(ORDO NEWS) — Although the fetus in the womb is not capable of making sounds, ultrasound has shown that baby marmosets practice the mouth and face movements necessary to call their parents for help even before they are born.
The first calls play an important role in the life of humans and other primates. They allow not only to attract the attention of parents, which is vital for the survival of the cub, but also lay the foundation for more complex communication in later life.
To understand how these first calls develop, the scientists conducted a study on four pregnant female common marmosets ( Callithrix jacchus ) who received ultrasounds two to three times a week, for a total of about fifteen sessions per animal throughout the pregnancy.
The team paid particular attention to the movements of the head, face, and mouth, and then compared these movements to those of newborn crying marmosets.
Using frame-by-frame analysis, the researchers found that as the fetus develops, its mouth movements become more distinct, after which they cannot be distinguished from the movements of crying newborn monkeys, briefly separated from their mothers during the first 24 hours after birth.
To make sure that these movements actually have something to do with cries for help, the team compared the prenatal and postnatal movements required for social “chirps” unrelated to danger.
The results showed that in the womb, marmosets reproduce only in general terms the movements necessary for “chirping”, apparently starting full-fledged learning after birth.
The data obtained are curious from the point of view of the similarity of the behavior of monkeys and humans: like marmosets, crying is the first sound with which a newborn child calls for help from parents.
So the baby should train to make this cry even in the womb. Indeed, studies of a developing fetus in the third trimester of pregnancy have shown that it opens and closes its mouth, mimicking movements during crying.
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