Culum Brown/Royal Society

ScienceShot: Human Handedness Is for the Birds

Staff Writer

Whether you're a righty or a lefty, parrots may be able to tell us why we've come to prefer one hand over the other. In a series of experiments, researchers watched as 322 parrots from 16 different species attempted to grab an object—a toy or a piece of food—with their feet. Since the birds' eyes are on the sides of their heads, they can't look straight ahead like we do; instead, they have to cock their heads to one side. But like us, individual parrots show a strong preference for one limb or the other: The researchers noticed that a "left-handed" bird would cock its head to the right to give its left eye a better view. It would then grab the object with its left foot, probably because this was the easier foot for the left eye to track. If early animals had eyes on the sides of their heads like birds do, their need to use either one eye or another to grasp objects may have led to the evolution of handedness, the researchers suggest online today in Biology Letters.

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Posted in Evolution