Monkeys Communicating in the Forrest

 Campbell’s monkeys have cells that notify others in their troupe to danger. Monkeys use a noise that sounds like a krak to alert others of a presence of a leopard, and make a sound like honk when they sense an eagle according to Recordings in the Tai Forest of the Ivory Coast. They add the suffix oo to show less of a threat. Krak-oo means to keep an eye on something below, and hok-oo alerts of a minor threat from above. Monkeys of Tiwai Island, Sierra Leone were studied and it was discovered that the same sounds had different meanings. “On the island, in an eagle situation, you did find a lot of hok but you also found a lot of krak,” Phillipe Schlenker of the French National Center for Scientific Research told Scientific American. “That was surprising because krak is supposed to be a leopard alarm call.” Tiwai has no leopards, so the meaning of the threat with the first species is not useful. Publishing in Linguistics and Philosophy Schlenker and colleagues figured that without the threat from below, krak “functions…as a general alarm call on Tiwai” It connects to human communication because of the way we prefer the specific to the general. “Words compete with each other,” Schlenker says. “And you use the more informative one.” Monkeys are usually viewed as simple creatures, so we sometimes forget that they are adapted to their environment very well, and they have found a language that maximizes survival. “The important thing is that in this situation, both krak-oo and hok are more informative thankrak,” Schlenker says. “By logic, if you hear krak you can infer there was a reason krak-ooand hok were not uttered, so you infer the negation.”