Monkeys call in different dialects, more linguistically sophisticated than imagined

Chuck Bednar for redOrbit.com – Your Universe Online
Monkeys living in two different parts of the world do not use identical alarm calls to warn of potential threats, even if they are members of the same species, according to research appearing in a recent edition of the journal Linguistics and Philosophy.
The study, which was led by Philippe Schlenker, a senior researcher at Institut Jean-Nicod within France’s National Center for Scientific Research (CNRS) and a Global Distinguished Professor at New York University (NYU), reveals that monkeys have dialects, and that their calls are more sophisticated linguistically than previously believed.
“Our findings show that Campbell’s monkeys have a distinction between roots and suffixes, and that their combination allows the monkeys to describe both the nature of a threat and its degree of danger,” Schlenker explained in statement Monday.
He and a team of linguists and primatologists from CNRS, the University of St. Andrews, the Université de Rennes, the University of Neuchâtel and elsewhere analyzed the alarm calls of Campbell’s monkeys at two different locations: the Tai forest in Ivory Coast and Tiwai Island in Sierra Leone. Each population faces different predatory threats, with the Tiwai island monkeys facing eagles and the Tai Forest ones facing both eagles and leopards.
They used recordings of predator calls (eagle shrieks and leopard grows) to create transcriptions of the primate calls, and discovered that they were more complex than previously believed. Not only was there found to be a distinction between roots and suffixes, which was used by the monkeys to indicate the degree of danger lurking in the vicinity, but there was a detectable difference in the alarm calls originating from each of the two research sites.
Specifically, they found that the monkeys used a combination of roots (primarily “hok” and “krak”) and suffixes (-oo), and the combination of those components allowed the monkeys to describe the nature of the threat and to indicate the amount of peril they faced. For example, “hok” was used to warn of aerial threats such as the eagle, while adding the suffix “-oo” served to amplify the warning, allowing it to be used for several types of airborne disturbances.
Furthermore, the result indicated that the calls were used differently in the Tai Forest than they were on Tiwai Island, according to NYU. In Tai, the root “krak” typically serves as a warning about leopards in Tai, but is a general alarm call on Tiwai and can also be used to warn against eagles. In their study, Schlenker’s team set out to discover explain why this phenomenon exists.
In their paper, they explained that the developed models “based on a compositional semantics in which concatenation is interpreted as conjunction, roots have lexical meanings, -oo is an attenuating suffix, and an all-purpose alarm parameter is raised with each individual call.” The first model helps to account for the differences between the two sites, while the second uses “a competition mechanism akin to scalar implicatures.”
According to the university, implicatures are a concept borrowed from human languages that suggests that a word’s meaning can be enriched when it competes with a more informative alternative (for instance, the relationship between ‘possible’ and ‘certain,’ in which “possible” implies that something is not a certainty).
The study authors suggest that ‘krak’ is always a general alarm, but has become enriched by competition by “hok” (which indicates an aerial threat) and ‘krak-oo’ (which indicates a weak threat) in Tai. The end result is that it is clarified by indicating a non-‘hok’ and non-‘krak-oo’ threat, meaning that a ‘krak’ is a threat that is not airborne in nature and is not a weak threat; it context, it becomes a ‘serious ground-related threat’ (usually a leopard).
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