Martha's Rest or Eastpool (Eastpool is a bit faster) and head for Cressida, the abandoned village on the east side of Greensheaves. The place is now full of Elder Antelopes, and each time you kill one it will drop an Elder Antelope Femur. They will barely put up a fight, and killing all of the Elder Antelopes will earn you some Bloody Hides.
Return to the Hideaway and give Charon the femurs, then speak to Harpocrates. He'll ponder Torgal's transformation, and wrap up the quest for you.