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10 animals that learn through play

By: Meredith Darlington on March 28, 2011, 3:48 p.m.

Photo: BBC Earth

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Eider duck

The Eider duck is so keen to be part of a flock that it suffers if it lacks companionship or social activity. Also, ducks raised in captivity seem to act as if the humans caring for them are their flock.