ANSWER: No wait at all. As recently as 1920 men and women in the U.S. enjoyed virtually equal life expectancy at birth--around 55 years. Then over the last century, while men increased their life expectancy to around 73 years, women advanced to 79 years, opening a 6-year gender gap.

Why the disparity? Lots of theories, but with changes of this sort, you would expect the causes to be cultural, not biological, says anthropologist Marvin Harris in "Our Kind." "People today seem to think that being the biologically stronger sex, women naturally live longer." But that ignores the hidden cost of machismo: Males smoke more cigarettes, eat more fatty meat, drink more and take more hard drugs, drive faster, expose themselves to more on- the-job industrial poisons, use more deadly weapons, and often acquire hard-driving, competitive personalities.

ANSWER: Gravity. The birds fly high with a heavy victim and drop it onto a splattering boulder.