As humans, one of our most unique traits is our ability to speak and comprehend language. Apart from us, only a choice few other species have this ability, the most well-known being parrots and parakeets. Their speech is mostly mimicry, in which they copy heard words quite accurately and form sentences; these sentences usually don’t mean anything but are impressive either way! So how do these birds share the ability of speech with humans, who are all the way on the other side of the evolutionary chart?
Image Source: silversaltphoto.j.senosiain
Recently, researchers at Duke University conducted a study to help find physical and evolutionary traits in birds that can help explain this phenomenon. Neurobiologist Erich Jarvis stumbled on this finding while investigating a gene in the brains of deceased parrots. He found that the gene PVALB was activated in two distinct areas of the parrots’ brain, which he believed were the “song nuclei” of the bird brain.
These “song nuclei” consist of what looks like an M&M, an inner core of neurons, and an outer shell, with the nuclei’s appearances varying across bird species. Some species had only the inner core, whereas others had both structures. According to the researchers, the neurons in these structures have allowed the birds to synchronize singing and learning, as well as mimic sounds.
The scientists studied the brains of nine species of birds and found that the song nuclei varied in size across the species. Species more adept at mimicry, such as parrots, had larger song nuclei, whereas species that are not very skilled, such as hummingbirds or songbirds, had much smaller song nuclei. The scientists came to the conclusion that the larger the song nuclei were, the better the bird species was at imitating speech.
Image Source: Science Photo Library – PASIEKA
The researchers believe that the structures originally evolved as mechanisms to help birds better communicate. In the wild, the song nuclei could be used for a variety of functions, including mating, raising alarms, protecting territory, or simply to call out one another. Furthermore, the scientists also think that over time the nuclei gained new functions when they duplicated within the brain. This could explain how parrots eventually gained the ability to mimic human speech.
However, according to Jarvis, the research is far from complete. So far, the research has only established a correlation between the brain and the mimicry ability in birds; there is no definite proof yet. The shell, in fact, is still hard to define anatomically within the birds’ brains. Research like this will hopefully help uncover more about our bird friends and what makes them so similar, and so different, from us humans.
Feature Image Source: Are you talking to me? by paweesit