Due to the success of the project, Gardner continued to expand it by obtaining four infant chimpanzees named Moja, Pili, Tatu, and Dar. Gardner wanted to begin the sign language training from younger than 10 months old, which was Washoe's age when she was first acquired. She also wanted to raise these infant apes alongside each other to determine whether cultural transmission of signing would occur, or whether the apes would use sign language to communicate with one another. At this point, Washoe moved to the Institute of Primate Studies in Norman, Oklahoma, under the care of Roger and Deborah Fouts, who were two of the original researchers that had helped to raise Washoe. In 1980, Washoe moved with the Fouts to Ellensburg, Washington, where she lived out her life until she died in 2007 at the age of 42.
