Baby bats and human infants engage in similar babbling behavior

Research on speech development stresses the challenges children face in gaining control over their vocal articulators, including the tongue, lips, and jaw, in order to be able to produce coherent speech sounds. An increasing number of scientists argue that this control is gradually gained during babbling, when infants start producing their first utterances which resemble typical speech sounds.

Babbling appears to be a universal form of human behavior, characterizing child development in all languages and cultures. 

Language use is considered one of the trademarks of humanity. Yet, its origins and development are far from being completely understood. Much knowledge about language evolution is gathered in the field of biolinguistics through comparing vocal ontogenetic processes in humans with similar processes in non-human animals. 

Babbling behavior seems to be quite rare in the animal kingdom. Until recently, this phenomenon had only been analyzed in songbirds. Due to significant differences in both brain organization and anatomy (birds have a syrinx instead of a larynx like humans), it has been very difficult to apply research findings about songbird babbling to humans. 

Recently though, a study conducted by a team of scientists from the Museum für Naturkunde Berlin discussed babbling behavior in a mammal species that, at first sight, seem to be highly different from humans: the greater sac-winged bat Saccopteryx bilineata. 

Researchers investigated this behavior of 20 bat pups in their natural habitats in Costa Rica and Panama, and discovered that these bats spend around seven weeks engaging in daily babbling behavior during their ontogeny, and employ long multisyllabic vocal sequences that include parts similar to the vocal repertoire of adult bats. 

“Pup babbling is a very conspicuous vocal behavior, it is audible at considerable distance from the roost and babbling bouts have a duration of up to 43 minutes,” researcher Martina Nagy said. While babbling, pups learn the songs of the adult males. 

Even more surprisingly, bat babbling is characterized by the same features as that of human infants, including reduplication of syllables and the use of rhythmic patterns. And whereas in the case of songbirds only young males babble, bat babbling behavior occurs in both male and female pups.

More studies of this fascinating bat species could give us new keys for unlocking the mysterious evolutionary origins of human language. 

The study is published in the journal Science.

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By Andrei Ionescu, Earth.com Staff Writer