The sexual modesty of the female animal is rooted in the sexual periodicity of the female, and is an involuntary expression of the organic fact that the time for love is not now. Inasmuch as this fact is true of the greater part of the lives of all female animals below man, the expression itself becomes so habitual that it even intrudes at those moments when it has ceased to be in place. We may see this again illustrated in the bitch, who, when in heat, herself runs after the male, and again turns to flee, perhaps only submitting with much persuasion to his embrace. Thus, modesty becomes something more than a mere refusal of the male; it becomes an invitation to the male, and is mixed up with his ideas of what is sexually desirable in the female. This would alone serve to account for the existence of modesty as a psychical secondary sexual character. In this sense, and in this sense only, we may say, with Colin Scott, that "the feeling of shame is made to be overcome," and is thus correlated with its physical representative, the hymen, in the rupture of which, as Groos remarks, there is, in some degree, a disruption also of modesty. The sexual modesty of the female is thus an inevitable by-product of the naturally aggressive attitude of the male in sexual relationships, and the naturally defensive attitude of the female, this again being founded on the fact that, while--in man and the species allied to him--the sexual function in the female is periodic, and during most of life a function to be guarded from the opposite sex, in the male it rarely or never needs to be so guarded.[11] Both male and female, however, need to guard themselves during the exercise of their sexual activities from jealous rivals, as well as from enemies who might take advantage of their position to attack them. It is highly probable that this is one important sexual factor in the constitution of modesty, and it helps to explain how the male, not less than the female, cultivates modesty, and shuns publicity, in the exercise of sexual functions. Northcote has especially emphasized this element in modesty, as originating in the fear of rivals. "That from this seeking after secrecy from motives of fear should arise an instinctive feeling that the sexual act must always be hidden, is a natural enough sequence. And since it is not a long step between thinking of an act as needing concealment and thinking of it as wrong, it is easily conceivable that sexual intercourse comes to be regarded as a stolen and therefore, in some degree, a sinful pleasure."[12]