how alarm calls work in the bush

This came from Cardinal Photo http://www.cardinalphoto.com

and article in the NY Times: http://judson.blogs.nytimes.com/2009/10/06/leopard-behind-you/?th&emc=th

‘Leopard Behind You!’ I’d like to continue Predator Appreciation Month with reflections on one of the more intriguing effects that predators can have on their prey: the development of a vocabulary of alarm. (Or should that be “an alarming vocabulary”?) . This isn’t a complicated vocabulary, with thousands of words. Nonetheless, it’s clear that for many animals, alarm calls are more than simple squawks of fear. Vervet monkeys, for instance, use different sounds to warn of different types of predator. “Leopard!” is not the same as “snake!” or “eagle!” If you hide a loudspeaker in the bushes, and startle unsuspecting monkeys by playing recordings of “snake!” at them, they will look around at the ground. “Eagle!” makes them look up. “Leopard!” sends them scampering to the trees.