havior to the caller. Cognizant of this criticism, subsequent studies of semantic alarm calls in vervet monkeys have been conducted in which the vervets responded to tape recorded playbacks of alarm calls: "These playbacks elicited the appropriate responses in most cases" (Griffin, 1992, p. 158). The monkeys climbed trees, dove into thick vegetation, or rose on their hind legs in response to the nature of the perceived danger. The experimental playback of animal vocal communication has allowed scientists to perform deeper analyses of animal behavior: "The vocal playback technique is a sensitiv
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