Why do people have sex in any phase of the sexual cycle?
Frankly speaking, no primates are not all the same in this regard: the lower, such as lemurs and lorişii not practice this type of copulation, but it is found in most other species of primate, more evolved. (An interesting exception are the gorillas, who copulate for a few days each cycle, around the time of ovulation.) Otherwise, however, other species of monkeys are acuplează and day further from the time of ovulation (but usually before it).
This behavior seems to be related to the growing complexity of the brain. Females more evolved species of monkeys, direct hormonal control over the availability for mating slowed, gaining greater importance more flexible control exercised by the brain, and this effect is more evident, as the species is higher on the ladder of evolution, culminating in the human species. Decrease the importance of hormonal control and the growth of the brain could explain, so why the human species this behavior is obvious everywhere. However, the author insists, is wrong to say that man is the only species that acuplează along the female sexual cycle; This behavior is common to man and several species of monkeys and probably was already present in the common ancestors of apes and of man ago 40 million years. But what is the point of such behavior? Seems counterproductive in terms of evolution, as partners to acupleze in times where there is no chance of fertilization or fertilization involves the risk that eggs and sperm “breathe”. (These cells have a very short breeding life – a day or two – and quickly lose their best qualities.) Participation in the fertilization of such an egg or sperm aging may lead to a defective embryo, resulting in miscarriage or birth of defective offspring – adverse events perpetuating the species.
From this point of view, seems more “wise” strategy other mammals – to breed only in a short period of time of each cycle of the female sex in the few days around ovulation, ensuring participation in fertilization reproductive cells “fresh” best fit.
How is it that the more evolved apes and humans, however, mating can be achieved in days away from the time of ovulation? Certainly produced by evolving a mechanism to eliminate risks. But still they gave during their development at a control mechanism so good in terms of biological, which would be provided, as well as other mammals, best chances to get a fertilization with reproductive cells in top shape? Mister.
Danger fertilization with sperm or ova aging was not really taken into account so far, so ignoring this aspect, some biologists have tried to explain this strange behavior by different assumptions of man and apes: copulation extended over a large parts of the sexual cycle.
Anthropologist Nancy Burley launched the idea of a link between this extended period of mating and so-called “concealed ovulation”: a male can not detect when ovulation occurs ie the female, if it does not deliver certain specific signals. In many species of mammals, olfactory and behavioral signals, indicating the male when the female ovulates and it is then (and only then) receptive to mating. In humans and many species of monkeys, there is such signals, a phenomenon linked to the expansion of female receptivity and mating period of the sexual cycle