Vigilant Vervets

Vervet monkeys are one of Africa's most widespread species of monkey, although there are at least six subspecies and they can also be found on some Cape Verde islands as well as the West Indies.  Vervets are sexually dimorphic with males being somewhat larger than the females.

Source:  Wikipedia

Vervets are a social species living in groups of sometimes more than 50 individuals with a definite hierarchical structure.  Vervets live in a variety of habitats from tropical rainforest to sub-Saharan desert and due to their adaptability have one of the most diverse diets in the primate world from leaves, fruits, nuts and seeds to bird eggs, rodents and lizards depending on the season and what is available.

Source:  Wikipedia

Dorothy Cheney and Robert Seyfarth have done long-term studies on vervets and were the first to discover some interesting things about their vocalizations.  Vervets have distinct alarm calls, different calls depending on the predator approaching and different responses to each call.  An approaching leopard elicits one type of alarm and those within hearing leap into the trees, while an overhead bird of prey invokes a different call, group members take a quick glance toward the sky and then dash under a bush.  And a snake prompts a third call; individuals quickly stand on their hind legs looking to see where it is. Youngsters learn these calls and often before responding, adults will look to see who gave the alarm.  Often youngsters will get a scold if the call they gave was incorrect according to the predator.  Youngsters and adults have to know the difference between actual birds of prey and other nonthreatening birds flying overhead.

Source:  Wikipedia

Vervet monkeys are just another example of how intelligent animals are when people bother to study them.   Click here to hear Robert Seyfarth talk about the significance of vervet vocalizations.