    4

    4

    4

    un

    death.  She offers a carnivore the options of dying by starvation or of

    killing for a meal.

    Nature is like a sculptor continually improving upon her work,

    but to do it she chisels away at living flesh.  What's worse, she has built

    her morally reprehensible modus operandi into our physiology.  If you

    occasionally feel that you are of several minds on one subject, you are

    probably right.  In reality, you have several brains.  And those brains

    don't always agree.  Dr. Paul D. MacLean was the researcher who first

    posited the concept of "the triune brain."  According to MacLean, near

    the base of your skull you'll find  the stem of the brain, poking up from

    the spinal column like the unadorned end of a walking stick.  Sitting

    atop that rudimentary stump is a mass of cerebral tissue bequeathed us

    by our earliest totally land-dwelling ancestors--the reptiles.8  When

    these beasts turned their backs on the sea roughly 300 million years ago

    and hobbled inland, their primary focus was simple survival.  The new

    landlubbers needed to hunt, to find a mate, to carve out territory  and

    to fight in that territory's defense.  The neural machinery they evolved

    took care of these elementary functions.  MacLean calls it the reptile

    brain.  The reptile brain still sits inside our skull like the pit at the

    center of a peach.  It is a vigorous participant in our mental affairs,

    pumping its primitive, instinctual orders to us at all hours of the day

    and night.

    Eons after the first reptiles ambled away from the beach, their

    great, great grandchildren many times removed evolved a few

    dramatic product improvements.  These upgrades included fur, warm

    blood, the ability to nurture eggs inside their own bodies, and the

    portable supply of baby food we know as milk.  The remodeled

    creatures were no longer reptiles.  They had become mammals.

    Mammals' innovative features gave them the ability to leave the lush

    tropics and make their way into the chilly north.  Their warm blood

    allowed them, in fact, to survive the rigors of the occasional ice age.

    But warm blood exacted its costs.  It demanded that mammal parents

    not simply lay an egg and wander off.  It forced mammal mothers to

    brood over their children for years.  And it required a tighter social

      iverse.  She presents her children with a choice between death and

    <<  <  GO  >  >>