looks like a human specialty: months of repeated, rhythmic, meaningless syllables before a baby asks for anything. pups learn their songs rather than inherit them, which makes them the obvious place to look for a practice stage. A team recorded pups in the wild and went through every bout. Does bat practice resemble a baby’s?
Pup babble, with the same hallmarks. Recordings in the wild caught sac-winged bat pups producing long bouts of repeated syllables. Those bouts carried the components that define babbling in human infants, among them syllables repeated in runs and sounds drawn from the adult song but not yet used for anything. The parallel holds in a mammal far from us on the family tree.
Human babbling is strange once you look at it plainly. For months a baby produces syllables in rhythmic runs that mean nothing, cost energy and draw attention, long before any of it serves to ask for something.
Greater sac-winged bats are one of the few mammals outside our own line that learn their vocalizations instead of inheriting them. Pups hear adult males singing and acquire the song. That makes them the natural place to look for a practice stage, and is the trait the whole comparison turns on.
Fernandez and colleagues recorded pups in the wild and went through the bouts feature by feature. The babble matched the human definition on the components that matter, among them repeated syllables, rhythm, and sounds that belong to the adult song without yet carrying any function.
is the interesting part here. If babbling turns up wherever a mammal has to learn its sounds, then it is less a quirk of human childhood than a requirement of the learning itself. The mechanism, not the species, would be doing the work.
wat. A bat pup practices its song the way a baby practices speech, in long meaningless runs that nothing in the moment requires.
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It moves babbling from a human milestone to a general feature of learning sounds, which gives speech development an animal model that can be watched in the wild.
How do we know?
Fernandez and colleagues recorded wild sac-winged bat pups through development and scored their vocal bouts against the features used to define babbling in human infants.
What is still unknown
One bat species shows the parallel. Whether the brain machinery behind it resembles the human one is a separate question, and nobody has answered it yet.
Learn something?
Where to next
What do elephants hear through the soles of their feet?communication
Do elephants call each other by name?communication
Does a dolphin have anything like a name?communication