Some Bat Babies Chatter Just Like Human Babies


Large marsupial winged bats are a field biologist’s dream. They hunt insects at dawn and dusk, staying awake most of the day and resting at night.

“They like places that are pretty well lit,” said behavioral ecologist Mirjam Knörnschild, who studies bats perching in trees or on the sides of buildings instead of gloomy, guano-filled caves at the Natural History Museum in Berlin.

And the bats, which are about two inches long, keep enough distance between them to tell them apart. Dr. “We mark them with colored plastic rings on their forearms,” Knörnschild said. “We can also use a directional microphone and record the sounds of individual bats.”

This is important because these bats are the only mammals other than humans known to babble like human babies. Bat cubs chatter includes only adult syllables and sounds produced by juveniles, and the nature of the chatter changes over time as bats learn territorial and courting songs. Also, their songs are not sung at the high frequencies that bats use for echolocation.

Dr. “This immediately reminds you of babies,” said museum resident Ahana A. Fernandez, who recently analyzed babbling with Knörnschild and other colleagues. Dr. The babble behavior is well known, but not rigorously studied, Fernandez said. The researchers wanted to “analyze puppy babbling behavior in detail and compare it to human infant babbling.”

They analyzed records of 216 “chatter fits” from 20 bats from two colonies in Costa Rica and Panama, lasting an average of seven minutes, but lasting as little as 43 minutes. The researchers found that the sounds the puppies make are similar to human infants in the repetition of syllables, the rhythmic nature of the babbling, and the universality of the babbling behavior.

As with human babies, all the pups babbled. Other similarities with the babbling of human infants included the early onset of babbling, long strings of sounds, and the fact that the offspring did not need any stimulus from other bats. Like babies, they just babbling, gradually acquiring more and more sounds. The researchers published their results Thursday in the journal Science..

D. Kimbrough Oller of the University of Memphis, who has studied the vocal development of human infants for decades, said there are “some remarkable parallels” with human chatter and birdcall in his extensive observations and analyzes of bats. it was just “the amount of chatter going on”.

They were making noise all the time, like human babies.

D., who was not part of this research, but collaborated with some authors for future papers. “They do this when they wake up,” Oller said. He said that bats babble, with or without any warning, just as human babies do. He said that human babies seem to be discovering the sounds they make, playing with them as auditory objects, similar to the physical objects they manipulate, taste and play with. “I think the larger marsupial winged bat is probably doing the same thing. They’re probably looking for these sounds,” said Dr. oller.

Although common in songbirds, no other mammal is known to engage in this type of chatter.

Among bats, both male and female cubs babble, but when females are weaned, they stop putting together syllables they have learned. Dr. Knörnschild said that adult women “do not sing”. They don’t do regional or courtship songs, and men do.”

Then why are you babbling? Dr. Fernandez said that when women learn what is in a courtship song, they can better evaluate the male song. It’s just a hypothesis, but females definitely judge male songs. Males compete intensely with bat songs to lure a harem of females. Females choose which male they prefer, and males constantly court them in some kind of ongoing talent show.

Dr. “Female selection seems to play an extraordinarily strong role in mating behavior,” said Knörnschild. “Males are slightly smaller than females and cannot physically force them to do anything.”

And according to women, they may not be just looking for the smartest or most energetic singers. Richard Prum, an ornithologist at Yale. In his book “The Evolution of Beauty” plumage or dancing behavior or singing, he argued, female birds and females of some other animals make choices that please them, mainly based on aesthetic criteria. When it comes to bats, he said aesthetic choice could drive the song’s development.

Dr. Knörnschild said aesthetic choice is certainly a possibility, but there are also acoustic qualities in bat song that indicate male suitability.

He also suspects that there are more types of babbling. So far the science of sound learning has focused on birds, but among mammals, mole rats, giant otters, dolphins and other marine mammals are good targets for research, he said.

“It would be really interesting to have more definitions of babbling from different species, then maybe the evolutionary pressures that caused babbling to appear in one species and not in another,” he said.


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