If you’ve wondered how parrots can imitate humans so well, you’re in good company – many scientists have marveled at the behavior. Among them is HHMI Investigator Erich Jarvis of Duke University, who studies how certain birds mimic humans.
Scientists have known that the brains of certain vocal-learning bird species have specialized neurons involved in learning to produce sounds, but they did not know why parrots are better at imitating compared to other rare vocal-learning bird groups. In a study published June 24, 2015, in PLOS ONE, Jarvis and his postdoc Mukta Chakraborty found that parrots have a “shell system” of vocal-learning neurons not found in other species. This shell surrounds a “core system” found in songbirds and hummingbirds.
By comparing nine different parrot species, the team learned that the larger this shell was in a particular species’ brain, the better those birds were at imitating spoken language. This suggested the shell might play a role in the skill.
Jarvis hypothesizes that the shell emerged from a duplication of the core language region millions of years ago, developing a more complex function as it evolved. “Maybe in the human brain we have multiple duplications of an ancient pathway that’s controlling our complex speech abilities.”