London, Aug 3 (IANS): In a significant breakthrough, Italian researchers have decoded the language of penguins.
Researchers collected, categorised and analysed hundreds of audio and video vocal recordings from a captive colony of 48 African penguins at the Zoom zoo in Turin, Italy.
The results revealed that all the penguins have four essential vocalisations: a contact call emitted by isolated birds, an agonistic call used to signal aggression, an ecstatic display song uttered by single birds during the breeding season, and a mutual display song sung by pairs at their nests.
"The African penguin is a highly social and vocal seabird. However, currently available descriptions of the vocal repertoire of African Penguins are mostly limited to basic description of calls," researchers said.
The vocalisation has a clear harmonic structure and during the call, the beak is half-open and the bird stands up, extending the neck upwards as much as possible.
Penguins make the calls through what's called the syrinx, which differs from the mammalian larynx, the study noted.
The syrinx is made of two parts - an independent set of muscles and membranes at the right and left sides.
"Unlike mammalian vocal folds, this means many birds, including penguins, can produce two independent signals at the same time," researchers added.
The team also identified two distinct vocalisations interpreted as begging calls by chicks, in the form of a begging peep, and a begging moan.
The study appeared in the journal PLOS One.