Most humans believe we are the only creatures on Earth that combine sounds to create meaningful languages, but new research suggests birds do it too.
Scientists observed that the Australia chestnut-crowned babbler has the ability to create new meanings by rearranging the sounds in its call, PLOS reported. The findings shed light on an early step in the emergence of language that may have implications for ancient human development.
"Although previous studies indicate that animals, particularly birds, are capable of stringing different sounds together as part of a complex song, these songs generally lack a specific meaning and changing the arrangement of sounds within a song does not seem to alter its overall message," said lead author Sabrina Engesser from the University of Zurich. "In contrast to most songbirds, chestnut-crowned babblers do not sing. Instead its extensive vocal repertoire is [characterized] by discrete calls made up of smaller acoustically distinct individual sounds."
The researchers believe the birds combine sounds to form new meanings because it is easier than developing entirely new sounds. The team observed the chestnut-crowned babblers reused two sounds "A" and "B" in a variety of arrangements that coincided with different behaviors. The birds responded differently to the variations, looking at their nests when they heard a "feeding prompt" call and looking at the sky for birds when they heard a "flight call."
"This is the first time that the capacity to generate new meaning from rearranging meaningless elements has been shown to exist outside of humans," said Simon Townsend from the University of Zurich. "Although the two babbler bird calls are structurally very similar, they are produced in totally different [behavioral] contexts and listening birds are capable of picking up on this."
The team noticed the "B" sound was what distinguished the flight and feeding prompt vocalizations, making it comparable to "cat" and "at" in the English language with the "B" sounds representing the letter "c."
"Although this so-called phoneme structuring is of a very simple kind, it might help us understand how the ability to generate new meaning initially evolved in humans" Townsend said. "It could be that when phoneme structuring first got off the ground in our hominid ancestors, this is the form it initially took."
The fimdings were published in a recent edition of the journal PLOS Biology.