Reindeer have "switched off" their internal body clocks to survive dark winters and light summers in the Arctic.

Seven times Tour de France winner Lance Armstrong of the US crosses the finish line on March 14, 2010 at the Cape Argus cycling race in Cape Town, South Africa

Seven times Tour de France winner Lance Armstrong of the US crosses the finish line on March 14, 2010 at the Cape Argus cycling race in Cape Town, South Africa