It comes down to sex calls – distinctive calls that female chimps make while mating. New research shows that they do this to advertise their availability to other males and garner both sperm and support. But the females use these sex calls strategically, and they keep things down when other females are around to avoid undue competition.

Chimpanzees are just one of a number of animals that make specific sex calls, but their reasons for doing so have been a mystery. To understand any animal communication, you need to work out who the audience is and until now, we didn’t know who was listening into the sex calls of chimps.

Enter Simon Townsend from the University of St Andrews. Together with