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I can't imagine being hooked to a sled and running as hard as I can through the snow all day every day until I die from exhaustion, but London implies that's exactly what a sled dog wants to do.


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Sled dogs have been bred to pull sleds. All dogs have been bred to love their masters. Very few of these dogs die, even in the iditerod ( the gruelling race from Anchorage to Nome ). Those that do, usually are found to have congenital heart problems.

The penguins are marching inland because the ice flows are constantly shifting and changing ( What starts out as 70 miles, may end up being far closer to shore by the time the eggs hatch.) Also, the penguins instinctively know where the ice is thickest and least likely to break, this happens to be quit a march inland. New born penguins can't cope with the sea and predators lurking near the sea.