Research published in the journal Science (Volume 391, Issue 6785, Pages 583-586) provides evidence of Kanzi the bonobo's ability to represent pretend objects. Kanzi, a language-trained bonobo, was tested in experiments where he had to respond to commands involving imaginary objects, such as a pretend banana or a ball. In 24 out of 30 trials, Kanzi correctly performed tasks that required manipulation of non-existent objects, such as "picking up" or "throwing" them. The study involved 12 different pretend objects and compared Kanzi's performance to a control condition with no imaginary elements. The success rate was 80% for complex commands versus 95% for real objects. The results suggest that Kanzi mentally represents these objects in a similar way to humans. The experiments were carried out in a controlled environment using the lexigram for communication.