Official Adoption
The duo was successful! Patterson and Cohn raised $12,000 to officially adopt Koko. After the adoption, Koko moved with the group to the Santa Cruz Mountains in 1979.
A Great Leap Forward
Let’s not move too quickly. The mere teaching of some American Sign Language to Koko was remarkable! Just by doing this, Patterson helped reveal that great apes have linguistic abilities similar to young children. In fact, Anne Russon, a researcher at York University, said that teaching Koko sign language, as opposed to solely verbal communication, was a “great leap forward.”