What social alarm call do vervet monkeys use to warn of an approaching eagle?

Vervet monkeys use an eagle alarm call to warn group members about an approaching eagle. Their alarm-call system is notable because different calls are associated with different predator categories.

An eagle alarm call can trigger protective behavior such as looking upward, moving into cover, or descending from exposed branches. Leopard and snake alarms produce different responses suited to threats from the ground. This makes vervet alarm calls a classic example in studies of animal communication.

The calls are not human words, and researchers debate how closely they resemble language. Nevertheless, their relatively consistent association with predator types shows that animal signals can carry specific information about danger.

Vervet monkeys live in social groups in sub-Saharan Africa. Their communication also includes grunts, screams, facial expressions, grooming, and body postures. The most important distinction is that the eagle call is a warning about a predator category, not simply a generic expression of fear.