latest stories:  Hormone Found Linked to Mother's Protective
Instincts  mice with newborn pups  Mothers often say they would
step in front of a bullet to save their child's life. Numerous
animals act in similar ways, but the biological basis of the
behavior, known as maternal aggression, is not well understood.
New findings indicate that levels of a specific peptide in the
brain may answer the question of what makes a mother willing to
lay down her life for her offspring.  ¿We've known for a long
time that fear and anxiety decrease with lactation,¿ Stephen
Gammie of the University of Wisconsin-Madison explains. ¿Maybe
it's this decrease that allows mothers to attack during a
situation that normally would evoke a fear response.¿ Gammie and
his colleagues studied mice a few days after they gave birth and
tested how the animals reacted to differing levels of
corticotropin-releasing hormone (CRH), which is released in the
brain and helps control behavior. For four days, some animals
received injections of CRH whi