In the Baroness's room, you'll find a combination lock that requires 4 animal symbols to open.
After leaving the room, go to your cabin and speak to Adil. Exit your cabin and speak to the Doctor. Go to the lower deck and read the magazine to get one symbol: the bear.
Go to the saloon and speak to the Captain and Lady Westmacott, the Captain will give you the lion. Exit and read the poster to the right of the Doctor. You'll discover the beaver. Finally, to get the achievement, don't return to the lock but speak with Adil again to learn the final symbol is also a bear.