Scientists have reported their findings in the journal Behavioural Ecology and Sociobiology. Using a recording of other colobus monkeys making noise, they managed to kick-start an entire morning chorus of growls and screeches.

They discovered that the morning chorus usually starts with one monkey calling out, and is soon followed by others “challenging” them with a louder call.

In the animal kingdom, sound is often used to intimidate rival animals and to show off, indicating larger size or dominance.