Bat pup 'babbling' similar to that of human infants, researchers say


Bat pups emit similar babbling tones to human infants,

 researchers say. Photo by Max Pixel/Pixabay

Aug. 19 (UPI) -- Pups of a bat species found in Central America make babbling sounds similar to those of human infants, a study published Thursday by the journal Science said.

The young of the greater sac-winged bat, or Saccopteryx bilineata, engage in "babbling bouts" for up to 43 minutes, the researchers said.

As in humans with speech, these babbling noises are a precursor to the tones or "songs" adults of this bat species use to communicate, they said.

"Pup babbling is a very conspicuous vocal behavior [that] is audible at a considerable distance from the roost and babbling bouts have a duration of up to 43 minutes," study co-author Martina Nagy said in a press release.

"While babbling, pups learn the song of the adult males," said Nagy, a researcher at the Museum for Natural History in Berlin.

Historically, researchers have studied vocal patterns in animals as a way to gain additional understanding of human language acquisition, according to Nagy and her colleagues.

However, in the animal kingdom, babbling behavior is rare, and limited almost exclusively to songbirds, they said.

Although studies of babbling in songbirds have provided researchers with important insights about speech development in children, the findings do not translate well to humans, the researchers said.

This is due in part to the fact that birds use their syrinx, a region of their spinal cords, to create and emit sounds, while humans use a larynx, which is an organ located in the throat that contains the vocal cords, according to the researchers.

From infancy, humans start the process of speech development with babbling, or the first sounds resembling speech, they said.

To study this process in the greater sac-winged bat, which is capable of vocal imitation and engages in a obvious vocal practice behavior, Nagy and her colleagues observed 20 pups in their natural habitat in Panama and Costa Rica for several weeks.

The bats were habituated to the presence of the researchers in close vicinity of their roosts, which enabled the scientists to collect daily acoustic and video recordings from birth until weaning, or the point at which mothers stop nursing their pups, the researchers said.

Back in Germany, the acoustic recordings were analyzed to investigate the characteristics of pup babbling.

Pup babbling is characterized by the same features as human infant babbling, including syllable repetition and alterations of different sounds, such as different vowels and consonants in humans, the researchers found

The pups spent seven weeks, on average, engaging in daily babbling behavior in which they used long, multi-syllabic vocal sequences, according to the researchers.

In addition, the pup babbling is rhythmic and occurs in both males and females, the researchers said.

"For example, pup babbling is characterized by reduplication of syllables, similar to the characteristic syllable repetition -- 'dadada' -- in human infant babbling," study co-author Lara Burchardt, also a researcher at the Museum for Natural History, said in a press release.