Captain Mary Oceaneer is or was a human woman.
An accomplished diver and treasure-hunter with a love of the sea, Mary Oceaneer, and her parrot Salty, sailed the oceans on her ship, the RV Oceaneer Lab, searching for treasure (mainly on Castaway Cay, where Oceaneer visited on her first expedition). Her ship was also a floating research laboratory, where she studied the sea. Mary also had a love of pirate lore, and would host "Pirate Nights" (pirate-themed feasts/parties) aboard the Lab.
A member of the Society of Explorers and Adventurers, Mary got along well with the other members, and would often meet with them in the secret dining area of the Skipper Canteen, where she kept several of her most important possessions, including her Society fez, several maps which she had created, and a book which she authored, titled Parrots as Pets. It would seem that she was close friends with Dr Albert Falls, who was also involved with voyaging on the water, as the head of the Jungle Navigation Co. Ltd, and appears to have granted him several certificates bearing her signature. She also visited, on occasion, the Tropical Hideaway, a popular rest stop for explorers, where she continued the S.E.A. tradition of placing a paddle from an expedition on display, using a paddle from an expedition on the Orinoco River in 1899.
Eventually, it would seem that the RV Oceaneer Lab was lost at sea or simply replaced, as Mary began sailing on the MS Salty IV (implying that there may have been three other MS Salty's in the interim). Likewise, Mary was, by this time, sailing with a parrot named Duncan, implying that Salty had either died or retired from traveling with Mary by then, probably the reason Mary's new ship was named after him. On this new ship, Mary once became shipwrecked on Typoon Lagoon while on an expedition, where she was stranded for several days, and was forced to set up a camp.
At some point during an expedition, Mary discovered an Atlantean artifact, inscribed with Atlantean characters, which she used as a bell on her ship. Among other famous treasures, the contract signed by Ariel to the sea witch Ursula somehow ended up in Mary's possession.
Behind the scenes
Mary Oceaneer first appeared in 2013 in a portrait of the Society of Explorers and Adventurers in Mystic Manor. Her character was later established further in the Oceaneer Lab play areas on the Disney Cruise line.