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Reindeer Clocks

April 5, 2010

Most mammals have internal clocks that regulate their daily cycles, but not reindeer.


Why the reindeer lost time…I’m Bob Hirshon and this is Science Update.

Most mammals have a circadian rhythm, an internal clock that controls their daily activity cycle. But according to University of Manchester neuroendocrinologist Andrew Loudon, reindeer lack this timekeeper. He and his colleagues found that the genes that control the circadian rhythms of other mammals are switched off in reindeer.

ANDREW LOUDON (University of Manchester):
So if you asked a reindeer what time of day it is, it would probably have a bemused look on its face. But if you asked it what time of year it was, it could probably tell you with greater precision than probably any other animal on the planet.

Loudon says reindeer don’t have much need for daily clocks in the high arctic, where it’s dark for nearly 24 hours a day in the wintertime. But they do need accurate annual clocks so they can start breeding when their offspring will have the greatest chance of survival. I’m Bob Hirshon, for AAAS, the science society.