Reminds me of a theory I came up with awhile ago.  Why do little humans have such a strong propensity for sticking everything in their mouths?  Well, way back when in the stone age, infant mortality was high.  Mortality among the newborn is high for many species.  As a result, low tech-level human communities don't invest in a little individual until they make it in the world for awhile.  In fact, the little buggers haven't really had <i>that</i> many physical resources devoted to them.  It takes a lot of food to make a baby.  But that's peanuts to the resources invested in an adult over 2 decades of life.  So who should be the food taster?  Who should try things out to see if they're safe to eat?  That's right, all those little ones!<p>It actually makes evolutionary sense for little humans to want to stick random things in their mouths and so become unwitting food tasters.  It's better for the community, overall.<p>(Also, it puts pressure on mothers to be <i>attentive</i>!  Another benefit to the community.)<p>Lots of female friends of mine <i>absolutely hate</i> this theory.  I can understand why.  But nature isn't always so nice.<p>(And yes, this theory is actually testable!)