Spring has arrived, the rape blossoms have blossomed, and the animal's hearts have begun to stir!
Many animals choose to breed in the spring, and the most fundamental reason is that everything recovers during this period, food is abundant, and the survival rate of offspring is higher.
However, human reproduction jumps out of the limitations of this season, and we reproduce all year round.
Obviously, this is because when we start living in groups and learn to use fire and other tools, it is related that we can get more food all year round.
Many people may think that human reproduction ability is relatively poor, but in fact, from this point of view, human reproductive ability is very strong, otherwise we would not have been able to become such a successful "invasive species".
It is not difficult to find that strong reproductive ability is very important for a species, but we have the opposite point, that is, men never know the ovulation period of women, or that there is no obvious signal of the ovulation period of human women.
This behavior in women is called concealed ovulation, which basically does not give any signal to the opposite sex and attracts the opposite sex.
How important is it to tell the other person that they are ovulating?
These animals, which reproduce in the spring, basically know each other that the other is in estrus, either through hormones or through changes in appearance.
For example, a female cat that is in the ovulation period will tell the surrounding male cats through pheromones and attract the male cats to come over, and then it will choose the one that it thinks is the best.
On the other hand, in some primates, if they are in the ovulation period, many females will have reproductive swelling and spread everywhere to attract males.
Obviously, it is only during ovulation mating that it is possible to successfully produce offspring.
Nature is efficient, and if you don't try your best to show yourself, then your genes will be difficult to continue, because no male wants to waste his limited resources to complete a fruitless mating.
Therefore, those who do not show themselves have basically been eliminated, and the rest are trying to express themselves like now.
So back to the human question, why don't human women have any signals to let men know they're ovulating?
Reproductive problems
The purpose of life is to reproduce and perpetuate their genes, but you will find that those species at the top of the food chain are very weak in their reproductive ability, in fact, they are limited by limited hunting resources.
Simply put, limited food does not feed their populations too large, so they generally prolong their pregnancies or, in some other cases, control their own populations.
But humans may not reduce their reproductive efficiency because of this, because humans are not picky eaters and have a strong ability to obtain food.
Let's look at the animal world.
There are two ways to make genes better continue, in the animal world, one is to win by quantity (more births at a time, there will always be adulthood), and the other is to win by quality (to have fewer births, and take care of young, improve survival rate).
Reptiles, fish, insects are basically like this, they are basically responsible for laying eggs, the rest depends on the cubs themselves, and the typical example of winning by quality is our mammals.
Around this increase in the survival rate of offspring, scientists have proposed a hypothesis to explain why women hide their ovulation periods – the paternal investment hypothesis.
About the parent investment hypothesis
This hypothesis is currently the most recognized, arguing that human women desperately need men to make supplementary investments in their offspring.
What does that mean?
Simply put, women want men to stay with them and provide more help to their offspring to improve their survival rate.
In the animal world, most of the time there is an irresponsible male, they are only responsible for injecting their own genetic factors into the female, feeding and raising are female affairs, sometimes the male is afraid of his own status or even to kill the offspring.
This is because females have limited or very few germ cells, while males have a large number, so the male's survival strategy is obviously to find more females, rather than staying and taking care of them together.
It is clear that the human male reproductive situation is also in line with this, and there is a tendency to retain this point.
Human cubs often need to be brought together
Think about the fragility of human babies, and the decline in women's ability to survive pregnancy, if men leave, it is difficult to take.
Therefore, the woman hides her ovulation period, the man does not know whether he can succeed in mating once, he can only stay, otherwise his investment may not have any return.
Then you may still ask, why is it that the low survival rate of offspring is affected by women? Aren't they also male offspring?
That's what we said earlier, male germ cells are cheap, and they can find a few more to hedge against this reduced cub survival rate, which is basically done by males in the animal world now.
Unexplainable parts
Although this hypothesis is now a relatively highly recognized one, it looks completely wrong, and many people also use it to explain hidden ovulation.
But in fact, it is full of loopholes, the most obvious point is, how did it evolve in the first place, shouldn't men go directly to those who are obvious ovulation?
Well, of course there is no way to explain, so it can only be considered a hypothesis.
In fact, the animals that hide ovulation are not only humans, dolphins and gray langurs are also typical, but their males do not show the care of pregnant females.
There is also an explanation for this behavior of dolphins and grey langurs – it is an adaptation to the hybrid system (both species are quite casual), and the advantage of hybridization is that the offspring do not know who it is and no one is responsible, but the male does not kill the cubs (the killing of cubs by males is common in the animal kingdom).
Well, using this situation to explain humans may be even more far-fetched.
Competition between women
Perhaps as Athena Aktipis, one of the authors of a recent paper on nature and human behavior, explains, the self-evident assumption that interaction with men is the driving force behind the evolution of female behavior and reproductive physiology, and it's time to leave it behind.
Aktipis and her colleagues, through mathematical modeling, found that female aggression is one of the main causes of hidden ovulation in women.
When women attack each other for people who are ovulating nearby, the hidden ovulation table shows a clear advantage.
Women certainly have reason to attack other women around them, because men are also a resource in their eyes.
At last
Hidden ovulation in women should indeed improve offspring survival, but for what reasons it is really difficult to explain with a set of hypotheses.
Perhaps, all explanations or hypotheses are one-sided, and the complexity of human society may be far from being understood.
However, this behavior of humans brings an evolutionary disadvantage, that is, we spend a lot of time on reproduction, which is a waste of energy.
For the advantages it brings, perhaps this disadvantage is not worth mentioning!