While the whole matter of sex differences is in a state of unsettlement, it seems very certain that males are more active and more variable than females.  This superabundant vitality appears in the males of the higher animals in secondary sex characteristics, such as more abundant and unnecessary hair and feathers, tusks, spurs, antlers, wattles, brilliant colors and scent pouches.  It also appears in mating calls, songs, and general carriage of the body.  Correspondingly, the female is smaller, duller colored, and less immediately attractive than the male.

All the studies that have been made on men and women, also confirm our ordinary observation that men are taller, heavier, stronger and more active than women, and this holds true in all stages of civilization, wherever tests have been made.  In strength, rapidity of movement, and rate of fatigue Miss Thompson’s studies[2] show that men have a very decided advantage over women.  Thus in strength tests, the men in Yale have double the power of women in Oberlin;[3] while our college athletic records place men far ahead of women in all events requiring strength and endurance.

[2] Helen B. Thompson, Psychological Norms in Men and Women, p. 167.  University of Chicago Press, 1903.

[3] Thomas, Sex and Society, p. 21.  University of Chicago Press, 1907.

The differences in structure between men and women are such as to correspond with the functional differences just stated.  A woman’s bones are smaller in proportion to her size, than are those of a man.  The body is longer, the hips broader, and the abdomen more prominent.  Relatively to the length of the body, the arms, legs, feet and hands are shorter than in men, the lower leg and arm are shorter in proportion to the upper leg and arm.  Man has the long levers and the active frame.  One has only to look at two good statues of a man and a woman to realize the greater strength and activity of the man.

Woman, as she actually appears in modern society, is also less subject to variation than man;[4] she is much less liable to be a genius or an idiot than her brother.[5] She offers greater resistance to disease, endures pain and want more stoically, and lives longer; so that while more boys than girls are born in all parts of the world, where statistics are kept, in mature years women always outnumber men.

[4] Karl Pearson denies this.  See The Chances of Death, Vol.  I, p. 256.  London, 1897.

[5] C.W.  Saleeby, in Woman and Womanhood, p. 54, New York, Mitchell Kennerley, 1911, maintains that woman is biologically more variable than man, and that woman’s less variable activity is due to her training.