KATARINA ZIMMER: ‘Human mothers will usually cradle their infants on their left sides, such that they can gaze into each other’s left eyes, a position thought to favor processing in the brain’s right hemisphere. A new study in Biology Letters… shows that walruses and flying foxes are no different, having such lateralized cuddling biases during maternal care, too.
“Several decades ago, it was a popular belief that [this] brain asymmetry is only a human thing,” says the lead author of the study, Andrey Giljov, a zoologist at St. Petersburg University. But recent research has shown that in addition to humans, primate mothers tend to hold their infants to the left, and some of Giljov’s previous work demonstrated that several species of mammal infants like to keep their mothers in their left visual fields when approaching their parents from behind.
A bias towards keeping a social partner on a certain side, the new study explains, reflects specialization of the brain’s right hemisphere for processing social information, as visual information is handled by an animal’s contralateral brain hemisphere. The work reveals that flying foxes and walruses not only have a left-biased cuddling preference, but also tend to rest face-to-face in the position that allows mother and young to keep each other within their left visual fields’. SOURCE…
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