In many animals in nature, the female is actually the bigger and more powerful one, so they do not need to fight against rape. On the contrary, the male has to be careful, and he may be eaten if he disagrees. But in those species where the female is the weaker one and does not have a fixed mate, the female has more or less anti-rape mechanisms, and in some cases where mating involves the safety of the female, their anti-rape strategies will be more aggressive.
Earlier, a study stated thatIn order to resist mating, a kind of European frog learns to pretend to be a male to deceive the males who are trying to mate with it. If all resistance strategies fail, they have an ultimate trick, which is to play dead directly.
This European frog isRanatemporaria, are widely distributed in Europe, but like many animals, people do not particularly understand how they survive and reproduce in the wild.
In terms of reproduction, male frogs usually adopt two methods, one is the "passive" method of chirping in place and waiting for the female to come over, and the other is the "active method" of actively looking for the female.
Most frogs are the former, and we should be familiar with them, but "active" frogs are very interesting, and they are much more aggressive than we think.
This kind of European frog is an active one. How aggressive are their males during the breeding season?
We can give a few examples:
First, they will start to become manic and rarely need any rest.
Second, they will hug anything that resembles a frog around them, including branches, male frogs, other types of frogs or other unrelated species, and even predators. Many people have said that they have seen this kind of frog hugging a salamander and not letting go.
Third, when they see or sense that other frogs are mating, they will not hesitate to fight for the right to mate. However, unlike other animals, they will not start a fight between males (probably for fear of getting hurt), but will also go up and hug the female frog.
Therefore, during the mating season, this frog often appears in a ball, which is called a "mating ball"-a female is at the innermost part of the ball, surrounded by a bunch of male frogs outside.
Because male European frogs are so aggressive, many females lose their lives during their breeding season.
In order to save their lives and prevent male frogs who are not strong enough from affecting their next generation, female European frogs have their own resistance strategies.
The new study actually discovered these frogs' resistance strategy by chance.
The researcher placed a male frog with two female frogs, one large and one small. Her original intention was to determine whether the male frog would prefer the larger female frog as we conventionally understand. After all, the larger frog has more eggs, and finding it means more offspring.
It turns out thatThe male European frog has absolutely no requirements for the female's size, and he doesn't even care whether she is a frog or not.
However, female frogs have very high requirements for males. Neither frog liked the male frog that was kept together, so they staged their resistance strategy under the camera.
A total of three strategies were observed in this study:
When the male is not particularly aggressive and just tries to hug the female frog, the female does not want to be hugged or is dissatisfied with the male. They will roll in the water to avoid the male's hug or directly release the hug.
When already firmly held by a male, the second method is triggered. They will imitate the male's call to inform the male that the male is holding the wrong one. This may be because this European frog often holds the wrong one, so when they are easily deceived, the female of this frog can easily get rid of the hug by imitating the male.
The last one is that when all their strategies fail, they will show off their ultimate trick - pretending to be dead, motionless and stiff. As long as they pretend for long enough, the male will lose interest anyway.
Pretending to be dead is actually an anti-predation strategy in nature. Many different animals have independently evolved this strategy, which shows that this strategy is indeed effective. They are the result of convergent evolution. However, this is the first time that scientists have observed an animal pretending to be dead in order to refuse to mate. It is quite interesting.
I don’t know if you have ever thought about why in nature only males rape females, but there is no animal in which females rape males.
Whether it is an animal with a strong female or a strong male, the one who takes the initiative is basically a male. Even those males who may be eaten accidentally will take the initiative to show love.
In fact, a large part of the reason for this is caused by the difference in the cost of germ cells between males and females.
Male germ cells are very cheap. In order to complete fertilization, the male needs to release a large number of germ cells every time.
Female reproductive cells are very precious, and the female reproductive cells of sexually reproducing animals are very limited. This may be related to the fact that they need to invest more resources in reproductive cells.
These two types of reproductive cells with different costs result in completely different reproductive strategies between the sexes.
Because males have a large number of reproductive cells, they are not afraid of waste and will look for as many mating opportunities as possible so that they can get more offspring. Even if they encounter a less than ideal female and get some less than ideal offspring, they don't have to worry about it. As long as there are enough offspring, their genes can be continued, so males usually tend to take the initiative.
Females are just the opposite. Their reproductive cells are very limited, so they need to invest very carefully. They must choose the best individuals to increase the competitiveness of their offspring and allow their genes to continue. Therefore, females usually tend to be passive. Even if they are not passive, they are the ones with more choice.
In some animals, the males become more aggressive or powerful. I think this is also related to this, because the choice lies with the female. If the male is not aggressive, there may be no chance of reproduction at all.
Similarly, since they cannot waste their precious reproductive cells casually, for some females, anti-rape mechanisms are naturally indispensable. This is definitely the case.
Original report: https://www.science.org/content/article/tired-aggressively-amorous-males-these-female-frogs-play-dead