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Poverty makes the spadefoot toad passive and inert. But the
coming of prosperity whets a spirited desire to get even more out of life.
The spadefoot toad is following a basic biological law. That same
principle makes the rapid rise in good fortune among humans a
dangerous thing indeed. Nature shuts down the expenditure of energy
when resources disappear. But she unleashes energy when fresh
resources arrive. She makes those who are deprived sit still and
endure their fate. But when good fortune lifts the curtain of
hopelessness, biology gives the lucky souls who've landed on an
upward track a burst of manic zeal.
The connection between the human supercharger testosterone
and the hyperactive states of creatures like the toad is not merely
metaphoric. Experiments indicate that testosterone is the hormone that
jolts hibernating creatures out of their torpid metabolic state when
environmental resources finally return.178 Testosterone has an equally
impressive impact on creatures who do not sleep the tough seasons
away. During the winter, when times are tough, the canary is a silent
bird. But when spring comes, his body produces a testosterone surge.
The result: a sudden desire to sing. How does testosterone produce
this musical enthusiasm? Among other things, by triggering a growth
of neurons in the brain.179
You can see a similar biological conservation device at work in
yourself. You sit down to a meal. A half hour or less after you've
started eating, you begin to feel warm.180 The food you're chewing
hasn't reached your bloodstream yet--in fact, it will take hours before it
is digested.181 So where does the sudden spurt of fuel that warms you
come from? The body has held energy in reserve, just as it does in the
case of the spadefoot toad. Those stored calories are designed to tide
you over in case you skip lunch or find yourself in the middle of a
famine. Once the first bite of a new meal passes your lips, however,
your metabolic regulators conclude that there's new food at hand and
release some of the hoarded nutrients into your bloodstream.
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