She was housekeeper, nurse, assistant and almost certainly more to a man named Dr Philibert Commerçon. We know that their relationship was a close one because, after sometime in his employment, she had become pregnant. She refused to name the father but it was generally believed to be Commerçon. The child was fostered and died young. Also he had made out a will leaving her money and all the furniture in their Paris apartment.
In 1766, Commerçon was asked to join a round the world expedition as naturalist. He would collect and catalogue new botanical species. It was a huge thing, the first circumnavigation for France, but the doctor was not sure that he wanted to go. He was not a well man. But he eventually agreed if he could have a servant along who would be paid out of royal expenses. Of course he had just the person in mind. But there was one problem. Women were absolutely forbidden on French ships. Baret still managed to get aboard though, she simply disguised herself as a man.
Because they needed to bring a lot of equipment for their work, they were able to commandeer the Captain’s cabin for themselves. This must have been a great help in their deception as it meant that Jeanne didn’t have to use shared toilet facilities. The doctor was terribly ill and needed a lot of looking after. He had an ulcer on his leg and was also very seasick. When they reached Montevideo and began searching the countryside for plants, it was Jeanne who had to carry all the specimens and supplies. By the time they reached Rio De Janeiro, Commerçon was confined to ship, so she had to do the collecting too. One of the new species, Bougainvillea, was named after the voyage’s navigator Louis Antoine de Bougainville.
Although there seems to have been some speculation about Jeanne Baret, they managed to keep up their pretence until they reached Tahiti. The people there immediately identified her as a woman and their cover was officially blown. When a Tahitian named Ahu-toro was questioned later, he said he thought she was a transvestite. The word he actually used was mahu, which means a third gender person, who had traditional roles in some Pacific societies.
When they arrived in Mauritius in 1770, Commerçon was pleased to find that a fellow botanist was governor there. When their ship sailed, the pair decided to stay on the island which was probably a huge relief for everyone else. The doctor died there in 1773 leaving Jeanne stranded and penniless. She seems to have run a tavern for a time and then in 1774 she married a French Officer who was passing through. She was able to return with him to France, completing her nine year round the world voyage in 1775. Once home she was able to claim everything that had been willed to her by Commerçon. She also later recieved a pension from the Ministry of Marine in recognition of her achievement, devotion to the late doctor and her bravery.