Science: Speedup

Physiologists S. W. Britton and R. F. Kline used to sit in their laboratory at the University of Virginia and wonder why the sloth is so slothful. As good Darwinians they realized that the basic reason for the slothfulness of the sloth is that he is beautifully adapted to his environment. He hides from his enemies instead of fleeing; being a vegetarian, he does not have to chase his food. But other animals have been known to alter their innate behavior because of outside influences.* Why not the sloth?

Physiologists Britton and Kline went down to Panama, collected a few sloths (which...

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