Psychologists Simon Townsend and Dr Klaus Zuberbuhler observed their behaviour in the Bundongo Forest, Uganda.

BBC: Monogamy shunned by female chimps

Slocombe and Zuberbuhler then ran an experiment to see if the chimps could tell the difference too.

FORBES

Slocombe and Zuberbuhler's study is the first experiment to show that vocal sound can carry meaning for chimpanzees.

FORBES: Can Chimps Talk?

After giving the chimpanzees six weeks to learn this pattern, Slocombe and Zuberbuhler added a twist to the experiment.

FORBES: Can Chimps Talk?

Even if Slocombe and Zuberbuhler are correct, mirror neurons may still have played an important part in the evolution of communication.

FORBES

Slocombe and Zuberbuhler argue that their results call into question the need to look to gestures for the origins of language.

FORBES

Chimpanzees prefer bread to apples, and Slocombe and Zuberbuhler discovered a corresponding difference in the rough grunts they made for each food.

FORBES: Can Chimps Talk?

Katie Slocombe and Kaus Zuberbuhler, two primatologists at the University of St.

FORBES: Can Chimps Talk?

The Cottagers failed in an attempt to have Pascal Zuberbuhler registered for the match, which Fulham won 1-0, after an injury crisis at the club.

BBC: Hodgson unhappy at keeper ruling