Over 25 years her senior, Toussaint Charbonneau obtains her through either trade, a gambling payoff, or outright purchase from her Native captors, and she becomes his property and nonconsensual “wife.” Charbonneau also purchases another young Shoshone girl, named Otter Woman. In 1804, Charbonneau accepts the offer of Lewis and Clark to join their expedition, where Sacagawea serves as guide and interpreter, while also caring for her infant son on the trail. She is six months pregnant during the trek and gives birth while on the trail (Burns, 1997).