Female Putty-Nosed Monkeys Use Calls Just to Recruit Males When Certain Predators Are Detected 

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Researchers with the Wildlife Conservation Society's (WCS) Congo Program and the Nouabalé-Ndoki Foundation found that female putty-nosed monkeys (Cercopithecus nictitans) use males as "hired guns" to defend from predators such as leopards.
Credit: Wildlife Conservation Society