In 1931, a comparative psychologist at Indiana University by the name of Winthrop Niles Kellogg convinced his pregnant wife Luella to engage in a unique family experience – he wanted to raise a baby chimp alongside their soon-to-be-born son Donald. Luella agreed [source: Inglis-Arkell].
Gua was nearly 8 months old when she joined the family; Donald was 10 months of age. Both underwent constant observations of blood pressure, depth perception, motor skills, obedience, memory, growth rates and other vital aspects of development. For the first year, Gua frequently showed advanced abilities beyond her human companion. She was able to accept basic obedience commands and use utensils to feed herself [source: McLaren].
Every day, for 9 months, the couple observed Gua's development and taught her various skills. Then, abruptly, the experiment was halted. The chimp's cognitive development hit a ceiling, while Donald caught up and surpassed Gua's mental capacity. However, the human baby began mimicking the chimp's vocalizations, and the parents had had enough, perhaps fearful that Donald would pick up on a few too many animalistic behaviors [source: Nuwer].
Gua was sent back to the primate center she'd come from. Less than a year later, shortly after turning 3 years old, she contracted pneumonia and died.