EFFECT OF STIMULATION DERIVED FROM OTHER ANIMALS OF THE SAME SPECIES ON OESTROUS CYCLES IN MICE

Abstract

SUMMARY 1. The pattern of mating following the introduction of a male to pairs of female mice was not consistent with an hypothesis of random mating over a 5-day period, as would be expected if the average cycle length were 5 days. The majority of mice mated on the 3rd and 4th days after introduction of the male. The age of the females was shown to significantly affect the distribution of mating and also the length of the gestation period. 2. When female mice were placed in groups of four after having been housed singly, a prolonged dioestrus was shown to occur. This effect was not apparent when a male was included. 3. The period of anoestrus, which normally follows extirpation of the olfactory bulb, was significantly reduced in mice with impaired vision. 4. The results serve to emphasize that the oestrous cycle in the mouse is easily influenced by external factors and that the effect of one factor may be modified by another.