fully ten months in each year the deer has all he can do to live without extra exertion incident to rutting.  Soon after the autumn rains commence vegetation becomes more luxurious, the antlers of the male and new suits of hair for both are fully grown, heat of the summer is gone, food and drink are plentiful everywhere, the fawns are weaned, and both sexes are in the very finest condition.  Then, and then only, in the whole year, comes the rut, which, to them as to most other animals, means an unwonted amount of physical exercise besides the everyday runs for life from their natural enemies, and an unusual amount of energy is used up.  If a doe dislikes the attention of a special buck, miles of racing result.  If jealous males meet, furious battles take place.  The strain on both sexes could not possibly be endured at any other season of the year.  With approach of cold weather, climatic deprivations and winter dangers commence and rut closes.  In all wild animals, rut occurs only when the climatic and other conditions favor the highest physical development.  This law holds good in all wild birds, for it is then only that they can stand the strain incident to love-making.  The common American crow is a very good study.  In the winter he travels around the ricefields of the South, leading a tramp’s existence in a country foreign to him, and to which he goes only to escape the rigors of the northern climate.  For several weeks in the spring he goes about the fields, gathering up the worms and grubs.  After his long flight from the South he experiences several weeks of an almost ideal existence, his food is plentiful, he becomes strong and hearty, and then he turns to thoughts of love.  In the pairing season he does more work than at any other time in the year:  fantastic dances, racing and chasing after the females, and savage fights with rivals.  He endures more than would be possible in his ordinary physical state.  Then come the care of the young and the long flights for water and food during the drought of the summer.  After the molt, autumn finds him once more in flock, and with the first frosts he is off again to the South.  In the wild state, rut is the capstone of perfect physical condition.” (A.W.  Johnstone, “The Relation of Menstruation to the other Reproductive Functions,” American Journal of Obstetrics, vol. xxxii, 1895.)

Wiltshire ("Lectures on the Comparative Physiology of Menstruation,” British Medical Journal, March, 1888) and Westermarck (History of Human Marriage, Chapter II) enumerate the pairing season of a number of different animals.

With regard to the breeding seasons of monkeys, little seems to be positively known.  Heape made special inquiries with reference to the two species whose sexual life he investigated.  He was informed that Semnopithecus entellus breeds twice a year, in April and in October.  He accepts Aitcheson’s statement that the Macacus