It's official: Most women carry babies on their left side. There's a special reason why.

Don’t you love it when scientists discover something completely kooky that we do as humans?

Something that has nothing to do with television or self-help-books or iPhones…just an animalistic human reaction?

Well, you and me baby ain’t nothing but mammals, so here’s a cute little fact that will have you beating your chest: mothers tend to carry children on their left side to connect them with their right brain.

Yep, all those years of hauling toddlers onto your left hip has been driven by a primal instinct millions of years old to connect you with your child.

According to research published in Nature Ecology & Evolution, mothers will hold their offspring to the left to spur the right brain into action.

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The right brain, you see, is in charge of language and emotional signals - so by holding the baby to the left, the mother is better equipped to read and understand their cues.

Like, ever notice how everyone else just hears a baby crying *shudders* but the mother understands it as, 'Yo woman, give me milk'?

Yeah. Yep. PRIMAL INSTINCT.

via GIPHY

This process is called 'lateralization', and is not limited to us human-apes: in fact, it's a trend that's been documented in other mammals too, from whales to horses to kangaroos.

In the 11 different species studied, mothers would keep their offspring to their left side to track everything from facial expressions to noises.

“The position of an infant on the mother’s left side may optimise maternal monitoring," notes the report, "by directing sensory information predominantly to the mother’s right hemisphere.”

Whoaaaa.

A previous report from the University of Sussex supports the claims, having published back in 2004 that 70–85 per cent of women and girls show a bias to hold infants, or dolls, to the left side of their body.

So, there you go, you monkeys. Your wonky back and left-stretched T-shirts all come down to the joys of evolution.

But just a quick question: if we hold our babies to the right, does that mean we can ignore their crying?