Some species of monkeys adopt the “accent” of other species while they are in the latter’s territory, a new study shows.
Published last month in Behavioral Ecology and Sociobiology, the study was conducted on 15 groups of two primate species in Brazil: pied tamarins and red-handed tamarins. While the former is an endangered species restricted to the Amazon rainforest, the latter is found across parts of South America. Researchers found the red-handed tamarins changed their accents when they entered their neighbors’ (the pied tamarins) area. In human terms, the changing of accents is a concept similar to how people practice “code-switching.”
Code-switching in people refers to the “natural phenomenon” of individuals alternating between languages, dialects, or accents — consciously or unconsciously. What inspires code-switching is the need to ‘fit in’ with a group; to communicate more clearly with someone who isn’t well-versed in the speaker’s language, dialect, or accent; or simply, to get things done — for instance, to get better deals, prices, or treatments in one’s non-native territories. “Code-switching helps people navigate the world because using multiple, different ‘codes’ help people bond better, communicate better, and get what they need done,” The Swaddle explained in a previous article.
Monkeys change their “accents” for much the same reason — to communicate better, researchers say. “They [monkeys] might need to say ‘tomahto’ instead of ‘tomayto’ – that’s the kind of nuance in the accent, so that they can really understand each other,” Jacob Dunn, an associate professor in evolutionary biology at Anglia Ruskin University in the U.K., who co-authored the study, told The Guardian.
However, unlike humans, the monkeys aren’t using actual words, of course. Instead, they use a variety of noises known as “calls” to communicate a diverse range of messages — these can be anything from predator warnings to mating propositions. To be more comprehensible, they simply adjust the frequency or duration of these calls. “…they can make the call longer or slightly higher or lower frequency, or a bit harsher or a bit more tonal,” Dunn explains.
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But what necessitates communication between different species at all? “…when you’re in this shared area and you’re a closely related species, you’re very likely to come into competition over resources, because you’ve got a similar diet and habitat requirements. You need a call that can be understood by this other species,” Dunn noted.
Given that the species are often competing for resources, switching “accents” to enhance communication helps red-handed tamarins establish their territory, and prevent territorial disputes that could otherwise turn into fights. “If they sound the same, everybody will understand that that area is occupied,” Tainara Sobroza, a biologist at the National Institute of Amazonian Research in Brazil, who was involved in the study, told the New Hampshire Public Radio.
The researchers noted the motivation behind their study was to understand how different species of primates behave in each other’s territories, since habitats of some species have begun converging with that of others — due to habitat loss caused by increasing urbanization, and the resultant deforestation.
Through the present study, the researchers wanted to assess the risk of “interference competition” between species — in order to design better reserves for their populations.
Besides helping conservation efforts, studies investigating animal behavior also offer insights into the evolution of human communication, researchers say. “Studying communication across this group of animals is likely to shed light on how, why, and when we evolved speech,” Dunn noted.