A male red deer’s loud, resonant mating call is called a roar.
Red deer roar during the autumn rut, when stags compete for access to females. The vocal display can advertise a male’s size and condition, while also helping rivals assess one another before or during confrontations. Stags may roar repeatedly over long periods and accompany the calls with parallel walking, antler displays, or fighting.
The red deer’s rutting season is one of the best-known examples of mammalian acoustic communication in temperate habitats. Although “bugle” is strongly associated with elk, red deer are conventionally described as roaring. That distinction matters because closely related deer species use different English names for similar breeding calls.
Roaring is energetically costly and can attract both rivals and potential mates. Scientists therefore treat it as both a sexual signal and a competitive assessment signal.