David Attenborough's Natural Curiosities

Curious Counters (4x4)

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Can animals count? This is a question that has intrigued and fooled investigators for a long time. Just over a hundred years ago, a German horse called Hans was declared a mathematical genius but all was not as it seemed. And strangely, some bamboos around the world flower exactly at the same no matter where they are – are they counting down the years?