I've already read a few reports that upon killing Bloodlord Mandokir in the new heroic 5-man ZG, the quest "An Old Friend" becomes available within the instance and players who have completed the lower level Lashtail Hatchling quest chain may obtain their very own baby raptor. :)
If you have not completed this prerequisite quest chain, though, you will probably not be eligible to save the baby raptor. feel free to correct me if I'm wrong. :)
To start the chain, you will need to be STV level-appropriate or higher (so about level 20+). Note: although the quest chain can be started and completed at lower levels, you must be level 85 to enter the instance and finally conclude this baby raptor's storyline.
Head to the Rebel Camp in Stranglethorn vale (alliance) or to Grom'gol (horde). Alliance will need to pick up and complete the quest Bad Medicine and horde will need to pick up and complete the quest The Defense of Grom'gol: Raptor Risk. Upon completion of either quest, players will either auto-accept a new quest (the quest item is included) or it will become available through the turn in NPC if your inventory was full. Hang onto the quest item and don't destroy it! I won't go into detail about the rest of the quests since it's quite lengthy and can get complicated later on, but the rest of the chain will require you to have the baby red raptor with you. Be sure to turn on your "track lower level quests" option, as some of the quests in the lashtail chain only unlock while doing other side/unrelated quests available from the quest hub NPCs.
NOTE: I HIGHLY recommend players pick up and complete the lashtail hatchling quest chain BEFORE picking up any part of the panther cub quest chain. Starting the panther quests will place you in a phased STV, and you will be unable to complete the lashtail hatchling quest until you've completed the full ZG quest.
I had this trouble while on the PTR and was unable to finish the lashtail quests, even after zoning into ZG. To be on the safe side, if you've already started the panther cub quests, complete the FULL chain. This means all quests up to an including the last part of the chain ("Booty Bay's Interests" and ends with "A Shiny Reward"). If at that point you are still unable to get back into the proper phase necessary to complete the lashtail quest chain, I would open up a ticket to a gamemaster to ask for assistance.
I can't wait to finally finish off this lengthy and long awaited quest chain! I must save Quintessence'aka! Blizzard did an especially great job with this companion. :)